Evaluation of Station Blackout Accidents at Nuclear Power Plants. Technical Findings Related to Unresolved Safety Issue A-44. Final Report

摘要

'Station Blackout' which is the complete loss of alternating current (AC) electrical power in a nuclear power plants, has been designated as Unresolved Safety Issue A-44. Because many safety systems required for reactor core decay heat removal and containment heat removal depend on AC power, the consequences of a station blackout could be severe. The report documents the findings of technical studies performed as part of the program to resolve this issue. The important factors analyzed include: the frequency of loss of offsite power; the probability that emergency or onsite AC power supplies would be unavailable; the capability and reliability of decay heat removal systems independent of AC power; and the likelihood that offsite power would be restored before systems that cannot operate for extended periods without AC power fail, thus resulting in core damage. The report also addresses effects of different designs, locations, and operational features on the estimated frequency of core damage resulting from station blackout events.