Most of the used, or spent, fuel that has been removed from nuclear power reactors is currently stored in pools at the reactor site. Once the fuel has been sufficiently cooled, it would ideally be transported to a long-term storage facility, but there is no immediate plan to provide such a facility in the US at this time. As an interim solution, cooled used fuel is being stored in dry casks at independent spent fuel storage installations, also known as ISFSIs. These sites must be monitored to ensure that the material they contain is not removed and used for nefarious purposes. Recent NSSPI graduate Dr. Jeremy King looked into the problem of monitoring the dry casks at these installations as part of his Ph.D. research with NSSPI Deputy Director Dr. Craig Marianno.
According to Dr. King, “Dry casks can contain many significant quantities of plutonium, yet safeguards monitoring for spent nuclear fuel in dry cask storage is limited to containment and surveillance.” A significant quantity is the amount of material defined by the International Atomic Energy Agency (IAEA) as potentially being capable of producing a nuclear weapon.
Dr. King’s research investigated the capability of a low-cost neutron detector system designed at Texas A&M to provide more rigorous nuclear safeguards monitoring for these dry storage casks. He conducted a series of measurement and MCNP simulation campaigns to develop and evaluate the detector for its viability as a safeguards instrument. The project included field measurements on dry casks loaded with civilian SNF located at a commercial ISFSI. King then ran high-fidelity Monte Carlo Radiation Transport (MCNP) simulations to determine the instrument’s ability to detect the diversion of used fuel assemblies.
“I even had the opportunity to take measurements of loaded dry casks at a commercial ISFSI,” King explained.
The results of Dr. King’s research offer an opportunity to bolster dry cask safeguards by offering an affordable non-destructive assay solution. Beyond safeguards, the design may offer monitoring opportunities to manufacturers and facility operators who wish to gain more information about deployed casks.
Dr. King graduated with a Ph.D. in nuclear engineering and a certificate of nuclear security from Texas A&M in May of 2022. During his time as a graduate student, he was funded through the Nuclear Regulatory Commission Fellowship program, the Texas A&M College of Engineering Graduate Teaching Fellowship program, and the Department of Defense Science, Mathematics, and Research for Transformation (DoD S.M.A.R.T.) Scholarship program. He is now working as an engineer for the Department of Defense in Virginia.