Refill Study of a CANDU-Type Header/Feeder System Under Near-Zero Header-to-Header Pressure Drop

Abstract

The behaviour of CANDU header/feeder piping during refill in a near-zero header-to-header pressure drop determines the delivery of emergency coolant to the fuel channels in certain postulated loss-of-coolant ace iden ts. This paper des er i bes an experimental test facility and program to examine this behaviour. The header/feeder behaviour vas examined to determine the effects of header preheat temperatures, injection flov rate, break size and break location. The thermalhydraulic behaviour during refill is described in detail for a selected experiment. The break size was found to have the least influence while the header preheat temperature and injection flow rate were found to have the largest. A preliminary simulation of one test with the two-fluid code CATHENA is shown. While the qualitative agreement between the simulation and experiment was good, the comparison shows that improvements in the code's constitutive relations are required.