NRC's Approach to Violations of Design Criteria: Regulatory Decision Philosophy and Control of Licensing Basis

'Safety enhancements' are the requirements to be undertaken if it proves to be beneficial to safety in terms of cost benefits, etc., beyond adequate protection, which are based on Article 161 (b)(i) of the Act. The division of these two dimensions has been gradually established through a number of court appeals and judgments. The case of the Union of Concerned Scientist (UCS) vs. the NRC judged by the Washington DC Court of Appeals in 1987 had a major impact on that distinction. The court stated that adequate protection need not to be specifically defined, but that it did not mean ^zero risk^, and that the Congress gave the NRC the power to determine its scope and content. Therefore, it is the NRC's authority and responsibility to determine the content and scope of 'safety enhancements' and the NRC will decide whether to consider costs and other factors when making decisions regarding safety enhancements. This paper introduces recent NRC decision cases to review the NRC's regulatory decision philosophy. The NRC's regulatory decision-making approach suggests the future study needs. The uniqueness of regulatory system of a country is based on the legal system (Roman vs. Anglo-Saxon), principles (precaution vs. pragmatism), regulatory target (public vs. private), etc. Our system is based on Roman law, however, using American standards and adopting European practices for regulatory inspection and enforcement. Thus, it is necessary to first check our position in the regulatory style.