[en] The nuclear safety approach imposes to take into account in the design of a reactor, a list of events and configurations that are considered as precursors of transients important for the safety of the reactor. These incidental or accidental transients should be thoroughly studied during the design phase in order to be sure that safety criteria are well respected with a sufficient margin. These studies are framed by procedures that are based on sets of input data, on simulation models and on computer codes and their validation domain. The operating life of a study procedure is usually over 10 years. A lot of procedures that date back in the seventies rely on simplified models and appear to be too conservative to today's standard. The generalization of 3-dimensional calculations for reactor core codes and the coupling between neutron transport codes and thermalhydraulic codes make necessary a progressive updating of the study procedures. (A.C.)

[en] The paper describes the IAEA programmes and capabilities contributing to the peaceful uses of nuclear technology on a global scale. The IAEA has developed and continues to support a global nuclear safety regime that is comprised of several facets. The principal elements are binding and non-binding international legal instruments such as the various conventions and codes of conduct; a comprehensive suite of nuclear safety standards; a suite of international safety reviews and services, based on the safety standards; and the need to ensure strong national infrastructures and a global community of experts. These elements are described in some detail and the future challenges are outlined. (author)

[en] The main objective of this paper is to provide on overview of the key safety issues and challenges addressed to the advanced light water reactor designs. (author)

No abstract available

[en] Periodic Safety Review (PSR) is a comprehensive study on a nuclear power plant safety, taking into account aspects such as operational history, ageing, safety analyses and advances in code and standards since the time of construction. In Korea, PSRs have been performed for 20 units and have been effectively used to obtain an overall view of actual plant safety to determine reasonable and practical modifications that should be made in order to obtain a higher level of safety approaching that of modern plants. Among many safety enhancements achieved from Korean PSRs, new safety analyses are the important methods to confirm plant safety by increasing safety margin for specific safety issues. Methods and effects of safety enhancements applied in Korean PSRs are reviewed in this paper in light of new safety analyses to obtain additional safety margins

[en] The IAEA Director General stressed the role of safety culture in his concluding remarks at the Meeting of the Contracting Parties to the Convention on Nuclear Safety in 2002: 'As we have learned in other areas, it is not enough simply to have a structure; it is not enough to say that we have the necessary laws and the appropriate regulatory bodies. All these are important, but equally important is that we have in place a safety culture that gives effect to the structure that we have developed. To me, effectiveness and transparency are keys. So, it is an issue which I am pleased to see, you are giving the attention it deserves and we will continue to work with you in clarifying, developing and applying safety culture through our programmes and through our technical cooperation activities.' The concept of safety culture was initially developed by the International Nuclear Safety Advisory Group (INSAG) after the Chernobyl accident in 1986. Since then the IAEA's perspective of safety culture has expanded with time as its recognition of the complexities of the concept developed. Safety culture is considered to be specific organizational culture in all types of organizations with activities that give rise to radiation risks. The aim is to make safety culture strong and sustainable, so that safety becomes a primary focus for all activities in such organizations, even for those, which might not look safety-related at first. SCART (Safety Culture Assessment Review Team) is a safety review service, which reflects the expressed interest of Members States for methods and tools for safety culture assessment. It is a replacement for the earlier service ASCOT (Assessment of Safety Culture in Organizations Team). The IAEA Safety Fundamentals, Requirements and Guides (Safety Standards) are the basis for the SCART Safety Review Service. The reports of INSAG, identifying important current nuclear safety issues, serve also as references during a SCART mission. SCART missions are based on the SCART Guidelines, which provide overall guidance to ensure the consistency and comprehensiveness of the safety culture review. At the same time, SCART missions are designed to be able to respond to more specific or detailed requirements in accordance with national or regional culture. SCART missions are conducted with the aim to develop recommendations and suggestions in areas of direct relevance to the safety culture of the reviewed nuclear organizations. Commendable good safety culture practices are identified and communicated to other nuclear organizations in order to effect improvements worldwide. SCART is available to all Member States, and to all kinds of organizations, using or regulating the use of nuclear materials (e.g. nuclear facilities, regulatory bodies, nuclear design organizations)

