In February 1968, when Rapsodie had been operating for one year, excavation work began at Marcoule for the construction of the 250 MWe (563 MWt) Phenix reactor. In 1969, the CEA and Electricite de France (EDF, France’s Government-owned utility) signed a protocol for the joint construction and operation of the Phenix plant. Ownership and costs were shared 80 percent by the CEA and 20 percent by EDF. The standard Phenix core contains 931 kg plutonium containing 77 percent plutonium-239. The reactor went critical on 31 August 1973 and was connected to the grid on 13 December 1973,3 a year ahead of the 250 MWe Prototype Fast Reactor (PFR) in the United Kingdom. Until 2005, the mean length of reactor runs was 90 days and the fuel reached burn-ups of up to 150,000 MWd/t.4

On 17 October 1973, between the dates of criticality and grid connection of Phenix, OPEC member countries halted oil deliveries to a number of countries that supported Israel and significantly increased the price of crude oil. In 1974, the French Government committed to its first large series of power reactors, 16 units. The International Atomic Energy Agency (IAEA) forecast up to 4,450 gigawatts (GW) of nuclear power installed by year 2000. Between 1973 and 1976 uranium prices increased from $6 to $40 per pound on the spot market. Plutonium was seen as a solution to long-term nuclear fuel supply concerns.

Until the end of the 1980s, Phenix had a remarkable operational record. Then, after a number of unexplained reactivity transients, the load factor plunged virtually to zero. The incidents had serious potential safety implications. The reactor remained shut down most of the period between 1991 and 1994 until an extensive research program was carried out. It was restarted for very short periods, however — probably to avoid the legal requirement of an entire new licensing procedure after a two-year shutdown. In addition, a costly refurbishment program was undertaken between 1994 and 2002 (see figure 2.1 for operational history).

[і — I Grid-connected operation

I Planned shutdown, fuel handling, tests I 1 Forced Outage

m

П

IIII III III

76 77 78 79 80 81 82 83 S4 85 86 87 88 89 90 91 92 93 44 95 96 97 98 99 00 01

Year

Figure 2.1 Operational history of France’s Phenix breeder reactor, 1974-2002.

Na is the chemical symbol for sodium. Source: IAEA, Fast Reactor Database 2006 Update.

In June 2003, the National Safety Authority ASN (Autorite de Surete Nucleaire) authorized the restart of Phenix for six refueling periods at less than two thirds of its original power. This allowed operation until the end of 2008 and into 2009. Nominal power was decreased from 233 megawatt electric (MWe) net to 130 MWe net. As of the end of 2007 the reactor had a cumulative load factor of 44.6 percent.5 Phenix was shut down in 2009.

Japan’s fast breeder reactor program was conceived in the Japan Atomic Energy Commission’s (JAEC) first Long Term Plan, published in 1956.1 Among various reactor types under review, the JAEC selected the fast breeder reactor and its closed fuel cycle as the preferred technologies for R&D and endorsed the importation of light-water reactor technology from the United States.2

A version of this chapter has been published in Science and Global Security 17 (2008): 68-76.

The JAEC’s 1967 Long Term Plan concluded that the fast breeder reactor should be the mainstream of future nuclear power generation3 and the Government established the Power Reactor and Nuclear Fuel Development Corporation (PNC) as the primary R&D institution for fast breeder reactor and nuclear fuel cycle development. The Plan envisioned that an experimental fast reactor would be built during the 1970s, and the first commercial fast breeder reactor by the late 1980s.

Japan’s first fast breeder reactor was the experimental Joyo (Eternal Sun), built at the Japan Nuclear Cycle Development Institute’s Oarai Engineering Center. Joyo achieved criticality in 1977 at an initial power level of 50 megawatt thermal (MWt). Power was increased to 75 MWt in 1979, and to 100 MWt with its Mark II core, which achieved criticality in 1982. From 1983 to 2000, Joyo operated as an irradiation test bed for fuels and materials for future Japanese fast reactors. Since 2003, Joyo has been operating at 140 MWt with its Mark III core, and in April 2007 it completed its 6th duty cycle. By 12 March 2007, Joyo had operated for 70,000 hours. Thus, in the 30 years between 1977 and 2007 Joyo operated approximately 27 percent of the time.

