NEW SAFETY BARRIER FOR CURRENT AND FUTURE NUCLEAR REACTORS

A proposal is formulated in the present paper to improve the safety of existing and future nuclear reactors. The proposal is based upon the introduction of new safety barrier against the release of radioactivity generated by the fission chain process. Basically, two motivations for the proposal arise: a) in the last two or three decades experimental evidence demonstrated that the established barrier constituted by the fuel pin clad is weak and easily trespassed by fission products during various phases of the fuel cycle, with main regard (here) to the in-core irradiation; b) the probability of core melt must (and can) be substantially lowered by adopting outcomes from recent researches with main reference to the reached capabilities of computational tools. Furthermore, the correct interpretation of the words ‘feedback from lessons learned’ impose that the conditions which led to the occurred severe accidents are understood to be not replicable in the future and, according to the statement of Australian and Chinese scientists, “upgrading and strengthening a nuclear regulatory system is not optional but imperative to prevent the next core meltdown”. The proposal aims at fixing bases for possible strengthening of current Nuclear Reactor Safety by combining the logical frameworks connected with the terms As-Low-As-Reasonably- Achievable (ALARA), Best-Estimate-Plus-Uncertainty (BEPU), Extended-Safety-Margin (ESM) and Independent-Assessment (IA). The cost for the implementation of the proposal is expected to be affordable from a financial viewpoint and to contribute to restoring the public confidence towards nuclear technology.