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Title: Nondestructive Assay for International Safeguards: Context, Science, and Technology


No abstract provided.

  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
Report Number(s):
TRN: US1800006
DOE Contract Number:
Resource Type:
Technical Report
Country of Publication:
United States

Citation Formats

Trahan, Alexis Chanel. Nondestructive Assay for International Safeguards: Context, Science, and Technology. United States: N. p., 2017. Web. doi:10.2172/1396165.
Trahan, Alexis Chanel. Nondestructive Assay for International Safeguards: Context, Science, and Technology. United States. doi:10.2172/1396165.
Trahan, Alexis Chanel. 2017. "Nondestructive Assay for International Safeguards: Context, Science, and Technology". United States. doi:10.2172/1396165.
title = {Nondestructive Assay for International Safeguards: Context, Science, and Technology},
author = {Trahan, Alexis Chanel},
abstractNote = {No abstract provided.},
doi = {10.2172/1396165},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2017,
month =

Technical Report:

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  • This is an end-of-year report for a project funded by the National Nuclear Security Administration's Office of Nuclear Safeguards (NA-241). The goal of this project is to investigate the feasibility of using Neutron Resonance Transmission Analysis (NRTA) to assay plutonium in commercial light-water-reactor spent fuel. This project is part of a larger research effort within the Next-Generation Safeguards Initiative (NGSI) to evaluate methods for assaying plutonium in spent fuel, the Plutonium Assay Challenge. The first-year goals for this project were modest and included: 1) developing a zero-order MCNP model for the NRTA technique, simulating data results presented in the literature,more » 2) completing a preliminary set of studies investigating important design and performance characteristics for the NRTA measurement technique, and 3) documentation of this work in an end of the year report (this report). Research teams at Los Alamos National Laboratory (LANL), Lawrence Berkeley National Laboratory (LBNL), Pacific Northwest National Laboratory (PNNL), and at several universities are also working to investigate plutonium assay methods for spent-fuel safeguards. While the NRTA technique is well proven in the scientific literature for assaying individual spent fuel pins, it is a newcomer to the current NGSI efforts studying Pu assay method techniques having just started in March 2010; several analytical techniques have been under investigation within this program for two to three years or more. This report summarizes a nine month period of work.« less
  • This paper examines two cases where gamma rays from Tl-208, including the 2614keV gamma ray, were used to detect anomalies in waste material. In addition to the characterization of waste for waste acceptance, and compliance with environmental and transportation laws, there is a safeguards element as well. The more sophisticated method of NDA at Y-12 includes a means to detect shielded special nuclear material (SNM). Excess count rates in the 2614keV gamma ray from Tl-208 are an indication of potential shielded HEU in waste as well as other containers. The 2614keV gamma ray is easy to monitor routinely. When amore » large 2614keV peak is detected, further investigation can be conducted from the gamma spectrum. This paper describes this further investigation in two cases. In one case self-shielded HEU was detected. In the other case the Tl-208 gamma rays came from a piece of Th-232 metal.« less
  • The various methods of nondestructive assay (NDA) of special nuclear material (SNM) have applications in nuclear nonproliferation, including detection and identification of illicit SNM at border crossings and quantifying SNM at nuclear facilities for safeguards. No assay method is complete without “error bars,” which provide one way of expressing confidence in the assay result. Consequently, NDA specialists typically provide error bars and also partition total uncertainty into “random” and “systematic” components so that, for example, an error bar can be developed for the total mass estimate in multiple items. Uncertainty Quantification (UQ) for NDA has always been important, but itmore » is recognized that greater rigor is needed and achievable using modern statistical methods.« less
  • In the work on prediction of calorimeter equilibrium, a newly derived single-exponential prediction equation has been shown to yield results equal to those from previously reported work, but allows for more versatility in the instrumentation selection. A single-precision rather than a double-precision calculator is all that is required to predict reliable equilibrium values using this new equation. A double-exponential prediction equation has also been derived and tested using simulated data. Engineering refinements have been incorporated in the Automated Plutonium Assay System (APAS) to provide for improvements in the gamma-ray spectroscopy system and the container pickup device. In addition, evaluation testsmore » on the assay instrumentation have been conducted. Calorimeter tests indicate that values within 1 percent of equilibrium can be obtained in 7 min. The Half-Life Evaluation Committee has completed measurements of the half-life of /sup 239/Pu. Preliminary results show that measurements by alpha and gamma counting, by mass spectrometry and by calorimetry agree sufficiently well that a recommended value with a relative standard deviation of +-0.1 percent will be reported. Papers describing these measurements are being prepared for journal publication. The committee concurs with the recent recommendation by Argonne National Laboratory representatives that the value 87.74 +- 0.04 yr be adopted for the half-life of /sup 238/Pu. Calorimetric assay has been used to prepare plutonium reference standards for use in verifying other NDA measurement systems. The reference samples contained plutonium oxide, nitride, and/or metal mixed with natural, depleted, and/or enriched uranium oxide, nitride, and/or metal. Eight samples have been certified, with plutonium uncertainties of less than 1 percent. They cover the weight range from 4.3 to 141.2 g of plutonium.« less