Les cahiers de l'ASN #01 - Nuclear power plants: going beyond 40 years

Glossary Basemat: thick, reinforced concrete foundation slab providing a stable support under the reactor building. CLI: Local information committee. Set up for each nuclear power plant, the CLI brings together the licensee, ASN, the representatives of the local authorities in the vicinity of the plant and the local residents, along with members of associations. Containment: leaktight concrete shell containing the reactor vessel, the reactor coolant system, the steam generators and the main elements important for safety in a pressurised water reactor. Corium: mass of molten fuels and nuclear reactor core structural elements mixed together, which could form in the event of a severe accident. Divergence: beginning of the chain reaction process in a reactor; beginning of reactor activity. EPR: new type of nuclear reactor incorporating numerous improvements in terms of safety, fuel use and economic operation. AnEPR reactor is under construction at Flamanville. Guarantors: the consultation takes place under the auspices of two guarantors, freely appointed by the HCTISN from among the national list of guarantors drawn up by the National Public Debates Commission. The guarantors are involved in the entire process. They ensure that it takes place satisfactory, verifying that the public receives all pertinent information and guaranteeing their effective participation in the consultation, notably through the expression of observations and proposals. They also draw up a consultation report which will be made public on the HCTISN website. HCTISN: High Committee for Transparency and Information on Nuclear Security. Hydrotest: required every 10 years by the regulations, the hydrotest is an overall strength test which involves subjecting the system to a pressure 20% higher than its design pressure. IAEA: International Atomic Energy Agency, an inter- governmental organisation created in 1957, which is part of the United Nations Organisation. Its role is to foster and promote the safe, secure and peaceful use of nuclear technologies worldwide. With 170 member countries, the IAEA is the main forum for cooperation in the field of nuclear activities. The IAEA produces and updates a body of nuclear safety standards. IRSN: Institute for Radiation Protection and Nuclear Safety; an industrial and commercial public institution (EPIC) which more particularly provides ASN with technical expertise. Periodic safety review: in-depth examination of a nuclear facility, scheduled by the regulations every 10 years, designed to ensure the conformity of the facilities, the management of the ageing of the facility’s components (materials, equipment, systems, etc.) and to raise their level of safety. This reviewmay lead to major works in those areas in which the regulatory and technical requirements have changed significantly. Radiation protection: radiation protection is defined as being all the rules, procedures and means of prevention and monitoring designed to prevent or mitigate the harmful effects of ionising radiation directly or indirectly affecting humans, including in the event of adverse environmental impacts. Stress tests: two weeks after the Fukushima accident, the European Council meeting of 24 and 25 March 2011 decided that stress tests should be performed in European NPPs in order to take account of the first lessons learned from the accident which occurred in Japan. In France, the stress tests were known as the “Évaluations complémentaires de sûreté (ECS)” on the nuclear facilities in the light of the Fukushima disaster. By comparison with the European framework, the French exercise was extended to include all nuclear facilities and enhanced by incorporating social, organisational and human factors. 80 priority facilities, including the NPPs, were examined in 2011 and all underwent specific inspections. Ten-yearly outage inspection: lengthy reactor outage (about five months) during which the licensee carries out checks and modifications in order to reinforce the safety level. The ten-yearly outage inspection is one step in the periodic safety review and leads to a conclusions report sent to ASN. 24 • Les cahiers de l’ASN • September 2018