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1. PROBABILITY FOR AN INITIALLY DAMAGED CANISTER Probability that a canister is penetrated at emplacement PROB CONST 1 E 3 PITFAQ CONST 1 OS CONST 1 CONHS CONST 1 DEFFS CONST 1 Nuclide solubility mol m3 CSOLA CONST 2 0E 4 CSOLB CONST 2 0E 5 Specific data to Material Dif m2 yr kd m3 kg 1 WATER f 2 BENTONITE 3 BENTONITE SAND 4 ROCK Specific to material 1 DIFA CONST 0 123 DIFB CONST 0 123 KDA1 CONST 0 0 KDB CONST 0 0 57 Specific to material 2 DIFA2 CONST 0 003154 DIFB2 CONST 0 003154 KDA2 CONST 3 0 KDB2 CONST 3 0 Specific to material 3 DIFA3 CONST 0 003154 DIFB3 CONST 0 003154 KDA3 CONST 0 1 KDB3 CONST 0 1 Specific to material 4 DIFA4 CONST 3 1536E 6 DIFB4 CONST 3 1536E 6 KDA4 CONST 3 0 KDB4 CONST 3 0 Hole growth data T_ZERO CONST 0 0 A ZERO CONST 5 0E 6 T LIMIT CONST 5 0E 3 A LIMIT CONST 0 1E 0 If any of the nuclides
2. FROM BLOCK 1 TO BLOCK 2 COUPLES 1 FROM DIRECTION Z TO DIRECTION Z FROM RESISTANCE FALSE TO RESISTANCE TRUE PLUG POSITION NONE EXTERNAL RESIST FALSE FROM COMP 1 TO COMP END DEF BEGIN DEF CONNECTION FROM BLOCK 2 TO BLOCK 3 COUPLES 1 FROM DIRECTION Z TO DIRECTION Y FROM_RESISTANCE TRUE TO RESISTANCE FALSE PLUG POSITION TO BLOCK EXTERNAL RESIST FALSE FROM COMP TO COMP END DEF BEGIN DEF CONNECTION FROM BLOCK 3 TO BLOCK 4 COUPLES 3 FROM DIRECTION Z TO DIRECTION Z FROM RESISTANCE TRUE TO RESISTANCE TRUE PLUG POSITION NONE EXTERNAL RESIST FALSE FROM COMP 1 TO COMP 1 FROM COMP 2 TO COMP 1 FROM COMP 3 TO COMP 1 END DEF BEGIN DEF CONNECTION FROM BLOCK 3 TO BLOCK 5 COUPLES 3 FROM DIRECTION Z TO DIRECTION Z FROM RESISTANCE TRUE TO RESISTANCE TRUE PLUG POSITION NONE 63
3. EXTERNAL RESIST FROM COMP TO COMP FROM COMP TO COMP FROM COMP TO COMP END DEF BEGIN DEF CONNECTION FROM BLOCK TO BLOCK COUPLES FROM DIRECTION TO DIRECTION FROM RESISTANCE TO RESISTANCE PLUG POSITION EXTERNAL RESIST FROM COMP TO COMP END DEF BEGIN DEF CONNECTION FROM BLOCK TO BLOCK COUPLES FROM DIRECTION TO DIRECTION FROM RESISTANCE TO RESISTANCE PLUG POSITION EXTERNAL RESIST FROM COMP TO COMP END DEF BEGIN DEF CONNECTION FROM BLOCK TO BLOCK COUPLES FROM DIRECTION TO DIRECTION FROM RESISTANCE TO RESISTANCE PLUG POSITION EXTERNAL RESIST FROM COMP TO COMP END DEF BEGIN DEF CONNECTION FROM BLOCK TO BLOCK COUPLES FROM DIRECTION TO DIRECTION FROM RESISTANCE E FALSI RUI RUI NON FALSI H H K N FH OW Cl p LH Cl RUI RUI NON FALSI Hd H K NH JO Cl LH E Cl RUI RUI NON FALSI HA NNE OB Cl DH E E NN F TRUE 64 TO_RES STANCE PLUG POSIT ON E XT ERNAL R ES FROM COMP TO COMP N DEF PLUG AT PLUG LENGT PLUG AREA QEQ FACTOR QEQ ON hi NK ROM BLOCK FROM COMP DIRECT NLET Li EXPONE DEF N DEF S
4. END DE DEF UM Z COMP UM Y COMP REA CHANCI A H O AL NAME N DEF BLOCK BLOCK NUMBER N N NUM X COMP A M B SCR ET ZAT ON BE NTONITE 333E 0 539E 0 0E 0 E 0 0 OE 0 0 E 0 NO BENTONITE tA 0 Hi EH O 000 ti tA oocoto ent NO ROHsONnNR NO SAND BENTONITE ND BENTONITE 125E 0 224E 1 97E 0 64E 01 61 eus I D H E D QUO ZU UU T E DEF DISCRET ZAT ON ppt D P F4 F4 OBEN DN I qo E y Y QU zu UJ T DISCRET ZAT ON Hola D v4 H H NI DN porto o 4 LT ry UO ol T N DEF BLOCK LO 2 Z WI MATE CK NUMBER UM Z COMP UM Y COMP UM X COMP EA CHANGE AL NAME zi BI DEF DISCRE ZAT ON 2 E p E Z H G ti
5. PLUG AT PLUG LENGT PLUG AREA EQ FACTOR ON H NT rs NK ROM BLOCK FROM COMP DIRECT NLET Li EQ EXPONE N DEF S Q Q END DEF G F F DIRECT PLUG AT PLUG LENGT PLUG AREA QEQ FACTOR QEQ ROM COMP ON H NT tal NK ROM BLOCK NLET Li EXPONE END DEF BEG N DEF S F FROM COMP DIRECT PLUG AT IN PLUG LENGT PLUG AREA EQ FACTOR Q Q ROM BLOCK ON H NT NK LET Li EO EXPONE END DEF z O BLOCK BEGIN H NT ST finition BLOCK CONTROL CASENAME RELEASE TYPE TRUI NON FALSI ti ti E KO CO HR O1 0 Z ONO OK K HO RS AE C2 OO OU sr95test Ba 65 TSTART NCREMENT FACTOR NUM STEP CONV EPS EWT NLOOP An AER R keyword would appear BEGIN D EF NUCL D n 1 NAME HALF LIFE SOL TYPE END DEF BEGIN D EF NUCL NAME HALF LIFE SOL TYPE END DEF D BLOCK
6. z Ej H E Z DATA STAT SI CS ta ND STAT ST CS END COMP23 JO NO ano E 6 E 18 3 in this block U238 4 47E9 OWNSOL PU239 2 41E4 OWNSOL 66 6 4 Results The predicted release by COMP23 for U 238 and Pu 239 are shown in Figures 6 4 and 6 5 respectively These releases were calculated assuming that the only limitation for the nuclides to be released is the solubility i e the solubility limit approach OWNSOL type Table 6 1 Data used in the calculations of the release Data on the KBS 3 repository design Deposition hole Diameter mm 1 750 Length mm 7 833 Canister Diameter mm 1 050 Thickness mm 50 Length mm 4 833 Tunnel Width mm 3 400 Height mm 4 000 Distance between canister centres mm 6 000 Canister bottom to deposition hole bottom mm 500 Thickness of the disturbed zone mm 1 000 Deposition hole bottom to fracture zone mm 3 000 Hydraulic properties Gradient m m 3 10 Fracture aperture mm 0 1 path Q1 path Q2 path Q3 path Q4 Flow porosity 2 10 10 1 7 10 10 10 Conductivity m s 10 107 109 108 Flux m3 m2 year 9 5107 9 5 10 9 5 1075 9 5 10 Qeq l year 0 25 4 0 5 6 Material properties Bentonite Sand bentonite Rock Density kg m 2 700 2 280 2 700 Porosity 96 25 24 0 5 Data on transport properties Bentonite Sand bentonite
7. Input data echoing and error messages are explained in the following section Input line echoing has the form of Line nnn The comment stripped left justified valid input line where nnn is the line number of the line read in the input file The line numbers include blank lines and comment lines Input data echoing Input data echoing takes the form Keyword assignments are Keyword lt KEYWORDI gt assigned value s valuel value Keyword lt KEYWORDn gt assigned value s valuel value End of Keyword assignments The value list may continue over several lines For keywords assigned filenames the filenames are just listed in the order they were read separated by one blank Error messages There are five types of error reports and one warning report Validity errors If the values read for a specific keyword do not lie within the specified limits the following message will be displayed ERRE VALIDITY error has occurred in routine ROUTINE after reading line HUINL Check failed for CBOUN keyword lt KEYWORD gt Upper bound Lower Bound Input value u uuuuE ee LilllE ee rrrrrE ee fiiiiiii eek End of Error where lt ROUTINE is the name of the routine that read the data lt HUINL is the number of lines including blank and comment lines that have been read CBOUN may be upper bound in lower bound in or empty string lt KEYWORD is the name of the keyword Upper bound i
8. For resistances added in the form of a plug these are codified by IPLUG index block number A or B This index block is used by the code to obtain the diffusion coefficient This plug concept is very useful when the transport is between a block of very small volume block A and a block of large volume block B The plug resistance value is V Anote 2 n 1 plug resistance D Arole D V 2 A note where Air is the cross sectional area of the block of small capacity Suppose that for some A B connection IPLUG block B number block of large capacity Then the coupling resistance calculated by the code is R Coupling resistance R 5 plug resistance The size of the block of small capacity may vary with time If this is the case the plug resistance will also vary The existence of other types of resistances added to the connection are indicated by IRADD 1 whose values are given following the description for such effects in the input file Suppose that for some A B connection IRADD 1 If the user specifies the resistance value as RADD the calculated coupling resistance is R R Coupling resistance R 2 RADD gt 30 The connections of the various sinks to the system repository are defined by identifying the position of the block and compartment connected to each sink In addition the user has to codify the direction of the nuclide transport IRZ and the contribution of the compartment to
9. dissolution precipitation and linear equilibrium sorption Dissolution and precipitation are controlled either by a fixed solubility limit for each nuclide or by a solubility limit shared between nuclides in a solubility group The notation used for the equations described in this report is given in Appendix 1 2 1 4 Radionuclide transport in the barrier Radionuclides leaking from a damaged canister spread into the backfill material surrounding the canister and then migrate through different pathways into water bearing fractures in the rock surrounding the repository If the backfill and other materials surrounding the canister have a low permeability the solute transport will be only by diffusion If there is water flow through some zones of the barrier then advection may also be a significant transport mechanism Some solutes may be sorbed on the materials surrounding the canister along the transport paths and their migration will be retarded Solutes may also precipitate It is a basic assumption in the COMP23 model that the dissolution precipitation reaction is very fast so that for nuclides that are solubility limited the aqueous concentration will be at the solubility limit if there is any precipitate present The COMP23 model allows groups of nuclides to share a solubility limit For example all the isotopes of a given element would be expected to share the same solubility limit The nuclides are labelled by consecutive integers begin
10. BLOCK MATERIAL NAME A mater MATNAM WATER BENTONITE SAND BENTONITE ROCK NUM Z COMP I NZ NUM Y COMP I NY NUM X COMP I NX AREA CHANGE A nbtd NBTD NO YES discretizationdef Either 1 or NZ NY NX times ADVECTION IQFLOW Switch IQFLOW Case TRUE FLOW_RATE F QFLOW INIT_CONC F CINPUT INLET_NODE I NWIN OUTLET NODE I NWOUT endswitch Discretizationdef BEGIN DEF DISCRETIZATION Z LENGTH F ZBLEN gt 0 Z AREA F ZBAR gt 0 Y LENGTH F YBLEN gt 0 Y AREA F YBAR gt 0 X LENGTH F XBLEN gt 0 X AREA F XBAR gt 0 END DEF END DEF j Connectiondef BEGIN DEF CONNECTION NCB FROM_BLOCK I IBA gt 0 TO_BLOCK I IBB 20 COUPLES I NCON 20 FROM DIRECTION A irza IRZA IZIXIXI TO_DIRECTION A irzb IRZB Z Y X FROM RESISTANCE A icra ICRA FALSE TRUE TO_RESISTANCE A icrb ICRB FALSE TRUE PLUG_POSITION A nplug IPLUG NPLUG NONE FROM BLOCK TO BLOCK EXTERNAL RESIST A iradd IRADD FALSE TRUE switch IRADD case TRUE EXTERNAL VALUE EX List of real values one for each nuclide in the same order as in BEGIN_DEF NUCLIDE section END_LIST endswitch FROM_COMP I IDCA TO_COMP I IDCB END DEF j sinkdef BEGIN DEF SINK NSINKS FROM_BLOCK I IBS FROM COMP I ICS DIRECTION A virz IRZ IZIXIXI PLUG AT INLET A icrs _ICRS NO YES 48 PLUG_LENGTH F H ZPFRA PLUG AREA F APFRA gt 0 0 QEQ FACTOR F 4 QFAC gt 0 0 QEQ E
11. CONTROL Required block General description of calculation control parameters and nuclide definitions The block definition holds data for the current input data block It is constructed from a set of keywords with optional values assigned or special keyword constructs The input data is case insensitive regarding keywords Filenames input may be case sensitive depending on computer system requirements and is always case sensitive on UNIX systems Sub blocks can also be included between blocks for example the SINK sub block is used within the GEOMETRY block CONTROL block definition The general structure syntax of the CONTROL block is given below A description of each keyword is given Keyword Variable type Comment BEGIN_BLOCK CONTROL nuclidedef RELEASE TYPE A itype ITYPE MOL BQ chaindef TSTART F AGEO gt SMALL INCREMENT FACTOR F RAT gt SMALL NUM STEP I NTERM gt SMALL CONV_EPS F EPS gt SMALL EWT F EWT gt SMALL NLOOP I NLOOP gt SMALL CASENAME A CASE ADVECTION TWFLOW SHARED_SOLUBILITY ISPSOL SOL_ GROUPS A itype ITYPE AUTO MANUAL solgroupdef If SOL GROUPS defined as MANUAL AER CONSTANT Only one AER keyword may be used AER DECAY for each problem AER_EXPLICIT KIAER NUM_SOL_LIMIT_STEP I NODES NUM SOL LIMIT RAMP I NODES NUM DIFF KD STEP I NODES NUM DIFF KD RAMP I NODES 43 NUM POROSITY STEP I NODES NUM POROSITY
12. The use of the term block should not be confused with the input data blocks CONTROL and GEOMETRY The model block consists of one or more connected compartments of the same material with identical properties For example the bentonite barrier around the canister can be divided in to several blocks where each block can be compartmentalized or subdivided into compartments Every model block is given an identification number that is later used to define the connections between the model blocks The connections between the model blocks are also given inside the GEOMETRY block This defines which model blocks are connected to each other and can thus exchange nuclides The final part of the GEOMETRY block is the SINK DEFINITIONS This section defines the locations in the model where nuclides can escape from the near field and the flow rates that the individual sinks should have Keyword Variable type Comment BEGIN_BLOCK GEOMETRY materialdef blockdef connectiondef sinkdef TUBE VOLUME F 4 VTUBE gt 0 NUM_ TUBE I NTUBES 20 TUBES DAMAGED IK NTDAM gt 1 VOID F VHEMA gt SMALL NUM_RAMP_NODES IK NNODE NUM_STEP_NODES NNODE END_BLOCK materialdef BEGIN DEF MATERIAL NMAT MATERIAL NAME A mater MATNAM WATER BENTONITE SAND BENTONITE ROCK DENSITY F DENSM 20 POROSITY pt PORM 1 PORM gt 0 END DEF j 47 Blockdef BEGIN DEF BLOCK NBLOCK BLOCK_NUMBER I
13. Ajaa f M b meSy q yb meSy 18 To summarize the model for congruent release of nuclides when there is no alpha radiolysis consists of equation 12 for each nuclide except nuclide M the uranium 238 matrix equation 14 for all nuclides and equation 16 which effectively determines the amount of uranium in the canister that is not in the matrix To complete these equations q and q are given by equations 13 and 18 respectively Parameters required The parameters required are as follow Solubilitv limit of each element in the water in the canister Volume of water in the canister e Nuclide inventories and half lives 2 1 5 Source term congruent release with alpha radiolysis COMP23 can include the effects of alpha radiolysis on the spent fuel dissolution 3 4 The model assumes that the dissolution rate is related to the alpha energy release of the fuel When an alpha radiolysis model is used an instantaneous release fraction IRF can be specified for each embedded nuclide This specifies the fraction of the nuclide that is assumed to dissolve instantaneously Typically as the matrix dissolves due to alpha radiolysis some of the uranium released will form as precipitate and the embedded nuclides will be freed to dissolve in the water Three different representations of the evolving alpha energy release are included in COMP23 a The dissolution rate of the fuel matrix occurs at a constant rat
