Thermal-hydraulic considerations in nuclear power plant license renewal

A major issue looming in the future for both the NRC and the regulated industry is the matter of license renewal. This is the renewal of licenses beyond the current 40 year plant life (not to be confused with license extension involving moving the start date of the 40 year life from the CP issuance to the OL issuance). While it is too early to speculate as to what shape the license renewal policy and regulations will take, it is not too early to conclude that each licensee will have to demonstrate why its plant can operate safely beyond 40 years. Exactly how this demonstration must be made is the subject of an extensive policy development program and rulemaking process at the NRC. There are certain areas of thermal hydraulic analysis that may be important to license renewal. These are 1) Pressurized Thermal Shock to Pressure Vessels, 2) Management of Severe Accidents, 3) Plant Simulators, and 4) Transient Histories. Each of these is briefly discussed