Safety Analysis Approach to Tank 241-SY-101 Remediation Activities

摘要

An Unreviewed Safety Question was declared related to the unexplained waste surface level growth in high-level radioactive waste storage Tank 241-SY-101 at the Hanford Site in Richland, Washington. Because the waste surface level in Tank 241-SY-101 was growing in a manner inconsistent with previous behavior, the following issues of concern were recognized: The continually rising surface level had the potential to reach physical encumbrances or limits within the tank (e.g., instrumentation, cameras, established Authorization Basis limits, and the double containment boundary) and the potential to significantly change the consequences of previously analyzed accidents (e.g., flammable gas deflagrations). The presence of new hazards because of significant quantities of flammable gas retained in the crust (e.g., crust collapse gas-release events). The potential to inhibit information gathering related to the existing hazards in the tank (e.g., unable to determine surface level to assess the potential for large gas releases).