Light water reactors use ordinary water as moderator and coolant. The line is composed of two variants: pressurized water reactors (PWRs) and boiling water reactors (BWRs). Only pressurized water reactors have been built in France.

The reactor is piloted by means of groups of absorbing rods (control bars) which take the place of fuel in a certain number of assemblies, and by the use of an absorbant chemical material, borium, dissolved in the coolant. The control bars and the boron absorb neutrons.

Each reactor contains three water circuits. The reactor vessel that holds the fuel is part of the primary circuit. This circuit extracts from the core the heat produced by fission and transfers that heat to the secondary circuit, by means of a steam generator, a gigantic heat exchanger. The water in the secondary circuit, transformed into steam by the heat of the primary circuit, turns a turbine, which runs an alternator producing electricity. The third circuit extracts the low calories from the secondary circuit and releases them to the environment.

With the exception of the first French PWR reactor, Chooz A1, coupled to the network in 1967 and shut down in 1991, the park is composed of several classes, each of which incorporates certain technological modifications. Fessenheim 1 and 2, put into industrial service in 1977 and 1978 respectively, introduced the first-class, CPO.

CPO: industrial pre-series: Bugey 2, 3, 4, and 5 (Ain); Fessenheim 1 and 2 (Haut-Rhin).

CPY: reactors of the CP1 program contract: Blayais 1, 2, 3, and 4 (Gironde); Dampierre 1, 2, 3, and 4 (Loiret); Gravelines B1, B2, B3, B4, C5, and C6 (Nord); Tricastin 1, 2, 3, and 4 (Drme).

CPY: reactors of the CP2 contract program: Chinon B1, B2, B3, B4 (Indre-et-Loire); Cruas1, 2, 3, and 4 (Ardèche); Saint-Laurent-des-Eaux B1 and B2 (Loir-et-Cher).

P4: Paluel 1, 2, 3, and 4 (Seine-Maritime); Flamanville 1 and 2 (Manche): Saint-Alban 1 and 2 (Isère).

P'4: Cattenom 1, 2, 3, and 4 (Moselle); Belleville 1 and 2 (Cher); Nogent-sur-Seine 1 and 2 (Aube); Penly 1 and 2 (Seine-Maritime); Golfech 1 and 2 (Tarn-et-Garonne).

To replace its current park of nuclear reactors, which in 1999 average about fourteen years in age, EDF invested in development of the European Pressurized-water Reactor, a Franco-German project.  (The EPR is known as a Generation Three reactor, to set it off from the reactors that preceded it and from Generation Four reactors, which the industry expects to design and build for the future.)   

In 1989 Framatome and the group Siemens created a common subsidiary Nuclear Power International (NPI) to design a nuclear plant that would be safer than currently operating plants and could be licensed in both France and Germany. In 1992, their likely customers, EDF and the majority of German electricity-generating companies joined the project. In 1995, the early planning completed, EDF and the German utilities charged Framatome, Siemens, and NPI with developing the basic design of an evolutionary reactor that would be based on the newest French (N4) and German (Konvoy) reactors. EDF through the Centre National d’Equipement Nucleaire (CNEN) joined in the work.

The basic design for a 1495 MWe EPR was completed in June 1997 and submitted to French and German safety authorities. A cost estimate showed that the reactor would generate electricity at a cost comparable to that of the N4 reactors, but would not be competitive with combined-recycle gas turbine plants. To be competitive with the latter the per kilowatt hour cost would have to be reduced by an additional 10% to 18 centimes. The project participants subsequently embarked on an “optimization” phase of study. The optimization study achieved the needed decrease in cost for EPRs—provided they are built as part of a series--mainly through a 15% increase in the reactor’s power [Bouteille 98].

The designers of the now-1750 MWe reactor intend that up to 50% of the core be composed of Mox fuel, that the uranium in the standard fuel be enriched to up to 4.9% uranium 235, that the fuel be discharged at a burn-up of up to 60 GWd/t, that the plant remain in service 60 years, that fuel reloads and regular maintenance require less than 20 days of down time, that plant availability average at least 90%. Special features would lessen the effects of a core meltdown. They include means of retaining within the double walls of the confinement building any gaseous effluents released; catalytic recombiners to prevent explosions by absorbing hydrogen; a compartment in which melted corium would be trapped and cooled; and inside the reactor building a reservoir of water, that would be released by passive means to flood a melting core. Critics of the EPR note that such safety features would be more impressive had not EDF’s N4 class of plants (the Civaux and Chooz B reactors) on which the EPR’s design is in part based, already experienced serious safety-related problems.

