Laboratory sensor design for fiber-optic detection of (sup 85)Kr

摘要

The goal of the fiber-optic detection of (sup 85)Kr project is to produce a sensor to detect (sup 85)Kr in real-time from either an airborne or ground-based platform. The (sup 85)Kr gas is a fission product which is released in large quantities during fuel reprocessing and in minor quantities during nuclear reactor operations. Thus an airborne plume of (sup 85)Kr is a radioactive signature of proliferation. Since (sup 85)Kr has a 10.72 year half life, it is difficult for a proliferator to contain the gas for several half lives to avoid releasing the radioactive signature of proliferation. The long half life also results in a plume that can extend several kilometers from the source, which allows initial proliferation monitoring from large distances. The sensor can be used to make stand-alone, real-time measurements of (sup 85)Kr that can be used as direct evidence for proliferation and/or as a screening sensor to determine when to collect air samples for further laboratory analysis. This report provides a summary of the (sup 85)Kr beta sensor design that PNL will use in the laboratory to: (1) demonstrate the measurement technique, (2) establish minimum detection limits, and (3) optimize the sensor design for the final airborne sensor package. The goal of the final airborne sensor package will be to measure (sup 85)Kr at activity levels as low as or as close to ambient background levels as possible with a reasonably sized sensor.