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Title: A Reload and Startup Plan for and #8233;Conversion of the NIST Research Reactor

Abstract

The National Institute of Standards and Technology operates a 20 MW research reactor for neutron-based research. The heavy-water moderated and cooled reactor is fueled with high-enriched uranium (HEU) but a program to convert the reactor to low-enriched uranium (LEU) fuel is underway. Among other requirements, a reload and startup test plan must be submitted to the U.S. Nuclear Regulatory Commission (NRC) for their approval. The NRC provides guidance for what should be in the plan to ensure that the licensee has sufficient information to operate the reactor safely. Hence, a plan has been generated consisting of two parts.The reload portion of the plan specifies the fuel management whereby initially only two LEU fuel elements are in the core for eight fuel cycles. This is repeated until a point when the optimum approach is to place four fresh LEU elements into the reactor each cycle. This final transition is repeated and after eight cycles the reactor is completely fueled with LEU. By only adding two LEU fuel elements initially, the plan allows for the consumption of HEU fuel elements that are expected to be in storage at the time of conversion and provides additional qualification of production LEU fuel under actualmore » operating conditions. Because the reload is to take place over many fuel cycles, startup tests will be done at different stages of the conversion. The tests, to be compared with calculations to show that the reactor will operate as planned, are the measurement of critical shim arm position and shim arm and regulating rod reactivity worths. An acceptance criterion for each test is specified based on technical specifications that relate to safe operation. Additional tests are being considered that have less safety significance but may be of interest to bolster the validation of analysis tools.« less

Authors:
 [1];  [1]
  1. Brookhaven National Lab. (BNL), Upton, NY (United States)
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1399697
Report Number(s):
BNL-112005-2016-IR-R1
R&D Project: 22642; TRN: US1800084
DOE Contract Number:
SC0012704
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; HIGHLY ENRICHED URANIUM; RESEARCH REACTORS; FUEL ELEMENTS; NEUTRONS; FUELS; NIST; research reactor; fuel management; shim arm

Citation Formats

Diamond, D. J., and Varuttamaseni, A. A Reload and Startup Plan for and #8233;Conversion of the NIST Research Reactor. United States: N. p., 2017. Web. doi:10.2172/1399697.
Diamond, D. J., & Varuttamaseni, A. A Reload and Startup Plan for and #8233;Conversion of the NIST Research Reactor. United States. doi:10.2172/1399697.
Diamond, D. J., and Varuttamaseni, A. Sat . "A Reload and Startup Plan for and #8233;Conversion of the NIST Research Reactor". United States. doi:10.2172/1399697. https://www.osti.gov/servlets/purl/1399697.
@article{osti_1399697,
title = {A Reload and Startup Plan for and #8233;Conversion of the NIST Research Reactor},
author = {Diamond, D. J. and Varuttamaseni, A.},
abstractNote = {The National Institute of Standards and Technology operates a 20 MW research reactor for neutron-based research. The heavy-water moderated and cooled reactor is fueled with high-enriched uranium (HEU) but a program to convert the reactor to low-enriched uranium (LEU) fuel is underway. Among other requirements, a reload and startup test plan must be submitted to the U.S. Nuclear Regulatory Commission (NRC) for their approval. The NRC provides guidance for what should be in the plan to ensure that the licensee has sufficient information to operate the reactor safely. Hence, a plan has been generated consisting of two parts.The reload portion of the plan specifies the fuel management whereby initially only two LEU fuel elements are in the core for eight fuel cycles. This is repeated until a point when the optimum approach is to place four fresh LEU elements into the reactor each cycle. This final transition is repeated and after eight cycles the reactor is completely fueled with LEU. By only adding two LEU fuel elements initially, the plan allows for the consumption of HEU fuel elements that are expected to be in storage at the time of conversion and provides additional qualification of production LEU fuel under actual operating conditions. Because the reload is to take place over many fuel cycles, startup tests will be done at different stages of the conversion. The tests, to be compared with calculations to show that the reactor will operate as planned, are the measurement of critical shim arm position and shim arm and regulating rod reactivity worths. An acceptance criterion for each test is specified based on technical specifications that relate to safe operation. Additional tests are being considered that have less safety significance but may be of interest to bolster the validation of analysis tools.},
doi = {10.2172/1399697},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sat Sep 30 00:00:00 EDT 2017},
month = {Sat Sep 30 00:00:00 EDT 2017}
}

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