The inspectors identified an Unresolved Item (
URI) regarding the risk-management aspects of the use of the temporary
CST system while the permanent
CST was out-of-service for various activities. As described in the previous section, in January 2010, the licensee used a temporary
CST system that was installed as an alternate water supply for the permanent
CSTs to accommodate several plant modifications for several issues including coating refurbishment,
license renewal inspection, and installation of new motor-driven
auxiliary feedwater system mechanical piping connections. During this evolution, the licensee credited the out-of-service
CST as available from a risk perspective through the use of the temporary
CST modification. The inspectors reviewed the risk management aspects of this issue and found that for the maintenance activities on the permanent
CST, procedures did not exist to support this risk mitigation activity. Additionally, the design of the system did not appear to meet the established guidance for risk mitigation. Therefore, the risk mitigation management aspects are considered unresolved pending future evaluation of these activities (
URI 05000266/2010002-04;
05000301/2010002-04; Potential Failure to Adequately Assess Risk During
CST Modifications)
