Performance Evaluation of a Multi-detector System for Unattended Uranium Enrichment Monitoring

摘要

Improving the quality of safeguards measurements at Gas Centrifuge Enrichment Plants (GCEPs) while reducing the inspection effort is an important objective given the number of existing and new plants that need to be safeguarded. A useful tool in many safeguards approaches is on-line monitoring of enrichment in process pipes. One requirement of such a monitor is a simple, reliable and precise passive measurement of the 186-keV line from ~(235)U. The other information required is the amount of gas in the pipe, which can be obtained by transmission or pressure measurement. We describe our research to develop such a passive measurement system. Unfortunately, a complication arises in the interpretation of the gamma measurements from the contribution of uranium deposits on the wall of the pipe to the 186-keV peak. A multi-detector approach to overcome this complication is presented where two measurements, one with signal primarily from gas and one with signal primarily from deposits, are performed simultaneously with different detectors and geometries. This allows a correction to be made to the 186-keV peak for the contribution from the deposits. We present the design of the multi-detector system and the results of the experimental calibration of the proof-of-principle prototype built at LANL.