Dancoff-based Wigner-Seitz approximation for the subgroup resonance self-shielding in the VERA neutronic simulator MPACT

Conference · Fri Jul 01 04:00:00 EDT 2022

DOI:https://doi.org/10.13182/PHYSOR22-37389· OSTI ID:23203941

Kim, K. S.; Graham, A. M.; Jessee, M. A. ^[1]

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1. One Bethel Valley Road, P.O.Box 2008, MS-6172, Oak Ridge, TN 37831 (United States)

The MPACT neutronics module of the Virtual Environment for Reactor Analysis (VERA) has used the subgroup method for resonance self-shielding calculation, for which two-dimensional (2D) fixed-source transport calculations are performed using the method of characteristics for resonance energy groups. When considering thermal feedbacks, the subgroup calculation must be performed at each outer iteration. Therefore, the computing time for cross section processing is a significant burden for computational efficiency. The Dancoff-based Wigner-Seitz approximation (DWA) capability has been implemented into MPACT in conjunction with the subgroup method, which has been used in SCALE/XSProc since SCALE version 6.0 and has recently been called an equivalent Dancoff-factor cell (EDC) method. The issue of relatively large reactivity bias in DWA for the gadolinia rods was resolved by introducing multiple Dancoff factors. Benchmark results for the VERA pressurized and boiling water reactor benchmark suites show that the DWA capability would significantly enhance computational efficiency with comparable accuracy. (authors)

• Research Organization: American Nuclear Society - ANS, La Grange Park, IL 60526 (United States)
• OSTI ID: 23203941
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
BWR TYPE REACTORS
COMPUTERIZED SIMULATION
DANCOFF CORRECTION
M CODES
NEUTRON TRANSPORT THEORY
PWR TYPE REACTORS
SELF-SHIELDING