The prototype fast breeder reactor Monju (280 megawatt electric) was developed in parallel with Joyo, but construction was delayed and it did not achieve criticality until 1994. On 8 December 1995, Monju experienced a serious sodium leak and fire when intense vibrations caused the failure of a thermocouple attached to the secondary sodium loop. The sodium reacted with oxygen producing a fire that melted the steel structures in the room. No injuries were reported and no release of radioactivity occurred since the sodium in the secondary loop was not radioactive.

PNC’s cover-up of the accident caused a social and political uproar that delayed the repair and restart of Monju. In June 2001, PNC submitted a re-license application for Monju, which was granted in December 2002. Legal challenges against PNC surrounded the relicensing causing further delays and on 27 January 2003, the Kanazawa branch of Nagoya’s High Court reversed its 1983 approval to build the reactor. Just over two years later, on 30 May 2005, Japan’s Supreme Court ruled for PNC, thereby clearing all legal barriers for the restart of Monju. Restart was scheduled for October 2008 but as of January 2010 the reactor is still off-line.

Japan Atomic Power Company (JAPCO) finalized plans for a 660 megawatt electric (MWe) demonstration commercial fast breeder reactor in 1994. The project experienced delays because of the Monju accident and was eventually canceled in the late 1990s.

R&D on reprocessing fast reactor spent fuel started in mid-1970s, and reprocessing of Joyo spent fuel was conducted at the experimental Chemical Processing Facility (CPF) starting in 1982. Following the experience gained at the CPF, PNC started construction of a Recycle Equipment Test Facility (RETF) in 1995, which is the

first pilot-scale reprocessing facility for fast reactor spent fuel, the counterpart of the Tokai pilot reprocessing plant for light-water reactor spent fuel. The Tokai plant adopted imported French technology but the RETF intends to employ technologies currently under development under the cooperative program with Oak Ridge National Laboratory (ORNL) in the United States. The first phase of construction was completed in 2000, but its scheduled completion date is currently unknown.

In 1971 and 1972, even prior to the first oil shock, utilities from France, Germany and Italy signed a number of agreements for joint construction of two commercial breeder reactors, one in France and one in Germany. In December 1972 the French Parliament passed a law that granted permission to create companies "that carry out an activity of European interest in the electricity sector".6 The legislation was tailor-made for the creation of a European fast-neutron reactor consortium (NERSA),7 which was established in 1974, shortly after the start-up of Phenix, with the purpose of building the first commercial-size plutonium-fueled fast breeder reactor in the world.8 The Superphenix Parliamentary Enquiry Committee later noted that the "public enquiry into the project was excessively short." It lasted only a month from 9 October to 8 November 1974.9

The project immediately attracted significant opposition. In November 1974, 80 physicists of the Lyon Physics Institute highlighted specific risks of breeder technology and, in February 1975, approximately 400 scientists initiated an appeal that detailed their concerns about France’s nuclear program in general and the fast breeder in particular. That same year, the German utility RWE transferred its NERSA shares to the European consortium, SBK, that planned to build the SNR-300 breeder reactor in Kalkar, Germany.10 Andre Giraud, then head of CEA, urged the rapid and massive introduction of breeders, since delays in their introduction would have "catastrophic consequences on the uranium savings that are expected."11 The public enquiry commission into the Superphenix project estimated that fast breeders would supply a quarter of France’s nuclear electricity by the year 2000.

In the middle of April 1976, the Restricted Energy Council chaired by President Valery Giscard d’Estaing made the political decision to build Superphenix. Site preparation work started immediately at Creys-Malville (45 km East of Lyon, 60 km from Grenoble and 70 km from Geneva). The Parliamentary Enquiry Committee noted 22 years later:

Once the decision to build was taken, the electricity utilities would not rest until they succeed. Convinced of the well founded decision, they did not allow local consultation to slow them down; the latter can be qualified as minimal.12

The official public decision to build Superphenix was only announced a year later. The Parliamentary Enquiry Committee wonders:

Finally, what to think of a governmental decision to authorize the creation of the plant dated 12 May 1977, thus taking place after the beginning of the preliminary infrastructure and site preparation work and after the beginning of the construction of the reactor?13

In the summer of 1976 some 20,000 people occupied the site to protest the construction of Superphenix. Around 50 municipalities in the region had come out in opposition to the project between 1974 and 1976 and, in November 1976, about 1300 scientists from the Geneva region issued an open letter to the Governments of France, Italy, Germany and Switzerland voicing their concerns over the project.

