EVAL OF RELIABILITY & USEFULNESS OF EXTERNAL-INITIATOR PRA METHODOLOGIES

THE DISCIPLINE OF EXTERNAL-INITIATOR PRA ANALYSIS IS RELA- TIVELY LESS MATURE AND LESS RELIABLE THAN THE CORRESPONDING INTERNAL-INITIATORS PRA ANALYSIS. THESE RELATIVE WEAKNESSESHAVE MADE MANY DECISION-MAKERS, IN BOTH INDUSTRY AND THE NRCRELUCTANT TO USE EXTERNAL-INITIATOR PRA RESULTS. THE EXTER-NAL-INITIATOR ANALYSES HAVE BEEN CONSIDERED TOO UNCERTAIN, OR TOO CONSERVATIVE, OR SUPPORTED BY TOO LITTLE SOLID DATA TTO BE OF MUCH USE. ALTHOUGH THIS PICTURE HAS RECENTLY BEGUNTO CHANGE, THERE IS A NEED TO EVALUATE THE EXTENT TO WHICH EACH CATEGORY OF EXTERNAL-INITIATORS PRA METHODOLOGY, AT ITSCURRENT STATE-OF-THE ART LEVEL, PRODUCES RELIABLE AND USEFULRESULTS AND INSIGHTS, IN ORDER TO ASSIST DECISION-MAKERS IN UNDERSTANDING BOTH THE BENEFITS AND THE LIMITATIONS OF EXTERNAL-INITIATOR PRA. THE PROPOSED PROJECT WOULD UNDERTAKE JUST SUCH AN EVALUATION. THE OBJECTIVE WILL BE, FOR EACH EXTERNAL-INITIATOR CATEGORY SEPARATELY, TO EVALUATE THE RELIABILITY AND USEFULNESS OF THE INSIGHTS AVAILABLE. SPECIALLY,THE EVALUATION WILL ADDRESS WHETHER THE RESULTS AND INSIGHTSEMERGING FROM CURRENT ANALYSES ARE RELIABLE AND USEFUL, AND WHY--AND IF NOT, WHY NOT. THE FIVE INIATOR CATEGORIES TO BESTUDIED ARE EARTHQUAKES, INTERNAL FIRES, EXTERNAL FLOODING, HIGH WINDS, AND TRANSPORTATION ACCIDENTS.