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New PARCS Cross Section Model

New PARCS Cross Section Model. School of Nuclear Engineering Purdue University September 2002. Original XS Model in PARCS (1997).  r : XS at unroded reference state  cr : Control rod XS; : roded fraction; Tf: Fuel temperature; Tm: moderator temperature

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New PARCS Cross Section Model

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  1. New PARCSCross Section Model School of Nuclear Engineering Purdue University September 2002

  2. Original XS Model in PARCS (1997) r: XS at unroded reference state cr: Control rod XS; : roded fraction; Tf: Fuel temperature; Tm: moderator temperature Sb: Soluble Boron Density; Dm: moderator Density • At most seven cross section data points can be referenced • 1 reference state • 2 moderator branches • 1 branches for each of other variables: Cr, Tf,Tm,Sb

  3. Example of Original Model comp_num 3 !corner reflector !------------------------------------------------------------------------------ base_macro 2.956090e-01 1.187820e-03 0.000000e+00 0.000000e+00 2.008080e-02 2.459310e+00 2.526180e-01 0.000000e+00 0.000000e+00 dxs_dppm 0.000000e+00 0.000000e+00 0.000000e+00 0.000000e+00 0.000000e+00 7.761840e-04 8.446950e-05 0.000000e+00 0.000000e+00 comp_num 4 !fuel 1 !------------------------------------------------------------------------------ base_macro 2.221170e-01 8.717740e-03 4.982770e-03 6.111896e-14 1.824980e-02 8.031400e-01 6.525500e-02 8.390260e-02 1.101520e-12 dxs_dppm 3.478090e-08 1.285050e-07 -1.120990e-09 -1.761878e-20 -1.085900e-07 -9.765100e-06 7.088070e-06 -2.430450e-06 -3.190845e-17 dxs_dtm -2.033100e-06 2.121910e-07 1.247090e-07 1.430354e-18 8.096760e-07 -1.086740e-04 -3.155970e-05 -4.164390e-05 -5.467221e-16 dxs_ddm 1.356650e-01 1.551850e-03 9.206940e-04 1.023919e-14 2.931950e-02 9.926280e-01 2.526620e-02 2.477460e-02 3.252554e-13 dxs_dtf -3.091970e-05 3.497090e-05 6.401340e-07 7.154124e-18 -2.755360e-05 -1.372920e-04 -3.718060e-05 -5.630370e-05 -7.391879e-16 cdf 1.0069 0.9307 1.0034 0.9646 1.1040 1.4493 1.0096 1.1580 delcr_comp 1 1 -5 7 -11 !compostions that this set applies !------------------------------------------------------------------------------ delcr_base 3.732200e-03 2.477700e-03 -1.027860e-04 -1.214480e-15 -3.192530e-03 -2.199260e-02 2.558750e-02 -2.823190e-03 -3.702378e-14

  4. Applications of Original Model:Static and Spatial Kinetics Problems • Eigenvalue Benchmark Problems IAEA3D, L336, … • OECD NEACRP Rod Eject Benchmarks • Coupled Code Problems • OECD TMI MSLB • OECD Peach Bottom Turbine Trip • Problems with Oconnee Control Rod Drive Cracking (CASMO Tables format)

  5. Absorb netron B C A β β n,γ Depletion Capability Added (2000) • Nuclide depletion equation (Bateman) • Neutron Transport Equation (Boltzmann)

  6. Depletion XS Model • Burnup and burnup “history” dependence • More than seven data points can be referenced

  7. Lattice Code (HELIOS/NEWT) Neutron Flux Solver (PARCS) T/H code (RELAP /TRAC) Σ Φ Cross Section Library (PMAX) Depletion Code (DEPLETOR) U.S. NRC Coupled Code Analysis

  8. Application of Depletion Model • DOE NERI Projects: • SBWR design • HCBWR Design • Iteration required between PARCS and Depletor … computationally inefficient • Not able to handle generalized cross section tables

  9. Standard “Two Step” Procedure for Generating LWR Cross Sections Lattice Calculations Neutronics Calculation XS of each region Output files XS library generator XS interpreter Cross section library

  10. Lattice Codes: SCALE HELIOS …. First Step of in NRC Neutronic Code System Input files for depletion at various base states and branches at some burnup points Output files GenpXS PMAXS

  11. Fuel temp. Tf1, Tf2… Fuel temp. Tf1, Tf2… mod temp. Tm1, Tm2… mod temp. Tm1, Tm2… Mod. den. Dm1, Dm2… Mod. den. Dm1, Dm2… Soluble B. ppm1, … Soluble B. ppm1, … Control rod … Control rod … 0GWD/T 1GWD/T 2GWD/T 3GWD/T 4GWD/T 5GWD/T Base State and Branches Performed with Lattice Physics Code Branches Base state

  12. Cross Section Library in NRC Neutronic Code System Dependent Variables: PMAXS Independent Variables:

  13. PARCS XS Model: Interpret XS base on instantaneous variables Neutronic Calculation XS of each region at given history value Power distribution PMAXS Depletor Second Step of in NRC Neutronic Code System T/H Code: RELAP TRAC ….

