Year
1982
Abstract
The storage of SNM requires periodic physical protection inventories to assure the presence of all material and to check for bulging containers that may cause contamination through eventual rupturing. A shelf-monitoring system has been developed for use in an operational storage facility to satisfy these requirements remotely. This system monitors the presence of every container many times each second so that security can respond immediately to a missing container. In addition, complete inventories can be taken on demand or at periodic intervals at the rate of about 600 containers per minute. This inventory system monitors container and ambient temperatures, providing a data base for calculating container heat flow (thereby inferring SNM heat production), as well as detecting temperature anomalies. A capacitively-read label has been invented to apply to the bottom of each SNM container. A 20-bit binary serial number is read and stored by shelf location in the memory of the system controller. A shelf monitor unit is placed under each SNM container to collect this data which is serially transmitted by cabling to the system processor. The system has been designed for a $60 unit cost and minimum vault installation time. It should greatly increase SNM safeguards and decrease employee radiation exposure.