14. PLUG_POSITION EXTERNAL_RESIST EXTERNAL_VALUE FROM_COMP TO_COMP SINK DEFINITION Addition of a plug an extra transport resistance between the model blocks between two blocks is indicated by an index block A particular case is a small hole connected to a large compartment For example the couple formed by the hole in the canister wall and the bentonite compartment outside the canister This keyword must give the number of the block with the largest capacity associated to the plug Set to TRUE if there exist resistances added by the user and not defined by the code FALSE TRUE Normally set to FALSE If EXTERNAL RESIST is set to TRUE this keyword defines the list of values one value for each nuclide for resistances added by the user and not defined in the system The number for the compartment inside the first model block that is part of the connection This and the next keyword have to be repeated as many times as defined by COUPLES The number for the compartment inside the second model block that is part of the connection FROM BLOCK FROM COMP DIRECTION PLUG AT INLET PLUG LENGTH PLUG AREA IQEQ FACTOR QEQ_EXPONENT Number BLOCK_NUMBER of the model block in contact with the sink Number of the compartment in contact with the sink Direction in which the transport of the species occurs Z Y X Contribution to the coupling resistance Rsw of the compartment in contact with the sink NO
15. RAMP I NODES END BLOCK nuclidedef BEGIN DEF NUCLIDE NAME HALF LIFE SOL TYPE switch SOL TYPE case FUELSURFACE A NAMES for example 1129 F TAU gt 0 A ispec ISPEC OWNSOL FUELSURFACE MATRIX case MATRIX and one of the AER_ keywords used IRF endswitch END DEF chaindef solgroupdef F CIRF CHAIN MOTHER DAUGHTER END_CHAIN SOLUBILITY GROUP NUCLIDE END_SOLUBILITY GROUP RELEASE_TYPE TSTART INCREMENT_FACTOR NUM_STEP CONV_EPS EWT NLOOP CASENAME ADVECTION SHARED_SOLUBILITY SOL_GROUPS Units in which the results will be given Itis specified as MOL for molar units and Bq for activity units Time for the first printed results Ratio between two successive times in output timeseries Number of printouts required For different reasons the code sometimes needs to take smaller time increments than defined by INCREMENT_FACTOR This can often create output time series with more time steps than defined by NUM_STEP On input the requested relative accuracy in the calculations of the solver EPS 0 is allowed On output the adjusted relative accuracy if the input value was too small Problem zero e the smallest physically meaningful value for the solution Setting EWT to zero provides pure relative error control Number of times the solver is called if there is no satisfactory solution Name for identifying model case Used to define the
16. Section 2 1 2 which is referred to as SOL TYPE MATRIX the dissolution of the uranium fuel matrix and the consequent liberation of the embedded nuclides must be considered In this case the quantity represents the total amount of nuclide n that is in the canister but is not embedded in the fuel matrix In addition it is necessary to keep track of the amount of nuclide embedded in the matrix and this quantity is denoted by b Note that both the and b depend only on time The equation for nuclide n becomes da al NEC dE 12 where q is the rate at which nuclide n is being liberated from the fuel matrix which is given in terms of the rate at which the uranium matrix is dissolving by n n b M q pu 13 where b is the amount of uranium 238 in the fuel matrix and q is the rate of dissolution of the uranium 238 The basic assumption underlying equation 13 is that the nuclides are uniformly distributed within the fuel matrix so that the ratio of the amount of nuclide n to the amount of matrix is uniform and equal to b b It is also assumed that all the nuclides embedded in the matrix are released when the matrix dissolves Equation 13 follows immediately from these two assumptions The equation for the amount of nuclide n embedded in the matrix b is M AAA 14 Equations 12 14 can be used to determine and b only once q is known In COMP23 the way q is determined depends on w
17. The compartment is fully defined by its capacity and the resistances defining a two dimensional nuclide transport The capacity is determined by the volume and the sorption coefficient and will also depend on the porosity and density of the material The diffusion length s cross sectional area s and the diffusion coefficient define the resistance The compartmentalization of the system is rather straightforward The system to be modelled is subdivided into compartments taking into consideration the different geometric shapes and the various materials found in the system COMP23 uses a coarse discretization 3 2 Temporal discretization Once the spatial discretisation has been carried out the equations to be solved consist of a set of ordinary differential equations for the amounts of each nuclide in each compartment a in the form of equation 30 In the congruent dissolution model equation 14 for the amount of each nuclide in the matrix b must also be solved together with the algebraic equation 19 for the rate at which uranium is leaving the canister These equations may be written in the general form F y y t 0 37 where y is a vector comprising all the a and b and qu when congruent dissolution is being treated and y is the time derivative of y These equations are stiff due to the wide range of timescales in the problem COMP23 uses the package DDASKR to solve this system of implicit differential algebraic equations
18. The transport resistance is then approximated by a plug through which the nuclides are transported The plug has a transport area equal to the cross sectional area of the fracture and a diffusion length equal to a factor times the fracture aperture Neretnieks analytically modelled the stationary transport from the bentonite surrounding a canister for spent nuclear fuel into a fracture 9 The procedure uses the exact solution of the steady state two dimensional diffusion equation for a sector of the clay barrier representing half the fracture spacing that allows symmetry conditions to be used After some simplifications the resistance of the plug at the mouth of the fracture is expressed as R F 5 5 D 4 18 The factor F 0 was calculated by Neretnieks for a number of fracture spacings fracture apertures and barrier thicknesses For fractures with an aperture varying between 107 and 10 m and a backfill thickness of 0 30 to 0 35 m the factor ranges between 3 and 7 It can be visualized as having a plug of clay at the mouth of the slit with a thickness of F 0 9 times the slit aperture 2 3 Assignment of material properties In the standalone version of COMP23 the physical parameters defining the transport in a repository are specified as constant In the version to be used as a module in the PROPER package 10 the transport parameters as sorption diffusion and equivalent flow rates may be specified as constant or as functi
19. flowing water Not to scale 56 6 3 Input file used for problem The INPUT file to execute this sample problem is shown below the results are shown in Figure 6 4 and 6 5 This format of the INPUT file is valid for running COMP23 as a submodel of the PROPER package The characteristic of this system is to provide a module type code package where submodels describing radionuclide transport etc are linked by the user and not by the programmer The PROPER Monitor controls the execution given to the interconnected system of submodels Only the parts that belong to COMP23 are included in this example The data used in the calculations are tabulated in Table 6 1 System Description File system dsc applied to the PROPER system Input file in the PROPER system f U 238 and Pu 239 copper iron canister KBS 3 BATCHES 1 1 SEED 930311 CPUTIME 00 15 00 VRMETHOD CMC 1 MACRO TS1HYDR11 UxCl UyC1 UzC PARAMETERS A and B Denote nuclides 1 2 3 and 4 denote different materials S1 S2 S3 and S4 denote Qegs for the various sinks Number of canisters Standalone only NCAN CONST 1 NUMBER OF IDENTICAL CANISTERS IN THIS STREAM TUBE CSYNCI UNIF 0 1 MULTIS1 COMPUTED Groundwater flux for NCAN canisters standalone only UC CONST 1 0E 3
20. for the solubility group Sz of element E Kz is given by Ko 16 Kp 32 where 0 is the porosity for element E in compartment i p is the density of the solid material in compartment i and kg is the sorption coefficient for element E in compartment i a is given by d Ya 33 meSy 16 The diffusional contribution to g is expressed in terms of diffusional resistances Each compartment makes a contribution to this resistance The diffusional resistance from compartment i to compartment j is R where Ri r 34 and R and R depend on the direction of transport and the nuclide through the diffusion coefficient R takes the form l R i AD 35 where l is the length of the compartment in the transport direction w can be either x y or z A is the cross sectional area of the compartment normal to the direction of transport and D is the effective diffusion coefficient for nuclide n in compartment i Additional resistances can be added to model special situations such as transport from a small compartment into a large one see the following sections The diffusional contribution to g may now be written in terms of R as 1 if ij Ri Y g if i j j i Sij 36 The elements required to define the compartmentalization are the geometry of the system dimensions of the system and the type of material The compartments are defined by their volume their diffusion leng
21. nuclide and Np237 U233 and Th229 are the daughter nuclides in the given order The maximum number of nuclides in a chain is defined by parameter NUN currently 6 and no nuclide can be defined in more than one CHAIN definition Limitations A group is either a CHAIN or a single nuclide defined by BEGIN_DEF NUCLIDE but not used in any CHAIN definition For example defining the nuclides C14 1129 and the CHAIN CHAIN Am241 Np237 U233 Th229 END_CHAIN 46 corresponds to 3 groups C14 is one group 1129 is the second group and the CHAIN is the third group It is very important to notice that every nuclide in a group must have the same SOL_TYPE SOLUBILITY GROUP DEFINITION SOLUBILITY_GROUP Keyword indicating start of a solubility group NUCLIDE The nuclide s in a solubility group For example SOLUBILITY GROUP Pu242 Pu240 END SOLUBILITY GROUP The maximum number of nuclides in a group is defined by parameter NSGR currently 25 and no nuclide can be defined in more than one SOLUBILITY GROUP definition GEOMETRY block definition The general structure syntax of the GEOMETRY block is given below A description of each keyword is given The contents of the GEOMETRY block define which materials are included in the simulation typically water bentonite sand bentonite and rock There are also keywords for describing the canister and its properties The basic entities for building a model with COMP23 are the model block
22. or damaged zones and 7 is the mean thickness of penetration into the water by diffusion from the compartment The residence time t is the time that the water is in contact with the compartment This time is obtained from the flux of water qo the flow porosity and the length of the pathway in contact with water Transport into a large compartment Species diffusing out of a small hole into a very large volume of material spread out spherically Very near the hole the cross section is still of the order of the size of the hole Further away the cross section increases considerably as the sphere grows Thus most of the resistance to diffusion is concentrated very near the mouth of the hole This resistance is calculated by integrating the transport rate equation oom p E dr from a small hemisphere into a very large volume between the limits of the sphere of radius Esp and an outer radius r Since the species spread over a large volume in the surrounding medium r gt gt Tsn the nuclide transport rate simplifies to N 2 Zz r ph De Ac In the model the real situation is approximated by using an equivalent plug This plug of a cross sectional area equal to the hole area has a thickness Ax given by Ax niu 312 Transport into a narrow slit For the diffusive transport into a narrow fracture most of the resistance to the transport will be located nearest to the fracture because of the contraction in the cross sectional area
23. that described in reference 5 is used the constants will need to be changed in the program However it is not likely that this model will be used extensively as the CONSTANT model provides an adequate representation of dissolution The constants obtained from reference 5 are given in the table below Nuclide A B Am 241 25 3 433 Np 237 0 04 2 1 108 Pu 239 1 1 2 4 104 Pu 240 2 2 6 570 EXPLICIT M X m Ja K exp Y Cb 29 mer where Ksxp is a constant I is the set of nuclide labels for the alpha emitting nuclides Cn are constants corresponding to the nuclides in I and b is the amount of nuclide m in the fuel matrix This model is included to allow flexibility of the program In the current version of the program the nuclides Am 241 Pu 239 Pu 240 and Np 237 are included and the values of the constants obtained from reference 5 are given in the table below Nuclide C Am 241 2 85 Np 237 8 8110 Pu 239 0 0261 Pu 240 0 0992 To summarize the form of the equations representing the model for congruent release of nuclides including alpha radiolysis depends on whether there is uranium precipitate in the canister or not When uranium precipitate is present in the canister the model consists of equations 12 and 14 for all nuclides together with equations 13 and the second part of 20 When there is no uranium precipitate present the model is the same as the case when there is no alpha radiolysis described
