The pseudo-resonant-nuclide subgroup method based global–local self-shielding calculation scheme

Figures & data

Figure 1. Equivalence between a fuel pin cell in lattice and a 1D cylindrical fuel pin cell.

Table 1. Materials compositions of the pin cell problems

	Number densities (atoms/barn-cm)
Nuclide	UO2	Moderator	Cladding
^238U	2.225E-02	–	–
^235U	8.650E-04	–	–
^1H	–	6.700E-02	–
^16O	4.622E-02	3.350E-02	–
Zr-nat	–	–	4.300E-02

Table 2. Upper energy boundary and number of subgroups for each energy group

Energy	Upper	Number of subgroups
group	boundary (eV)	Pseudo nuclide	^238U	^235U
15	9.1180E+03	5	5	0
16	5.5300E+03	6	6	0
17	3.5191E+03	6	6	0
18	2.2394E+03	6	6	3
19	1.4251E+03	6	6	3
20	9.0690E+02	6	6	3
21	3.6726E+02	6	6	4
22	1.4873E+02	5	5	5
23	7.5501E+01	6	6	5
24	4.8052E+01	6	6	5
25	2.7700E+01	6	6	5
26	1.5968E+01	4	2	5
27^a	9.8770E+00	6	6	5

^aThe lower boundary is 4.0 eV.

Figure 2. Comparison of the pin-averaged ²³⁵U absorption cross sections.

Figure 3. Comparison of pin-averaged ²³⁸U absorption cross sections.

Figure 4. Comparison of ²³⁸U absorption cross sections in 25th group.

Table 3. Comparisons of the k_inf of the UO₂ pin cell problem

	Reference	BIM	RIFM	PRNSM	PRNSM SPH
kinf	1.43973 ± 0.00004	1.43491	1.43649	1.43730	1.43932
Error (pcm)	–	−482	−324	−243	−41

Figure 5. Configurations of the 3 × 3 assemblies problem.

Figure 6. Pin power results of the 3 × 3 assemblies problem.

Figure 7. Pin power error (%) of the 3 × 3 assemblies problem.

Table 4. Error comparisons of the 3 × 3 assemblies problem

	Reference	BIM	RIFM	PRNSM	PRNSM SPH
kinf	1.01024 ± 0.00001	1.00724	1.00874	1.00896	1.01039
Error (pcm)	–	−300	−150	−128	15
Max pin power error (%)	–	0.46	0.49	0.51	0.47
Pin power RMS (%)	–	0.10	0.11	0.11	0.11

Table 5. Computation time analysis of the 3 × 3 assemblies problem

	BIM	RIFM	PRNSM	PRNSM SPH
Self-shielding time (s)	90.65	297.12	76.65	83.31
# 1 G 2D MOC	1	1	1	1
# 1 G 1D fixed source	62,094	62,094	36,972	55,458
# 0D slowing down	0	948	84	84
Transport time (s)	406.40	406.40	406.40	406.40