Pulsed Neutron Activation Measurement of Emergency Core Coolant Bypass Flow on the LOFT (Loss of Fluid Test) Reactor

摘要

Pulsed Neutron Activation (PNA) techniques were used to measure the relative ECC bypass flow at the Loss of Fluid Test (LOFT) reactor during Loss of Coolant Experiment (LOCE) L1-5, the last test of the non-nuclear series of experiments. In this test, the fuel modules of the core were installed and the configuration of the LOFT facility was identical to that of the planned nuclear test series. The L1-5 test simulated a 200 percent double-ended offset shear break in one of the cold legs of a four-loop PWR. During the test, the average ratio of the ECC bypass flow to the total ECC flow was measured twice and found to be about 40 percent. The capability of PNA techniques to measure two phase flow distribution in large systems, at high flow velocities and low densities was demonstrated.