Year
2012
Abstract
A new versatile safeguards tool, Partial Defect Tester (PDET), that can verify various characteristics as well as the integrity of Pressurized Water Reactor (PWR) spent fuel assemblies (SFAs), has been developed so that desired safeguards verification can be achieved in situations where conventional safeguards techniques failed in the past. The major feature of PDET is its capability to detect pin diversion from PWR spent fuel without requiring any data from facility operators and without movement of SFAs from their storage positions. Pin diversion detection is achieved by analyzing a unique set of signatures in PWR SFA based on normalized neutron, gamma, and gamma-to-neutron ratio signals that are principally dependent on the geometric layout of the guide tubes present in the assembly where the signal measurements are taken. Diversion of as low as a few percent missing fuel can be detected using this tool. In addition to the pin diversion detection capability, the data from PDET can be used to ensure that operator declared data are free from any falsification or fabrication. This article describes the concept of pin diversion detection, and the methodology for confirming operation parameters such as burn-up, cooling time and initial enrichment, and how this information is used for shipper/receiver verification of PWR spent fuel. In addition, the article will also describe the design and functioning of the PDET hardware.