24. this example water flow rates are taken as input timeseries from HYDRASTAR and output mass flow for the two nuclides are sent as output timeseries to a subsequent submodel e g FARF31 The unit of mass flux is moles year or Bq year depending on the value of the keyword RELEASE TYPE in the CONTROL BLOCK described below 5 4 4 Module specific input data COMP23 also needs a number of non sampled parameters specified in the module specific DATA section within the module definition The general syntax for the DATA section is DATA GEOMETRY BLOCK CONTROL BLOCK END DATA 42 The DATA section for COMP23 is read in free format using the HUI input format very similar to the input structure used for HYDRASTAR in casename hyd The input in the DATA section to the COMP23 submodel is supplied as module specific data and consists of two input data blocks The input data blocks may appear in any order Between the input data blocks comment lines and system commands may be inserted in any order The lines in the input file must not exceed 71 characters The program ignores multiple white space That is two or more consecutive occurrences of white space characters White space is defined as lt blank gt or lt tab gt The general format of a block is described in Section 5 3 The block_id identifies the current input data block Valid input data block names are GEOMETRY Required block Contains definitions of compartments sinks materials etc
25. 23 PRIN23 IPRINT NAMES This subroutine prints out results of the execution such as concentrations in the various compartments release into the various sinks and solid inventory in the canister The results are printed at times determined by TIME23 It also prints out the variation with time of the hole size in the canister wall The main program CMP23 calls PRIN23 READ23 NAMES EPS EWT NLOOP NPREPAR LSTALON UO CASE This subroutine reads the data from the INPUT files with help of an auxiliary subroutine HUIM23 created specially to operate in the PROPER environment The main program CMP23 calls READ23 SET23 NAMES Y CASE This subroutine sets the initial conditions for the problem and the flags IFLAG for the material balance control in the various compartments The main program CMP23 calls SET23 SSJAC NEQ TIME Y YPRIME PD CJ RPAR IPAR This subroutine computes the Jacobian matrix for F y y t the equations defining the DAE at time to be evaluated at Y YRPIME and TIME A return from this function passes control back to DDASKR 27 SSRES TIME Y YPRIME CJ DELTA IRES RPAR IPAR This subroutine computes F y y f the equations defining the DAEs When this subroutine is called the entries in Y are intermediate approximations to the solution components and the entries in YPRIME are intermediate approximations to their derivatives A return from this function passes control back to DDASKR SS
26. COMP23 version 1 2 2 users manual K A Cliffe M Kelly Serco Assurance Harwell Oxford UK November 2006 R 04 64 Svensk K rnbr nslehantering AB Swedish Nuclear Fuel and Waste Management Co Box 5864 SE 102 40 Stockholm Sweden Tel 08 459 84 00 46 8 459 84 00 Fax 08 661 57 19 46 8 661 57 19 ISSN 1402 3091 SKB Rapport R 04 64 COMP23 version 1 2 2 users manual K A Cliffe M Kelly Serco Assurance Harwell Oxford UK November 2006 Contents 1 Overview of COMP23 2 Conceptual model 2 1 Processes modelled 2 1 1 Radionuclide transport in the barrier 2 2 Treatment of the source term 2 1 3 Source term solubility limited 2 1 4 Source term congruent release without alpha radiolysis 2 1 5 Source term congruent release with alpha radiolysis 2 0 Geometric framework 2 2 1 Analytical solutions used in the model 2 3 Assignment of material properties 2 4 Initial conditions 3 Numerical methods 3 1 Spatial discretization 3 2 Temporal discretization 4 Description of the COMP23 code 4 1 Subroutines and functions used by COMP23 4 1 1 Key variables used by the subroutines 4 1 2 Description of key subroutines 4 1 3 Additional subroutines 4 2 General description of the input requrements 5 Simulation setup using Proper 5 1 Overview 5 2 Input files required 5 3 HUI input 5 3 1 Typefaces 5 3 2 Separators 5 3 3 Format specifiers 5 3 4 Program validity check 5 3 5 Format syntax 5 4 The system description file 5 4 1 O
27. D 0 TUBE VOLUME 4 655E 5 NUM TUBE 1440 TUBES DAMAGED 1 0 NUM_STEP_NODES 2 dE Materials definition BEGIN DEF MATERIAL MATERIAL NAME WATER DENSITY 1000 0 POROSITY 1 0 END DEF BEGIN DEF MATERIAL MATERTAL NAME BENTONITE DENSITY 2700 0 POROSITY 0 25 END DEF BEGIN DEF MATERIAL MATERIAL NAME SAND BENTONITE DENSITY 2280 0 POROSITY 0 24 END DEF BEGIN DEF MATERIAL MATERIAL NAME ROCK DENSITY 2700 0 POROSITY 0 005 END DEF Blocks definition BEGIN DEF BLOCK BLOCK NUMBER 1 MATERIAL NAME WATER NUM Z COMP 1 NUM Y COMP 1 NUM Y COMP 1 AREA CHANGE NO BEGIN DEF DISCRETIZATION Z LENGT 0 0E 0 Z AREA 1 0E 0 Y LENGT 0 0E 0 Y AREA 1 0E 0 X LENGT 0 0E 0 X AREA 1 0E 0 END DEF END DEF 59 N DEF BLOCK LOCK_NUMBER B NUM Z COMP NUM Y COMP NUM X COMP AREA CHANGE MATERIAL NAME BEGIN DEF DISCRETIZATION Z LENGT Z AREA Y LENGT Y AREA X LENGT X AREA END DEF END DEF BEGIN DEF BLOCK BLOCK NUMBER NUM Z COMP NUM Y COMP NUM X COMP AREA CHANGE MATERIAL NAME BEGIN DEF DISCRETIZATION Z L
28. DAES The package uses backward difference methods of varying order of accuracy and chooses the order and the size of the time step to maintain a specified level of accuracy whilst minimizing the computational time 11 DDASKR can produce results at intermediate time very efficiently The user of COMP23 specifies points at which output is needed DDASKR also has a facility for monitoring user defined functions and finding the time at which any of these functions becomes zero The methods used in DDASKR rely on the solution to the equations 37 being sufficiently smooth The degree of smoothness required depends on the highest order of method to be used which is typically 5 The main technical difficulty with the equations arising in COMP23 is that the smoothness assumption breaks down at various points in time such as when the amount of nuclide in a compartment exceeds the solubility limit or when the size of the hole in the canister changes abruptly or when the rate of uranium dissolution changes type in the congruent release model This is dealt with in COMP23 by monitoring various A method of order n has an error that is proportional to the nth power of the size of the timestep 21 quantities that mark these changes The root finding capabilities in DDASKR are used to identify the precise time at which the change takes place The computation is then restarted from that time using the appropriate new set of equations The essential poi
29. ENGT Z AREA Y LENGT Y AREA X LENGT X AREA END DEF BEGIN DEF DISCRETIZATION Z LENGT Z AREA Y LENGT Y AREA X LENGT X AREA END DEF BEGIN DEF DISCRETIZATION Z LENGT Z AREA Y LENGT Y AREA X LENGT X AREA END DEF END DEF BEGIN DEF BLOCK BLOCK NUMBER NUM Z COMP NUM Y COMP NUM X COMP AREA CHANG E tA D E Ed EH tA OO OD OO ti tA NO Oo oo Hh BEN TON E e E E 0 Ed ti tA O OO E C E E D 1 CO ti a I DO O E ED E Ed Ed E 1j I NO 60 OO SCRET ZAT ON END DE DEF BLOCK_NUMB N DEF BLOCK UM Z COMP UM Y COMP REA CHANG ER CT ATERIAL NAM N N NUM X COMP A M B SCRET ZAT ON END DE DEF UM Z COMP UM Y COMP UM X COMP A H E N DEF BLOCK BLOCK NUMBER E N Mee ou AREA CHANGI M B AL NAME EGIN DEF SCR ET ZAT ON
30. LBM2 CONST 2 0E 3 The next parameters are repeated in the order stated below for each material type in the model Usually there are four materials used water bentonite sand bentonite and rock For every material type the data for every nuclide must be defined Note that the order of nuclides as defined within the DATA section must be followed Suggested name Units Description DIF nm m year Effective diffusivity for nuclide n in material m KD nm m kg Ka for nuclide n in material m For example if two nuclides A and B and four materials 1 to 4 are used the definition would look like Specific to material 1 DIFA1 CONST 0 123E0 DIFB1 CONST 0 123E0 KDA1 CONST 0 0E0 KDB1 CONST 0 0E0 Specific to material 2 DIFA2 CONST 0 3154E 2 DIFB2 CONST 0 3154E 2 KDA2 CONST 3 0E0 KDB2 CONST 3 0E0 Specific to material 3 DIFA3 CONST 0 3154E 2 DIFB3 CONST 0 3154E 2 KDA3 CONST 0 1E0 KDB3 CONST 0 1E0 Specific to material 4 DIFA4 CONST 3 1536E 6 DIFB4 CONST 3 1536E 6 KDA4 CONST 3 0E0 KDB4 CONST 3 0E0 38 Time dependent Parameters When it is necessary to incorporate time dependent parameters into a system model extra parameters must be specified that define the times at which ramp or step changes occur see Section 2 3 and also the values of the various parameters in each of the different time regimes Sorption coefficient porosity diffusion coefficient and solu
31. NITION The BLOCK definition is repeated once for each block used in the model BLOCK_NUMBER MATERIAL_NAME NUM_Z_COMP NUM_Y_COMP NUM_X_COMP AREA_CHANGE ADVECTION FLOW_RATE INIT_CONC INLET_NODE OUTLET_NODE Z LENGTH Z AREA Y LENGTH V AREA X LENGTH X AREA Block identitv number a unique integer number for each model block Define the material in the present model block Number of subdivisions in the z axis directions That is the number of compartments verticallv in this model block Number of subdivisions in the v axis That is the number of compartments in one horizontal direction in this model block Usually only one of NUM Z COMP NUM Y COMP NUM X COMP is greater than 11 Number of subdivisions in the x axis That is the number of compartments in one horizontal direction in this model block Usually only one of NUM Z COMP NUM Y COMP NUM X COMP is greater than 11 Optional keyword indicating the contact area of this model block will change size Used to model increased hole size for the damage in the canister Optional Default is no advection If ADVECTION selected defines the flow of water through the block If ADVECTION selected concentration in incoming water usually zero Can only be non zero if only one nuclide is modelled If ADVECTION selected node number for inlet If ADVECTION selected node number for outlet Diffusion length in the z axis The vertical length of the m
32. OR m Porosity of barrier material m If the System Command USE NUCLIDE DEPENDENT POROSITIES is present Suggested name Units Description POR nm Porosity of barrier for nuclide n in material m The next group of parameters defines the hole growth depending on the hole growth model chosen For each step in the hole growth model a time and area must be given including the initial and final times Suggested name Units Description T HOLE n y Time at which following are is attained A HOLE n m Area of hole For example if the hole growth model is a linear ramp from the initial size to the final size the following data would be given T HOLEO CONST 1 0E 3 A HOLEO CONST 1 0E 6 T HOLEI CONST 1 0E 6 A HOLEI CONST 2 0E 3 The next parameter defines the solubility of the nuclides If the system command USE MATERIAL DEPENDENT SOLUBILITY LIMITS is not present Suggested name Units Description CSOL mol m Solubility for the nuclides one parameter for each nuclide n 37 For example if two nuclides A and B are used the definition would look like CSOLA CONST 2 0E 4 CSOLB CONST 2 0E 5 If the system command USE MATERIAL DEPENDENT SOLUBILITY LIMITS is present then a solubility limit is required for each material For example if two materials MI and M2 are present then the definition would look like CSOLAMI CONST 2 0E 4 CSOLBMI CONST 2 0E 5 CSOLAM2 CONST 2 0E 3 CSO
33. ROPER version of COMP23 is given in Section 5 4 33 5 3 1 Typefaces CAPITAL Keywords lowercase italics Variable name or variable text CAPITAL ITALICS Object name or name of variable in the code underlined Fixed text bold underline Program validity check 5 3 2 Separators U lt gt Beginning of comment List of items Enclosed list of optional items Optional items separator Zero or more occurrences of preceding expression One or more occurrences of preceding expression Keystrokes or special characters 5 3 3 Format specifiers AK A wordlist F wordlist Free format string Free format string must be member of wordlist Free format floating point number Free format integer List of alternative keywords wordl wordN which are allowed for the specified context 5 3 4 Program validity check zmo Validity Consistency Existence Warning 5 3 5 Format syntax input file system commands fa block fa block comments BEGIN BLOCK block id fblock definition END BLOCK fblock definition keywords lists y definition block switchcommands comments keywords KEYWORD I F A A wordlist comments 34 lists KEYWORD I F A A wordlist fcomments END_LIST definition block BEGIN DEF def id keywords comments I F A A wordlist END DEF switch comma
34. RT NEQ TIME Y YPRIME NRT RVAL RPAR IPAR This subroutine computes the values of the various functions being monitored by DDASKR A return from this function passes control back to DDASKR SSINI TIME Y YPRIME Calculates the values of y YPRIME based on the values of y Y at time TIME TIME23 TINIT ICALL This subroutine determines the time series at which the user wishes to obtain results The time step is determined by a geometric progression The main program CMP23 calls TIME23 URC23 TIME This subroutine updates the coupling resistances between compartments including the external coupling with the flowing water surrounding the barrier system to taking into account the effect changes in the size of the hole in the canister URC23 is called by IMAT23 WRIT23 NAMES This subroutine gives information on capacities and resistances of the various compartments It also gives information on the matrix of the coefficients F initially executed WRIT23 is called by FMAT23 4 1 3 Additional subroutines A description of these subroutines is found in the Proper Monitor User s Manual 12 and Proper Submodel Designer s Manual 10 These subroutines are implemented and of use only in the PROPER version of the code COMP23 Some of them are part of the PROPER package They are service routines for setting up communications with the database for acquiring values of sampled parameters for handling time series a
35. Rock Nuclide Solubility Half life De Ka D Ka D Ka mol l yr m s m kg m s m kg m s m kg U 238 104 447108 1070 3 0 1070 0 1 10 18 3 0 Pu 239 10 24 100 1070 3 0 1070 0 1 10 18 3 0 67 3 10 U 238 Canister initially Total release damaged at the top 10 The damage is a small hole that reaches its maximum size at 5 000 yrs 42 path 1 5 10 2 5 path 3 10 g path 2 G 2 e 107 o pathr4 20 10 1 2 3 4 5 6 7 8 9 10 1 10 10 10 10 10 10 10 10 10 10 10 Time years Figure 6 4 Release of U 238 from the repository for a copper iron canister with a suddenly rupture of the canister at 10 years after deposition See Figure 6 1 or 6 3 for the location of the various paths Pu 239 Canister initiallv damaged at the top The damage is a small hole that reaches its maximum size at 5 000 yrs Total release Release GBq year Time years Figure 6 5 Release of Pu 239 from the repository for a copper iron canister with a suddenly rupture of the canister at 10 years after deposition See Figure 6 2 or 6 3 for the location of the various paths 68 References 1 12r 3 4 5 6 Tl 8 9 Romero L Thompson A Moreno L Widen H 1999 COMP23 NUCTRAN Users s Guide Proper version 1 1 6 SKB R 99 64 Svensk K rnbr nslehantering AB Olsson O B ckblom G Gustafson G R