CEA Chairman and soon to be named Minister of Industry Andre Giraud was more optimistic than ever and, at the December 1976 meeting of the American Nuclear Society in Washington D. C., forecasted 540 commercial breeders in the world for the year 2000, of which 20 would be in France. By 2025, he projected the number of Superphenix-size fast breeder reactors units worldwide would reach exactly 2766.14 In fact, not a single Superphenix-size fast breeder reactor was in operation in the world in 2000.

On 31 July 1977, a large international demonstration close to the construction site in Creys-Malville, with some 50,000 participants, turned extremely violent. The riot police used grenades that led to the death of Vital Michalon, a local teacher. Another demonstrator lost a foot and a third had a hand amputated. The events were a profound trauma for the French anti-nuclear movement. The State did not alter its plans. Three days after the events, Rene Monory, then Minister, of Industry, declared: "The Government will continue the construction at Creys — Malville and Superphenix, because it is a matter of life and comfort of the French people."15 The construction proceeded.

The combination of the EURODIF uranium enrichment consortium that started up its plant at Tricastin in 1979 and the push for a European plutonium industry were attempts to acquire independence from what some decision makers and industry leaders perceived as U. S. nuclear supremacy. France’s President Giscard d’Estaing declared that "if uranium from French soil is used in fast breeder reactors, we in France will have potential energy reserves comparable to those of Saudi Arabia."16 U. S. President Jimmy Carter’s non-proliferation policy, highly critical of plutonium separation and use, was considered "totally absurd" by the CEA.17

In 1982, Jean-Louis Fensch, a CEA engineer, produced a 250 page report on fast breeders for the Superior Council on Nuclear Safety, a consultative body. Fensch concluded that "fast breeder reactors are the most complicated, the most polluting, the most inefficient and the most ambiguous means that man has invented to date to reduce the consumption of nuclear fuel".18

By the time Superphenix went critical in 1985, international enthusiasm for nuclear power had already peaked and the number of construction starts in the world had gone down from a peak of 40 units in 1975 to 13 in 1985 and 1 in 1986.19 The Chernobyl catastrophe in 1986 only accelerated the decline in nuclear projects. Superphenix, whose objective was to save uranium, was outdated by the time it began operating. Uranium prices had dropped from $40 to $15 per pound on the spot market, little more than the 1974 price. In comparison with the demand, uranium resources were abundant.

France’s nuclear decision makers did not alter their plans, however. The result was that the country built up both a large electric-power generating overcapacity (at least a dozen excess nuclear units by the middle of the 1980s) and a full-scale plutonium economy that had long lost its raison d’etre. Between 1987 and 1997 the rate of reprocessing of spent fuel at La Hague quadrupled to almost 1700 tons per year, of which approximately half was for foreign clients. With an approximate one percent content of plutonium, the La Hague facilities separated about 17 tons of plutonium in 1997. This was roughly the magnitude of the total cumulated quantity of plutonium that had been irradiated in French breeder reactors as of the end of 1996 when Superphenix was permanently shut down.20

Theoretical electricity generaaon at moti capacity igclor (10.BSU I Wh gross

T.433

I леї

9J9v4

0 ,2

ms saa ias7 ш issa mo mi issi паї ЮЭ4 isss із а в

Figure 2.2 Superphenix annual electricity generation. Source: CEA, WISE-Paris.

The core of Superphenix contained 5780 kg of plutonium (4054 kg of plutonium-239). Operated at a nominal capacity with annual one-third core refueling, Superphenix would have absorbed over 1900 kg of plutonium per year. But during its 11 years of operations, the reactor did not even use the equivalent of one reactor core.

Superphenix had a rated power of 1200 MWe net (1240 MWe gross). On 7 September 1985 it went critical and was connected to the grid on 14 January 1986. It was plagued by a number of technical and administrative problems, however, and was shut down more than half of the time until 24 December 1996 when it produced its last kilowatt hour (kWh). Superphenix generated 8.2 terawatt hours (TWh) (gross) in total, almost half of which was generated during its last year of operation. Its lifetime load factor was less than 7 percent.

