Results of the Swedish spent fuel measurement field trials with the Differential Die-Away Self-Interrogation Instrument

Journal Article · 22 December 2019 · Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment

DOI: https://doi.org/10.1016/j.nima.2019.163329 · OSTI ID:2346075

Trahan, Alexis C. ^[1]; McMath, Garrett E. ^[1]; Mendoza, Paul M. ^[1]; Trellue, Holly R. ^[1]; Backstrom, Ulrika ^[2]; Balkeståhl, Li Pöder ^[3]; Grape, Sophie ^[3]; Henzl, Vlad ^[1]; Leyba, Daniel ^[1]; Root, Margaret A. ^[1]; Sjoland, Anders ^[2]

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1. Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
2. Swedish Nuclear Fuel and Waste Management Company (SKB), Stockholm (Sweden)
3. Uppsala Univ. (Sweden)

In this study, Differential Die-Away Self-Interrogation (DDSI) is a method by which the characteristic die-away of neutrons from spontaneous and induced fissions is used to characterize a spent nuclear fuel assembly. A nondestructive assay (NDA) instrument was built at Los Alamos National Laboratory to implement and test the DDSI method. The DDSI instrument contains ³He detectors which measure thermal neutrons, and the time and location of detection of each neutron is recorded via list-mode data acquisition. The instrument was sent to the Clab interim storage facility in Sweden for measurement and characterization of 50 spent pressurized water reactor (PWR) and boiling water reactor (BWR) fuel assemblies. The result was over 40 h of neutron list-mode data from a wide variety of fuel assemblies with high enough efficiency to perform neutron coincidence counting, i.e. detection of time-correlated neutrons from fission. Analysis algorithms for characterization of the fuel assemblies were tested on the Swedish spent fuel dataset. Using the measured data, multiplication, fissile mass, initial enrichment, burnup, and total plutonium mass were determined in the 50 assemblies with root mean square errors ranging from 1.5% for PWR multiplication to 11.4% for BWR fissile mass. The results in this work demonstrate that the DDSI concept is capable of characterizing spent power reactor fuel with levels of accuracy that are compatible with the requirements and objectives of various applications such as safeguards verification or facility material control and accounting.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA), Office of Defense Nuclear Nonproliferation
• Grant/Contract Number: 89233218CNA000001
• OSTI ID: 2346075
• Report Number(s): LA-UR--19-29013
• Journal Information: Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment, Journal Name: Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment Vol. 955; ISSN 0168-9002
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English