36. XPONENT F QEXP gt 0 0 END DEF outputdef BEGIN DEF OUTPUT FROM SINK I gt 0 END_DEF GEOMETRY DEFINITION TUBE_VOLUME Water volume in one zircaloy tube NUM_TUBE Number of tubes in the canister Source TUBES DAMAGED Number of tubes damaged in the canister source VOID Water volume inside the canister If these data are given they will override any data set in the INPAR block see Section 5 4 2 Note The volume of the source is calculated by Volume TUBE VOLUME TUBES DAMAGED VOID NUM RAMP NODES Hole grows linearly with this many defining points NUM STEP NODES Hole grows as step functions with this many defining points If neither of these keywords are given then there is no hole growth and the appearance time and hole area are the first T HOLE and A HOLE data in the INPAR block see Section 5 4 2 Hole growth may be defined using only one of these keywords and its value must be set to 2 at present The start time and area and end time and area are given by data in the INPAR block MATERIAL DEFINITION The MATERIAL definition is repeated once for each material used in the model MATERIAL NAME Defines the material type Available options are WATER BENTONITEJ SAND BENTONITE ROCK DENSITY Density of the material POROSITY Porosity of the material If density and porosity data are given they will override any data set in the INPAR block see Section 5 4 2 49 BLOCK DEFI
37. YES Length of the plug extra resistance added to the connection between IDCS and the sink Cross sectional area of the plug added to the connection between compart ment and the sink If this parameter is present it must be positive See below See below The QEQ_FACTOR and QEQ_EXPONENT values are used to calculate the equivalent groundwater flow at the sink according to the formula Qeq OFactor qQexponent where q is the groundwater flux at the canister position obtained from HYDRASTAR Ifthe PLUG_LENGTH PLUG_AREA QEQ_FACTOR and QEQ_EXPONENT data are given they will override any data set in the INPAR block see Section 5 4 2 OUTPUT DEFINITION It is possible to produce more than one set of output time series from COMP23 If there are no OUTPUT BLOCKS present then the output from all the sinks is summed to give the total output for each nuclide If one or more OUTPUT BLOCKS are present then an output time series for each nuclide is produced for each BLOCK and the sinks contributing to the output are specifed in the OUTPUT BLOCK as shown below FROM SINK n List of sinks connected to this output one line per sink 51 Limitations The maximum number of material definitions that can appear in the system dsc file 1s defined by the parameter MATER in file nvol23 inc MATER is set to 4 in the latest version of COMP23 The maximum number of block definitions that can appear in the system dsc file is defined
38. YPE MATRIX when an alpha radiolysis model is used When MATRIX is used without an alpha radiolysis model IRF values must not be specified The alpha radiolysis model underestimates ingrowth of U 238 This is unlikely to introduce a significant error since the amount of U 238 will usually be much greater than the amount of the U 238 parent nuclide The final six parameters define the nature of any time dependences that are to be modelled NUM SOL LIMIT STEP NODES Defines the number of piecewise constant regions for modelling time dependent solubility limits NUM SOL LIMIT RAMP NODES Defines the number of piecewise linear regions for modelling time dependent solubility limits NUM DIFF KD STEP NODES Defines the number of piecewise constant regions for modelling time dependent diffusion and sorption coefficients NUM DIFF KD RAMP NODES Defines the number of piecewise linear regions for modelling time dependent diffusion and sorption coefficients NUM POROSITY STEP NODES Defines the number of piecewise constant regions for modelling time dependent porosities NUM POROSITY RAMP NODES Defines the number of piecewise linear regions for modelling time dependent porosities It should be noted that a parameter can be modelled as either piecewise constant or piecewise linear but not both simultaneously Therefore for example one cannot set both the NUM SOL LIMIT STEP NODES and NUM SOL LIMIT RAMP NODES in the same model simulation The ti
39. and the geometrical dimensions of the block These properties are used by the code to calculate the capacity of the block and its resistance to transport for each of the two defined transport directions These data are the input data for the problem to be solved The capacity and the resistance are determined by the following expressions Capacity V 6 1 6 k p x Resistance AD e where x is the diffusion length of the block in the direction of transport A is the cross sectional area of the block perpendicular to the direction of transport and D is the effective diffusion coefficient The porosity and the density of the material solid are denoted by and p respectively k is the sorption coefficient and V is the volume of the block As two transport directions have been defined the code needs to know the geometrical dimensions of the block for both directions to define the transport Such geometrical dimensions are diffusion length and cross sectional area for each direction The volume of the block is calculated by the code from the given dimensions for transport in the z direction Any block except the source may be subdivided into compartments in any of the two directions named above The block itself is a compartment if it is not subdivided A simple subdivision is that by discretization in the z direction the code makes the block into compartments of equal capacities The code needs only to know the desired number
40. ate the mass transport between a small compartment and a large one This is applied to the nuclide transport from the small hole in the canister wall into the bentonite outside the hole d Addition of a plug situated inside the canister source when the backfill material is granulated This is a special use for copper iron canister as source where the nuclide transport into the damage in the canister wall is approximated by a plug at the inlet of the damage This plug has the same dimensions as the plug at the outlet of the damage The effective diffusion coefficient D is established beforehand and is 101 m s Note The dimensions of both plugs inlet and outlet depend on the size of the hole at the canister wall So if the size of the hole varies the dimensions of both plugs vary too 25 4 1 Subroutines and functions used by COMP23 4 1 1 Key variables used by the subroutines AREA variable that defines the cross sectional area for a compartment whose size changes with time AGQ partial matrix of constant coefficients AINV vector storing the input amount inventory of the species EPS requested relative accuracy in all solution components EWT problem zero 1 e the smallest physically meaningful value for the solution ICALL index controlling the recall of the solver from the main program or the stopping of the program execution ICH index identifying the decay chain number INABS absolute index identifying a nuc
41. ated into the HYDRASTAR code and the COMP23 code The main objectives of the HUI are Free format input in a single input file Input data validity testing Input data consistency checking A general description of the HUI input file is given in Section 5 3 of this report A detailed description of the COMP23 input required is given in Section 5 4 Details of the output produced by the HUI interface are discussed in Section 5 5 5 2 Input files required The following input files are required to run COMP23 as a submodel of PROPER Name Description system dsc The system description file that is used for all PROPER simulations The input requirements for this file are described in more detail below casename inv These two files hold the information on the radionuclide inventories for one canister casename nam The inventory files used by COMP23 are identical to the files used by TULLGARN 14 so these two files should preferably be links if TULLGARN is used in the same simulation casename is read in from the CONTROL block of the system dsc file submod lib Lists the modules that are used by PROPER The module name for COMP23 is COMP23 and it is connected as an internal submodel 12 5 3 HUI input The following notational conventions are used to describe the format of the input data for this model In general the definition follows that of INFERENS 15 A detailed description of the input required when running the P
42. bility limit can all be made time dependent In order to explain the procedure for setting up time dependent parameters in COMP23 it is easier to proceed with an example Suppose in the examples given above it is desired to make the diffusion coefficient for nuclide A in material 1 piecewise constant as shown in the figure in Section 2 3 It is first necessary to define the times T1 T2 and T3 in system dsc For example this could be done as follows TIME TI CONST 1 0E2 TIME T2 CONST 1 0E4 TIME T3 CONST 1 0E5 Next it is necessary to define the values of the diffusion coefficient for the various time regimes For example DIFAITI CONST 0 123E 2 DIFA1T2 CONST 0 123E 1 DIFA1T3 CONST 0 123E0 For the non time dependent case described in the previous subsection the INPAR section would contain the following lines in the appropriate place DIFA1 KDAI DIFB1 KDBI DIFA2 KDA2 DIFB2 KDB2 DIFA3 KDA3 DIFB3 KDB3 DIFA4 KDA4 DIFB4 KDB4 In the time dependent example we are considering the INPAR section would look as follows TIME TI DIFAITI KDAI DIFBI KDBI DIFA2 KDA2 DIFB2 KDB2 DIFA3 KDA3 DIFB3 KDB3 DIFA4 KDA4 DIFB4 KDB4 39 TIME T2 DIFAIT2 KDAI DIFB1 KDB1 DIFA2 KDA2 DIFB2 KDB2 DIFA3 KDA3 DIFB3 KDB3 DIFA4 KDA4 DIFB4 KDB4 TIME_T3 DIFAIT3 KDA1 DIFB1 KDBI DIFA2 KDA2 DIFB2 KDB2 DIFA3 KDA3 DIFB3 KDB3 DIFA4 KDA4 DIFB4 KDBA It should be noted that it is necessary to define all of the parameters for all
43. by the parameter NBOX in file nvol23 inc NBOX is set to 10 in the latest version of COMP23 The maximum number of connection definitions that can appear in the system dsc file is defined by the parameter NVOL 2 in file nvol23 inc NVOL is set to 20 in the latest version of COMP23 The maximum number of sink definitions that can appear in the system dsc file is defined by the parameter NPATH in file nvol23 inc NPATH is set to 7 in the latest version of COMP23 System commands The SYSTEM_COMMANDS may be inserted in the input data at any point outside a block The format of a SYSTEM COMMAND is SYSTEM KEYWORD The SYSTEM keywords available in the latest version of COMP23 are LIST_DICTIONARY This command toggles the flag that controls listing of a dictionary and the accompanying wordlists whenever a dictionary is loaded A subsequent LIST_DICTIONARY command will turn the listing off This option is off by default LIST ALL DICTIONARIES At the instant the LIST ALL DICTIONARIES command is encounte red all dictionaries with accompanying wordlists will be listed IGNORE FATAL ERRORS This command toggles the IFATDO flag If a fatal error is encountered the program will stop if the flag is off If the flag is on the program stops after reading all input data The flag is off by default SAVE SCRATCH FILES This command toggles the ISAVSC switch It allows temporary files used by the code to be retained they are normally deleted when th
44. c where ne S i e nuclide n is an isotope of element E may now be related to a by n a 4 T S if ap Ke n E E ca 3 E if ar X6 apg where K is a distribution coefficient for element E and E is the solubility limit for the solubility group Sz of element E Kp is given by K 0 1 6 kzp 4 where is the porosity for element E p is the density of the solid material and k is the sorption coefficient for element E The amount of nuclide n per unit volume that is in solution is c and the amount that is sorbed is l 9 kf p so that the total amount dissolved and sorbed per unit volume is K e Note that the COMP23 model allows the porosity to depend on the element so that effects such as anion exclusion can be treated Expression 3 may be derived in the following way When the total amount of element E per unit volume a a 1s less than the total amount that can be dissolved and sorbed per unit volume K ja there will be no precipitate of any of the isotopes of E present because of the assumption that the precipitate dissolution reaction is fast The amount of nuclide n present in solution and sorbed per unit volume will be Kc and this must be equal to the total amount of nuclide n present per unit volume so that Kc a 5 and the first part of equation 3 follows immediately When the total amount of element E per unit volume is greater than the total amount that can be dissolved a
45. e CONSTANT type b The dissolution rate is a function of the alpha radiolysis dose rate of the fuel and decreases with time as a result of radioactive decay DECAY type c The dissolution rate is a function of the alpha radiolysis dose rate of the fuel and decreases with time as a result of radioactive decay and dissolution of alpha emitting solids from the fuel matrix EXPLICIT type 12 The alpha radiolysis model specifies the rate at which the uranium matrix dissolves due to alpha radiolysis denoted by qu This rate can depend on time and on the amount of various alpha emitting nuclides in the matrix but is independent of the rate at which the uranium is leaving the canister which is denoted by q And pop EST O e 19 da so meSy The rate of dissolution of the uranium matrix q is specified by 20 M M lt p AT q de if ay S Veco e AT s da if ay SV ne When the effects of alpha radiolysis are included in the model the rate of dissolution of the uranium matrix is always at least the alpha radiolysis rate If there is uranium precipitate in the canister and qu lt q 4 the amount of precipitate will decrease until such time as either qu gt q or else all the uranium precipitate has been dissolved The rate of dissolution of uranium will still be de during this period because the precipitate dissolves much more readily than the matrix Once all the uranium precipitate in the canister has been d
