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Superphénix; still more problems ahead

Nuclear Monitor Issue: 
#487
27/02/1998
Article

(February 27, 1998) The shutdown of Superphénix, the fast-breeder reactor in France, which has been reaffirmed by Prime Minister Lionel Jospin on February 2, 1998, heralds a new era of unknown length. Although not very likely, the possibility of reopening is a large step further away, with unloading of its fuel and of its liquid sodium serving for cooling. But this can take a while.

(487.4830) WISE Amsterdam - The decommissioning problems faced are so complex and new that the publication of the official decree with the plan how to close the reactor are to take several months, probably not before summer 1999. Electricité de France (EdF) confirmed that starting February 3, 1998, they would tell what they know about the dismantling. And the Direction de la Surét´e des Installations Nucléeaires (DSIN), the French nuclear installations safety authority, has already made a sketch of the operations. The unloading of fuel is an operation which would take about a year (they can handle only three elements a day and thereare about 600 fuel elements). Theoretically this could begin in 1999. The used assemblages (containing nearly 6,000 kilograms of plutonium) would be stored for several years at the so-called l'Atelier Pour Evacuation du Combustible (APEC), the cooling pool on site. After that, these would be transported to La Hague.

In the design and development phase of Superphénix, no provisions have been made how to exactly remove the sodium from the core. It represents a total of 4,800 (metric) tons of sodium, of which 3,300 tons of radioactive sodium used would be used for the cooling of the core. After this removal is finished (theoretically, one to two years), and the sodium is in reservoirs, the next stage would be to neutralize it. The danger lies in the inflammability of sodium in contact with air and the explosive character of sodium in contact with water. As the neutralization consists of injection of the sodium into water, precautions are very important. For this treatment it is necessary to construct a specific plant inside the site of Creys Malville.

The decommissioning and decontamination of liquid sodium at the 10 MW Rapsodie plant caused an explosion in 1994, killing a worker and injuring a number of others. At that time, the injections consisted of 20 kilograms of sodium per hour. If this is also the case for this operation, it would last about 28 years, working 24 hours a day and 365 days a year. However, it seems that in Great Britain, at the fast-breeder reactor at Dounreay, the operations have succeeded in increasing the injection to 100 kilograms an hour. This means a reduction of the operation time to about six years without taking into account the construction of the building of the specific plant. Dounreay has imported 88 tons of liquid sodium from Germany, although the proposed treatment plant has been shut down after a leak, because of disquiet among regulators, and is also building a plant to deal with about 1,500 tons of sodium in the two fast reactors at the site.

EdF, 51-percent shareholder of the Creys-Malville owner consortium Nersa, issued a statement saying it would comply with the closure. EdF estimates that costs associated with closure would be FF16.5 billion (US$2.5 billion). EdF said it had set aside an additional FF4.5 billion in decommissioning provisions in its 1997 budget, taking into account negotiations with the Nersa partners. The Nersa partners were silent during the French debate over Superphénix. A convention has committed Italy's utility Enel and the German-Dutch-Belgian SBK consortium to support Superphénix operations through December 31, 2000, in exchange of guaranteed power from EdF.
After the dismantling operation, the total outcome of electricity balance of Superphénix could result in a minus, as it has consumed more electricity than it actually produced. For instance, Superphénix consumes electricity for continuous heating of the sodium in the core to prevent the liquid from coagulating into an enormous solid mass.

In the same February two policy package the government confirmed the reprocessing strategy, but also announced a FF500-million-a- year boost for renewable energy and energy efficiency so they would be more credible alternatives to more nuclear power in the future. However, Economics Minister Dominique Strauss-Kahn praised France's choice of nuclear power and declared that this nuclear option "in no way is called into question" by the shutdown of Superphénix. The government opened the door to the creation of an "independent" nuclear regulatory authority in the name of greater democracy and transparency, but its proposed structure is still very unclear. At the same time, the government for the first time officially opened the door to a very long-term interim storage of spent fuel and/or waste. Jospin postponed the decision on licensing underground high- level waste research laboratories until later this year, but there was an announcement that at least two laboratories would be licensed.
The Phenix prototype breeder can resume operation. It has been down since April 1995 and has undergone major refurbishment. The reopening would allow the continuation of experiments in actinide transmutation. The restart is expected after March.

Sources:

  • ContrAtom, November 1997
  • La Gazette Nucleaire, January 1998
  • Le Progres, 3 February 1998
  • Nucleonic Weeks, 5 February 1998

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