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Varuttamaseni, A.

Publications and source records attributed to Varuttamaseni, A..

6 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Irradiation Experiment Design Parameters for NBSR Fuel Conversion

It has been proposed to convert the National Institute of Standards and Technology research reactor, known as the NBSR, from highly-enriched uranium (HEU) fuel to low-enriched uranium (LEU) fuel. The motivation to convert the NBSR to LEU fuel is to reduce the risk of proliferation of special nuclear material. This report is a compilation of relevant information from recent studies related to the proposed conversion using a metal alloy of LEU with 10 w/o molybdenum. The objective is to inform the design of irradiation experiments that are being planned. This report provides relevant nominal dimensions of the proposed LEU fuel element, and average and maximum power densities and fission densities. The latter profiles are given for different plates to show the variation throughout the core. A summary of the methodology to obtain these results is presented. Fuel element tolerance assumptions and hot channel factors used in the safety analysis are also given.

42 ENGINEERING↗
DOE OSTI2019

Irradiation Experiment Design Parameters for NBSR Fuel Conversion

It has been proposed to convert the National Institute of Standards and Technology research reactor, known as the NBSR, from high-enriched uranium (HEU) fuel to low-enriched uranium (LEU) fuel. The motivation to convert the NBSR to LEU fuel is to reduce the risk of proliferation of special nuclear material. This report is a compilation of relevant information from recent studies related to the proposed conversion using a metal alloy of LEU with 10 w/o molybdenum. The objective is to inform the design of irradiation experiments that are being planned. This report provides relevant dimensions of the fuel elements, and average and maximum fission rate densities and fission densities. The latter profiles are given for different plates to show the variation throughout the core. A summary of the methodology to obtain these results is presented. Fuel element tolerance assumptions and hot channel factors used in the safety analysis are also given.

42 ENGINEERING↗
DOE OSTI2017

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

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.

42 ENGINEERING↗