46. e D ti a e D ENGT U pj gt mo A Bj D DEF BLOCK BLO D a MATE CK NUMBER B NUM Z COMP NUM Y COMP NUM X COMP EA CHANGE AL NAME zi ul DEF DISCRE ZAT H E Z Q H ti U e D ti e D SENA mA El D Si U Oz dO se se na nq por O T nj ON O one bi Bd C 15E 0 224E 97E 0 2 17E 01 0 0E 0 1 0E 0 2 125E 0 1 224E 1 97E 0 2 64E 01 0E 0 NO BENTONITE C E 0 E Ed ti OO se Q ki tA OC Oo NO ROCK N Hi Ho O Oo oO OR Oo ti tA 0 OOo tb 62 Connection definition BEGIN DEF CONNECTION
47. e code finishes executing IGNORE ERRORS This command toggles the IGNERR flag If an error is encountered validity consistency syntax or existence in the input data the program will stop after reading all input if the flag is off If the flag is on the program continues The flag is off by default SKIP USER INTERFACE This command sets IGNERR flag to 1 WRITE INPUT FILE This flag is intended for debugging purposes If turned on the code will generate a COMP23 input file of the old format via routine WOFC23 That is a FORTRAN formatted data file The flag is off by default NO SIMULATION This command sets the INOSIM flag to 1 This is not used in the latest version of COMP23 READ INVENTORY IN EACH LOOP This command causes the casename inv file to be read for each simulation When this flag is not set the file will be read only once 52 OUTPUT_DEBUG_FILES SKIP_USER_INTERFACE USE NUCLIDE DEPENDENT POROSITIES USE MATERIAL DEPENDENT SOLUBILITY LIMITS This flag is intended for debugging purposes If turned on the code will generate four files that give the following information a summary of the properties of the compartments including capacitances and resistances the release rate of each nuclide the aqueous and solid amount of each nuclide and flow rate fractions for each nuclide The flag will also cause debug information to be written to standard output If this command is found the rest of the input data bl
48. e solved It also sets the flag ICALL to indicate whether initialisation needs to be carried out or if a fatal error has occurred 26 DDASKR SSRES NEQ T Y YPRIME TOUT INFO RTOL ATOL IDID RWORK LRW IWORK LIW RPAR IPAR SSJAC PSOL SSRT MROOT JRTSS This subroutine solves the implicit differential algebraic equations DAEs of the form F y y t 2 0 given the initial conditions yo y t 0 which must be used to supply consistent initial values for yo DDASKR is called once for each output point of T The subroutines SSRES SSJAC and SSRT are part of COMP23 and their functions are described below The main program CMP23 calls DDASRT FLOW23 IFSTOP IPRINT MULTI This subroutine calculates the release by molar flow rate from the source and into the various sinks These data are written to the PROPER database via a call to PUTS The time series at which the molar flow rates are calculated is determined beforehand by the user The main program CMP23 calls FLOW23 FMCO23 ICH This subroutine defines the coupling resistances between compartments including the external coupling with the flowing water surrounding the barrier system FMCO23 is called by IMAT23 FMDE23 ICH This subroutine defines the capacity and individual resistances to transport of all compartments FMDE23 is called by IMAT23 MAT23 TIME This subroutine computes the coefficients that appear the governing equations MAT23 is called by IMAT
49. e solves three types of specific situations I Solubility limited approach All species in the canister are available for release independently of the structure they are part of The only limitation on the nuclide release is the solubility of the individual species IT A particular case for nuclides initially located at the fuel surface The handling of this situation is similar to I but considers that only a fraction of the total nuclide inventory is available for release IT Congruent approach for nuclides embedded in a fuel matrix Since the matrix is mostly formed by uranium oxide the escape rate for the embedded nuclides will depend on the escape rate of the uranium Thus to calculate the release of these nuclides the U 238 is simultaneously run with the nuclides of interest The solubility limits may be either fixed or calculated from a shared solubility limit for a group of nuclides There are also special uses of the code that are easy to manage They are a Addition of a transport resistance between two compartments The code needs know only the value and where the resistance will be placed b The damage in the canister wall is handled as a special compartment where the user has the alternative of choosing a growing hole or a hole of stationary size For the situation ofa growing hole the user may choose a linear function or a step function for the growth c Addition of a plug at the outlet of the source in order to approxim
50. e version UC m m yr Water flow rate outside canister Only used for standalone version CSYNC Random number seed MULT Number of assumed identical canisters in region PROB Probability of a single canister being penetrated at time of emplacement 36 If COMP23 finds that there is a single canister that has been penetrated at time of emplacement it ignores the other canisters and calculates the rate using one initially damaged canister If no canister is initially damaged no release calculations are performed in the present version The next parameters define the densities of the barrier materials They must be present 1f this data is not defined in the MATERIAL section of the GEOMETRY block but will be overridden by that data if it is present Suggested name Units Description DENS m kg m Density of barrier material m The next parameters define the porosities of the barrier materials They must be present 1f this data is not defined in the MATERIAL section of the GEOMETRY block but will be overridden by that data if it is present If the System Command USE NUCLIDE DEPENDENT_POROSITIES is present then the porosity data must be entered here and must not be entered in the MATERIAL section of the GEOMETRY block In this case the porosity for each nuclide in each material must be entered If the System Command USE NUCLIDE DEPENDENT POROSITIES is not present Suggested name Units Description P
51. ential Algebraic Equations Elsevier New York 12 Proper Monitor User s Manual SKB TS 99 09 Svensk K rnbr nslehantering AB August 1999 13 User s guide to HYDRASTAR 1 5 February 1996 14 TULLGARN User s Guide 15 Maddock R Hailwood E Rhodes E Muir Wood R Direct fault dating trials at the Asp Hard Rock Laboratory SKB AR 93 24 Svensk K rnbr nslehantering AB 69 Notation a amount of nuclide n per unit volume a amount of nuclide n in the canister not embedded in matrix a total amount of element E per unit volume es total amount of element E in the canister not embedded Ay area b amount of nuclide n embedded in the fuel matrix c concentration e concentration of nuclide n fe concentration of nuclide n in the water in the canister e solubility limit for element E D effective diffusivity for nuclide n D diffusivity in free water y dg rate at which nuclide n is leaving the canister by diffusion gi transport coefficient linking compartments i and j kg sorption coefficient for element E Kg distribution coefficient for element E ly diffusion length N dissolution rate or molar flow rate q dissolution rate of fuel matrix qu dissolution rate of fuel matrix due to alpha radiolysis qv rate at which uranium leaves the canister Q4 X equivalent flow rate R resistance to transport r radius Sz set of nuclides in solubility group for element E Su set of nuclides that are isoto
52. ently CONSTANT with the fuel The fuel dissolution rate is controlled by a variable MATRIX note 3 Yes AER_DECAY rate of alpha radiolysis Decay of alpha emitters is represented in the model Radionuclides dissolve congruently with the fuel note 4 The fuel dissolution rate is controlled by a variable MATRIX rote 3 Yes AER_ rate of alpha radiolysis Decay and transport of alpha EXPLICIT emitters are represented in the model Radionuclides dissolve congruently with the fuel notes 4 and 5 Notes 1 All nuclides in a chain must have the same SOL_ TYPE 2 The IRF value specified by the user for the first nuclide in a chain will be used for all nuclides in that chain when the FUELSURFACE model is used 3 The chain containing U238 must be the first chain defined The U238 chain must be defined as SOL_ TYPE MATRIX 4 The expression used for this model is only valid for a specific fuel See reference 5 for more details 5 One or more of the following nuclides must be included as SOL TYPE MATRIX when this option is used Am 241 Np 237 Pu 239 Pu 240 CHAIN DEFINITION CHAIN Keyword indicating start of a decay chain MOTHER The first modelled nuclide in a decay chain DAUGHTER The nuclide s following in the decay chain The list of the daughter nuclide must be given in the correct decay order for example For example CHAIN Am241 Np237 U233 Th229 END_CHAIN Where Am241 is modelled as the mother
53. f the parameters is given below Suggested name s Description CSYNC Random number seed MULT The number of canisters the calculation segment normally from HYDRASTAR PROB Probability for initial damage to canister PITFAQ QS CONHS DEFFS Corrosion data not used by present version of the model DENS Density of different barrier materials if not defined in BLOCK data POR Porosity of different barrier materials if not defined in BLOCK data T HOLE A HOLE Hole growth data for chosen growth model CSOL Solubility of the nuclides DIF Effective diffusion coefficient in the different barrier materials for all nuclides KD Ka value in the different barrier materials for all nuclides VTUBE NTUBES NTDAM Tube volume number of tubes tubes damaged and void if not defined in VHEMA BLOCK data AER Alpha radiolysis parameter K for chosen model if required ZRFRA APFRA QFAC QEXP Data for each sink if not defined in BLOCK data IRF Instantaneous Release Fraction IRF values only required for nuclides that use a FUELSURFACE or alpha radiolysis model The order that these are listed above is the order that the parameters must be specified within the INPAR section When COMP23 is used as a standalone model two extra parameters are given as the first parameters These are NCAN and UC Suggested name Units Description NCAN E Number of canisters to be modelled recommended value 1 Only used for standalon
54. h n I Stanfors R Wikberg P 1991 The Structure of Conceptual Models with Application to the Asp HRL Project SKB TR 94 08 Svensk K rnbr nslehantering AB Haworth A Ilett D J Thompson A M Worth D J 1996 Developments to the NUCTRAN Computer Program Haworth A Thompson A M Worth D J 1997 Developments to the PROPER Version of NUCTRAN Were L Sellin P Forsyth R 1990 Radiolytically Induced Oxidative Dissolution of Spent Nuclear Fuel SKB TR 90 08 Svensk K rnbr nslehantering AB Narasimhan T N Witherspoon P A 1976 An Integrated Finite Difference Method for Analyzing Fluid Flow in Porous Media Water Resour Res 12 57 Romero L Moreno L Neretnieks I 1995 Fast Multiple Path Model to Calculate Radionuclide Release from the Near Field of a Repository Nucl Technol 112 89 Neretnieks I 1982 Leach Rate of High Level Waste and Spent Fuel Limiting Rates as Determined by Backfill and Bedrock Conditions Proc Scientific Basis for Nuclear Waste Management V Berlin Germany June 7 10 1982 W Lutze Ed p 559 Neretnieks I 1986 Stationary Transport of Dissolved Species in the Backfill Surrounding a Waste Canister in Fissured Rock Some Simple Analytical Solutions Nucl Technol 72 194 10 PROPER 1993 Proper Submodel Designer s Manual Version 3 0 Edition I Svensk K rnbr nslehantering AB 11 Brenan K E Campbell S L Petzold LR 1989 Numerical Solution of Initial Value Problems in Differ
55. he actual volume available for the water in the canister will increase but since the rate of dissolution is slow this volume change can be neglected COMP23 treats three types of situation I Solubility limited approach All species in the canister are available for release independently of the structure they are part of The only limitation in the nuclide release is the solubility of the individual species IT A particular case for nuclides initially located at the fuel surface The handling of this situation is similar to I but only a fraction of the total nuclide inventory is available for release III Congruent approach for nuclides embedded in a fuel matrix Since the matrix is mostly formed by uranium oxide the release rate for the embedded nuclides depends on the rate at which the uranium fuel matrix is dissolving Several models are available to treat the dissolution of the fuel matrix and the effects of alpha radiolytically induced dissolution can be treated These different models are described in Sections 2 1 4 and 2 1 5 2 1 3 Source term solubility limited The model for cases I and IT in Section 2 1 2 is essentially the same Case I is referred to as SOL TYPE OWNSOL and case ll as SOL TYPE FUELSURFACE Since the dissolved nuclides in the canister are assumed to be well mixed the amount of each nuclide in the canister is determined by a single quantity 4 that represents the total amount of nuclide in the canister and
56. hether alpha radiolysis is modelled or not The case without alpha radiolysis is considered in this section The case with alpha radiolysis is treated in Section 2 1 5 When alpha radioloysis is not included in the model the rate of dissolution of the uranium matrix is determined by the solubility of the uranium in the canister The model assumes that the rate at which the matrix dissolves is just fast enough to maintain the uranium in the water in the canister at its solubility limit without any precipitate forming A faster rate of dissolution would obviously lead to the formation of uranium precipitate in the canister and a situation where the matrix would be dissolving rather than the precipitate which is physically unreasonable in the absence of effects such as alpha radiolysis and contradicts the basic assumption that the rate of dissolution of the precipitate is very fast On the other hand it is possible that the matrix could dissolve at a slower rate that is not sufficient to maintain the dissolved uranium at its solubility limit However the current assumption is conservative and leads to a well defined and relatively simple model Summing equation 12 over all the isotopes of uranium and using equation 13 gives 0 Am m m m m A 39 Sar y aa S X jir mm ot meSy meSy meSy 11 Since the uranium in the water in the canister 1s at the solubility limit P o Viei 16 so that 225 Voc 0 17 Therefore Y 2 2
