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Title: Passive assay of plutonium metal plates using a fast-neutron multiplicity counter

Authors:
; ; ; ; ; ; ;
Publication Date:
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1416602
Grant/Contract Number:
NA0002534
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment
Additional Journal Information:
Journal Volume: 855; Journal Issue: C; Related Information: CHORUS Timestamp: 2018-01-11 06:04:59; Journal ID: ISSN 0168-9002
Publisher:
Elsevier
Country of Publication:
Netherlands
Language:
English

Citation Formats

Di Fulvio, A., Shin, T. H., Jordan, T., Sosa, C., Ruch, M. L., Clarke, S. D., Chichester, D. L., and Pozzi, S. A.. Passive assay of plutonium metal plates using a fast-neutron multiplicity counter. Netherlands: N. p., 2017. Web. doi:10.1016/j.nima.2017.02.082.
Di Fulvio, A., Shin, T. H., Jordan, T., Sosa, C., Ruch, M. L., Clarke, S. D., Chichester, D. L., & Pozzi, S. A.. Passive assay of plutonium metal plates using a fast-neutron multiplicity counter. Netherlands. doi:10.1016/j.nima.2017.02.082.
Di Fulvio, A., Shin, T. H., Jordan, T., Sosa, C., Ruch, M. L., Clarke, S. D., Chichester, D. L., and Pozzi, S. A.. Mon . "Passive assay of plutonium metal plates using a fast-neutron multiplicity counter". Netherlands. doi:10.1016/j.nima.2017.02.082.
@article{osti_1416602,
title = {Passive assay of plutonium metal plates using a fast-neutron multiplicity counter},
author = {Di Fulvio, A. and Shin, T. H. and Jordan, T. and Sosa, C. and Ruch, M. L. and Clarke, S. D. and Chichester, D. L. and Pozzi, S. A.},
abstractNote = {},
doi = {10.1016/j.nima.2017.02.082},
journal = {Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment},
number = C,
volume = 855,
place = {Netherlands},
year = {Mon May 01 00:00:00 EDT 2017},
month = {Mon May 01 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1016/j.nima.2017.02.082

Citation Metrics:
Cited by: 3works
Citation information provided by
Web of Science

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  • This paper reports on a new neutron multiplicity counter developed that can provide International Atomic Energy Agency inspectors a means of verifying plutonium samples by a full neutron multiplicity analysis where conventional neutron coincidence counters yield outliers. This prototype detector comprises an array of {sup 3}He and liquid scintillator neutron detectors and is one of a new generation of multiplicity counters under development for nuclear safeguards. A moments analysis solution to the plutonium mass, (a,n) rate, and multiplication is calculated using the measured neutron multiplicity distributions, and an expression for the uncertainty in the multiplication-corrected mass has been derived.
  • Measurements were performed at the Joint Research Centre in Ispra, Italy to field test a fast-neutron multiplicity counter developed at the University of Michigan. The measurements allowed the assessment of the system's photon discrimination abilities, efficiency when measuring neutron multiplicity, ability to characterize 240Pu eff mass, and performance relative to a currently deployed neutron coincidence counter. We describe how this work is motivated by the need to replace and improve upon 3He neutron detection systems for nuclear safeguards applications.
  • In the past several years, many facilities have identified the need for a large multiplicity counter to support safeguards for excess weapons materials and the measurement and control of large, unusual samples. We have designed and fabricated two large thermal-neutron multiplicity counters to meet this need at Rocky Flats and at Lawrence Livermore. This paper briefly discusses the design and operation of these counters.
  • The large neutron multiplicity counter (LNMC), also known as the 30-gal.-drum neutron multiplicity counter, has now been used successfully by the International Atomic Energy Agency (IAEA) for the Initial Physical Inventory Verification (IPIV) and the first annual Physical Inventory Verification (PIV) of excess weapons plutonium oxide at the Rocky Flats Environmental Technology Site (RFETS). These excess plutonium oxide materials contain a variety of impurities. They are stored two cans to a 10-gal.-drum. The drums contain from 1.3 to 4.0 kg of plutonium. The isotopic declarations vary from can to can but the material averages 6% {sup 240}Pu. During the IPIV,more » 94 samples were measured in the LNMC; 19 were measured during the PIV. The assays for all but a single drum agreed to within three standard deviations of the declared value. This problematic drum could not be measured by the LNMC because of its unusually high neutron emission rate. In this paper we will report on the overall performance of the LNMC in these inspections.« less