The System 80+ Standard Plant Design Reduces Operations and Maintenance Costs

Abstract

To be cost-competitive, nuclear power plants must maximize plant availability and minimize operations and maintenance (O&M) costs. A plant whose design supports these goals will generate more power at less cost and thereby have a lower unit generating cost. The ABB Combustion Engineering Nuclear Systems (ABB-CE) System 80+TM Standard Nuclear Power Plant, rated at 1400 megawatts electric (MWe), is designed for high availability at reduced cost. To demonstrate that the duration of refueling outages, the major contributor to plant unavailability, can be shortened, ABB-CE developed a detailed plan that shows a System 80+ plant can safely perform a refueling and maintenance outage in 18 days. This is a significant reduction from the average current U.S. plant outages of 45 days, and is possible due to a two-part outage strategy: Use System 80+ advanced system design features and relaxed technical specification (TS) time limits to shift some maintenance from outages to operating periods: and Use System 80+ structural, system, and component features, such as the larger operating floor, permanent pool seal, integral reactor head area cable tray system and missile shield, and longer life reactor coolant pump seals, to reduce the scope and duration of outage maintenance activities. Plant staffing level is the major variable, or controllable contributor to operations costs. ABB-CE worked with the Institute of Nuclear Power Operations (INPO) to perform detailed staffing analyses that show a System 80+ plant can be operated reliably with 30 percent less staff than currently operating nuclear plants of similar size. Safety was not sacrificed when ABB-CE developed the System 80+ refueling outage plan and staffing level. The outage plan was developed utilizing a defense-in-depth concept for shutdown safety. The defense in-depth concept is implemented via systematic control of outage risk evaluation (SCORE) cards. The SCORE cards identify primary and alternate means of satisfying critical safety functions during all phases of the outage. Shutdown defense-in-depth is a major contributor to the System 80+ shutdown core damage frequency of 8.4E-07 events per year, a factor of 50 better than current plants.