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An improved methodology for numerical forensics analysis of spent reactor fuel

Sternat, Matthew R.

An improved system was developed to recover the initial parameters and operating conditions from spent nuclear fuel. This work is an expansion of a previous proof-of-concept system developed by the author. The improved system increases the fidelity of the forward model within the spent fuel forensic inverse analysis using two unique methodologies. The first improvement consists of developing a system to accurately create one-group neutron crosssection libraries for any user-specified reactor system. As such, a detailed model using the depletion code MONTEBURNS is developed. During MONTEBURNS execution, cross-section libraries are generated at every user specified burnup step in time. These libraries could be developed for many reactor systems, then housed in a database and used for analyzing spent fuel.

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High Fidelity Forward Model Development for Nuclear Reactor Spent Fuel Technical Nuclear Forensics

Sternat, Matthew R.

The fidelity of the forward model within a spent fuel forensic analysis system was improved by using two unique methodologies. The first consisted of developing a system to create accurate one-group neutron cross-section libraries for any user specified reactor system. In such, a detailed model is developed using the depletion code MONTEBURNS. During MONTEBURNS execution, cross-section libraries are generated at every user specified burnup step in time. These libraries could be developed for many reactor systems, then housed in a database and used for analyzing unknown fuel samples. The forensic analysis system for spent fuel resulted in higher accuracy at predicting the initial uranium isotopic compositions and burnup from spent fuel samples. Using this method, the error in results was reduced from the order of 1-6% down to less than 1% when recovering a fuel sample's burnup and initial uranium isotopic composition. The second method consisted of implementing 2D/3D reactor depletion codes as the forward model within the system's framework. This method would allow the usage of potentially recoverable geometric information from an unknown sample. No predetermined cross-section library is required for the system using this method, therefore potentially reducing model error associated with the neutron flux spectrum. The accuracy of the recovered initial uranium isotopic compositions and burnup from spent fuel samples was also improved using this method, even more so than the first. For MTR reactors, the error using this method was significantly reduced and was driven to below 0.5%. However, additional research may be required to determine the ideal fission yield and recoverable energy per fission for cases where significant amounts of 239 PU are bred and burned throughout the life of the fuel. INTENTIONALLY LEFT BLANK

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International Nuclear Safeguards at Sandia

Sternat, Matthew R.

As global nuclear energy expands, assuring peaceful uses of nuclear technology becomes increasingly important. In addition to complying with international nuclear safeguards, a responsible nuclear energy program promotes a corresponding safeguards culture. Establishment of transparent peaceful uses of nuclear technologies starts with cooperative international engagements and safeguards systems. Developing states investing in nuclear energy must assure the international community of their longterm commitment to safeguards, safety, and security (3S) of nuclear materials and technologies. Cultivating a safeguards culture starts in the initial phases of infrastructure planning and must be integrated into the process of developing a responsible nuclear energy program. Sandia National Laboratories supports the implementation of safeguards culture through a variety of activities, including infrastructure development.

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13 Results
13 Results