Owing to the fact that the resistance of these facilities to the seismic risk specific to the Cadarache site cannot be demonstrated and their incompatibility with current seismic design rules, COGEMA halted industrial activities in the ATPu in mid-July 2003. The effectiveness of this shutdown was confirmed by the ASN's inspectors during the course of an unannounced inspection on 1 August 2003.

This shutdown commits the ATPu and the LPC to a common decommissioning and dismantling process to be covered by a decree. In 2006, for each of these two installations, the licensee will therefore be required to submit the dossier specified in article 6 ter of the above-mentioned decree of 11 December 1963 and the impact assessment required by the Environment Code.

Since industrial production ceased in the installation, the licensee has been making the necessary modifications to be able to start packaging the scrap from previous fabrication work as well as other discarded materials containing plutonium and present in other installations on the Cadarache site, for shipment to COGEMA La Hague. These operations should last until the end of 2006.

In July 2004, the ATPu was also authorised to produce rods for four test assemblies based on American military plutonium, as part of the EUROFAB project. The purpose of this project was to demonstrate the feasibility of eliminating surplus American military plutonium stocks in the form of MOX fuel. In March 2005, all the assemblies produced, and the waste arising from their fabrication, were returned to the United State. The relatively small operation, which has a limited safety impact, does not call into question the cessation of industrial production in the ATPu.

Radiation protection

The operations to package old materials containing plutonium, owing to the rise in their americium level, mean that the licensee is required to reinforce its radiation protection measures.

Unlike the new UP2 800 and UP3 plants, most of the waste produced during operation of the first plant, UP2 400, was placed in interim storage without packaging for disposal. The operations involved in recovering this waste are technically difficult and require the use of considerable resources. The problems linked to the age of the waste, in particular its characterisation prior to any recovery and reprocessing, confirms the ASN's approach to the licensees which is to require that for all projects, they assess the corresponding production of waste and plan for processing and packaging as and when the waste is produced.

Further to review of the former waste recovery programme by the Advisory Committees for laboratories and plants and for waste at the end of 1998, the ASN asked COGEMA in 1999, to undertake retrieval of the sludge in the STE2 silos, the waste in the HAO silo, and the waste in the 130 building silo.

The ASN notably asked COGEMA to present as soon as possible firm commitments regarding the startup date for these operations, to submit estimated schedules for the operations with the associated R&D actions and to present an annual report indicating progress made on the work in question. In November 2005, the Advisory Committees for waste and for plants reviewed the La Hague establishments waste management policy, and in particular the solutions envisaged by the licensee for recovery and packaging of the legacy waste stored on the site.

STE2 sludge

In recent years, processing of STE2 sludge has been the subject of research and development work, in particular with a view to determining the methods for retrieval and transfer required prior to any packaging.

• Sludge recovery from silos

The recovery and transfer trials carried out in recent years, between one of the silos of the STE 2 facility and the STE 3 facility, demonstrated the efficiency of the equipment developed by the licensee. Improvements were however made in order to optimise the excavation operations. At the end of 2005, a similar device was installed and started up on another silo, for joint recovery of sludge from both of them.

• Sludge packaging

The packaging system today adopted by COGEMA consists in bituminisation using a process employed in the STE3 facility. In 2002, COGEMA was authorised to carry out sampling in one of the silos with a view to conducting bituminisation tests on about twenty drums in the STE3 facility in order to validate the adequacy of this process. The result of the analysis conducted in 2003 by the ASN and its technical support organisation showed that major developments were still needed before industrial retrieval of the sludge could take place.

In 2004, the licensee therefore forwarded additional justifications to enable packaging to start as of 2005. It also agreed to produce 3000 drums in the first three years of operation, while continuing to investigate alternative solutions. Before authorising industrial recovery of sludge from the silos, the ASN asked the licensee to validate the scenarios given in the safety analysis file transmitted in 2004, by carrying out experimental trials. These trials are based on the production of about fifty instrumented drums. Experience feedback from these trials, consisting chiefly of temperature recordings, should shortly be transmitted to the ASN. If the scenarios of the 2004 dossier are validated by these experimental results, operational approval could be given for industrial scale recovery.

• Alternative processes

In August 2005, the licensee presented the ASN with its latest research into alternative processes. The areas studied were vitrification, ceramic encapsulation, cement encapsulation and the drying process (DRYPAC). The first two were ruled out owing to technical feasibility problems, while the last two require additional research into prior drying of the sludges.

HAO silo

The nuclear installation safety is primarily based on the supervision carried out by the licensee itself. COGEMA is considering dealing with the hulls and end-pieces in this silo by compaction. The first step would consist in characterisation of these hulls and end-pieces prior to retrieval, sorting and transfer of the waste to packaging units.

The programme to characterise the fines and resins, which began in 2002, is still in progress. The report on washing and characterisation of hulls and end-pieces should be sent to the ASN soon.

Recovery requires prior dismantling of the equipment installed on the silo slab, construction of the recovery cell and qualification of the equipment to be used. Initial dismantling work should begin in 2006. In 2005, through inactive testing, the licensee also qualified the gripper and the "approach" rake.

Recovery work should be complete en 2018.

Silo 130

COGEMA is currently developing a mechanical waste retrieval system in this silo and is improving its knowledge of this waste.

This project is linked to the creation of a dedicated disposal facility and definition of an associated waste package. These recovery operations will not therefore be able to take place before 2010 and will involve a number of phases, with packaging of waste containing graphite and then the other waste. The retrieval systems will be likely to change during the course of the various phases, depending on the materials encountered and the retrieval conditions.

Old fission product solutions stored in the SPF2 unit in the UP2 400 plant

To package fission products from reprocessing of gas-cooled reactor fuel, in particular that containing molybdenum, COGEMA opted for vitrification with a specific glass formulation. Initial hot pot vitrification tests showed significant corrosion of the melting pot (lifetime of about 30 to 40 packages). Research therefore turned towards cold pot production of this glass. The particular advantage of this technique is that higher temperatures can be reached, enabling new glass formulations to be used. Sensitivity studies concerning the reference formulation are still continuing today. ASN representatives also visited the CEA's "cold pot" R&D installations at Marcoule. Commissioning of the first cold pot on the La Hague site is scheduled for 2010, with packaging operations scheduled to start in 2011.

Other waste

In September 2002, COGEMA sent the ASN a safety case about the characterisation and stowage of the waste drums present in the ATTILA pit. In August 2003, COGEMA was authorised to carry out these operations, which were completed in 2005. The results will shortly be sent to the ASN. On the basis of the characterisation results, the licensee draws up the dossiers for a new installation for sorting waste drums. Once sorted, the waste can be sent to the appropriate disposal channels.