57. in Section 2 1 4 15 Parameters required The parameters required are as follow Solubilitv limit of each element in the water in the canister Volume of water in the canister Nuclide inventories and half lives Parameters for the alpha radiolysis dissolution model 2 2 Geometric framework To represent the barrier system through which the species are transported COMP23 makes use of the integrated finite difference method 6 and of the concept of compartments The barrier system is discretized into compartments Average properties over these compartments are associated with nodes within the compartment From the theoretical point of view the compartments may have any shape but consist of only one material The material balance over a compartment is given by da ot z ms SUA TA SGH 30 J where a is the amount of nuclide n in compartment i c is the concentration of nuclide n in the pore water in compartment i and 4 are as defined in Section 2 1 1 and g is the transport coefficient linking compartments i and j The concentration ci where ne S i e nuclide n is an isotope of element E is related to a by n a T s if aki lt VK y Cp n ViK ps 31 C Sa 31 if ar VE ay where KF is the distribution coefficient for element E in compartment i V is the volume of compartment i ar is the total amount of element in compartment i and ce is the solubility limit
58. issolved 1t is assumed that the rate of matrix dissolution will be such as to keep the concentration of uranium in the water at the solubility limit provided that qu lt qv still holds This implies that the rate of dissolution is equal to the rate at which uranium is leaving the canister qv As was pointed out in Section 2 1 4 this particular assumption is conservative Note that the uranium concentration in the canister cannot drop below its solubility limit until the entire uranium matrix has been dissolved which would take a very long time in most situations In previous versions of COMP23 a slightly different model was used in which the uranium dissolution rate was taken to be the maximum of q and q This earlier model would imply that in the case where there is uranium precipitate present and gs lt q gt the matrix would dissolve instead of the precipitate which is both physically unrealistic and unnecessarily conservative If q M PS then it is easy to show that there must be uranium precipitate in the canister see below So if there is no precipitate in the canister the maximum of qu and qv must be qu y Le the first part of equation 20 is equivalent to the original COMP23 model Thus the model represented by equation 20 only differs from the original COMP23 model when there is uranium precipitate in the canister and qu lt qv and then it is physically more realistic than the original COMP23 model although it is also
59. k failed for keyword KEYWORD File filename Exist YON REX End of Error where ROUTINE is the name of the routine that read the data HUINL is the number of lines including blank and comment lines that have been read KEYWORD is the name of the keyword filename is the name of a file specified YON may be either YES or NO It may be YES since all files are listed if one or more files do not exist The last line is repeated for all files specified in the file list for the particular keyword Syntax errors If a syntax error has occurred the following message will be displayed Kakak akak SYNTAX error has occurred in routine ROUTINE after reading line HUINL where ROUTINE is the name of the routine that read the data HUINL is the number of lines including blank and comment lines that have been read System errors A system error may be over indexed arrays etc This type of error should not be very common to the normal user If a system error has occurred the following message will be displayed RR SYSTEM error has occurred in routine ROUTINE after reading line HUINL where ROUTINE is the name of the routine that read the data HUINL is the number of lines including blank and comment lines that have been read 75 Warnings warning is a note to the user that there may something wrong in the input A warning does not terminate the program If a warning has occurred the following message wil
60. l be displayed RRE WARNING in routine ROUTINE after reading line HUINL where lt ROUTINE is the name of the routine that read the data e HUINL is the number of lines including blank and comment lines that have been read 76
61. less conservative To prove the assertion made in the previous paragraph suppose qu 2q at time f then summing equation 12 over all the isotopes of uranium and using equation 13 gives Y CA f 4 Sb de 21 D meSy meSy 13 Using equation 19 to eliminate the first sum on the right hand side of equation 21 and rearranging gives d 1 MOM a 0 Ja q 22 ot meSy meSy The right hand side of this equation is strictly positive since x gt b gt 0 and q Ue by assumption Thus mesu d gt 0 dt meSy Gu which means that the total amount of uranium in the canister that is not embedded in the fuel matrix is strictly increasing when qu 2q It follows immediately that Y a 0 gt Y a 1 81 24 meSy meSy for all sufficiently small positive t Since the concentration of uranium in the canister never drops below its solubility limit until all the fuel matrix has been dissolved ya 1 81 2 V c 25 meSy Combining equations 24 and 25 gives ay t V t gt Ma 1 81 Voci 26 meSy me Sy as required The three models for the alpha radiolysis dissolution rate qu are CONSTANT da Keon 27 where Kcoy is a constant 14 DECAY l tIn2 EX B 28 izi i where Kpzc is a constant t is the time and A B i 1 4 are constants specific to the nuclides Am 241 Pu 239 Pu 240 and Np 237 in a particular fuel type 5 If a different fuel to
62. lide without reference to a chain INUC index identifying the nuclide in a chain IPRINT position index in the time series ISPSOL shared solubility flag O if no shared solubility 1 if shared solubility is required NEQ the number of differential equations NROOT the number of equations whose roots are desired If NROOT is zero the root search is not active This option is useful for obtaining output at points that are not known in advance but depend upon the solution QDURAN dissolution rate of the fuel matrix ADURAN dissolution rate of the fuel matrix due to alpha radiolysis T independent variable in the ODEs DAEs TIME independent variable in the ODEs DAEs TOUT the point time at which the solution is desired Y vector of nuclide amounts solution of ODEs DAEs YPRIME vector of derivatives of the solution to the ODEs DAEs 4 1 2 Description of key subroutines ALPH23 TIME Y ADURAN This subroutine calculates the dissolution rate of the fuel matrix U238 ADURAN due to alpha radiolysis CONC23 Y IPRINT ICALL This subroutine stores the output data such as concentrations for all compartments and time at which they were calculated The main program CMP23 calls CONC23 CSTO23 IPRINT ICALL T Y This subroutine called by CMP23 if DDASKR indicates that a zero has been found in one of the conditions being monitored It sets LSOLIM and IMFLAG do indicate the change in the equations to b
63. me dependence is either one or the other NUCLIDE DEFINITION NAME Name of the nuclide HALF LIFE Nuclide half life SOL TYPE OWNSOL FUELSURFACEJ MATRIX Dissolution model to use within the canisters Use OWNSOL for nuclides that are not embedded in the fuel matrix FUELSURFACE when only a fraction of the nuclide is available for release and MATRIX when nuclides are embedded in the fuel matrix All nuclides in a CHAIN definition must have the same SOL TYPE When MATRIX is used for any of the nuclides the chain that contains U 238 must be the first chain defined in the CONTROL block IRF Instantaneous release fraction for this nuclide Only used when i SOL TYPE is set to FUELSURFACE or ii SOL TYPE is set to MATRIX and an alpha radiolysis model is used Note for the FUELSURFACE model the IRF specified for the first nuclide in the chain is used for all nuclides in the chain 45 Summary of data required for each dissolution model Description SOL TYPE rote 1 IRF AER keyword Dissolution rate controlled by the solubility of each OWNSOL No No radionuclide Dissolution rate controlled by the solubility of each FUELSURFACE Yes 2 No radionuclide Only a fraction of the nuclide inventory is available for release Radionuclides dissolve congruently with the fuel MATRIX note 3 No No The fuel dissolution rate is controlled by a constant rate MATRIX rote 3 Yes AER_ of alpha radiolysis Radionuclides dissolve congru
64. names of input and output files Optional keyword indicating if advection should be modelled Not fully developed Optional keyword for shared solubilities AUTO MANUAL How the shared solubility groups will be defined AUTO means the groups are generated by COMP23 based on nuclide name MANUAL means the used will specify them in the input file with the SOLUBILITY_GROUP keyword Three different models of alpha radiolytically induced spent fuel dissolution are available in COMP23 The models are described in Section 4 of this report The models are selected by including a keyword value pair in the CONTROL block of the system dsc file a different keyword is used to select each of the models and the AER parameter in the INPAR section must be set to the appropriate value of K Only one of the keywords can be used for each simulation If two or more of the keywords are found an error message will be given and the code will stop 44 AER_CONSTANT The CONSTANT model is used see Section 2 1 5 AER_DECAY The DECAY model is used see Section 2 1 5 AER_EXPLICIT The EXPLICIT model is used see Section 2 1 5 For each of the three alpha radiolysis models U 238 must be defined as SOL_TYPE MATRIX and must be in the first group defined in the CONTROL block Any nuclides that are assumed to dissolve congruently from the fuel matrix should also be defined as SOL_TYPE MATRIX An IRF value must be included for each nuclide that is defined as SOL_T
65. nd switch switch var case VALUEI keywords case VALUEn keywords endswitch comments f any text end of line system commands SYSTEM KEYWORD 5 4 The system description file 5 4 1 Overview The system description file system dsc is used to specify for PROPER the module intercommunication sampled parameters etc The general format of the system description file is only the parts relevant to this manual have been included PROPER KEYWORDS MACROS definitions PARAMETERS section MODULE definitions each MODULE definition has the general format MODULE module Input Timeseries Output Timeseries INPAR section DATA section END module Note the order of the INPAR and DATA sections is not significant Any lines beginning with the character are handled as a comment line 35 5 4 2 Parameters The PARAMETERS section in the system description file defines the sampled parameters and their distributions The general syntax for the PARAMETERS section is PARAMETERS Parameter name distribution type arg1 arg2 END PARAMETERS The order in which the parameters are passed to COMP23 is defined within the INPAR section within the MODULE definition The general syntax for the INPAR section is INPAR parameter namel parameter name2 END INPAR No Time dependent Parameters The following parameters need to be defined in the PARAMETERS section for COMP23 A detailed description o
66. nd for handling data from external submodel specific files 10 INVEN FILNAM IUNAM FILINV IUINV NNUCL NAMES TBREAK AINV This subroutine gives information on the inventory in the canister SET23 calls INVEN PRELUD FILE Set up communication with the internal database POSLUD Closing down communication with the internal database GETP INDEX Used to obtain sampled parameters from the internal database 28 PUTS IDD TSERIE VALUE Used to send output time series to the internal database To avoid conflict service routines are used to obtain an unused unit number and the unique name of a data file when opening They are IGETUN IDUM to get the unit number GETDAT IDUM to get the unique name of a data file and when closing the file PUTUN IUDAT to return the unit number to the monitor 4 2 General description of the input requrements The physical geometry of the system is simplified by dividing it into blocks The blocks are numbered in ascending order The discretization in blocks considers the geometry and the various materials by which the nuclides migrate Not all blocks have the same geometry and orientation so each block has its own axes of references So far there are only two transport directions defined for the block horizontal x or y direction and z direction The transport in a block is completely defined by the physical properties of the material the nuclide transport properties
67. nd sorbed per unit volume the aqueous concentration of E will be at the solubility limit so that Se 6r 6 meSg When the system is in equilibrium the relative proportions of the isotopes must be the same in the sorbed dissolved and precipitated material This means that 1 6 kzpc E DC a K c 7 1 0 kici c a Ki i Rearranging equation 7 gives the second part of equation 3 Note that it has been assumed that all the isotopes of E are chemically identical so that they have the same distribution coefficient Kz Parameters required The parameters required are as follow Solid density and porosity of the materials Sorption coefficient and diffusivity of each radionuclide in each of the different materials Solubility limit of each element in each of the different materials lt Nuclide inventories and half lives The groundwater flux 2 1 2 Treatment of the source term In the COMP23 model the radionuclides in the canister may be present in three forms in solution in the water in the canister in the form of precipitate in the canister and embed ded in the fuel matrix It is assumed that there is no sorption in the canister and that the time taken for the nuclides to mix in the canister is very short so that the concentration of the dissolved nuclides is uniform It is also assumed that the volume of water in the canister is constant during the calculation As the fuel matrix dissolves t
