June 20, 2007 — Comprehensive risk analysis provided by Oak Ridge National Laboratory researchers plays a crucial role in keeping billions of dollars of electricity generation on line — without compromising safety. In the absence of license renewal, more than 40 percent of the nation's 104 nuclear power plant licenses will expire by 2015. The replacement cost value of electricity generation capacity being submitted by industry in 2007-2008 for 20-year extensions is close to $20 billion, according to Richard Bass of ORNL's Computational Sciences and Engineering Division. The major concern is pressurized thermal shock, caused by either a rapid temperature or pressure change in the reactor vessel. This combined with the fact reactor vessels become embrittled over time increases the potential for a pre-existing crack to propagate through the vessel wall, causing failure. Using advanced risk-assessment engineering technologies and high-performance computing resources, ORNL provides the technical basis for the Nuclear Regulatory Commission to set standards used in the license renewal process. This research is funded by the NRC.