Criticality Concerns During Decommissioning

摘要

Legal Disclaimer: The authors are members of the Technical Staff of the Defense Nuclear Facilities Safety Board (Board). The views expressed are solely those of the authors, and no official support or endorsement of the article by the Board or the Federal Government is intended or should be inferred.rn An inadvertent nuclear criticality accident is one of the most serious accidents that can occur duringrndecommissioning. As decommissioning programs go forward, continued vigilance must be maintained to ensurernthat an inadvertent criticality accident does not occur. After the bulk inventories of fissile material are removedrnfrom a fissile material processing facility it is still possible to have a nuclear criticality accident with the holduprnfissile material remaining in the processing equipment. Holdup is usually determined by nondestructive assayrntechniques, such as, gamma spectroscopy, neutron counting, and calorimetry. A larger trained staff of assayrnscientists and technicians, compared to the staff for production operations, is required to implement these assayrntechniques in a timely manner to support D&D operations.