- 27 - More broadly, on most of the sites, the inspectors noted that the only training requirement with regard to the subject of earthquakes is that covering the earthquake event approach. ASN finds that EDF must define awareness-raising and training measures in addition to those that already exist, for the site personnel, whether on-site staff or external staff, in order to ensure that the seismic risk is continuously taken into account on the site on a long term basis. Shutdown after earthquake All of the sites apply fundamental safety rule (RFS) I.3.b concerning seismic instrumentation. Section 2.3 ("Operation of seismic instrumentation") states that: "if the earthquake level corresponding to a spectrum with an amplitude half the design response spectrum for the site is exceeded by any of the measurements, the licensee shall immediately go to the shutdown state considered, for each unit, to be the safest". The time to shutdown does not appear in the operating instructions presented. Furthermore, the sites told the inspectors that no earthquake simulation exercises had been held (see training section of this chapter). The estimated emergency shutdown time therefore has to be tested and confirmed in the field. Finally, during the exercises performed, some sites were unable to correctly respond to this requirement (longer than 1 hour at Le Blayais, 1h30 at Fessenheim), in particular as a result of insufficiently precise instructions and a lack of operator awareness. ASN finds that, for all of its reactors, EDF must check that the organisation in place today enables all of its reactors to comply with the abovementioned requirement of the RFS I.3.b. As applicable, the sites shall deploy an appropriate organisation (procedure and training). In the light of the shortcomings observed, ASN will require that EDF study the possibilities for installing an emergency shutdown device in the event of an earthquake. Performance of earthquake exercises Most of the sites informed the inspectors that they had not carried out any exercises on the subject of earthquakes. This type of exercise permits determining the effectiveness of the arrangements made to deal with an earthquake and the training given. ASN finds that it is necessary that EDF's crisis exercise programme take account of the earthquake topic and the resulting consequences (fire, explosion, etc.). Instrumentation training During most of the inspections, an exercise was held in the control room to simulate the occurrence of an earthquake and overshoot of an accelerometer alarm threshold. This exercise required familiarity with the working of the acceleration electronic recording cabinet (containment instrumentation system for seismic monitoring and measurement or EAU rack) and an accelerograph, used if the EAU rack is unavailable. It was also necessary to calculate the intensity of the earthquake using the values recorded by the EAU rack. The result of this calculation was then used to help guide the operating crews with management of the event. On some of the sites, training is provided on use of the EAU rack. However, in some cases, the inspectors were able to observe: that this training had not been given or written up in the individual training logs; that this training had not led to an evaluation; that no exercises had been carried out concerning this rack; that the staff were unable to calculate the values enabling a decision to be reached on whether or not to shut down the reactor; that the operators were insufficiently familiar with all the instrumentation functionalities (in particular the EAU rack). Finally, during the course of an exercise simulating a malfunction of the EAU rack (at Chooz and Cruas), the inspectors observed that the operators were unable to interpret the peak accelerograph sensor data. In the event of an earthquake and unavailability of the rack, the plates of the peak accelerograph located in the control room are sent by transporter to the Thermal and Nuclear Studies and Project Service
RkJQdWJsaXNoZXIy NjQ0NzU=