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Title: Design of a californium source-driven measurement system for accountability of material recovered from the Molten Salt Reactor Experiment charcoal bed

Abstract

The Molten Salt Reactor Experiment Facility (MSRE) operated from 1965 to 1969. The fuel was a molten salt that flowed through the reactor core which consisted of uranium tetrafluoride with molten lithium and beryllium salt used as the coolant. In 1968 the fuel was switched from {sup 235}U to {sup 233}U. The Molten Salt Reactor Experiment was canceled in 1969 at which time approximately 4800 kg of salt was transferred to the fuel drain tanks. There was about 36.3 kg of uranium, 675 grams of plutonium and various fission products present in the fuel salt. The salt was allowed to solidify in the fuel drain tanks. The salt was heated on a yearly basis to recombine the fluorine gas with the uranium salt mixture. In March 1994, a gas sample was taken from the off gas system that indicated {sup 233}U had migrated from the fuel drain tank system to the off gas system. It was found that approximately 2.6 kg of uranium had migrated to the Auxiliary Charcoal Bed (ACB). The ACB is located in the concrete-lined charcoal bed cell which is below ground level located outside the MSRE building. Therefore, there was a concern for the potential ofmore » a nuclear criticality accident, although water would have to leak into the chamber for a criticality accident to occur. Unstable carbon/fluorine compounds were also formed when the fluorine reacted with the charcoal in the charcoal bed. The purpose of the proposed measurement system was to perform an accountability measurement to determine the fissile mass of {sup 233}U in the primary vessel. The contents of the primary containment assembly will then be transferred to three smaller containers for long term storage. Calculations were performed using MCNP-DSP to determine the configuration of the measurement system. The information obtained from the time signatures can then be compared to the measurement data to determine the amount of {sup 233}U present in the primary containment assembly.« less

Authors:
 [1]; ; ; ;  [2]
  1. Univ. of Tennessee, Knoxville, TN (United States). Dept. of Nuclear Engineering
  2. Oak Ridge National Lab., TN (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
672051
Report Number(s):
ORNL/CP-98159; CONF-980606-
ON: DE98005583; TRN: 99:000806
DOE Contract Number:  
AC05-96OR22464
Resource Type:
Conference
Resource Relation:
Conference: Annual meeting of the American Nuclear Society, Nashville, TN (United States), 7-12 Jun 1998; Other Information: PBD: May 1998
Country of Publication:
United States
Language:
English
Subject:
22 NUCLEAR REACTOR TECHNOLOGY; 05 NUCLEAR FUELS; REACTOR DECOMMISSIONING; OFF-GAS SYSTEMS; MSRE REACTOR; ADSORBENTS; URANIUM 233; NUCLEAR MATERIALS MANAGEMENT; CONTAINMENT SYSTEMS; MATERIALS RECOVERY; CALIFORNIUM 252; NEUTRON SOURCES; HE-3 COUNTERS; DESIGN

Citation Formats

Bentzinger, D L, Perez, R B, Mattingly, J K, Valentine, T E, and Mihalczo, J T. Design of a californium source-driven measurement system for accountability of material recovered from the Molten Salt Reactor Experiment charcoal bed. United States: N. p., 1998. Web.
Bentzinger, D L, Perez, R B, Mattingly, J K, Valentine, T E, & Mihalczo, J T. Design of a californium source-driven measurement system for accountability of material recovered from the Molten Salt Reactor Experiment charcoal bed. United States.
Bentzinger, D L, Perez, R B, Mattingly, J K, Valentine, T E, and Mihalczo, J T. 1998. "Design of a californium source-driven measurement system for accountability of material recovered from the Molten Salt Reactor Experiment charcoal bed". United States. https://www.osti.gov/servlets/purl/672051.
@article{osti_672051,
title = {Design of a californium source-driven measurement system for accountability of material recovered from the Molten Salt Reactor Experiment charcoal bed},
author = {Bentzinger, D L and Perez, R B and Mattingly, J K and Valentine, T E and Mihalczo, J T},
abstractNote = {The Molten Salt Reactor Experiment Facility (MSRE) operated from 1965 to 1969. The fuel was a molten salt that flowed through the reactor core which consisted of uranium tetrafluoride with molten lithium and beryllium salt used as the coolant. In 1968 the fuel was switched from {sup 235}U to {sup 233}U. The Molten Salt Reactor Experiment was canceled in 1969 at which time approximately 4800 kg of salt was transferred to the fuel drain tanks. There was about 36.3 kg of uranium, 675 grams of plutonium and various fission products present in the fuel salt. The salt was allowed to solidify in the fuel drain tanks. The salt was heated on a yearly basis to recombine the fluorine gas with the uranium salt mixture. In March 1994, a gas sample was taken from the off gas system that indicated {sup 233}U had migrated from the fuel drain tank system to the off gas system. It was found that approximately 2.6 kg of uranium had migrated to the Auxiliary Charcoal Bed (ACB). The ACB is located in the concrete-lined charcoal bed cell which is below ground level located outside the MSRE building. Therefore, there was a concern for the potential of a nuclear criticality accident, although water would have to leak into the chamber for a criticality accident to occur. Unstable carbon/fluorine compounds were also formed when the fluorine reacted with the charcoal in the charcoal bed. The purpose of the proposed measurement system was to perform an accountability measurement to determine the fissile mass of {sup 233}U in the primary vessel. The contents of the primary containment assembly will then be transferred to three smaller containers for long term storage. Calculations were performed using MCNP-DSP to determine the configuration of the measurement system. The information obtained from the time signatures can then be compared to the measurement data to determine the amount of {sup 233}U present in the primary containment assembly.},
doi = {},
url = {https://www.osti.gov/biblio/672051}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri May 01 00:00:00 EDT 1998},
month = {Fri May 01 00:00:00 EDT 1998}
}

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