Semi-quantitative determination of a tritium removal facility characteristic risk

Abstract

Due to its radiotoxicity tritium, especially in its oxide form, represents the characteristic hazard of a Tritium Removal Facility (TRF). Consequently, the risk of uncontrolled releases of tritiated water (HTO) into the free atmosphere is considered to be the characteristic risk (Rc) of these non-reactor nuclear installations.The Rcmax of a TRF will be characterized by the maximum and credible probability and by the maximum possible consequences of the most unfavorable accident scenario, usually meaning uncontrolled release of tritium as oxide in the outer atmosphere, by failing of all defense-in-depth barriers.Locating it in the acceptable zone of the risk matrix would be the best confirmation of the project quality from the perspective of life and environment security, generating a consolidation of public trust in the safety of nuclear energy.The paper presents a semi-quantitative determination of the maximum characteristic risk for the TRF pilot plant which can be applied or can serve as an approach for other tritium extraction facilities connected to fission CANDU (Canada Deuterium Uranium) or fusion type reactors, like ITER (International Thermonuclear Experimental Reactor) or DEMO (DEMOnstration Power Plant).The advantage of this method is that it requires a low consumption of man-hours and can be carried out from the design phase with minimum input data. The results allow the verification of compliance with national legal provisions, of the location choice and the development of the emergency plan in case of a maximum credible accident.