The thermohydraulic response of a nuclear reactor containment vessel to a loss-of-coolant accident.

摘要

A general review is given of containment technology for water-coolednuclear reactors, including discussion of the methods ofanalysis of the pressure response of the containment to a loss-of-coolantaccident. Particular attention is paid to considerations ofheat transfer from the consequent reactor efflux in the situation offull-pressure containments, and various schemes given in the literatureand used in computer codes for calculating condensation heat transferare critically examined.An experimental study has been made in conditions typical of thepostulated reactor accident situation using a rig consisting of aO 0.014 m high pressure vessel which could discharge its contentsthrough a defined flow path into a 2 m3 steel containment vessel. Therig is instrumented to measure the instantaneous pressure and temperaturedistribution during a pressure vessel blowdown. It includes asystem for measuring the condensation heat transfer coefficient transientin which the transient heat flux and surface temperature at ametal plug are derived from a single measurement of temperature withinthe plug by use of a Fourier Transform method. A simple point modelanalysis of the thermohydraulic conditions throughout the blowdown/containment rig is derived and used to demonstrate the effect onprediction of containment pressure response of various heat transferschemes and the relationship to the measured response.A new heat transfer scheme is found, based on the measured heattransfer transients which, when used in the derived code, gives reasonablefit to the measured pressure transients over a wide range ofinitial conditions.