Given a German government pledged to phase out nuclear power, an initial EPR would have to be constructed in France, presumably at the site of a current nuclear plant. The German government is not now committed to participating in a safety review of the reactor [NucW 25.iii.99); and German utilities are not nearly ready to decide to buy into a project to build an EPR in France [NucW 9.ix.99]. Nevertheless, in July, 1999, Framatome and Siemens signed an agreement with EDF giving structure to their cooperation on the reactor.

Christian Bataille and Robert Galley in L’aval du cycle nucléaire: Tome II: Les couts de production de l’électrité, recommend that EDF order an EPR, but they want it to be a 1495, not a 1750 MWe reactor. The smaller reactor, they say, would avoid pushing to the limit equipment designed for a reactor of lower power, would make better use of experience gained from the N4 plants, and would better accommodate the needs of possible foreign clients.

For the reasons that industry supporters favor construction of an EPR, people who favor a phase out of nuclear power and support alternative forms of energy are strongly opposed to its construction. In mid-99 in fact, the Green Party threatened to leave the government if Prime Minister Lionel Jospin were to give EDF a green light to go ahead with a plant.

The next stage of reactor development—the detailed design phase—cannot be carried out until a site for the first reactor has been selected. In October 1999, Jean-Daniel Lévi, delegate director general of Framatome, stated during a colloquium that “the political decisions to be taken on this program are very distant, around 2003-2004.” At the same time an EDF officer spoke of “rework[ing] this dossier” and of “proposing other options” [Ener 15.x.99]. Apparently Lionel Jospin has been relieved of the need to make a decision before the next presidential election.

At the beginning of December 1999, Siemens and Framatome announced their fusion, which enables them to become the world’s premier nuclear industrialists.

The main source of effluents in normal operations is the water from the primary circuit, which is contaminated by direct contact with the core. The radioactivity comes from the activation of products of corrosion and abrasion and chemical elements subject to the flux of neutrons in the core; from the fission of uranium within the fuel; from tritium produced by ternary fission within the fuel; and from the action of neutrons on the borium, the lithium made from the borium, and the hydrogen in the circuit [CFDT 80]. Radionuclides can escape from the fuel either by filtration through the cladding or through breaks in the cladding. The water in the primary circuit contaminates the water in the secondary circuit through fissures in the thousands of small tubes that constitute the steam generator. Because of the pressure and the vibrations that the generator undergoes, some leaks from one circuit to another are practically inevitable [Dreicer 95].

I.E.1.LIQUID EFFLUENTS

--Effluents coming directly from the primary circuit, because of changes in the volume of water in the circuit, withdrawals of water as a result of the chemical piloting, and leaks. These effluents undergo treatment by filtration, demineralization (ion exchange) and degassing. A part is reused in the primary circuit, the remainder is rejected in order to rid the circuit of tritium.

--The aqueous effluents coming from the secondary circuit and other sources like decontamination of equipment. They undergo simple filtration followed, if necessary, by treatment with ion exchange resin (or by concentration in the evaporator) [Burtheret 88].

Originally each power plant, like all the INBs, was the subject of prefectoral authorizations regarding the withdrawal of water and nonradioactive releases into water.  These authorizations were granted for a limited time period.  On the other hand, the authorizations for radioactive liquid and gaseous releases were the subject of interministerial decrees without time limits.  Decree 95-540 of May 4, 1995, covers both the withdrawal of water and radioactive releases.  When the initial prefectoral authorizations have to be renewed, the authorizations for radioactive releases are being renewed.  The new limits, which generally represent a decrease are determined on the basis of actual releases as well as of considerations of health [Con xi.00].  