68. ning with 1 in such a way that the parent of nuclide n if it has one is always nuclide n 1 Clearly nuclide 1 cannot have a parent The fundamental equation expressing material balance for nuclide n is da n n n n n l FU Ne VD Ve A a 14 3 1 where a is the total amount dissolved sorbed and precipitated of nuclide n per unit volume c is the concentration of nuclide n in the pore water u is the Darcy velocity D is the effective diffusivity for nuclide n 4 is the decay constant for nuclide n and A is the decay constant for nuclide n 1 if nuclide n is the daughter of nuclide n 1 and zero if nuclide n does not have a parent Note that the quantities a and c are functions of both position and time and that u and D may also depend on position n Equation 1 is to be regarded as an equation for a and so c must be specified as a function of a To do this the assumption that the precipitation dissolution reaction is very fast is used Each nuclide is considered to belong to a solubility group Normally there will be one solubility group for each different element and a group will consist of all the nuclides that are isotopes of a particular element Let S denote the solubility group for element E Then is the set of labels of the nuclides that are isotopes of element E The total amount of element E per unit volume is denoted by a and it is clear that al Ng 2 meSg The concentration
69. nt here is that DDASKR is only ever solving smooth systems of equations and so its methods work well and the program is reasonably robust The conditions that are monitored by the code will now be described When the OWNSOL or FUELSURFACE models are used the following quantities are monitored E y a V K c for each compartment i and each element E When this quantity meSg passes through zero and is increasing the element E is changing from being not solubility limited to being solubility limited and the other way round if the quantity is decreasing When the quantity changes sign the calculation is restarted using the appropriate form of equation 31 to compute c in terms of a Times at which the size of the hole in the canister changes abruptly In these cases some of the coefficients in the equations change When COMP23 detects an abrupt change in the hole size it recalculates the relevant coefficients and restarts the calculation When the MATRIX model is used the following quantities are monitored Y ay V K ci for each compartment i and each element E except for uranium in meSg the canister When this quantity passes through zero and is increasing the element E is changing from being not solubility limited to being solubility limited and the other way round if the quantity is decreasing When the quantity changes sign the calculation is restarted using the appropriate form of equation 31 to compute c in term
70. ock is skipped and the code continues with the main COMP23 code This command indicates that the porosities depend on the nuclides as well as the materials When this command is present the porosities must be entered as parameters in the INPAR section of the input one value for each nuclide in each material They must not be entered in the geometry block This command indicates that the solubility limits depend on the materials as well as the nuclides When this command is present the solubility limits must be entered as parameters in the INPAR section of the input one value for each nuclide in each material 1 Whenever a new block is to be read the dictionary for that block is loaded The dictionary consists of the keywords and associated wordlists that are valid in the current block 5 5 HUI output All output is sent through the routine WLINI1 This means that currently all output is sent to the standard output A description of the output format used by HUI is given in Appendix 2 53 6 Example 6 1 Desription of problem Release of U 238 and Pu 239 from the KBS 3 repository type will be calculated A view of this repository 1s showed in Figure 6 1 including a view of the canister and the small hole in the canister wall These nuclides escape from a copper iron canister through a small hole into the bentonite by diffusion In the bentonite they migrate through various pathways into the water flowing in the rock As this reposi
71. odel block Cross sectional area for transport in the z direction Diffusion length for transport in the y direction One horizontal length of the model block Cross sectional area for transport in the y direction Diffusion length for transport in the x direction One horizontal length of the model block Cross sectional area for transport in the x direction If NUM Z COMP and one of NUM X COMP or NUM Y COMP are gt 1 then compartment numbers loop fastest in the z direction moving in the other direction once one lot of compartments have been numbered in the z direction CONNECTION DEFINITION FROM BLOCK TO BLOCK COUPLES FROM DIRECTION TO DIRECTION FROM RESISTANCE TO RESISTANCE Number BLOCK NUMBER of the first model block in this connection Number BLOCK NUMBER of the second model block in this connection Number of connections or couples of compartments involved in the connection between two blocks FROM COMP and TO COMP have to be repeated COUPLES times Direction in which the transport of the species occurs from first block in connection Z Y X Direction in which the transport of the species occurs to second block in connection Z Y X Set to TRUE if the resistance from the first block is to be included in the coupling resistance and to FALSE otherwise Set to TRUE if the resistance from the second block is to be included in the coupling resistance and to FALSE otherwise 50
72. of subdivisions in the z direction NZ so that NX NY 1 which means no subdivision in the x or y directions For any other subdivision all compartments have to be defined in the INPUT file The compartments are numbered by the code following the z axis for the block while the other direction is kept constant 29 The first block defined in the INPUT data is the source interior of the canister followed by the block describing the damage of the source hole in the canister wall Each block may be connected to one or more than one block except the source At present the source can only be connected to one compartment Each couple of connected blocks A and B is specified by the user in the INPUT file Several control numbers define the connection Such numbers are used to define the position of each block A and B the numbers of the couples of compartments involved in the connection of block A and B the direction z axis or x or y axis of each block and the contribution of each block to the coupling resistance After the connection of the two blocks is specified the code needs to know the position of the couples of compartments involved in each connection All this information is used to calculate the coupling resistance R 66599 1 where R and R are the individual resistances of the compartment compartment j respectively and the adjacent External resistances specified in the input data may be added between two blocks
73. of the time regimes In words this INPAR section states that for times between 0 and TI the diffusion coefficient takes a value DIFA1T1 Between times T1 and T2 it takes the value DIFAIT2 Between times T2 and T3 it takes the value DIFAIT3 Time dependence for the porosity and solubility limits are set up in a very similar way and the corresponding parts of the INPAR section of system dsc must be written in the form shown above It is also necessary to specify in the control block the details of the form of the time dependence that is to be modelled see Section 5 4 4 subtitle Control block definition Remaining Parameters The next parameters give details of the modelled canister comprising a number of tubes surrounded by void space The number of damaged tubes is specified here They must be present if this data is not defined in the GEOMETRY block but will be overridden by that data if it is present Suggested name Units Description VTUBE m Volume of water in one tube in the canister NTUBES Total number of tubes in the canister NTDAM Number of damaged tubes in the canister VOID m Water volume inside the canister 40 The next parameter is the constant in the alpha radiolysis model It s exact meaning and units will depend on the model chosen see Section 2 1 5 It is optional but must be present if alpha radiolysis is modelled Suggested name Units Description AER depends Alpha radiolysi
74. onal correlations Porosity sorption coefficient diffusion coefficient and solubility limit can also be made time dependent in version 1 2 2 of COMP23 The time dependence can be in the form of piecewise constant step or piecewise linear ramp variations These are illustrated in the figure below Parameter Piecewise linear Parameter Piecewise constant 19 2 4 Initial conditions COMP23 solves an initial value problem comprising a system of differential and possibly algebraic equations The solution of this system is straightforward once the initial conditions have been defined The variables defining these conditions are determined by the amount of the species dissolved the amount of the species as solid inventory in the compartments and the amounts of nuclides embedded in the fuel matrix when a congruent dissolution model is used The default initial condition is zero for all compartments except for the compartment acting as the source where the initial condition is determined by the inventory and the solubility of the species 20 3 Numerical methods 3 1 Spatial discretization The compartment model COMP23 formulates the near field transport in terms of integrated finite differences introducing the concept of compartments to define the discretization of the system This concept is very useful when the transport is through materials with different properties and the geometry of the whole system is complex
75. ory is simplified as shown in Figure 6 2 for the bentonite surrounding the canister It is clear that errors are introduced in the solution given by COMP23 but these errors are minimized by an additional subdivision into a few compartments as is the case when the transport is controlled by sensitive points such as at the small hole in the canister wall for the KBS 3 repository Figure 6 3 shows the coarse discretization of the whole repository A finer compartmentalization next to the hole in the canister wall bentonite surrounding the canister may be made in order to get a better accuracy in the calculations of the early release This finer subdivision into two to four compartments is important for the short lived nuclides 2 thickness y area A for transport in z direction area A W L for transpor in y direction Bentonite thickness y Deposition hole Compartment next to section the hole in the canister Figure 6 2 A schematic view of the simplification process of the volume of bentonite surrounding the canister into a compartment W is an average dimension width path Q3 Tunnel LI I Sand Bentonite Canister B 1 C 2 B 8 Bentonite B 9 Rock path Q4 Figure 6 3 The coarse compartmentalization of the KBS 3 repository where each rectangle is a compartment and the dash lines are finer divisions of the blocks The arrows show the various pathways followed by the species from the canister to the
76. pes of uranium t time i residence time Uo flux of water W width V volume Greek dp porosity for element E decay constant fracture aperture n mean penetration thickness p densitv 71 Appendix 1 mol m mol mol m mol m2 mol mol m mol m mol m mol m m year m vear mol vear m year m kg m mol vear mol vear mol vear mol vear m year vears m m year year m m year m n year kg m Appendix 2 HUI output The HUI output starts with the following lines of output HYDRASTAR User Interface Initialize Opened unit nn as file filename and ends with the following lines of output HYDRASTAR User Interface Error Report Number of validity errors nv Number of consistency errors nc Number of existence errors ne Number of syntax errors nv Input data is correct Continuing Output from the various input BLOCKS read are initiated by the following lines Start of block block identifier and ended by End of block block identifier Between these two sets there exists four types of output Input line echoing Input data echoing Error messages Definition block IO Definition block IO are initiated by the following lines End of definition definition identifier Between these two sets there exists three types of output Input line echoing Input data echoing Error messages
77. require IRF values they should specified her For example IRFC14 CONST 0 5 END PARAMETERS M aa MODULE COMP23 HYDR11 TS1HYDR11 UB1 UB2 INPAR The parameters are numbered following the order indicated below For instance DIFAl corresponds to GETP 5 NCAN CSYNC1 MULTIS1 UC PROB PITFAQ OS CONHS DEFFS T ZERO A ZERO T LIMIT A LIMIT CSOLA CSOLB DIFAI DIFB1 KDA1 KDB DIFA2 DIFB2 KDA2 KDB2 DIFA3 DIFB3 KDA3 KDB3 DIFA4 DIFB4 KDA4 KDB4 Any nuclides with an IRF must have one parameter for the IRF value These should be the last items in the END INPAR 58 INPAR section DATA Input file for COMP23 with HUI f U 238 and Pu 239 copper iron canister KBS 3 SYSTEM WR TE INPUT FILE BEGIN BLOCK GEOMETRY VOI
78. s of a e b the amount of uranium 238 in the fuel matrix When this quantity becomes zero the calculation is restarted without fuel dissolution The model becomes the same as the OWNSOL or FUELSURFACE models Times at which the size of the hole in the canister changes abruptly In this cases some of the coefficients in the equations change When COMP23 detects an abrupt change in the hole size it recalculates the relevant coefficients and restarts the calculation The other quantity to be monitored depends on whether uranium precipitate is present in the canister or not If uranium precipitate is present then the following quantity is monitored e ya V cg where by convention compartment is the canister This quantity meSy should only pass through zero in the decreasing direction otherwise there cannot be uranium precipitate in the canister When this quantity passes through zero the rate of dissolution due to alpha radiolysis is not sufficiently high to keep the uranium in the canister at the solubility limit so the fuel matrix dissolution rate will be controlled by rate at which uranium is leaving the canister The calculation is restarted with the amount of uranium 238 in the canister that is not in the matrix being calculated from equation 16 22 If there is no uranium precipitate present in the canister then the following quantity is monitored qu A Initially this quantity must be negative otherwise there wo
