Research and experience report 2009. Developments in the technical and legal basis of nuclear oversight

In terms of research into regulatory safety, ENSI awards and coordinates research projects designed to develop current scientific knowledge and expertise and to make the results available to the regulatory process. ENSI currently supports research in four different areas: Reactor Safety; Radiological Protection; Transport and Waste Management; and Human Influence, Organisation and Safety Culture. Research in reactor safety focuses on materials research of relevance to the monitoring of ageing mechanisms such as fatigue, corrosion, embrittlement and the development of cracks, together with research into incidents and accidents and their relevance to improvements in safety analyses. It investigates issues such as the interaction between core meltdown and water and concrete, as well as the development of methodologies and software. In addition, ENSI is a partner in a range of international database projects giving it access to information on the causes, frequency and characteristics of individual incidents. The aim of radiological protection is to protect personnel, local people and the environment in the vicinity of nuclear facilities from ionising radiation. ENSI supports research into dosimetry and radio analysis. Another area of particular importance is research designed to improve the methodologies used to monitor the release of radioactive materials into the environment. In the area of transport and waste management, ENSI investigates the suitability of geological strata for the deep storage of radioactive waste. Experiments are being conducted at the Mont Terri Rock Laboratory into the geological, hydro-geological, geochemical and rock-mechanical properties of the Opalinus clay. ENSI is supporting an experiment designed to characterise the fracture generation in the excavation damage zone of a gallery triggered by stress changes in the surrounding rock. The research is also looking at the chemical reactions occurring in a deep repository, together with the physical transport processes and the management of all radioactive waste. ENSI supports research projects into the influence of human behaviour on incident management together with the development of requirement profiles for staff in the control rooms of nuclear power stations. Incidents in nuclear facilities provide concrete data on shortcomings and the potential for improvements in all areas of design and operation. Information on incidents in Swiss nuclear facilities is included in ENSI's (separate) Surveillance Report. Some incidents in nuclear facilities outside Switzerland were analysed in order to identify any relevance for Swiss nuclear facilities. There has been increase worldwide in the number of incidents involving the transport of loads. In Switzerland also, the Interim Storage Facility of Wuerenlingen AG reported an event in 2009 involving a lifting device. ENSI has increased its surveillance of cranes and other lifting devices. The Ringhals nuclear power plant (NPP) in Sweden had been operating at power for 72 days before it was discovered that the automatic initiation of the containment isolation system was not operational: the bypasses in the reactor protection system were not correctly removed. Investigations identified the absence of a clear demarcation between the responsibilities of operating and maintenance personnel. Although very improbable, a similar incident might occur in Switzerland; however it is very likely that it would be picked up during the obligatory functionality check. Nevertheless, ENSI considered it important that facilities took note of this incident. Following heavy rain, debris blocked the cooling water intake at the Cruas 4 NPP; this caused the main water sink to fail. At the Fessenheim 2 NPP, plant residues found their way into the cooling water system after the cleaning system failed. By such an incident in a Swiss NPP, the plant could be made safe because the Swiss NPPs are fed with water from their own wells or from additional intake points in the cooling water outlet. There have been defects and incidents in the construction of the new plants at Olkiluoto (Finland) and Flamanville (France) relating to concreting work and inadequate welding specifications. ENSI will develop a new surveillance concept for the construction of NPPs, so that Switzerland is prepared in time for any new builds. ENSI maintains active links with international organisations, particularly with IAEA, OECD/NEA and WENRA and also has a series of bilateral agreements with France, Germany, Austria and the USA. The ENSI contribution to current negotiations on greater global harmonisation is based on the stringent nuclear safety standards in Switzerland. At the 3rd Review Conference of the Joint Convention on the Safety of Spent Fuel Management and on the Safety of Radioactive Waste Management, Switzerland received a rating of good for its Country Report: other countries welcomed the transparency of the master plan procedure and the participation of the public and neighbouring countries. The research programme at the rock laboratories of Mont Terri and Grimsel also received a positive reception. According to the main requirements of IAEA and the Swiss Nuclear Energy Act, since 1 January 2009 ENSI has been an independent nuclear regulatory body reporting directly to the Federal Council (Swiss national government). The existing ordinances and guidelines are continuously amended to accord with the recent legislation on nuclear energy and also are harmonised with international standards. A new ordinance based on the Nuclear Energy Act took effect in 2009. In addition ENSI completed 8 guidelines, either new or revisions