I have a -404 pcm difference between the k_effective values for an OpenMC model and a Serpent Model for a HTTR pincell. I am importing the same coordinates for the TRISO fuel locations for both models so I know the packing fraction and fuel particle location is exactly the same. What could the discrepancy between these models be due to? The Serpent model more closely agrees with MONK and WIMS values for the same problem.
I have attached the input files below.
PinCell5HPC.py (10.0 KB)
Serpent Input:
% --- HTTR single fuel pin --------------------------------------
set title "httr_single_fuel_pin_2d"
% -----------------------------------------------------------------------------
% Geometry
% -----------------------------------------------------------------------------
particle 11
fuel34 0.03
buffer 0.036
pyc 0.039
sic 0.0415
pyc 0.046
matrix_overcoat
pbed 12 13 "/home/annamaria/Documents/Serpent/HTTR_Emma/part_pin_1cm.inp"
%the values on the right hand side are coordinates
surf 11 cylz 0.0 0.0 0.5 0.0 1.0 %cylinder of radius r=0.5
surf 12 cylz 0.0 0.0 1.3 0.0 1.0
surf 13 cylz 0.0 0.0 1.325 0.0 1.0
surf 14 cylz 0.0 0.0 1.7 0.0 1.0
surf 15 cylz 0.0 0.0 2.05 0.0 1.0
cell 11 5 fill coolant_uni -11
cell 12 5 fill fuel_uni 11 -12
cell 13 5 fill coolant_uni 12 -13
cell 14 5 fill sleeve_uni 13 -14
cell 15 5 fill coolant_uni 14 -15
cell 16 5 fill block_uni 15
surf 17 inf
cell 31 coolant_uni coolant -17
cell 32 fuel_uni fill 12 -17
cell 33 coolant_uni coolant -17
cell 34 sleeve_uni pin_sleeve -17
cell 35 coolant_uni coolant -17
cell 36 block_uni ig110 -17
surf 16 hexxprism 0.0 0.0 2.575 0.0 1.0
cell 17 0 fill 5 -16
cell 18 0 outside 16
% Define cell of infinite graphite
cell 19 13 matrix_overcoat 11 -12
% -----------------------------------------------------------------------------
% Material data:
% -----------------------------------------------------------------------------
% -- Fuel: UO2 6.7% enriched
mat fuel34 sum tmp 300
92234.70c 1.2026E-05
92235.70c 1.5743E-03
92238.70c 2.1634E-02
8016.70c 4.6386E-02
8017.70c 1.7633E-05
5010.70c 1.7299E-07
% --- 1st coating layer
mat buffer sum moder grph 6000 tmp 300
6000.70c 5.5153E-02
5010.70c 1.8290E-08
% --- 2nd/4th coating layer
mat pyc sum moder grph 6000 tmp 300
6000.70c 9.2758E-02
5010.70c 3.0761E-08
% --- 3rd coating layer
mat sic sum moder grph 6000 tmp 300
14028.70c 4.4327E-02
14029.70c 2.2508E-03
14030.70c 1.4837E-03
6000.70c 4.8061E-02
5010.70c 5.3208E-08
% --- Graphite overcoat
mat matrix_overcoat sum moder grph 6000 tmp 300
6000.70c 8.5237E-02
5010.70c 2.6187796E-08
% -- Coolant
mat coolant sum tmp 300
2003.70c 3.3724E-11
2004.70c 2.4616E-05
% -- Pin sleeve material: IG110 graphite
mat pin_sleeve sum moder grph 6000 tmp 300
6000.70c 8.8747E-02
5010.70c 7.2596E-09
% -- Fuel block material: IG110 graphite
mat ig110 sum moder grph 6000 tmp 300
