A PROCEDURE FOR THE ANALYSIS OF ERRORS OF COMMISSION IN A PROBABILISTIC SAFETY ASSESSMENT OF A NUCLEAR-POWER-PLANT AT FULL POWER

This paper describes an analytical procedure that has been developed t o facilitate the identification of errors of commission for inclusion in a Probabilistic Safety Assessment (PSA) of a nuclear power plant op erating at full power. The procedure first identifies the opportunitie s for error by determining when operators are required to intervene to bring the plant to a safe condition following a transient, and then i dentifying under what conditions this is likely to occur using a model of the causes of error. In order to make the analysis practicable, a successive screening approach is used to identify those errors with th e highest potential of occurrence, The procedure has been applied as p art of a PSA study, and the results of that application are summarized , For the particular plant to which the procedure was applied, the con clusion was that, because of the nature of the procedures, the high de gree of redundancy in the instrumentation, the operating practices, an d the control board layouts, the potential for significant errors of c ommission is low.