Determining initial enrichment, burnup, and cooling time of pressurized-water reactor spent fuel assemblies by analyzing passive gamma spectra measured at the Clab interim-fuel storage facility in Sweden

Journal Article · 26 February 2016 · Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment

DOI: https://doi.org/10.1016/j.nima.2016.02.072 · OSTI ID:1267063

Favalli, Andrea ^[1]; Vo, D. ^[1]; Grogan, Brandon R. ^[2]; Jansson, Peter ^[3]; Liljenfeldt, Henrik ^[2]; Mozin, Vladimir ^[4]; Schwalbach, P. ^[5]; Sjoland, A. ^[6]; Tobin, Stephen J. ^[1]; Trellue, Holly ^[1]; Vaccaro, S. ^[5]

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1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
3. Uppsala Univ., Uppsala (Sweden)
4. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
5. European Commission (Luxemburg)
6. Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)

The purpose of the Next Generation Safeguards Initiative (NGSI)–Spent Fuel (SF) project is to strengthen the technical toolkit of safeguards inspectors and/or other interested parties. The NGSI–SF team is working to achieve the following technical goals more easily and efficiently than in the past using nondestructive assay measurements of spent fuel assemblies: (1) verify the initial enrichment, burnup, and cooling time of facility declaration; (2) detect the diversion or replacement of pins; (3) estimate the plutonium mass [which is also a function of the variables in (1)]; (4) estimate the decay heat; and (5) determine the reactivity of spent fuel assemblies. Since August 2013, a set of measurement campaigns has been conducted at the Central Interim Storage Facility for Spent Nuclear Fuel (Clab), in collaboration with Swedish Nuclear Fuel and Waste Management Company (SKB). One purpose of the measurement campaigns was to acquire passive gamma spectra with high-purity germanium and lanthanum bromide scintillation detectors from Pressurized Water Reactor and Boiling Water Reactor spent fuel assemblies. The absolute ¹³⁷Cs count rate and the ¹⁵⁴Eu/¹³⁷Cs, ¹³⁴Cs/¹³⁷Cs, ¹⁰⁶Ru/¹³⁷Cs, and ¹⁴⁴Ce/¹³⁷Cs isotopic ratios were extracted; these values were used to construct corresponding model functions (which describe each measured quantity’s behavior over various combinations of burnup, cooling time, and initial enrichment) and then were used to determine those same quantities in each measured spent fuel assembly. Furthermore, the results obtained in comparison with the operator declared values, as well as the methodology developed, are discussed in detail in the paper.

• Research Organization: Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE; USDOE National Nuclear Security Administration (NNSA)
• Grant/Contract Number: AC05-00OR22725; AC52-06NA25396
• OSTI ID: 1267063
• Report Number(s): LA-UR--15-29638; DN4001030; MDGA517
• 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. 820; ISSN 0168-9002
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English