Summary of the Semiscale Program, 1965-1986

This document summarizes significant results from the Semiscale Program, which examined pressurized water reactor (PWR) safety issues from 1965 to 1986. Most of these issues were related to plant response during loss-of-coolant accidents and operational transients. The Semiscale program utilized a series of non-nuclear, scaled, PWR plant simulators to provide thermal-hydraulic data at prototypical pressures and temperatures for a wide range of nuclear safety issues. Presented are: a historical perspective of the Semiscale Program relative to reactor safety with a catalog of the Semiscale experimental facilities and data bases, the relationship of Semiscale results to 10 CFR Part 50 (Appendix K), the impact of Semiscale results on scaling experimental results to full sized operating plants, a summary of safety issues that were addressed by Semiscale testing as they arose throughout the operational lifetime of Semiscale, the contributions of the Semiscale Program to safety technology, a description of phenomena observed during Semiscale testing, the impact of Semiscale data on code development and assessment, the applicability of the Semiscale data base for code development and assessment, and finally, major conclusions and accomplishments of the Semiscale program