METHOD FOR DETERMINING FAILURE OF FUEL ROD, METHOD FOR ESTIMATING BURN-UP OF FAILED FUEL AND METHOD FOR OPERATING NUCLEAR REACTOR

摘要

PPROBLEM TO BE SOLVED: To improve accuracy in detecting failure of a fuel rod other than a failed fuel rod while a nuclear reactor loaded with the failed fuel rod is in operation. PSOLUTION: The method includes: detecting a first failure while a nuclear reactor is in operation (step S1); identifying a cell containing the failed fuel body (step S2); continuing the operation of the nuclear reactor by inserting a control rod into the cell and reducing the thermal output (step S3); and measuring a ratio of radioactivity of cesium 136 to that of cesium 137 in the nuclear reactor water (step S4) to detect failure of a fuel rod other than the first failed fuel rod. Thus, it is determined that failure of a fuel rod has newly occurred if a change of the radioactivity ratio per unit time is larger than a predetermined threshold. PCOPYRIGHT: (C)2009,JPO&INPIT