[en] This paper presents an assessment of the safety system coverage for the McMaster Nuclear Reactor (MNR) for reactivity initiated accident (RIA) events. A recent assessment was included in the latest Safety Analysis Report (SAR) update (2002). This has since been supplemented by application of the power reactor methodology of trip coverage map generation using the simulation code PARETANL. Results of the trip coverage map analysis, showing the degree and limits of safety system coverage, are presented and discussed in the context of accident characteristics for the specific event categories, software limitations, and MNR operating and accident safety limits. (authors)

[en] Industrial radiography brings substantial benefits to society, and as long as the standards and codes prescribe the use of radiography, it is a justified practice. However the application of the high activity sources and powerful x-ray equipment posses a risk for the radiographers and members of the public, especially in the case of site radiography. This risk or radiation dose must be kept as low as reasonably achievable (ALARA). Accidents in which radiographers or members of the public receive doses that lead to deterministic effects must be prevented by all means. Regulations drawn up by the international and national authorities form the basis for radiation safety. The prime responsibility of radiation safety however lies with the operating company. Simply having policies and procedures in place is not sufficient in itself to ensure the required level of radiation safety. A safety culture needs to be fostered and maintained by the company to encourage a positive attitude to radiation safety and to discourage complacency. In this paper, a general introduction on safety culture and the development thereof will be given. This will be compared with the way in which RTD Netherlands developed, and improves its safety culture. (orig.)

[en] The use at nuclear power plants of balanced score cards including a safety index as one of its measures has been investigated with the purpose to add to the knowledge about how the use of this method affects safety. Measures and associated targets are widely used in the management of companies and organizations. This tends to make management concentrate on activities which are amenable for measurements. Surrogate measures are often used when it is difficult to measure the quality which is of primary interest. 'Balance score cards' is a management method. With the vision and the strategy as starting points, company activities are described within the framework of four perspectives: 'Financial', 'Customer', 'Process' and 'Learning and Growth'. Critical success factors are identified and measures and targets established. There is within the nuclear community a strong interest in defining measures for nuclear safety and possibly also to establish safety targets. However, as a concept, safety is not easy to define. Even more difficult is the establishment of a clear definition of an adequate level of safety. Nonetheless, there is a general understanding of what attributes a nuclear power plant should have in order to operate safely. Based on this general understanding a number of surrogate measures for nuclear safety, safety indicators, have been defined. A safety index is based on a combination of a set of measures for selected safety indicators. There are a number of problems associated with the use of safety indexes one of them being that an unfavourable development of one indicator could be hidden by the positive development of another indicator. Safety indexes are used at the Forsmark and Ringhals nuclear power plants. The use of safety indexes is only one of several methods used to monitor the safety. Safety indexes as currently used primarily provide historical information. Due to the nature of the safety indexes, they do not appear to be effective as measures for nuclear safety or as tools for safety management. There are other methods which are more effective and safety indexes are considered as complements

[en] To reduce the unnecessary burden of a regulation, NRC prepared three options for the risk informed regulatory framework known as Option 1, Option 2 and Option 3. In Option 2, all safety related Structure, System and Components (SSCs) and non-safety related SSCs are evaluated from a safety point of view, and the low safety significant SSCs belonging to the safety related group are called 'Risk Informed Safety Class (RISC) - 3' SSCs. The 'RISC-3' SSCs can be exempted from the special treatment requirements such as a seismic and environmental requirement, of 10 CFR 50. Two years ago, a paper was published which described the Option 2 method applied to the high pressure safety injection system (HPSI) and the essential service water system (ESW) of UCN 3. However, this paper describes the results when Option 2 is applied to the other 4 systems such as a low pressure safety injection system(LPSI), safety depressurization system(SDS), instrument air system(IAS), safety injection tank(SIT). First of all, this paper includes the results from the importance analysis in view of a Fire PSA and Level 2 PSA