  14. Format of PMAXS in DepletionCross Section Model

  15. Motivation for New PARCSCross Section Model • Old Model has limited accuracy and applicability for practical cross section data sets which are multi-dimensional tables (e.g. Ringhalls) • New Model performs multi-dimensional interpolation to construct partial derivates • This increases the range of applicability and yet preserves applicability of old PARCS XSEC files

  16. Advantages of New Model • If there are more than 2 points in a line, then New Model is actually quadratic interpolation. • Can obtain good accuracy even with smaller number of branches

  17. Ringhalls Stability Benchmark • Ringhals XS in TABLES format • Multiple 3-Dimensional tables • Multiple Control rod compositions

  18. Application of New Model to Ringhalls The partials will be obtained by piece wise linear interpolation If the XS at blue point are also available, New Model gives same XS as Model 2 better than Model 1 Other wise New Model gives same XS as Model 1 better than Model 2

  19. Important to Choose Best Sequence to Evaluate Variables • Suggested sequence: • Dm DB Tf Tm

  20. Dm 1.0 0.9 Original Data point 0.8 0.7 0.6 Selected point 0.5 0.4 415 515 615 Tm 0.3 Example: Moderator temperature and density

  21. Effect of Different Sequence: Using Temperature then Density

  22. Effect of Different Sequence: Using Density then Temperature 90% error reduced

  23. Tree structure of states at which XS/partials are calculated or stored

  24. New PMAXS/XSEC Format

  25. New Model Successfully Applied to Previous TRACM/PARCS Benchmarks • OECD MSLB & PBTT Benchmarks: NEMTAB format * NEM-Cross Section Table Input * * T Fuel Rho Mod. Boron ppm. T Mod. 5 6 0 0 * ******* X-Section set # 1 1 * * Group No. 1 * *************** Diffusion Coefficient Table * .5000000E+03 .7602200E+03 .8672700E+03 .9218800E+03 .1500000E+04 .6413994E+03 .7114275E+03 .7694675E+03 .7724436E+03 .7813064E+03 .8100986E+03 .1467049E+01 .1469641E+01 .1470751E+01 .1471347E+01 .1477128E+01 .1401975E+01 .1404351E+01 .1405441E+01 .1405939E+01 .1411216E+01 .1353822E+01 .1356107E+01 .1357086E+01 .1357581E+01 .1362596E+01 .1352366E+01 .1354638E+01 .1355630E+01 .1356125E+01 .1361236E+01 .1345620E+01 .1347891E+01 .1348843E+01 .1349338E+01 .1354390E+01 .1322122E+01 .1324319E+01 .1325308E+01 .1325803E+01 .1330615E+01 * *************** Total Absorption X-Section Table

  26. Application of New XSEC Model to OECD Ringhalls Instability Benchmark

  27. Continuing Cross Section Work • Future work • New interface between PARCS and Depletor (12/31/02) • GENPXS to convert other lattice code cross sections to PMAXS (e.g. CASMO, ORNL SCALE/NEWT) (FY03)

  28. Modifications of Cross Section Model for ESBWR Task 3: Modifications in Spatial Kinetics Feedback Task 3.1: Lattice Physics (Purdue) • Improve cross section model in PARCS for ATRIUM-10 and GE-12/14 • The cross section model in PARCS will be improved to provide feedback based on both bypass liquid temperature and channel internal fluid field. • Concerning fuel temperature feedback, the cross section model will be updated to handle both full length and part length fuel rods. • Perform lattice physics calculations • The work on this subtask will be completed by November 30, 2002.

  29. Advanced BWR Fuel Design GE-12 Fuel Configuration

  30. Advanced BWR Fuel Design ATRIUM-10 Framatome SVEA-96 (ABB) Westinghouse 1/3 part length full length 2/3 part length

  31. Modifications for ESBWR (cont.) Task 3.2: Monte Carlo Studies (Purdue) • A new energy partitioning algorithm will be developed for PARCS taking into account bypass water regions, water rod regions, intra-channel fluid regions, and fuel rods. • A Monte Carlo calculation will be performed to validate this new algorithm. All results will be documented. • The Monte Carlo study will be completed by December 31, 2002.

  32. Modifications for ESBWR (cont.) Task 3.3/3.4: Modify Mapping / Test Spatial Kinetics Feedback (ISL) • Modify Mapping to Accommodate new assembly cross section model • To test the spatial kinetics feedback with a Browns Ferry full core model will be built and a sample steady-state and control rod move transient calculation will be performed. • The spatial kinetics model feedback testing will be completed by February 28, 2003.

  33. ESBWR Core Configuration

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