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Title: Summary of the Effort to Use Active-induced Time Correlation Techniques to Measure the Enrichment of HEU

This document summarizes the effort to use active-induced time correlation techniques to measure the enrichment of bulk quantities of enriched uranium. In summary, these techniques use an external source to initiate fission chains, and the time distribution of the detected fission chain neutrons is sensitive to the fissile material enrichment. The number of neutrons emitted from a chain is driven by the multiplication of the item, and the enrichment is closely coupled to the multiplication of the item. As the enrichment increases (decreases), the multiplication increases (decreases) if the geometry is held constant. The time distribution of fission chain neutrons is a complex function of the enrichment and material configuration. The enrichment contributes to the probability of a subsequent fission in a chain via the likelihood of fissioning on an even-numbered isotope versus an odd-numbered isotope. The material configuration contributes to the same probability via solid angle effects for neutrons inducing subsequent fissions and the presence of any moderating material. To simplify the ability to accurately measure the enrichment, an associated particle imaging (API) D-T neutron generator and an array of plastic scintillators are used to simultaneously image the item and detect the fission chain neutrons. The image is usedmore » to significantly limit the space of enrichment and material configuration and enable the enrichment to be determined unambiguously.« less
Authors:
 [1] ;  [2] ;  [2] ;  [1] ;  [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Tennessee, Knoxville, TN (United States)
Publication Date:
OSTI Identifier:
1325423
Report Number(s):
ORNL/TM--2015/465
DN2001000; NNPORES; TRN: US1700070
DOE Contract Number:
AC05-00OR22725
Resource Type:
Technical Report
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL PROTECTION; FISSION NEUTRONS; FISSION; ENRICHMENT; HIGHLY ENRICHED URANIUM; NEUTRON GENERATORS; CONFIGURATION; CORRELATIONS; TIME DEPENDENCE; PLASTIC SCINTILLATOR DETECTORS; DISTRIBUTION; PROBABILITY; DAUGHTER PRODUCTS; EMISSION