Lightning

Further to the ASN request of 15 October 2002, EDF forwarded the "lightning studies" defining the work needed before 31 December 2003 to ensure conformity with the above-mentioned order of 31 December 1999. EDF also completed conformity work on the plants concerned (Penly and Cruas) on 31 December 2004.

The ASN notified EDF of its additional requests, including a study of the impact of the lightning risk on the safety of the facilities. The ASN considers that the lightning risk studies transmitted by EDF are of high quality and in conformity with the applicable standards.

Heavy loads carried over the reactor vessel

During exceptional maintenance operations such as vessel head replacement and more conventional maintenance operations such as "tightening-loosening" vessel studs, handling of associated elements may require them to be carried over the vessel with the core loaded. These operations may also take place with the containment's equipment hatch open. The general operating rules (RGE) prohibit fuel handling when the reactor building is not correctly isolated from the outside.

At the request of the ASN, EDF conducted on all its nuclear power plants an analysis of these cases of equipment being carried over the loaded core vessel, whether or not the vessel head is in place. The analysis looked at ways of limiting these movements and, for those which remain necessary, how to prevent a load dropping and if it did, minimising its consequences.

The conclusions of this analysis led EDF to modify its practices to limit these handling situations and to submit a proposal to the ASN for modification of the general operating rules, particularly in order to define containment configurations for which these load movements over the reactor vessel remain authorised. Review of this subject began in 2005. The ASN asked EDF to apply additional constraints for certain types of load handling operations.

Heatwave and drought

Following the heatwave EDF had to deal with in 2003, steps were taken to ensure an appropriate response to any similar situation during the summer of 2004. 2005 was marked by a severe drought, although this had no safety or environmental protection consequences as a result of discharges from the nuclear power plants.

In 2005, in compliance with requests for changes to the general operating rules, EDF reassessed the maximum temperature limits allowable in premises containing equipment important for safety. Some of these requests are still being reviewed and the licensee will be required to submit additional safety justifications. The renewal of the discharge and water intake licence for the Nogent-sur-Seine nuclear power plant at the end of 2005 was also an opportunity to include the possibility of higher temperature discharges in certain climatic and power demand conditions, as with the Bugey, Golfech and Tricastin, NPPs.