EPRI program concerning reactor vessel pressurized thermal shock

The long-term potential for neutron embrittlement of reactor vessels has been a recognized concern for a number of years. Recently, significant attention has been focused on the performance of certain vessels during overcooling transients. Such an overcooling system transient can occur in a variety of ways. These include primary system breaks, secondary system breaks, and excessive feedwater flow. The Electric Power Research Institute (EPRI) has been supporting research on reactor vessel integrity for a number of years. This work in the past focused mainly on materials and dosimetry. In June 1981, thermal hydraulics research also was expanded and accelerated. In addition, a cooperative program with four utilities was initiated to evaluate reactor vessel thermal shock for four specific plants