The average radioactivity of the liquid released by the reactor, with the exception of tritium and carbon 14, is 1 GBq per year, according to EDF [Con xi.00].  The limits per year for two 900 MWe reactors after the application of the decree of May 4, 1995, are 40,000 GBq of tritium, 0.3 GBq of iodine, 30 GBq of other radioelements (except potassium 40 and radium) and 300 GBq of carbon 14; for two reactors of 1300 MW, 60,000 GBq of tritium, 0.1 GBq of iodine, 25 GBq of other radioelements, and 400 gBq of carbon 14 [Con xi.00].jjk

--Effluents from ventilation of the nuclear facilities and normally not radioactive. They are released after filtration [Burtheret 88 and Cri i-iii.89].

--Effluents from degassing of primary liquid effluents. The effluent from the primary circuit is usually stored for thirty days to permit the decay of short-lived radioactive emitters.

 The limits per year for two 900 MW reactors after application of the decree of May 4, 1995, are 4000 GBq of tritium, 36,000 GBq of rare gases, 1100 GBq of carbon 14, 0.8 GBq of other radioelemnts; for two 1300 MW reactors, 5000 GBq of tritium, 45,000 GBq of rare gases, 1400 GBq of carbon 14, 0.8 GBq of iodine and 0.8 GBq of other radioelements [Con xi.00].  

Reactors of this line do not slow down neutrons. As a result, there is no moderator. For the fuel, either plutonium as fissile material mixed with natural or depleted uranium, or enriched uranium is used.

Ordinarily a fast neutron reactor is composed of a core proper composed of the fissile-fertile mixture of plutonium and uranium in the form of mixed oxides (Mox), and around the core, a cover, composed only of fertile material.

As coolant, a fast reactor uses liquid sodium in spite of the fact that sodium presents the great inconvenience of catching fire in the presence of air and exploding in the presence of water. To try to decrease the danger, a fast reactor has two sodium circuits and a steam circuit. The second sodium circuit, not radioactive unless the primary circuit leaks, transfers heat to the steam circuit.

Excepting critical assemblies and small research reactors, three fast neutron reactors have been constructed in France: Rapsodie, 40 MWth (Cadarache), Phénix, 233 MWe net (Marcoule) and Superphénix, 1200 MWe net (Isère). Rapsodie (undergoing dismantling) and Phénix entered into service in 1967 and 1973 respectively, even before the first big pressurized water reactors. Superphénix is undergoing final shutdown operation.

European Fast Reactor—Under Development

The EFR project was officially launched in 1989 as an initiative in international cooperation, with the participation of a consortium of electric utilities: EFRUG (European Fast Reactor Utilities Group) including EDF of the consortium of construction companies EFR-Associates including Framatome/Division Novatome, and the group of research and development bodies that includes the CEA. The purpose was to create a reactor that could, in the immediate future, help manage wastes and, in the long term, assure a source of energy [EFRA 93]. After ten years of study, the researchers had developed the conception of a nuclear reactor that could equip a commercial power plant (1500 MWe) and meet “the most recent safety standards.” However, because Europe is not lacking in energy at present, electricity producers decided, at the end of 1998, to freeze the EFR program. The detailed study will not be begun in the near future [Lefèvre 99]. However, certain studies of future fast neutron reactors are being carried on in different frameworks, such as that of the French Capra project.

Generation IV Reactors

France is a member of the Generation IV International Forum, created at the initiative of the US Department of Energy in 2000 to collaborate on research and development of advanced reactors to go into industrial operation around 2040. 

In 2002 the Forum chose six types of reactors on which to concentrate:  the gas-cooled fast reactor (GFR) Very-high-temperature reactor (VHTR), Supercritical-water-cooled reactor (SCWR), the Sodium-cooled fast reactor (SFR), the Lead-cooled fast reactor (LFR), and the Molten salt reactor (MSR),  

The French government wants Generation IV reactors to differ from Generation III reactors (represented in France by the EPR) in reducing the volume and radiotoxicity of wastes; producing the same quantity of energy with much less uranium, being safer and more secure, and reducing the risks of proliferation.

For electricity production, France is interested in two of the four fast neutron reactors: the Gas-Cooled Fast Reactor (GFR), which would be cooled by helium and the Sodium-Cooled Fast Reactor, which, as its name indicates, would be cooled by sodium. It is also interested, for industrial purposes, in the thermal Very High Temperature Reactor (VHTR).

