Partial Defect Verification of the Pressurized Water Reactor Spent Fuel Assemblies
The International Atomic Energy Agency (IAEA) has the responsibility to carry out independent inspections of all nuclear material and facilities subject to safeguards agreements in order to verify compliance with non-proliferation commitments. New technologies have been continuously explored by the IAEA and Member States to improve the verification measures to account for declared inventory of nuclear material and detect clandestine diversion and production of nuclear materials. Even with these efforts, a technical safeguards challenge has remained for decades for the case of developing a method in identifying possible diversion of nuclear fuel pins from the Light Water Reactor (LWR) spent fuel assemblies. We had embarked on this challenging task and successfully developed a novel methodology in detecting partial removal of fuel from pressurized water reactor spent fuel assemblies. The methodology uses multiple tiny neutron and gamma detectors in the form of a cluster and a high precision driving system to obtain underwater radiation measurements inside a Pressurized Water Reactor (PWR) spent fuel assembly without any movement of the fuel. The data obtained in such a manner can provide spatial distribution of neutron and gamma flux within a spent fuel assembly. The combined information of gamma and neutron signature is used to produce base signatures and they are principally dependent on the geometry of the detector locations, and exhibit little sensitivity to initial enrichment, burn-up or cooling time. A small variation in the fuel bundle such as a few missing pins changes the shape of the signature to enable detection. This resulted in a breakthrough method which can be used to detect pin diversion without relying on the nuclear power plant operator's declared operation data. Presented are the results of various Monte Carlo simulation studies and experiments from actual commercial PWR spent fuel assemblies.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 991526
- Report Number(s):
- LLNL-CONF-423300; TRN: US1007504
- Resource Relation:
- Conference: Presented at: Workshop on Advanced Safeguards Technology for the Nuclear Fuel Cycle, Tokai-mura, Japan, Nov 10 - Nov 13, 2009
- Country of Publication:
- United States
- Language:
- English
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Development of a Safeguards Verification Method and Instrument to Detect Pin Diversion from Pressurized Water Reactor (PWR) Spent Fuel Assemblies Phase I Study
Development of a Safeguards Verification Method and Instrument to Detect Pin Diversion from Pressurized Water Reactor (PWR) Spent Fuel Assemblies
Related Subjects
SAFEGUARDS AND PHYSICAL PROTECTION
COMPLIANCE
COOLING TIME
DEFECTS
DETECTION
FUEL ELEMENT CLUSTERS
GEOMETRY
IAEA
MEMBER STATES
NEUTRONS
NUCLEAR FUELS
NUCLEAR POWER PLANTS
PROLIFERATION
PWR TYPE REACTORS
RADIATIONS
REMOVAL
SAFEGUARDS
SPATIAL DISTRIBUTION
SPENT FUELS
VERIFICATION