- 287 - Pursuant to ASN's request, the CEA will submit before the end of 2011 a document describing the measures it intends implementing in view of reactor shut down scheduled for 31 December 2015 at the latest. ASN will analyse this document and make the necessary requests where applicable. JHR Loss of the electrical power supplies The JHR receives its electrical power from the CEA Cadarache on-site power network via two substations (PDL A and B). If the normal 15kV network is lost, the following networks are automatically activated: The standby diesel generator set (DS) provides an emergency supply for part of the priority power network (MEPA); The 2 backup diesel generators (DAS) each supply one train (trains A and B) of the backup power network (MEQ); The 2 ultimate backup sources (SUS A and B) comprising inverters and batteries, each supplying one train of the ultimate backup power network (MEU). If the off-site power supply is lost, the backup power network (MEQ), designed to the JHR design basis earthquake (DBE) presented in part 2 of this report (all the equipment items constituting this network must be operational during and after an earthquake), is automatically activated. It comprises two geographically separate trains ensuring redundancy of the actions necessary to place and maintain the reactor and experimental systems in safe condition. Each train is supplied by a backup diesel generator (DAS) with an estimated autonomy of 4 days. If the backup electrical power supply is lost, the facility has an ultimate backup power network (MEU), designed to the DBE (all the equipment items constituting this network must be operational during and after an earthquake), which for at least 2 hours supplies more particularly the equipment that removes residual power from the core in the short term (RUC, RUP, mixing pump, natural convection valves), and their support functions (ventilation, lighting, etc.). It comprises two trains (A and B), each energised by a system of batteries/inverters (ultimate backup sources SUS A and B). Nevertheless, these two trains do not provide complete functional redundancy, since particularly the natural convection valves are supplied by train A only and the mixing pump by train B only. Furthermore, the backup instrumentation and control has its own internal power supply providing an autonomy of at least 6 hours. Moreover each backup diesel generator can be replaced up by a mobile generator set via connections external to the buildings that house them. A mobile generator set can be available in less than 8 hours, or less than 4 hours if it comes from Cadarache Centre's own inventory. Measures envisaged to reinforce the robustness of the facilities to loss of the electrical power supplies The CEA envisages design changes to reinforce the availability of the backup electrical power supplies, such as: Use the standby diesel generator set (DS) to replace one of the two backup diesel generators (DAS). In this context, for an effective and rapid response (few hours) to the failure of a DAS, it is envisaged to: o reinforce the DS by classifying it as SI/O (Integrated System during earthquake/Operational after earthquake) so that it can also supply one of the backup trains; o move this DS (renamed GUS - ultimate backup diesel generator set) to a raised platform to protect it against any risk of flooding from the BMR building; Give the two ultimate backup sources (SUS) the same power capacity. To increase the autonomy of the equipment powered by train B, the licensee proposes increasing the capacity of SUS B by increasing its autonomy from the current 2 hours to 6 hours, making it identical to that of SUS train A. ASN notes the improvements envisaged by the licensee to reinforce the robustness of the JHR facility in the event of electrical power supply loss. It will issue requests to the licensee to reinforce the availability of the backup electrical power sources.
RkJQdWJsaXNoZXIy NjQ0NzU=