In January 2006 President Chirac committed France to constructing a prototype of one type of Generation IV reactor.  The prototype, he stated, will go into operation in 2020.  France is exploring the options and will make a decision in 2012 as to what type of reactor to build.

                                                                                          --updated 2 May 2007

UNGG reactors use natural uranium as fuel, graphite as moderator, and carbonic gas (CO2) under pressure as coolant. In French reactors, the core was in the form of a pile of graphite bricks in hexagonal shape. Each brick was pierced by a canal in which the fuel was placed in the form of cartridges along which gas circulated.

No UNGG operates in France today. Apart from research reactors, the UNGG were G1, G2, G3 at Marcoule (Gard), Chinon A1, A2, and A3 (Indre-et-Loire), Saint-Laurent-des-Eaux A1 and A2 (Loir-et-Cher), and Bugey 1 (Ain). At the end of the sixties, EDF decided to abandon the UNGG line to the benefit of pressurized water rectors. The first UNGG reactor, G1, was put into service in 1956: the last, Bugey 1, in 1972.

Heavy water reactors use natural uranium as fuel and heavy water as moderator. The coolant can be “heavy water” or ordinary boiling or pressurized water, gas, or organic liquid. In the most common variants the coolant circulates in pressure-holding tubes holding pressure, within which the fuel is placed. These force tubes cross the vessel containing heavy water. The fuel is uranium oxide [CFDT 80].

In France, the reactors Zoé or EL1 (Fontenay), EL2 and EL3 (Saclay) and EL4 or Brennilis (Finistère) , which are no longer in service, belong to this line. The difficulties encountered with EL2 “even well after its going critical in 1952, contributed to turning the programs [of the CEA] towards electricity generating reactors with graphite” [EnNu xii.65].

The propulsion reactors for French submarines are all types of PWR. They belong to three generations, each is, or was, represented by a prototype on land at Cadarache. A fourth is in the planning stage.

The CEA is designing a new prototype on land, named at present simply le réacteur d’essais à terre (RES).

The mission of RES will include irradiation and qualification of fuel to the extent possible on land; training teams to operate reactors at sea; experimentation with innovative concepts; and maintenance of the capacity to develop and to adapt with a view to other possible prototypes and applications.

As of 1999 the reactor will likely be either 1) a pressurized water reactor derived from that of the Charles de Gaulle but with numerous adaptations or 2) a metallic enclosure partially submerged in a large pool of water. Plans call for the reactor to go critical in mid-2006.

Initially the reactor will serve as the prototype for the reactors in the future Barracuda class of nuclear attack submarines. These reactors will be based on the following considerations, among others: a redesign of the compact reactor type; an increase in the useful life of the core to ten years; limits on the use of uranium enriched to a high level—use of commercial uranium fuel will be favored; a decrease in the length of time for refueling from five to three months; and, during refueling, the replacement of selected individual fuel rods rather than of entire cores [Fribourg, 1999; défi 99].

The site for the reactor has been prepared [CEARa 98].

Wastes from propulsion reactors

Submarines like all the other pressurized water reactors, generate radioactive wastes such as ion exchange resins used for the decontamination of the reactors’ primary coolant, this water after filtration, and the wastes resulting from maintenance operations. Irradiated fuel that has not been reprocessed and that is destined to remain for a long time in the Cascad storage installation at Cadarache, should also be considered as waste [see CDRPC 94].

Research reactors furnish elevated fluxes of neutrons for use in basic and applied research. The inventory of these reactors is large, although there are two main types.

--heavy water reactors that furnish strong fluxes of neutrons in the form of beams, essentially used in basic research;

--light water reactors, better adapted to materials tests, with two subtypes:

1.) pool reactors with open cores, cooled and moderated by light water, generally multi-purpose and simple to use and access;

2.) and light water reactors with closed, pressurized vessels, able to operate at powers greater than those of the pool reactors, but more difficult to use because of the closed vessels [Techin B 3030].

Research reactors are located at present at the Institut Laue-Langevin in Grenoble and in several CEA centers: Cadarache, Grenoble, Saclay, Valduc, and, if one counts Phénix, Valhro--Marcoule. Fontenay also housed research reactors.