6000.70c 8.7804E-02
5010.70c 1.1453E-08
therm grph 300 grph.10t grph.11t
% -----------------------------------------------------------------------------
% Calculation parameters
% -----------------------------------------------------------------------------
% --- Cross section library file path:
%set acelib "/home/es2517/serpent/xsdata/jeff31/sss_jeff31u.xsdata"
%set acelib "/home/emmajstewart/serpent/serpent2.2.0/xsdata/endfb7u/endfb7/sss_endfb7u.xsdata"
%set acelib "/rds/general/user/es2517/home/serpent/serpent2.2.0/xsdata/endfb7u/endfb7/sss_endfb7u.xsdata"
set acelib "/home/annamaria/Documents/DataLibraries/ENDFB7-0/aceFiles/sss_endfb70.xsdata"
ene 6grp 1 1.100000E-10 140.0000E-09 625.0000E-09 4.0000E-06 9.1188E-03 820.8500E-03 1.96403E+01
set gcu 0
%coolant_uni fuel_uni sleeve_uni block_uni
set nfg 2 0.625e-6
%set nfg 6grp
set ures 1
set mcvol 100
set micro wms172
set cfe 10.0
set pop 1000 500 20
%set genrate 1.0
set power 1.0E1
set bc 2
src 1 n sm fuel34 sr 92235.72c 18
% --- Geometry and mesh plots:
plot 3 500 500
plot 2 500 100
% -----------------------------------------------------------------------------
% Detectors:
% -----------------------------------------------------------------------------
% --- Detector materials:
mat m92234fuel sum 92234.03c 6.1026E-06
mat m92235fuel sum 92235.03c 7.9888E-04
mat m92238fuel sum 92238.03c 2.2405E-02
mat m8016fuel sum 8016.03c 4.6404E-02
mat m5010fuel sum 5010.03c 1.7299E-07
%mat m6000coat1 sum 6000.03c 5.5153E-02
%mat m5010coat1 sum 5010.03c 1.8290E-08
%mat m6000coat2 sum 6000.03c 9.2758E-02
%mat m5010coat2 sum 5010.03c 3.0761E-08
%mat m14028coat3 sum 14028.03c 4.8061E-02
%mat m6000coat3 sum 6000.03c 4.8061E-02
%mat m5010coat3 sum 5010.03c 5.3208E-08
%mat m6000coat4 sum 6000.03c 9.2758E-02
%mat m5010coat4 sum 5010.03c 3.0761E-08
%mat m6000matrix sum 6000.03c 8.5237E-02
%mat m5010matrix sum 5010.03c 1.5452E-08
%mat m6000sleeve sum 6000.03c 8.8747E-02
%mat m5010sleeve sum 5010.03c 7.2596E-09
%mat m6000block sum 6000.03c 8.7804E-02
%mat m5010block sum 5010.03c 1.1453E-08
% --- Energy grid structures:
ene 1 1 0.0 0.625e-6 1.96403E+01
%ene 1 2 1 1E-11 20.0
%ene 1 1 0.625e-6
%ene 1 4 wms69
%ene 2 4 wms172
% --- Spectral indices (in fuel):
%det fuel_fiss n de 1 du fuel_uni dr -6 void
%det fuel_cap n de 1 du fuel_uni dr -2 void
%det coolant_cap n de 1 du coolant_uni dr -2 void
%det sleeve_cap n de 1 du sleeve_uni dr -2 void
%det block_cap n de 1 du block_uni dr -2 void
det fuel_fiss n de 1 dm fuel34 dr -6 void
det fuel_cap n de 1 dm fuel34 dr -2 void
det buffer_cap n de 1 dm buffer dr -2 void
det pyc_cap n de 1 dm pyc dr -2 void
det sic_cap n de 1 dm sic dr -2 void
det matrix_overcoat_cap n de 1 dm matrix_overcoat dr -2 void
det coolant_cap n de 1 dm coolant dr -2 void
det sleeve_cap n de 1 dm pin_sleeve dr -2 void
det block_cap n de 1 dm ig110 dr -2 void