[en] In Korea, twenty units of nuclear power plant are operating at present and especially Kori Unit 1 and Wolsung Unit 1 beyond twenty years. Usually it takes several years for operators to prepare the long-term decommissioning strategic plans of their own facilities before starting decommissioning, and also for regulator to revise the Atomic Energy Act and its regulations, which are the basis of operators' activities. In the light of this situation, it is time that we are going to check and, if necessary, to enhance the domestic regulatory institutional system for decommissioning of nuclear facilities. Of course, a lot of studies of the safety and costs for decommissioning have been carried out in domestic, but the study on the regulatory institutional aspects is less enough than them. At the Spring Proceedings of the Korean Nuclear Society in this year, the status of regulatory system for decommissioning of the EU countries, such as France, Germany and the United Kingdom, was presented. In this paper, the results of survey and analysis of the regulatory system for decommissioning of the United States of America (USA) and Japan is described. This will be also useful in developing of the direction of enhancement in our own system

[en] In Korea, twenty units of nuclear power plant are operating at present and especially Kori Unit 1 and Wolsung Unit 1 beyond twenty years. Usually it takes several years for operators to prepare the long-term decommissioning strategic plans of their own facilities before starting decommissioning, and also for regulator to revise the Atomic Energy Act and its regulations, which are the basis of operators' activities. In the light of this situation, it is time that we are going to check and, if necessary, to enhance the domestic regulatory institutional system for decommissioning of nuclear facilities. Of course, a lot of studies of the safety and costs for decommissioning have been carried out in domestic, but the study on the regulatory institutional aspects is less enough than them. In this paper, the results of survey and analysis of the regulatory system for decommissioning of the EU countries such as France, Germany and the United Kingdom are described, which will be useful in finding the direction of enhancement in our own system

[en] It is well known that on-line maintenance (OLM) has some potential for safety enhancement of operating nuclear power plants. The Korea Institute of Nuclear Safety (KINS) is developing a regulatory framework for OLM implementation under the auspices of MEST. This paper introduces drafts of regulatory technical requirements which will constitute the regulatory framework for OLM

[en] Since 2007, new innovative reactors, such as VHTR (Very- High-Temperature Reactor) for hydrogen production and Gen. IV SFR (Sodium-cooled Fast Reactor) have been developed by the KAERI (Korea Atomic Energy Research Institute) under auspices of the MEST (Ministry of Education, Science and Technology). The design concepts and characteristics of new innovative reactors are substantially different from existing LWRs, as denoted in Table 1. USNRC and IAEA have proposed to adopt regulatory technology-neutral framework (TNF) which can be applied regardless of their reactor types in order to enhance the effectiveness, efficiency, and predictability of future plant licensing. Especially, USNRC has provided an approach that appropriately integrates deterministic and probabilistic elements in the development of technical requirements for future reactors. The approach considers more extensive use of risk-informed and performance-based applications. In this study, utilizing the approach by the USNRC, the general safety and technical requirements for new innovative reactors are developed through several steps

[en] Many of preventive maintenance (PM) tasks have been restricted for deterministic safety reasons to be performed only during a refueling outage of NPPs. However, if the licensee has a reasonable expectation that OLM (On-line maintenance) will improve safety by making equipment more reliable, then the licensee may implement OLM even though it may increase the unavailability of equipment. OLM implementation needs the development of the regulatory technology for confirming the adequacy of the licensee's OLM program and its performance. As a part of regulatory technology of OLM, the regulatory and industrial documents published by foreign countries were investigated and analyzed. In this paper, we provide technical elements which need to be considered in developing regulatory technology of OLM. Also we propose measures considered in the development of the regulatory guidance for OLM

[en] It might be meaningful to analyze IAEA safety requirements. In this study, requirements in Appendix I “Requirements specific to uranium fuel fabrication facilities” and Appendix V “Requirements specific to fuel cycle research and development facilities” of IAEA Safety Requirements No. NS-R-5 (Rev.1), “Safety of nuclear fuel cycle facilities” are compared to figure out different and/or stringent requirements for the fuel fabrication facility and for the fuel cycle research and development facility. In this study, the safety requirements for the fuel fabrication facility and the fuel cycle research and development facility were compared. Through comparison of the safety requirements for the nuclear fuel fabrication facility and the nuclear cycle research and development facility, it can be seen that most of the safety requirements are common but some are different. Most of the requirements are common because the nuclear fuel fabrication facility and the nuclear cycle research and development facility deal with radioactive materials in common. For the nuclear fuel fabrication facility, a large amount of UF6 or UO₂ containing low enriched uranium 235 is treated in the process.

