Pressure relief structures of multi-unit candu nuclear power plants

Abstract

Ontario Hydro's three principal nuclear power plants, Pickering, Bruce and Darlington GS incorporate a sequence of pressure relief structures linking all reactors to a vacuum building where accident produced volatile radioactive substances are contained. The paper discusses the design of Pickering's elevated pressure relief duct and its connection to the reactors by rupture panels. The development of the Pickering prototype pressure relief valve is described. At Bruce and Darlington a linear duct cuts through solid rock beneath the reactors, serving both as an access tunnel for their fuelling machines and as part of the pressure relief system. Its continuation, the reinforced concrete manifold, comprises an above-ground toroidal structure partially or fully encircling the vacuum building. The nature of the manfold and its supporting structures is outlined, with emphasis on the special loading conditions at Darlington arising from high seismic forces, hydrostatic uplift, tornado, and explosion.