Partial defect verification of spent fuel assemblies by PDET: Principle and field testing in Interim Spent fuel Storage Facility (CLAB) in Sweden
20 Apr 2015-pp 1-7
TL;DR: In this paper, the authors presented the first successful field testing using the integrated PDET system and actual spent fuel assemblies performed in a commercial spent fuel storage site, known as Central Interim Spent fuel storage facility (CLAB) in Sweden.
Abstract: The need for the development of a credible method and instrument for partial defect verification of spent fuel has been emphasized over a few decades in the safeguards communities as the diverted spent fuel pins can be the source of nuclear terrorism or devices. The need is increasingly more important and even urgent as many countries have started to transfer spent fuel to so called "difficult-to-access" areas such as dry storage casks, reprocessing or geological repositories. Partial defect verification is required by IAEA before spent fuel is placed into "difficult-to-access" areas. Earlier, Lawrence Livermore National Laboratory (LLNL) has reported the successful development of a new, credible partial defect verification method for pressurized water reactor (PWR) spent fuel assemblies without use of operator data, and further reported the validation experiments using commercial spent fuel assemblies with some missing fuel pins. The method was found to be robust as the method is relatively invariant to the characteristic variations of spent fuel assemblies such as initial fuel enrichment, cooling time, and burn-up. Since then, the PDET system has been designed and prototyped for 17×17 PWR spent fuel assemblies, complete with data acquisition software and acquisition electronics. In this paper, a summary description of the PDET development followed by results of the first successful field testing using the integrated PDET system and actual spent fuel assemblies performed in a commercial spent fuel storage site, known as Central Interim Spent fuel Storage Facility (CLAB) in Sweden will be presented. In addition to partial defect detection initial studies have determined that the tool can be used to verify the operator declared average burnup of the assembly as well as intra-assembly bunrup levels.
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01 Jan 2019
9 citations
Cites background from "Partial defect verification of spen..."
...from nuclear reactors globally, countries like Finland and Sweden are taking the lead to develop underground repositories to store their used nuclear fuel [6] [7]....
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TL;DR: This study found that the classification accuracies using SINRD and PDET are higher compared to Fork, and k-nearest neighbors models reached higher classified accuracies compared to decision tree models, and for the considered NDA techniques the gamma-ray detectors were the most sensitive to the fuel pin diversion.
6 citations
TL;DR: The feasibility of developing an efficient and cost-effective method for detecting partial defects of spent fuel assemblies by using the proposed SPDD method for screening purposes and the cost associated with SPDD was estimated in comparison to that of existing partial defect technologies.
4 citations
30 Sep 2016
TL;DR: In this paper, the authors described the development of two passive non-destructive assay (NDA) techniques: the Self-Indication Neutron Resonance Densitometry (SINRD) and the Partial Defect Tester (PDET).
Abstract: The safeguards verification of spent nuclear fuel is one of the major concern for the safeguards community, as this material represents about 80% of all material placed under safeguards.This PhD thesis described the development of two passive non-destructive assay (NDA) techniques: the Self-Indication Neutron Resonance Densitometry (SINRD) and the Partial Defect Tester (PDET).The NDA methods were investigated with Monte Carlo simulations and the benchmark experiments for SINRD were performed at the GELINA facility of JRC-IRMM in Geel, Belgium.The results for the SINRD technique showed promising results for the direct quantification of 239Pu in spent fuel, and both techniques gave encouraging results for the detection of partial defects.
4 citations
11 Dec 2016-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this article, a theory of multiplicity counting with fission chambers is developed by incorporating Bohnel's concept of superfission into a master equation formalism, developed recently by the present authors for the statistical theory of fission chamber signals.
Abstract: In nuclear safeguards, estimation of sample parameters using neutron-based non-destructive assay methods is traditionally based on multiplicity counting with thermal neutron detectors in the pulse mode. These methods in general require multi-channel analysers and various dead time correction methods. This paper proposes and elaborates on an alternative method, which is based on fast neutron measurements with fission chambers in the current mode. A theory of "multiplicity counting" with fission chambers is developed by incorporating Bohnel's concept of superfission [1] into a master equation formalism, developed recently by the present authors for the statistical theory of fission chamber signals [2,3]. Explicit expressions are derived for the first three central auto- and cross moments (cumulants) of the signals of up to three detectors. These constitute the generalisation of the traditional Campbell relationships for the case when the incoming events represent a compound Poisson distribution. Because now the expressions contain the factorial moments of the compound source, they contain the same information as the singles, doubles and triples rates of traditional multiplicity counting. The results show that in addition to the detector efficiency, the detector pulse shape also enters the formulas; hence, the method requires a more involved calibration than the traditional method of multiplicity counting. However, the method has some advantages by not needing dead time corrections, as well as having a simpler and more efficient data processing procedure, in particular for cross-correlations between different detectors, than the traditional multiplicity counting methods.
