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Title: A more accurate and penetrating method to measure the enrichment and mass of UF6 storage containers using passive neutron self-interrogation

Abstract

This paper describes an unattended mode neutron measurement that can provide the enrichment of the uranium in UF{sub 6} cylinders. The new passive neutron measurement provides better penetration into the uranium mass than prior gamma-ray enrichment measurement methods. The Passive Neutron Enrichment Monitor (PNEM) provides a new measurement technique that uses passive neutron totals and coincidence counting together with neutron self-interrogation to measure the enrichment in the cylinders. The measurement uses the neutron rates from two detector pods. One of the pods has a bare polyethylene surface next to the cylinder and the other polyethylene surface is covered with Cd to prevent thermal neutrons from returning to the cylinder. The primary neutron source from the enriched UF{sub 6} is the alpha-particle decay from the {sub 234}U that interacts with the fluorine to produce random neutrons. The singles neutron counting rate is dominated by the {sub 234}U neutrons with a minor contribution from the induced fissions in the {sub 235}U. However, the doubles counting rate comes primarily from the induced fissions (i.e., multiplication) in the {sub 235}U in enriched uranium. The PNEM concept makes use of the passive neutrons that are initially produced from the {sub 234}U reactions that track themore » {sub 235}U enrichment during the enrichment process. The induced fission reactions from the thermal-neutron albedo are all from the {sub 235}U and provide a measurement of the {sub 235}U. The Cd ratio has the desirable feature that all of the thermal-neutron-induced fissions in {sub 235}U are independent of the original neutron source. Thus, the ratio is independent of the uranium age, purity, and prior reactor history.« less

Authors:
 [1];  [1];  [1]
  1. Los Alamos National Laboratory
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1011482
Report Number(s):
LA-UR-10-03040; LA-UR-10-3040
TRN: US1102179
DOE Contract Number:  
AC52-06NA25396
Resource Type:
Conference
Resource Relation:
Conference: INMM 51 Annual Meeting ; July 11, 2010 ; Baltimore, MD
Country of Publication:
United States
Language:
English
Subject:
11; 46; 97; 98; ALBEDO; CONTAINERS; COUNTING RATES; DECAY; ENRICHED URANIUM; FISSION; FLUORINE; MONITORS; NEUTRON SOURCES; NEUTRONS; POLYETHYLENES; STORAGE; THERMAL NEUTRONS; URANIUM

Citation Formats

Menlove, Howard O, Swinhoe, Martyn T, and Miller, Karen A. A more accurate and penetrating method to measure the enrichment and mass of UF6 storage containers using passive neutron self-interrogation. United States: N. p., 2010. Web.
Menlove, Howard O, Swinhoe, Martyn T, & Miller, Karen A. A more accurate and penetrating method to measure the enrichment and mass of UF6 storage containers using passive neutron self-interrogation. United States.
Menlove, Howard O, Swinhoe, Martyn T, and Miller, Karen A. Fri . "A more accurate and penetrating method to measure the enrichment and mass of UF6 storage containers using passive neutron self-interrogation". United States. https://www.osti.gov/servlets/purl/1011482.
@article{osti_1011482,
title = {A more accurate and penetrating method to measure the enrichment and mass of UF6 storage containers using passive neutron self-interrogation},
author = {Menlove, Howard O and Swinhoe, Martyn T and Miller, Karen A},
abstractNote = {This paper describes an unattended mode neutron measurement that can provide the enrichment of the uranium in UF{sub 6} cylinders. The new passive neutron measurement provides better penetration into the uranium mass than prior gamma-ray enrichment measurement methods. The Passive Neutron Enrichment Monitor (PNEM) provides a new measurement technique that uses passive neutron totals and coincidence counting together with neutron self-interrogation to measure the enrichment in the cylinders. The measurement uses the neutron rates from two detector pods. One of the pods has a bare polyethylene surface next to the cylinder and the other polyethylene surface is covered with Cd to prevent thermal neutrons from returning to the cylinder. The primary neutron source from the enriched UF{sub 6} is the alpha-particle decay from the {sub 234}U that interacts with the fluorine to produce random neutrons. The singles neutron counting rate is dominated by the {sub 234}U neutrons with a minor contribution from the induced fissions in the {sub 235}U. However, the doubles counting rate comes primarily from the induced fissions (i.e., multiplication) in the {sub 235}U in enriched uranium. The PNEM concept makes use of the passive neutrons that are initially produced from the {sub 234}U reactions that track the {sub 235}U enrichment during the enrichment process. The induced fission reactions from the thermal-neutron albedo are all from the {sub 235}U and provide a measurement of the {sub 235}U. The Cd ratio has the desirable feature that all of the thermal-neutron-induced fissions in {sub 235}U are independent of the original neutron source. Thus, the ratio is independent of the uranium age, purity, and prior reactor history.},
doi = {},
url = {https://www.osti.gov/biblio/1011482}, journal = {},
number = ,
volume = ,
place = {United States},
year = {2010},
month = {1}
}

Conference:
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