As figures 2.2 and 2.3 illustrate, Superphenix experienced a series of significant incidents and administrative hurdles. The reactor never operated more than 17 months in a row. Operations halted in May 1987 with the discovery of a major sodium leak in the fuel transfer tank or storage drum. The tank could not be repaired and it took 10 months to develop a new method to load and discharge fuel from the reactor core.

The incident also revealed major deficiencies in the French fast breeder reactor organization. Before the leak, at the end of 1985, FRAMATOME’s engineering subsidiary NOVATOME laid off more than half of its staff, 430 of 750 employees. NOVATOME was losing a lot of money because it could not invoice NERSA for work on Superphenix until it had gone into commercial operation.21 In the course of the relocation of its thinned-out engineering teams from Paris to Lyon, many experts took up attractive offers to leave NOVATOME. As a result, when the storage tank leak occurred, NERSA realized that the specialist who had managed the electronic database for the tank had left the organization and it took some time before the database could be accessed. The re-qualification and authorization of the new fuel transfer and storage method absorbed another 13 months before the reactor could restart in April 1989. Low-power operation lasted until July 1990 when a defective compressor led to major air leakage into the system and oxidation of the sodium. Sodium purification took another eight months. In December 1990, the roof of the turbine hall collapsed after a heavy snowfall (figures 2.4 and 2.5).

On 3 June 1991, NERSA requested permission to restart the reactor by July 1991. On 27 May 1991, however, the French Conseil d’Etat invalidated the 1989 restart license that had been legally challenged by Swiss and French opponents. The restart, unlike the original licensing procedure, became subject to a lengthy process of parliamentary hearings and debates on a national and regional level. In June 1992, the Government decided to commission expert reports and to request a new public enquiry that was carried out between 30 March and 14 June 1993. The public enquiry commission issued its report on 29 September 1993 and the safety authorities reported to the Government in January 1994. A new operating license was finally issued on 11 July 1994. The unit had been back on line for only seven months, however, when an argon leak in a heat exchanger forced a new outage. When the reactor restarted in September 1995, it was for the last time.

On Christmas 1996, Superphenix was shut down for maintenance, core reconfiguration and the launch of a research program into transmutation. On 28 February 1997, however, the Conseil d’Etat nullified the July 1994 operating permit and, on 19 June 1997, incoming Prime Minister Jospin told the National Assembly that "Superphenix will be abandoned." The political decision became official on 2 February 1998 when the communique of an inter-ministerial committee meeting stated that "the Government has decided that Superphenix will not restart, not even for a limited period of time".

A Green Party representative had entered a European National Government with a senior ministerial position for the first time. Dominique Voynet became Environment Minister, and thereby shared oversight over civil nuclear safety in France with the Industry Minister. Point number one on the Green Party electoral platform had been the closing of Superphenix. The issue had always been highly symbolic for France’s nuclear power opponents. It would have been difficult to imagine anything less than the end of the Superphenix project after the Green Party joined the Government. It is also perfectly clear, however, that at least part of EDF’s top management had long considered Superphenix and reprocessing a costly error.22

French diplomats were quick to downplay the strategic significance of the end of Superphenix. The French Embassy in the U. S. stated in its "Nuclear Notes from France":23

In the wake of recent decisions, made by the French Government, including the closure of the Superphenix fast breeder reactor, some may wonder if France is changing its nuclear policy. Basically, the answer is no. Both Prime Minister Lionel Jospin and Economic Minister Dominique Strauss-Kahn have made it clear France is satisfied with its nuclear "wise" commitment, stressing the large return on investment it provides in terms of economic competitiveness, self-sufficiency and environmental protection. France will stick to its policy of reprocessing and plutonium recycling, a good way to optimize waste management while producing more electricity. Is it surprising? Just remember what everybody in France has in mind: no oil, no gas, and no coal means no choice! It sometimes helps!

A decree dated 30 December 1998 formalized the decision to proceed with the final closure of Superphenix and the first decommissioning steps. As of 2008, the fuel has been discharged and transferred to the storage facility APEC on site. The turbine hall has been emptied. A permit for full decommissioning was issued on 20 March 2006.