3 citations
Cites background from "Partial defect verification of spen..."
...Because of their small size, fission chambers can be inserted even inside the fuel assembly in BWRs [6]....
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References
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01 Jan 1993
TL;DR: In this article, the authors present a practical guide for the use of general-purpose Monte Carlo code MCNP, including several examples and a discussion of the particular techniques and the Monte Carlo method itself.
Abstract: This manual is a practical guide for the use of our general-purpose Monte Carlo code MCNP. The first chapter is a primer for the novice user. The second chapter describes the mathematics, data, physics, and Monte Carlo simulation found in MCNP. This discussion is not meant to be exhaustive---details of the particular techniques and of the Monte Carlo method itself will have to be found elsewhere. The third chapter shows the user how to prepare input for the code. The fourth chapter contains several examples, and the fifth chapter explains the output. The appendices show how to use MCNP on various computer systems and also give details about some of the code internals.
6,481 citations
"Partial defect verification of spen..." refers background in this paper
...Only a selection of guide tube location data is presented Data in Table III shows that in the region where the assembly is intact, the declared and measured burnups match very well as does the overall assembly average burnup with 12 percent of the fuel missing in the assembly....
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...The fission chambers are operated in pulse mode in which individual neutron events are detected....
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12 Nov 2002
19 citations
"Partial defect verification of spen..." refers background in this paper
...However, the DCVD does not work well for fuel that has been cooled for a long time or low burnup fuel or in murky spent fuel pool conditions....
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27 Sep 2002
TL;DR: In this article, the authors investigated the possibility to use a fork detector for partial defect verification of spent LWR fuelassemblies and showed that a general partial defect test based on the fork method is not possible without making use of operator's declared data.
Abstract: The possibility to use a fork detector for partial defect verification of spent LWR fuelassemblies has been investigated in Task JNT A 1071 “Partial Defect Test on Spent FuelLWRs”. The task was arranged as a joint task between the Finnish, Swedish and Belgiansupport programmes to IAEA safeguards.This task studied the prospects of both a conventional fork detector and an enhancementwhere the gross gamma and neutron signals of a conventional fork are combined withsimultaneous gamma spectrometry using a CdZnTe detector.The fork method was investigated by measuring BWR and VVER-440 spent fuel assem-blies and a fresh MOX mock-up assembly. Correction methods were developed to improvethe analysis of measurement results. Also model calculations were performed to clarify theeffect of the geometrical configuration of the defect.The investigations have shown that a general partial defect test based on the fork methodis not possible without making use of operator’s declared data. There exist configurationseven with 50% of pins removed, which cannot be detected, either with the conventionalfork or with the enhanced fork detector. Using the operator declared data cannot beavoided due to the influence of both the fuel design and the irradiation history to themeasured signals. If operator’s data are available and considered reliable, the detectionlimit of a partial defect is at about 20% of pins missing for BWR assemblies with theburnup 18 MWd/kg or higher. For developing a reliable, operator data independent partialdefect verification device a totally different approach must be applied.
12 citations
"Partial defect verification of spen..." refers background in this paper
...The current detection requirement by the IAEA for partial defect tests for irradiated fuel assemblies should assure that at least half of the fuel pins (50...
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TL;DR: In this article, a novel methodology to detect diversion of spent fuel from pressurized water reactors (PWRs) has been developed in order to address a long unsolved safeguards verification problem for an internatio...
Abstract: A novel methodology to detect diversion of spent fuel from pressurized water reactors (PWRs) has been developed in order to address a long unsolved safeguards verification problem for an internatio...
8 citations
"Partial defect verification of spen..." refers background in this paper
...In the discharged spent fuel assembly (SFA), the guide tubes are filled with water when stored in the spent fuel pool....
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01 Jun 2009
TL;DR: In this paper, a set of simulations with various symmetric patterns of diversion were examined and the results from these studies indicated that symmetric diversions as low as twelve percent could be detected by this methodology.
Abstract: Since the signature from the Partial Defect Detector (PDET) is principally dependent on the geometric layout of the guide tube locations, the capability of the technique in detecting symmetric diversion of pins needs to be determined. The Monte Carlo simulation study consisted of cases where pins were removed in a symmetric manner and the resulting signatures were examined. In addition to the normalized gamma-to-neutron ratios, the neutron and gamma signatures normalized to their maximum values, were also examined. Examination of the shape of the three curves as well as of the peak-to-valley differences in excess of the maximum expected in intact assemblies, indicated pin diversion. A set of simulations with various symmetric patterns of diversion were examined. The results from these studies indicated that symmetric diversions as low as twelve percent could be detected by this methodology.
6 citations
"Partial defect verification of spen..." refers background in this paper
...In the discharged spent fuel assembly (SFA), the guide tubes are filled with water when stored in the spent fuel pool....
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