Sampling Approach to Validate the Safe Storage of Plutonium-Bearing Materials

The 3013 surveillance sampling approach combines statisticaland judgmental sampling to provide a powerful, cost-effectivemethod for ensuring the safe storage of 3013 containers. To selectthe statistical sample, the population of containers is organizedinto three bins based on a container’s contents and estimated potentialfor degradation. Using pressure and corrosion as the potentialdegradation mechanisms, the three bins are Pressure andCorrosion, Pressure Only, and Innocuous. The requirement of99.9 percent probability of observing at least one of the worst 5percent (in terms of potential degradation) is used to guide thestatistical sampling process for the Pressure and Corrosion andPressure Only bins. The statistical sample for the Innocuous binis based on evaluating the assumption that these containers willshow no degradation; therefore, these containers will have almostno variability in the surveillance results. The judgmental samplinguses engineering judgment and results of the shelf-life studies toaugment the statistical sample with additional containers that arejudged to have the greatest potential for degradation.