skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Increasing Compositions In NBSR Neutronics Model – Part 2

Abstract

Calculations in support of the NIST research reactor (NBSR) use a Monte Carlo neutronics model in conjunction with a burnup capability. The representation of compositions within the fuel plates for the current reactor has assumed that with burnup there is a single uniform composition within all plates in each half fuel element. That model has been validated using operational data and leads to acceptable conservative results for safety analyses. However, for the conversion of the reactor to the use of low-enriched uranium (LEU) fuel, there has been an effort to change the modeling for several reasons. The use of large composition zones is inconsistent with the rigor in the rest of the neutronics model. There is also the possibility that the conservatism in maximum fission density may lead to excessive requirements for LEU fuel qualification. A new composition model has been proposed that would break each half fuel element into 15 composition zones improving the rigor while still allowing reasonable running time. This approach was tested, and results show that although it is an improvement over the previous model that had one composition zone (and an interim model with six zones) in each half fuel element, it falls short ofmore » being the ideal composition model. This report documents the objectives for the new model and the analysis of the resulting calculations.« less

Authors:
 [1];  [1];  [1]
  1. Brookhaven National Lab. (BNL), Upton, NY (United States). Nuclear Science & Technology Dept.
Publication Date:
Research Org.:
Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Org.:
National Institute of Standards and Technology (NIST); USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1526695
Report Number(s):
BNL-211784-2019-INRE
DOE Contract Number:  
SC0012704
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; NIST; neutronics; low-enriched uranium

Citation Formats

Kohut, Peter, Varuttamaseni, Athi, and Diamond, David. Increasing Compositions In NBSR Neutronics Model – Part 2. United States: N. p., 2019. Web. doi:10.2172/1526695.
Kohut, Peter, Varuttamaseni, Athi, & Diamond, David. Increasing Compositions In NBSR Neutronics Model – Part 2. United States. https://doi.org/10.2172/1526695
Kohut, Peter, Varuttamaseni, Athi, and Diamond, David. 2019. "Increasing Compositions In NBSR Neutronics Model – Part 2". United States. https://doi.org/10.2172/1526695. https://www.osti.gov/servlets/purl/1526695.
@article{osti_1526695,
title = {Increasing Compositions In NBSR Neutronics Model – Part 2},
author = {Kohut, Peter and Varuttamaseni, Athi and Diamond, David},
abstractNote = {Calculations in support of the NIST research reactor (NBSR) use a Monte Carlo neutronics model in conjunction with a burnup capability. The representation of compositions within the fuel plates for the current reactor has assumed that with burnup there is a single uniform composition within all plates in each half fuel element. That model has been validated using operational data and leads to acceptable conservative results for safety analyses. However, for the conversion of the reactor to the use of low-enriched uranium (LEU) fuel, there has been an effort to change the modeling for several reasons. The use of large composition zones is inconsistent with the rigor in the rest of the neutronics model. There is also the possibility that the conservatism in maximum fission density may lead to excessive requirements for LEU fuel qualification. A new composition model has been proposed that would break each half fuel element into 15 composition zones improving the rigor while still allowing reasonable running time. This approach was tested, and results show that although it is an improvement over the previous model that had one composition zone (and an interim model with six zones) in each half fuel element, it falls short of being the ideal composition model. This report documents the objectives for the new model and the analysis of the resulting calculations.},
doi = {10.2172/1526695},
url = {https://www.osti.gov/biblio/1526695}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Jun 17 00:00:00 EDT 2019},
month = {Mon Jun 17 00:00:00 EDT 2019}
}