Reactor no. 2 of the nuclear power plant of TRICASTIN : The French Nuclear Safety Authority (ASN) assesses that the new technical solution proposed by France's Electric Power Company (EDF) is satisfactory.
On 8 September 2008 during the fuel unloading operation on the no. 2 reactor of the EDF nuclear power plant of Tricastin, two fuel assemblies remained stuck to the upper internal structures of the reactor vessel.
EDF presented to ASN on 30 September 2008 a process to recover both fuel assemblies. This process was not implemented by EDF.
ASN analysed the new technical solution proposed by EDF on 14 October and considered that the file presented by EDF was satisfactory. ASN asked EDF to carry out additional inspections on the upper internal structures to which the fuel assemblies are suspended after the intervention in order to confirm their condition.
ASN participated in the qualification operations of the new process which took place on 17 October at the Center for Experimentation and Validation of Pressurized Water Nuclear Boiler Intervention Techniques (CETIC) at Chalon-sur-Saône, France. In particular, EDF committed itself to secure the assemblies against the risk of falling prior to any contact between the equipment used during the intervention and the fuel assemblies. ASN considers that this arrangement is satisfactory.
The ASN analysis was based particularly on the appraisal rendered by its technical support, the Institute for Radiation Protection and Nuclear Safety (IRSN).
The event which occurred on reactor no. 2 of the nuclear power plant of Tricastin did not lead to any releases inside or outside the reactor building's containment enclosure and the assemblies are being cooled by the normal cooling circuit used when the reactor is shut down.
The recovery operations of both fuel assemblies of reactor no. 2 will be performed according to the schedule established by EDF.
ASN also asked EDF for the analyses conducted to explain this event and the envisioned corrective actions.
The incident is provisionally classified a level 1 incident on the INES scale.