Moderator temperature coefficient positive / negative judgment method and positive / negative judgment device

摘要

PPROBLEM TO BE SOLVED: To provide a method and device for determining positive/negative of the moderator temperature coefficient before output control by control rod operation is required. PSOLUTION: A neutron flux monitor 26 calculates a reactor period based on a value of a neutron flux detected from a reactor 1 with a neutron flux detector 12, and a reactor water temperature difference calculation apparatus 29 calculates reactor water temperature difference occurring while the control rod drive stopping state continues. When the inverse number of the reactor period is a preset value or more, the reactor water temperature difference is a preset value or higher, and the control rod drive stopping state continues for a certain time or longer, a positive/negative determining apparatus 35 determines that the moderator temperature coefficient is positive. When the inverse number of the reactor period is the preset value or less, the reactor water temperature difference is the preset value or higher, the control rod drive stopping state continues for the preset certain time or longer, and the last driving before stop of the control rod is performed in the pulled direction, the moderator temperature coefficient is determined to be negative. PCOPYRIGHT: (C)2007,JPO&INPIT