Data reconcilation study of Tank 241-AN-105 at the Hanford Site

The Project Hanford Management Contractor gave the Los Alamos National Laboratory Nuclear Systems Design and Analysis Group (TSA-10) the task of performing data reconciliation studies on flammable-gas watchlist tanks at the Hanford Site. This task is being performed in support of the flammable-gas programs at the Hanford Site and for closure of the flammable-gas unreviewed safety question. In our data reconciliation studies, we examine all available data from a global point of view. Our goal is to find an explanation, or conceptual model, of the tank behavior that is consistent with all available data. Our primary tool in this study of Tank 241-AN-105 is the maximum likelihood method of data reconciliation, which we have applied successfully to other tanks in the past. This method helps us (1) determine whether a model is consistent with the data, and (2) obtain quantitative estimates that are consistent with the data. A release of a flammable quantity of hydrogen in Tank 241-AN-105 is possible but unlikely at the current time. Any changes to the waste that could cause large releases would be accompanied by a measurable increase in the surface level of the waste. We also theorize that a significant increase in the waste temperature may signal a qualitative change in the behavior of the waste and an increase in the flammability hazard.