Peer Review of the Three Mile Island Unit 2 Vessel Investigation Project Metallurgical Examinations

摘要

Fifteen samples recovered from the lower head of the Three Mile Island (TMI) Unit 2 nuclear reactor pressure vessel were subjected to detailed metallurgical examinations by the Idaho National Engineering Laboratory, Argonne National Laboratory (ANL) and several of the European participants. These examinations determined that a portion of the lower head reached temperatures as high as 1100 degrees C during the accident and cooled from these temperatures at approximately 10-100 degrees C/min. The remainder of the lower head was found to have remained below 727 degrees C. A panel of three outside peer reviewers was formed to conduct an independent review of this metallurgical analyses. The review determined that the conclusions resulting from the INEL study were fundamentally correct. In particular, the panel reaffirmed that four lower head samples attained temperatures as high at 1100 deg C, and perhaps as high as 1150-1200 deg C in one case, during the accident. They concluded that these samples subsequently cooled at a rate of approximately 50-125 degrees C/min in the temperature range of 500-400 degrees C. The reviewers also agreed that the remainder of the lower head samples had not exceeded 727 degrees C during the accident and suggested several refinements and alternative procedures that could have been employed in the original analysis.