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Title: Increasing Compositions in NBSR Neutronics Model

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 assumes that with burnup there is a single uniform composition within all plates in each half fuel element. The current model has been validated using operational data and leads to acceptable conservative results for safety analyses. However, 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 fuel qualification. A new composition model has been proposed that would break each half fuel element into six composition zones improving the rigor without increasing running time significantly. This approach was tested, and results show that although it is an improvement, 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.

Authors:
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA), Office of Defense Nuclear Nonproliferation (NA-20)
OSTI Identifier:
1497373
Report Number(s):
BNL-210826-2018-INRE
DOE Contract Number:  
SC0012704
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; NIST; neutronics model

Citation Formats

Kohut, Peter. Increasing Compositions in NBSR Neutronics Model. United States: N. p., 2019. Web. doi:10.2172/1497373.
Kohut, Peter. Increasing Compositions in NBSR Neutronics Model. United States. doi:10.2172/1497373.
Kohut, Peter. Fri . "Increasing Compositions in NBSR Neutronics Model". United States. doi:10.2172/1497373. https://www.osti.gov/servlets/purl/1497373.
@article{osti_1497373,
title = {Increasing Compositions in NBSR Neutronics Model},
author = {Kohut, Peter},
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 assumes that with burnup there is a single uniform composition within all plates in each half fuel element. The current model has been validated using operational data and leads to acceptable conservative results for safety analyses. However, 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 fuel qualification. A new composition model has been proposed that would break each half fuel element into six composition zones improving the rigor without increasing running time significantly. This approach was tested, and results show that although it is an improvement, 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 = {10.2172/1497373},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2019},
month = {1}
}