RHONE-ALPES

Purpose: production of electricity and plutonium

Location: 175-ha site in the community of Creys-Mépieu, near the hamlet of Malville, on the left bank of the Rhône (Isère), 50 km east of Lyon and 100 km west of Geneva

Owner:   originally Nersa (EDF 51%, Enel [Italy] 33%, SBK[Germany, Belgium, the Netherlands, and the United Kingdom] 16%); since Dec. 30, 1998, only Electricité de France

I.  Superphénix 

Nominal capacity: 1242 MW electric gross; but 1200 MW electric net

Production: 8.2 TWh in total (average availability factor : 6.3%)

The reactor was inaugurated as a commercial industrial prototype. The objectives were the production of electricity and of plutonium. From its entry into operation, into 1994, the Superphenix had operated only the equivalent of 174 days at full power and, in the words of, deputy Bataille, in 1996, had “collected an impressive series of accidents.”

On 3 July 1990, the reactor was shut down because of impurities in the sodium in the core. This shut down lasted so long that Nersa was forced to relaunch the administrative procedure for an authorization to operate, necessary after two years without operating.

The new authorization decree, dated 11 July 1994, authorized Superphénix to operate as a research and demonstration reactor. The program, which was to cover the 1995-2000 period, had two new objectives: evaluation of the operation of a fast breeder reactor (RNR) as “net consumer of plutonium” and study of the possibility of destroying long-lived radioactive wastes in fast breeder reactors.

In February 1997 the Conseil d’Etat annulled the decree of 11 July 1994. Subsequently Nersa filed a new request for authorization to operate the reactor. In February 1998 the government decided not to grant this request and in April Nersa was asked to begin the permanent shutdown process [DSIN 98, p. 303].  Decree 98-1305 of 30 December 1998  authorized the initial stages in the shutdown process and a change in the operator of INB 91 and INB 141.

EDF acquired the Superphénix December 30, 1998 from Nersa for one symbolic franc.  EDF is responsible for the costs of dismantling the reactor; but EDF's partners in Nersa will pay their share of Nersa's debts and the cost of reprocessing the fuel.   

Unloading of the fuel, the fertile assemblies, and the control rods was scheduled to begin in September 1999 and to last until mid-2001 [RGN.v-vi.99]. The unloading was delayed because of problems relating to residual sodium on the assemblies but was completed by early 2003.  The fertile and fissile assemblies and the control rods stored in APEC. 

The 2200 t of nonradioactive sodium, which were in the secondary circuit, associated auxiliary circuits, and barrel have been unloaded and stored, frozen, in reservoirs on site. The 3300 t of radioactive sodium in the primary circuit remain in the reactor, where they are heated to keep them in a liquid state.  The sodium is to be neutralized in the facility TNA constructed in the Superphénix's machine room, which has been emptied of its pumps and turbines.  

TNA consists of two chemical installations, in which sodium will fall drop by drop into water in a neutral atmosphere of nitrogen. The resulting soda will be incorporated into cement.  It will take four to five years to neutralize the 5500 tons of sodium, and about 36,700 cubic meters (70,000 tons) of cement blocks will be produced [Le Hir 07; NucF 23.vi.04]. The method was developed by the CEA and employed for Rapsodie at Cadarache, where, it should be noted, an explosion occurred, and more recently by the UK Atomic Energy Authority at Dounreay in Scotland.

 Decree 2006-321 of 20 March 2006 authorizes the last stage of the final shutdown and the complete dismantling of Superphénix.  The work is to take place in three stages, each of which requires various additional authorizations and reports.  The first stage includes the destruction of sodium in the primary circuit and reservoirs and residual sodium in the tank of the reactor, treatment of cold traps, and demolition of the conventional buildings.  The second consists of dismantling the reactor block and, if necessary, cleaning the buildings.  The third consists of destruction of the cleaned buildings.  Stage two cannot start until stage one is complete.  Therefore, the time spent destroying the sodium is key to the length of time that the entire process will take.  EDF hopes to complete dismantling around 2025.  

II. Workshop for the Evacuation of Fuel (APEC)

      APEC was officially created by a decree dated 24 July 1985.  Decree 2006-319 of 20 March 2006 modified the original decree to allow APEC to store not only irradiated fuel from Superphénix, but an unirradiated core created for the reactor before the decision to stop the reactor's operation, and various other waste from the dismantling of the Superphénix (Article 1).  The 2006 decree authorizes operation of APEC until 31 December 2035.  At the latest, three years before that date, the operator must request an extension of the period of operation or begin the shut down process (Article 2). The decree also authorizes the administrative removal of various support facilities from INB 91 and their addition to INB 141. It thus reduces the perimeter of INB 91 and expands that of INB 141.  The facilities as of 2007 are :

1) A building for wet storage.  The radioactive assemblies removed from the Superphénix are stored under water in the main basin of a pool.  Also stored in this basin is an unirradiated fuel core, half of which was on site when the reactor stopped operating and half of which was brought from Cadarache.  The fuel totals 115 tons of heavy metal, of which 60 tons are unirradiated.  France owns 75 of the 115 tons [Andra 06].  Steel assemblies and structural waste are stored in the pool in special containers or in the dry storage building, depending , on their radioactivity. In addition to the pool, the wet storage building contains cells for handling the fuel, corridors for its transfer, and stations for closing transport and storage containers.

2) A building for dry storage. As noted above, steel assemblies and structural waste in special containers may be stored here.  According to the impact study for the modification of INB 141, EDF plans to evacuate to Soulaines assemblies stored dry for ten years at APEC.  EDF plans to package control rods from Superphénix and store them at Apec.  They are then to be shipped to the Installation for the Surveillance of Irradiated Assemblies (ISAI) at Marcoule for treatment (cutting up, washing, and packaging).  Afterwards the structures resulting from the dismantling of the control bars are to be returned to APEC for storage in the pool.  We do not know if these plans have been or will be carried out.  The facility includes installations for the receipt and dispatch of transport packages, with a hall accessible to trucks, and a hall for storing transport containers [EDF 03]. 

3) A zone for storage of the blocks of soda in concrete resulting from the neutralization of sodium. According to the impact study, the concrete blocks are to be stored in a zone prepared for them, in cells, between five and nine in number, each approximately 40 meters long and 12 meters wide.  The cells will occupy a maximum surface of about 5000 square meters and will be on a platform to protect them from any flooding.  According to EDF, after deconstruction of the reactor, the blocks will have reached the same level of radioactivity as granite [EDF 03].

4) Auxiliary facilities: a pump station, a station for treating effluents, a station for monitoring effluents, the chimney for releasing gaseous effluents from the Superphénix building, administrative buildings, a guard post [EDF 03].

--last entered 21 September 2008

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