Containment and siting of high power reactors

Abstract

Developing technology has made it feasible to construct power reactors of a few thousand MWt capacity. The problems of siting such very high power reactors are different from those encountered in siting of reactors of a few hundred MWt capacity. Environmental safety in the case of very high power reactors (say 10 000 MWt) can no longer be ensured through taller stacks or large exclusion distances. It has to be provided through engineered safeguards by improved containment of induced gaseous activity during normal operation and of noble gas and volatile fission products in the event of a serious accident and core melt. No single containment system such as pressure, low pressure, pressure suppression, pressure relief, negative pressure, multiple barrier or underground is adequate. A judicious combination of high integrity containment with auxiliary safeguards such as core cooling and building spray may be considered a step in the right direction. Containment of liquid wastes generated in an MCA and containing highly radiotoxic fission products is a serious problem for desalination reactors which are the large sources of water used over extensive areas for irrigation industry and drinking purposes. In this paper, the concept of ARE (acceptable release in emergency) has been used to assess the requirements of containment capability of very high power reactors and their siting problems. The dose levels due to release of fission products in the containment are given. From the safety point of view no more than one high power reactor should be located within the exclusion radius for a reactor, so that MCA to one of them does not jeopardise the operation of the other reactors.