| 摘要 |
PURPOSE:To prevent temperature rise of a fuel and a fuel canning tube caused by reduction of reactor core flow by detecting reactor core flow and generating a scram signal when the reactor core flow becomes prescribed value of less. CONSTITUTION:A reactor core flow monitor 17 receives a reactor core flow signal 19 from a reactor core flow sensor 18 and outputs a flow displacement signal 20 to a scram logic circuit 16. Reactor core flow is given as conversion of differential pressure before and after a reactor core support plate 22 into flow. The circuit 16 always compares present value x(t) of the reactor core flow with the reactor core flow X(t-tau) before only a prescribed time tau, computes the value Z(t), Z(t)=x(t)-A.x(t-tau)+B (A, B are prescribed constant), and the reactor core flow displacement signal 20 is output when said value is negative. The circuit 16 receives a signal 20, outputs a scram signal 15 to a control rod drive mechanism 13, the mechanism 13 rapidly inserts all control rods into a reactor core 2 and the scram of the reactor is performed. |
