Source Terms for Emergency Planning In Ontario

Abstract

Following a severe reactor accident, it isestimated that it would take about four hours toinitiate an off-site response action. Decisionsto implement such actions are based on predictionsof the source term. During the first few hours,such predictions must be based on calculations,until reliable measurements can be obtained, andan emergency response is developed on this basis.The ase of overly conservative assumptions, suchas those used for licencing assessments, resultsin over predictions of the source term to such anextent that they may lead to inappropriateemergency responses, the risk of which may exceedthe radiation risk. This paper discusses recentdevelopments in the source term area and advocatesthe use of more realistic models and assumptionsfor source term predictions as input to emergencyplanning in the Province of Ontario.