Pressure relief structures of multi-unit CANDU nuclear power plants

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 the their fuelling machines and as part of the pressure relief system. Its continuation, the reinforced concrete manifold, comprises an above-ground toroidal structure partially of 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. (orig./HP)