Shipper/receiver difference verification of spent fuel by use of PDET

Conference · Fri Jul 01 00:00:00 EDT 2011

DOI:https://doi.org/10.1109/ANIMMA.2011.6172949· OSTI ID:22039831

Ham, Y S; Sitaraman, S ^[1]

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1. Global Security Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States)

Spent fuel storage pools in most countries are rapidly approaching their design limits with the discharge of over 10,000 metric tons of heavy metal from global reactors. Countries like UK, France or Japan have adopted a closed fuel cycle by reprocessing spent fuel and recycling MOX fuel while many other countries opted for above ground interim dry storage for their spent fuel management strategy. Some countries like Finland and Sweden are already well on the way to setting up a conditioning plant and a deep geological repository for spent fuel. For all these situations, shipments of spent fuel are needed and the number of these shipments is expected to increase significantly. Although shipper/receiver difference (SRD) verification measurements are needed by IAEA when the recipient facility receives spent fuel, these are not being practiced to the level that IAEA has desired due to lack of a credible measurement methodology and instrument that can reliably perform these measurements to verify non-diversion of spent fuel during shipment and confirm facility operator declarations on the spent fuel. In this paper, we describe a new safeguards method and an associated instrument, Partial Defect Tester (PDET), which can detect pin diversion from Pressurized Water Reactor (PWR) Spent Fuel Assemblies in an in-situ condition. The PDET uses multiple tiny neutron and gamma detectors in the form of a cluster and a simple, yet highly precise, gravity-driven system to obtain underwater radiation measurements inside a Pressurized Water Reactor (PWR) spent fuel assembly. The method takes advantage of the PWR fuel design which contains multiple guide tubes which can be accessed from the top. The data obtained in such a manner can provide spatial distribution of neutron and gamma flux within a spent fuel assembly. Our simulation study as well as validation measurements indicated that the ratio of the gamma signal to the thermal neutron signal at each detector location normalized to the peak ratio of all the detector locations gives a unique signature that is sensitive to missing pins. The signature is principally dependent on the geometry of the detector locations, and little sensitive to enrichment or burn-up variations. A small variation in the fuel bundle, such as a few missing pins, changes the shape of the signature to enable detection. After verification of the non-diversion of spent fuel pins, the neutron signal and gamma signal are subsequently used to verify the consistency of the operator declaration on the fuel burn-up and cooling time. (authors)

• OSTI ID: 22039831
• Resource Relation: Conference: ANIMMA 2011: 2. International Conference on Advancements in Nuclear Instrumentation, Measurement Methods and their Applications, Ghent (Belgium), 6-9 Jun 2011; Other Information: Country of input: France; 10 refs.; IEEE Catalog Number: CFP1124I-CDR
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
FAILED ELEMENT DETECTION
FUEL CYCLE
FUEL ELEMENT CLUSTERS
GUIDE TUBES
HEAVY METALS
IAEA
MIXED OXIDE FUELS
PWR TYPE REACTORS
RADIATION DETECTION
REPROCESSING
SAFEGUARDS
SHIPPER-RECEIVER DIFFERENCES
SIMULATION
SPATIAL DISTRIBUTION
SPENT FUEL STORAGE
SPENT FUELS
THERMAL NEUTRONS
UNDERWATER
WASTE TRANSPORTATION