Pressure monitoring of Special Nuclear Material containment

Abstract

All Magnox Nuclear Reactors are now in the process of decommissioning and nearly all Magnox spent fuel has been reprocessed, producing uranium and plutonium and small volumes of highly radioactive waste. The recovered plutonium is stored in specialist containers in secure facilities while the government reaches a decision on possible re-use or disposal, following the completion of technical studies. There is potential for the containment to become pressurised over time due to alpha decay and radiolysis of the plutonium, and highlights the need for continuous monitoring to assess the integrity of the containment. This paper presents a new technique of interpreting the internal pressure of the containment by understanding the change in the vibrational response of the outer containment wall for different internal pressures. Electromagnetic acoustic transducers have been used to excite the outer containment wall in a non-contact and non-destructive manner, and capture the changes in the resonant frequency response of the system for different internal pressures.