79. s parameter K for chosen on model model if required The next parameters define the sink data and must be present if this data is not defined in the SINK section of the GEOMETRY block but will be overridden by that data if it is present Suggested name Units Description PLUG LEN n m Length of the plug extra resistance added to the connection between compartment and sink n PLUG AREA n m Cross sectional area of the plug added to the connection between compartment and sink n This parameter must be positive QFAC n See below QEXP n See below The QFAC and QEXP values are used to calculate the equivalent groundwater flow at the sink according to the formula Qeq OFAC qeu where q is the groundwater flux at the canister position obtained from HYDRASTAR For example if two sinks are used the definition would be as follows Sink 1 PLUG LENI CONST 5 0E 4 PLUG AREAI CONST 5 5E 4 QFACI CONST 0 03 EQXP1 CONST 0 5 H Sink 2 PLUG LEN2 CONST 0 002 PLUG AREA2 CONST 0 006 QFAC2 CONST 1 0 EQXP2 CONST 0 5 The next parameter defines the IRF for the nuclides in the model Note that the order of nuclides as defined within the DATA section must be followed Suggested name Units Description IRF n E Instantaneous Release Fraction for nuclide n One value for each nuclide that uses a FUELSURFACE or alpha radiolysis model 41 For example if two nuclides A and B are
80. s the specified upper limit Lower bound is the specified lower limit REAL is the real value that has been read for the keyword INT is the integer value that has been read for the keyword The last line is repeated for all values that have been read for the particular keyword Consistency errors If a required keyword or an optional keyword that depends on the value assigned to a required keyword has not been found in the input file the following message will be displayed 74 e CONSISTENCY error has occurred in routine ROUTINE after reading line HUINL These are Keyword KEYWORD Not set Tok TOKEN Keyword KEYWORD Not set Tok TOKEN depend on lt KEYWORD WORD gt which has been set Tok TOKEN Setting keyword lt KEYWORD gt has no effect it depend on lt KEYWORD WORD gt which has not been set ss Eng of Error where lt ROUTINE is the name of the routine that read the data lt HUINL is the number of lines including blank and comment lines that have been read KEYWORD is the name of a keyword e TOKEN is the token value for the keyword see HYDRASTAR USER INTERFACE Programmers reference WORD is the word in a wordlist applicable to the keyword see the Input Data Chapter Existence errors If any of the files in a list of files specified for a specific keyword does not exist the following message will be displayed ask EXISTENCE error has occurred in routine ROUTINE after reading line HUINL Chec
81. th and cross sectional area Conceptually the model uses a rather straightforward compartmentalization process This coarse compartmentalization could yield poor or even meaningless numerical results To avoid this analytical or semi analytical solutions are introduced in the model in zones where a finite difference scheme would require a fine discretization to obtain an accurate result Some of the approaches used by the model to describe the solute transport in these sensitive zones are shown below 2 2 1 Analytical solutions used in the model The approaches developed at present include transport by diffusion into the flowing water transport of solute through a small contacting area into a large volume compartment and transport of solute into a narrow slit 7 Other approaches could be included in the code in the future Transport into flowing water For compartments in contact with water flowing in fractures in the rock the diffusive transport is determined by an equivalent flow rate Q This parameter is a fictitious flow rate of water that carries with it a concentration equal to that at the compartment interface 17 It has been derived by solving the equations for diffusional transport to the passing water by boundary layer theory 8 This entity is obtained from Em 4D t Q q Wn q W T where D is the diffusivity in free water W is the width of the compartment in contact with water flowing in fractures fracture zones
82. that is a function of time The equation for nuclide n is 4 4 WA a f 8 where f is the rate at which nuclide n leaves the canister by diffusion into the rest of the barrier system If o is the area of the canister that is breached and so is in direct contact with the rest of the barrier system then f D nve 9 where n is the outward pointing normal to c and c is the concentration of nuclide n in the barrier system outside the canister as in the previous section Again equation 8 is to be regarded as an equation for In order to determine f and so complete equation 8 the concentration of nuclide n in the canister must be provided as a boundary condition on o for the nuclide transport equation outside the canister The relationship between a and C where nuclide n is an isotope of element E is a p AT S if ap SCE An E lesar 10 E A AT S if ap gt Vee E where Vc is the volume occupied by the water in the canister and r is the total amount of element E in the canister SF am ag 21 0 11 meSg The derivation of equation 10 is similar to the derivation of equation 3 Parameters required The parameters required are as follow Solubility limit of each element in the water in the canister Volume of water in the canister e Nuclide inventories and half lives 10 2 1 4 Source term congruent release without alpha radiolysis In case III in
83. the coupling resistance ICRS For the situation of one fracture intersecting the system a plug approximates the nuclide transport into the fracture The dimension of this plug have to be defined by the user For this situation ICRS 0 As the code for COMP23 exists in two different operative versions there are two input data files The differences between them are in the structure of the subroutines to read the input data to process the output data and to get information of the initial nuclide inventory The variable definition is the same for both versions In the standalone version of COMP23 the nuclide inventory has to be given in the INPUT file In the PROPER version of COMP23 the nuclide inventory is implicitly obtained by the code it needs only to know the names of the nuclides and the break time TINIT for the canister In the next section the INPUT file for the PROPER version will be presented The standalone version is described in a separate manual 31 5 Simulation setup using Proper 5 1 Overview COMP23 can be run as a submodel ofthe PROPER package A User Guide for the PROPER package is given in reference 12 This section gives details specific to running COMP23 as a submodel of PROPER Section 5 2 describes the input files that are required by the PROPER package when COMP23 is included as a submodel The PROPER version of COMP23 uses the HYDRASTAR User Interface HUI 13 HUI is a preprocessing facility incorpor
84. tory has been well described in several SKB reports details on this repository will not be given here 6 2 Compartmentalization of the KBS 3 repository The compartmentalization of the barrier system in the KBS 3 repository is made considering the geometry of the system and the materials through which the species are transported The material the transport properties and the dimensions of the compartment define the transport in a compartment They are used by COMP23 to calculate the capacity of the compartment and the transport resistance in each transport direction The capacity of a compartment includes the nuclide either in 1ts water volume or sorbed in on the solid The volume of the compartment and the distribution coefficient K in the compartment determines this term The diffusion coefficient diffusion length s and cross sectional area s of the compartment determine the transport resistance These resistances are used to determine the nuclide flow rate between coupled compartments EE ASAS YC VAS A E CAE SE ASA E A RAPPA PARA RA RARA RARA RA AAA A A ADA e V T UA A it SRE VAL UA TAC UA MON ON NON NON x ERRATA CR A AR A AA NARA Canister Bentonite Deposition hole Canister wall Fracture zone Q4 Figure 6 1 Schematic view of the KBS 3 repository design showing the small hole in the canister and the location of the various escape routes 55 In the compartmentalization the geometry of the reposit
85. uld be uranium precipitate present see the discussion in Section 2 1 5 When this quantity goes through zero uranium is about to be precipitated in the canister The calculation is restarted using q as the fuel matrix dissolution rate and solving equations for all the nuclide amounts including the uranium 238 It can be shown that when the calculation is restarted the rate of increase of uranium precipitate in the canister is initially zero but that the second derivative of the total amount of uranium in the canister is positive So although uranium will be precipitated the initial amount precipitated will be small This can cause numerical problems if the accuracy of the solution is not sufficiently high Finally note that the case when there is no alpha radiolysis can be considered as a special instance of the case with alpha radiolysis with qu 0 as far as the quantities monitored is concerned 23 4 Description of the COMP23 code The COMP23 code is written in FORTRAN There are two versions depending on the environment it works in a standalone version and a special version to be used as a submodel of the PROPER code The code consists mainly of three parts that are MAIN PROGRAM CMP23 SOLVER DDASKR INPUT FILES system dsc casename inv casename nam and submod lib The main program CMP23 makes use of several subroutines that will be described later The INPUT files are described in detail in the next sections The cod
86. ully defined by a local equivalent flow rate The purpose of this document is to assist the user in managing problems with COMP23 An overview of the theory numerical method and the code designed to solve the problem will be presented in the following sections Finally an example will be described in detail The current version of COMP23 has been extensively revised from earlier versions of the program The earlier standalone version of the program was called NUCTRAN A description of the earlier version of the program can be found in reference 1 Sink 1 FARF31 canister compartments COMP23 Figure l I A schematic of the conceptual model used by COMP23 2 Conceptual model The presentation of the conceptual model used in COMP23 follows the definition given by Olsson et al 2 a relatively general description or a definition of the way the model is constructed This should be separated from any specific realization or application of the conceptual model The concepts that make up the conceptual model are specification of the processes modelled geometric framework specification of the parameters specification of the assignment of material properties and specification of boundary and initial conditions required by the model Each of these concepts will be described for COMP23 in the following subsections 2 4 Processes modelled The processes modelled are radioactive decay and ingrowth diffusion advection
87. used the definition would look like IRF values only for FUELSURFACE or alpha radiolysis models IRFA CONST 0 1E0 IRFB CONST 0 1E0 5 4 3 Input timeseries As with the TULLGARN code COMP23 needs to obtain the Darcy groundwater velocities outside the canister s as an input timeseries from another model There are three pseudo timeseries that are to be supplied to COMP23 The pseudo timeseries must be specified in the order below within the MODULE definition Suggested name Units Description UOX m3 m l yr Darcy velocity of groundwater in first horizontal direction outside canister UOY m n yr Darcy velocity of groundwater in second horizontal direction outside canister UOZ m m yr Vertical Darcy velocity of groundwater outside canister Note that the number of entries in the input time series is not equal to the sampled parameter MULTI Normally when using HYDRASTAR to generate the input pseudo timeseries there is only one entry in the input pseudo timeseries The input timeseries are defined in the MODULE definition in the system description file The general syntax for the MODULE definition is MODULE mod sub pml ts1 ts2 pm2 tso1 tso2 END sub mod For example the module definition for a segment can look like MODULE COMP231 COMP23 HYDR 11 TS1IHYDR11 TSICOMP23 when the Macros MACRO TSIHYDRII UxC1 UyCl UzCI MACRO TSICOMP23 QACI QBCI have been defined earlier In
88. verview 5 4 2 Parameters 5 4 3 Input timeseries 5 4 4 Module specific input data 5 5 HUI output 6 Example 6 1 Description of problem 6 2 Compartmentalization of the KBS 3 repository 6 3 Input file used for problem 6 4 Results References Appendix 1 Notation Appendix 2 HUI output 1 Overview of COMP23 COMP23 is a fast multiple path model that calculates nuclide transport in the near field of a repository as occurring through a network of resistances and capacitances coupled together like an electrical circuit network The model which is a coarsely discretized integrated finite difference model was designed to be fast and compact by making use of analytical solutions in sensitive zones The code allows the user to simultaneously consider many pathways for nuclides transport by advection and diffusion to the flowing water in fractures surrounding the barrier system The nuclide dissolution may be calculated using either a solubility limited approach or a congruent dissolution approach The conceptual model used in COMP23 can be represented by three bodies as shown in Figure 1 1 The bodies are the source the barrier system and the sinks The source is treated as a well mixed compartment The barrier system is the physical medium through which the nuclides migrate to reach the sinks located in the surrounding system or outside of the region considered as the barrier system The sinks considered as recipients where the water flows are f

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