- 331 - Measures envisaged to reinforce the existing measures and proposed studies The licensee proposes no measures to reinforce the existing provisions, as decommissioning is in progress. ASN has no particular remarks concerning the ATPu. Masurca Loss of the electrical power supplies for the Masurca facility does not lead to the risk of a cliff-edge effect, and no cooling is necessary given the current status of the facility. Only the post-earthquake management is handled by the CEA. The review conducted by the IRSN, ASN's technical support organisation, put forward that - contrary to the conclusions of the licensee - there is apparently a real toxicity risk in the event of fire due to the presence of sodium on the facility. This risk could complicate management of an accident situation. Existing severe accident management measures The CEA specifies that a procedure specific to Masurca has been put in place to define the initial actions to take in the event of an earthquake, the aim being to reach a shutdown state immediately after the earthquake and conduct investigations to assess the situation and take conservative measures to lastingly maintain the facility in safe condition. The actions to take depend on the intensity of the earthquake. In the case of a "weak" earthquake, that is to say in which the BSM (storage and handling building) remains intact and the functions are operational, the actions will consist in verifying the assumption of "good behaviour" of the facility through inspections targeting the points judged to be sensitive. In the case of a "strong" earthquake (substantial damage to the BSM and many functions out of service), safeguard actions shall be implemented to prevent possible aggravation of the situation (fire, explosion, collapse, leaks, etc.). Among the recommended actions, the CEA plans cutting off the supplies of electricity, water, diesel fuel and argon-CO2 to avoid risks of an indirect effect further to an earthquake. The CEA also indicates that depending on the nature and severity of the damage suffered by the facility, measures would be taken to prevent or mitigate environmental contamination. With regard to the fire risk, the fact that sodium is present in the facility means that the risk of a sodium-water reaction when fighting a fire must be considered. The CEA has specified in this respect that the use of water for fighting fires in the Masurca facility is prohibited by the emergency intervention instructions. The CEA plans for manual cut-off of the electricity, water, diesel fuel and argon-CO2 supplies in the event of an earthquake. The intervention instructions underline that the security duty watch (PMS) is ensured by a single person outside working hours. Due to the risk of the BSM collapsing in an earthquake, the CEA has decided to temporarily store the fissile material from BSM storeroom No.1 - the main contributor to the radioactive material inventory of the BNI on 30 June 2011 - in the MAGENTA facility, until the new BSM designed to seismic standards enters service in 2017. ASN considers that the currently stored fissile material must be removed in the short term. ASN will issue a requirement to set the deadline in this respect. In addition, the licensee has not specified the concrete measures envisaged to mitigate the radiological consequences on the environment. It has nevertheless developed the description of post-earthquake management. In the event of an earthquake causing partial or total collapse of the BSM and leading to a cliff-edge effect, the centre's own means will be called upon, along with external means if necessary. In this latter situation, emergency management will be coordinated by the Crisis Coordination Centre (CCC), which will be able to deploy the human and material resources of GIE INTRA (group deploying robot intervention on accident sites). This group is capable of getting its teams and equipment to the site within 24 hours at the most. The review has revealed that the CEA has no means of limiting environmental contamination.
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