[en] With the increasing economic pressures being faced and the potential for shortening outage times under the conditions of deregulated electricity markets in the world, licensees are motivated to get an increasing amount of online maintenance (OLM). OLM means a kind of planned maintenance of nuclear reactor facilities, including structure, systems, and components (SSCs), during power operation. In Korea, a similar situation is made up, so it needs to establish a regulatory framework for OLM. A few years ago, foreign countries' practices related to OLM were surveyed by the Working Group on Inspection Practices (WGIP) of OECD/NEA/CNRA. The survey results and additional new information of countries' status will be helpful to establish our own regulatory framework for OLM, which are analyzed in this paper. From the analysis, some considerable points to be addressed for establishing a regulatory framework for OLM are suggested

[en] Three units of fuel fabrication plants are operating now in Korea. These fuel fabrication plants produce fuels for PWR, CANDU and HANARO research reactor, respectively. To enhance our regulatory systems for fuel cycle facilities including fuel fabrication plants, the related system of foreign countries is surveyed. In this study, the overall regulatory systems of the United States of America, France, Germany, the United Kingdom and Japan are surveyed. The survey items consist of laws and regulations, regulatory organization, licensing procedure, documents to be submitted with a license application, regulatory inspection, and etc

[en] It is well known that proper maintenance at nuclear power plant is essential to plant safety and that there is a clear link between effective maintenance and safety as it relates to such factors as the number of transients and challenges to safety systems and the associated need for operability, availability, and reliability of safety equipment. Good maintenance is also important in providing assurance that failures of non-safety related structures, systems, and components (SSCs) that could initiate, adversely affect, or mitigate a transient or an accident are also minimized. Maintenance is also important to ensure that design assumptions and margins in the original design basis are maintained and are not degraded to an unacceptable level. Therefore, good maintenance practice at nuclear power plants is of utmost importance in protecting public health and safety. This paper introduces the status of the development of regulatory technical requirements (Drafts) for utility's management of maintenance effectiveness. The process of Maintenance Effectiveness Management is shown in Figure 1

[en] The following five Safety Requirements publications were amended: Governmental, Legal and Regulatory Framework for Safety (GSR Part 1, 2010), Site Evaluation for Nuclear Installations (NS-R-3, 2003), Safety of Nuclear Power Plants: Design (SSR-2/1, 2012), Safety of Nuclear Power Plants: Commissioning and Operation (SSR-2/2, 2011), and Safety Assessment for Facilities and Activities (GSR Part 4, 2009). Figure 1 shows IAEA Safety Standards Categories Major amendments of five Safety Requirements publications were introduced and analyzed in this study. The five IAEA safety requirements publications which are GSR Part 1 and 4, NS-R-3 and SSR-2/1 and 2, were amended to reflect the lesson learned from the Fukushima accident and other operating experiences. Specially, 36 provisions were modified and the new 29 provision with 1 requirement (No. 67: Emergency response facilities on the site) of the SSR-2/1 were established. Since the Fukushima accident happened, a new word, design extension conditions (DECs) which cover substantially the beyond design basis accidents (BDBA), including severe accident conditions, was created and more elaborated by the world nuclear experts. Design extension conditions could include conditions in events without significant fuel degradation and conditions with core melting. Figure 2 shows the range of the DECs. The amendment of the five IAEA safety requirements publications are focused at the prevention of initiating events, which would lead to the DECs, and mitigation of the consequences of DECs by the enhanced defense in depth principle. The following examples of the IAEA requirements to prevent the initiating events are: margins for withstanding external events; margins for avoiding cliff edge effects; safety assessment for multiple facilities or activities at a single site; safety assessment in cases where resources at a facility are shared; consideration of the potential occurrence of events in combination; establishing levels of hazard for the design basis for the installation and their associated uncertainties; consideration of hazards due to surface faulting and flooding; monitoring of hazards and periodic review of site specific hazards; strengthening the prevention of unacceptable radiological consequences to the public and the environment; preventing severe accident through strengthening the plant design basis, including strengthening the independence of level four of defense in- depth, consideration of external hazards and sufficient margins; periodic safety review; emergency preparedness; feedback of operating experience. The following examples of the IAEA requirements to mitigate the consequences of DECs are: role of the government and the regulatory body for emergency preparedness and response, strengthening severe accident mitigation measures; well defined and updated accident management program