THE PASSIVE ALWR APPROACH TO ASSURING CONTAINMENT INTEGRITY

Design requirements for the advanced light water reactor (ALWR) have b een developed so as to provide high assurance of containment integrity even in the event of a severe accident. The containment integrity req uirements are in the farm of two design criteria, and associated metho dology, which address containment severe accident performance and offs ite dose and are specified in the ALWR utility requirements document ( URD), a set of detailed design requirements for next generation plants in the US. The containment performance criterion, which is the main f ocus of this paper, specifies that plant design characteristics and fe atures shall be provided to preclude core damage sequences which could bypass containment and to withstand core damage sequence loads. This containment performance capability, along with the associated dose mit igation capability, provides a technical basis for emergency planning change since there would not be the same need for rapid offsite emerge ncy response that is called for under the existing US emergency planni ng basis.