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Verification of the Re-Released ENDF/B VIII.0 Based Thermal Scattering Libraries

Conference · · Transactions of the American Nuclear Society
DOI:https://doi.org/10.13182/T123-32994· OSTI ID:1908506
 [1];  [1];  [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

An accurate description of the scattering of thermal neutrons (E < 4 eV) is crucial for the design and safety of nuclear reactors, criticality safety, and shielding. The thermal scattering libraries (TSL) of evaluated nuclear data describe these low energy effects. ENDF/B-VIII.0 provides a major update to the ENDF thermal scattering library. Indeed, it is nearly a completely new sub-library with 34 materials (with only 10 materials carried over from ENDF/B-VII.1) and many different temperatures for a total of 253 evaluated data files. The first ACE formatted library released in 2018 by Los Alamos of this ENDF/B VIII.0 data was flawed, especially for TSL materials with incoherent thermal elastic scattering. Therefore, the thermal scattering evaluation files of the ENDF/B-VIII.0 library have been recently re-processed at Los Alamos with NJOY2016. This new library has been subjected to extensive verification testing: (1) continuity of scattering cross sections from the S(α,β) to the free gas values, (2) consistency of the processed data and MCNP4 test problem results with respect to material temperature, (3) comparison of ACER produced thermal cross sections with multi-group thermal cross sections from GROUPR.

Research Organization:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Sponsoring Organization:
USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP)
DOE Contract Number:
89233218CNA000001
OSTI ID:
1908506
Report Number(s):
LA-UR-20-24679
Journal Information:
Transactions of the American Nuclear Society, Journal Name: Transactions of the American Nuclear Society Journal Issue: 1 Vol. 123; ISSN 0003-018X
Publisher:
American Nuclear Society
Country of Publication:
United States
Language:
English