Incorporation of Unit 1 Inspection Results on the STP Reactor Vessel Head Nuclear Asset Management Analysis

Abstract

Including local experience information with generic data can maximize operational flexibility and help make better informed nuclear asset management decisions. Experience data are particularly helpful in risk-informed asset management decision-making. In 2004, South Texas Project (STP) used a risk-informed study to help decide the proper timing for reactor vessel head replacement. The decision to replace the reactor vessel heads was based on a previous study. Up to the time of decision-making inspections had not been performed at STP and therefore, the likelihood of finding a J-Groove failure in an inspection was based on generic industry information in both of the studies. In the Unit 1 fall outage, a full volumetric reactor vessel head penetration inspection was performed. The inspection method is briefly described. The algorithm for optimal timing of the reactor vessel head is presented and solved for the STP case. The generic industry J-Groove failure data is updated with the recent results from the Unit 1 outage inspection and the new failure projections are summarized. The optimal timing model is again run using the updated data and compared with the previous results.