Military plutonium from Phenix

The CEA’s military department had a keen interest in fast breeders because of the fact that, as a by-product, they generate super-grade plutonium in the breeder blankets.24 Even if the utilities involved in the Superphenix project always categorically rejected the idea of a military link, it is clear that Phenix was used for the generation of plutonium for France’s nuclear-weapon program. The potential militarization of Superphenix raised considerable concern, especially in Germany, and was discussed in the context of the possibility that France might develop and deploy neutron bombs in Europe.25

In the case of Phenix, the fuel design allowed not only for the use of the radial blanket but also part of the axial blanket to produce plutonium for weapons. Usually the axial blanket is integrated with the core fuel in the same fuel pins but it seems that in the case of Phenix the upper axial blanket was separate. Phenix blanket material was reprocessed at the military UP1 plant in Marcoule, while core material, diluted with gas-graphite reactor fuel, was reprocessed at La Hague and at a dedicated pilot plant at Marcoule (APM with the head end SAP-TOP, later SAP-TOR).

In unusually blunt statement, General Jean Thiry, former director of the French nuclear test sites in the Sahara and in the Pacific, who prior to these positions had been responsible for eight years for plutonium "counting" at the CEA, told the daily Le Monde in 1978: "France is able to make nuclear weapons of all kinds and all yields. It will be able to fabricate them in large numbers as soon as the fast breeder reactors provide it with abundant quantities of the necessary plutonium."26 In 1987 General Thiry confirmed his statement and declared: "One can always get plutonium, especially if one develops… This is apparently an idea that one should not say (openly) because it is not moral,27 but I defend Creys-Malville (Superphenix) and the fast breeder reactor type, because there you have plutonium of extraordinary military quality."28 Dominique Finon states that Phenix was used for military purposes starting in 1978 but that the idea to use Superphenix for defense needs was abandoned in 1986.29

Research and development, construction, operation and decommissioning costs

France’s fast breeder reactor program was costly to the French taxpayer. A comprehensive historical economic assessment is not available. An extensive analysis to the middle of the 1980s was carried out and the national Court of Auditors provided a cost estimate in 1996.30 In addition a number of assessments have looked at specific aspects (R&D, decommissioning, etc.). Figure 2.6 provides an overview of Phenix operating costs between 1972 and 2003.

Between 1973 and 1996 the CEA alone spent an undiscounted FRF 15.8 billion ($2008 3.8 billion) on breeder R&D, 50 percent more than on light-water reactors (including the EPR development).31

According to an agreement signed in 1969, the CEA provided 80 percent and EDF 20 percent of the construction and operational costs of Phenix. Construction costs totaled FRF1974 800 million ($2008 880 million). Approximately €600 million ($2008 950 million) were spent on Phenix upgrades between 1997 and 2003.

The French state spent some FRF1985 44 billion ($2008 17.4 billion) on the fast breeder program between 1960 and 1986. The Superphenix construction costs increased by 80 percent to reach FRF1985 26 billion ($2008 9.5 billion) by the time the reactor went on line in 1986.32 At that time, the investment cost ratio per installed kilowatt (KW) between breeder and PWR was evaluated by the CEA at 2.58.33

The Court of Auditors, in its 1996 annual report, provided an evaluation of the cost of Superphenix, assuming that it would operate until the end of 2001. It estimated that the unit had cost FRF 34.4 billion by the end of 1994 and that financial, spent fuel management, decommissioning and waste management costs would reach an additional FRF 27.4 billion. Operating costs were given at FRF 1.7 billion per year. Considering the fact that the unit shut down at the end of 1996, adding two years of operating costs but also of power generation (approximately 3.65 TWh), the total estimated cost would be somewhere around FRF 64 billion, minus approximately a FRF one billion electricity generation credit.34 Jacques Chauvin, president of the directorate of NERSA stated that "in total, cumulating investment and operating costs and taking into account all future costs, Superphenix will have cost FRF 65 billion of which EDF will have paid 38 billion."35

The NERSA and Auditor Court figures are closer than the level of uncertainty attached. In particular, the decommissioning costs contain a substantial potential margin of error. They have been raised several times. As of 2003, the Court of Auditors estimated Superphenix decommissioning and waste management alone would cost €2.081 billion.

