Because there is no radioac-tivity involved, Japanese researchers expect that results will be available within a few weeks. The Japan Science and Technology Agency, which organized the accident investigation, published an interim report earlier this month. Further informa-tion including data on the loop section will be considered in a second report, to be released about the end of March. After that report, the cause of the leak will presumably be clear, and PNC can consider how to resolve the problem. A Surprise Possible design modifications to the thermocouple will be a major consideration.
Japanese researchers admit that the problem came as a surprise.
During computer tests, vibration had not been serious. Tests were conducted using water, and some thought piping with greater mechanical strength was probably needed. But it is very hard to predict the life of metal under vibration conditions. In the course of developing the reactor, the official continued, different tests were conducted to validate different phenomena. Since the accident, scientists have compared the two types and found differences in hydrodynamics and mechanical strength.