- 176 - the creation of a Nuclear Rapid Intervention Force (FARN) and defining of its material and human resources; the functional earthquake resistance of the U5 system. ASN considers that all these lines for improvement contribute to the reinforcement and robustness of accident and severe accident management on the sites. ASN nevertheless considers that some of the points identified by EDF need to be clarified. It will therefore issue requirements instructing EDF to integrate in the hard core: the emergency management rooms. They must display high resistance to hazards and allow the management of a long-duration emergency; the mobile devices vital for emergency management; the active dosimetry equipment, the measuring instruments for radiation protection and the personal and collective protection equipment are also included in the hard core. They must be permanently available in sufficient quantity on the sites; the technical and environmental instrumentation for diagnosing the state of the facility and assessing and predicting the radiological impact on the workers and populations; the communication means vital for emergency management are included in the hard core provisions. They more particularly comprise the means of informing the public authorities and alerting the populations if the off-site emergency plan (PPI) is triggered in the reflex response phase. The requirements concerning the FARN must be supplemented, particularly in that it must be capable of intervening on the accident site in less than 24 hours to relieve the shift teams and deploy the emergency means of resupplying power, with operations on a site starting within 12 hours after the start of mobilisation. The FARN teams must be dimensioned to intervene on a 6 reactors-site, including a site where a massive release has taken place, and have appropriate instrumentation that can be deployed on the sites on arrival. 6.2 Existing accident management measures further to loss of core cooling In the CSA specifications, ASN asked EDF to describe the accident management measures currently in operation at the different stages of a severe accident, particularly further to loss of the core cooling function: before the fuel in the reactor vessel becomes damaged; o possible actions to prevent fuel damage; o elimination of the possibility of fuel damage at high pressure. after the fuel in the reactor vessel has been damaged; after failure of the reactor vessel (core meltdown in the reactor pit). 6.2.1 Before the fuel in the reactor vessel becomes damaged In the CSA reports, EDF indicates that the safety procedures for the reactor fleet in service and the EPR rely on a strategy of defence in depth, which can be summarized as follows: measures are taken to avoid incidents; if an incident occurs, the protection systems bring the reactor to a safe condition; safeguard systems prevent a more severe accident from leading to core meltdown. The existing measures to prevent entry into a severe accident situation (therefore before the fuel in the reactor vessel becomes damaged), particularly further to situations of flooding, earthquake, loss of electrical power or of the heat sink, come under the incident/accident operation (CIA) procedure.
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