While the public commitment of J apan’s Government to the fast breeder reactor and closed fuel cycle has not wavered, the fast breeder reactor R&D budget has steadily declined, and, by 1996 had dipped below a 10 percent share of the nuclear R&D budget. The fast breeder reactor program share of total nuclear R&D peaked at 35 percent in early 1970s during the construction of Joyo. In 1989 it fell to 20 percent (¥77 billion) during peak construction at Monju. Since 1989, both the fast breeder reactor budget and its share of Japan’s total nuclear R&D budget have steadily declined. Cumulative spending on fast breeder reactor R&D from 1956 to 2007 was ¥1,480 billion, representing approximately 12 percent of total spending. Figure 4.1 shows the budget trends for all nuclear energy and fast breeder reactor R&D. The

1967 1970 1973 1976 1979 1902 19B5 19ЙЙ 1991 1994 1997 2000 2003 2006

Figure 4.1 History of Japan’s R&D budgets for nuclear power and breeder reactors.

Peak-year budgets and fast breeder reactor budget percentages are indicated.

target date for fast breeder reactor commercialization has slipped by 80 years in a period of 50 years. In 1956, the Long Term Plan anticipated commercialization in the 1970s. In 1967, the year that the PNC was established, fast breeder reactor commercialization was pushed back to the 1980s and the PNC decided that an Advanced Thermal Reactor (ATR) was required as an interim reactor between the light-water reactor and the fast breeder reactor. In 1987, the JAEC confirmed that light-water reactors would remain the main power generation source for the foreseeable future, and the commercialization target for fast breeder reactors was pushed back to the 2020-2030s. The most recent JAEC Framework for Nuclear Policy, which supersedes the Long Term Plan, has revised the goal for fast breeder reactor commercialization to approximately 2050 (table 4.1).4

In the end nobody seems to contest the judgment of the Court (of Auditors) that ‘the record of the fast breeder experience appears unfavorable today in any case on the financial level’. Christian Pierret (Secretary of State for Industry) goes as far as qualifying it as ‘unacceptable’.36

All three reactors, Rapsodie, Phenix and Superphenix, encountered significant safety problems during start-up, operation and dismantling periods; including sodium leaks, reactivity incidents, explosions and material failures.

Rapsodie — sodium leaks and a lethal explosion

After a rather smooth operational period from Rapsodie’s start-up at the beginning of 1967, at the end of 1978 a small primary sodium leak was detected, which led to the decision to reduce the operational capacity from 40 MWt to approximately 22 MWt. In January 1982, another small sodium leak was detected in the nitrogen system surrounding the primary vessel. Localization of the leak was believed to be too costly and too uncertain. The reactor was therefore shut down on 13 October 1982.

The secondary sodium was drained in April 1983 and is still stored on the Cadarache site. The primary sodium was drained by April 1984. It took two years to retrieve the 468 highly irradiated reflector assemblies from around the core (222 made of nickel, 246 made of steel) from the vessel, wash them to eliminate traces of sodium, and install them in a storage container. The 37 tons of primary sodium were treated in a specially designed facility (DESORA) that turned it into 180 cubic meters of concentrated sodium hydroxide.

On 31 March 1994, an explosion occurred during the cleaning of the residual primary sodium contained in a tank located in a hall outside the containment building.37 An experienced, highly specialized 59 year old CEA engineer was killed instantly and four people were injured. Approximately 100 kg of residual sodium had remained at the bottom of a tank at the end of the treatment campaign. An analysis of the accident concluded later:

The process selected to perform this clean up operation consisted in progressively introducing in the tank a heavy alcohol called ethylcarbitol, while monitoring the reaction through temperature, pressure, hydrogen and oxygen measurements. The major cause of the accident was due to the formation of an heterogeneous physical — chemical environment, complex and multiphasic made of three basic components: alcohol, alcoholate and sodium. This environment turned out to be particularly favourable to the development of thermal decomposition reaction and/or catalytic exothermal reactions. Large quantities of gases (including hydrogen and light hydrocarbon compounds) were thus produced. Shortly after the last alcohol injection on 31 March, the phenomenon ran out of control, leading to a sudden rupture of the overpressurised tank, then to the explosion of the gases mixture blown out in the hall.38

Since this accident, the use of ethylcarbitol or other heavy alcohol has been forbidden in the treatment of sodium. But the circumstances of the accident are subject to an ongoing legal dispute. In 2001 an expert court-commissioned analysis accused the CEA, the IPSN (Institute for Nuclear Protection and Safety, predecessor of IRSN) and the safety authorities of "faults by imprudence, negligence and violation of safety obligations."39 As of December 2009, there still is no published information indicating that there has been a final judgment.

As of 1988, Phenix had a cumulative average load factor of 60.5 percent. Operation was not without problems, however. The first fuel pin leak occurred in June 1975, secondary sodium leaks occurred in September 1974, March and July 1975 (approximately 20 liters each for the first two and 1 liter for the last). "Leakage generally led to the slow spontaneous combustion of this sodium in the insulation, without triggering fires external to the insulation."40 Repair operations proved ineffective and valves in the three secondary systems were eventually replaced by diaphragms.

On 11 July 1976, a sodium leak occurred at the intermediate heat exchanger (between the primary and secondary sodium loops) that led to what was later labeled as the "first real sodium fire in the Phenix plant." The fire was extinguished manually. On 5 October 1976, another sodium fire broke out at an intermediate heat exchanger and was again manually brought under control. Figure 2.7 provides an illustration of the impact of a sodium fire at an unidentified date. A further sodium leak was identified in August 1977. Further secondary sodium leaks were identified in the 1980s, including incidents in March and November 1984, and in September 1988.

In July 1978, two control rods showed a level of swelling that prevented normal extraction from their guide tubes. However, since the blocking was positioned above the insertion level during normal operation, the phenomenon was considered not to constitute an immediate safety issue.

In the first years no events directly impacted the steam generators. Steam generator failures, which can lead to violent sodium-water reactions are the most feared incidents in fast-neutron reactors. But various incidents took place in the steam generator environment, including four water leaks in the economizer-evaporator inlet of the steam generators between November 1975 and September 1976. The first cladding failure was detected in May 1979. It led to the "greatest release of fission gas (xenon-135) ever seen in the Phenix plant".

Between April 1982 and March 1983, sodium-water reactions in the reheater stages affected all three steam generators in at least four incidents. In the first event, on April 1982, approximately 30 liters of water leaked into the sodium and created a combustion flame that burned a hole in two tubes and damaged the reheater module’s shell. The other three events apparently involved quantities of water limited to a few liters. These four sodium-water incidents resulted in a total of six months of outage and nine months of operation limited to two-thirds capacity.

The most costly and potentially most significant incidents were rapid reactivity transients in the core on three occasions in 1989 (6 and 24 August, 14 September) and on 9 September 1990. In spite of a research program costing hundreds of millions of francs, 200 person-years of work, and the elaboration of some 500 documents, the cause of the phenomenon was never conclusively identified.

The events were particularly worrying since following reactivity and power drops of 28 percent to 45 percent within 50 milliseconds, power actually increased above the original state of the reactor. The fear was that such an event could trigger a power excursion. The cause could possibly have been an argon gas bubble going through the core, but this hypothesis was never confirmed. Subsequent investigations revealed that similar events had taken place in April 1976 and June 1978 and that the explanation at the time (control rod slippage) was wrong.

Safety concerns related to the operation of the Superphenix reactor were a key objection of the critics of the project from its very early stages. Over 5,000 tons of highly reactive sodium combined with several tons of highly toxic plutonium raised numerous safety issues. After the Chernobyl accident, which occurred only three months after connection of Superphenix to the grid, the question of the positive void coefficient inherent in the design, theoretically favoring power — excursion accidents, only increased the concerns of a number of scientist-critics. Safety concerns played a significant role in generating the opposition, including its most extreme forms.41

The first exceptional event took place at Creys-Malville before construction of the reactor was completed. A group of anti-nuclear activists succeeded in obtaining an RPG-7 (Rocket Propelled Grenade launcher) and eight warheads ("bonbons") from the German terrorist organization Rote Armee Fraktion (RAF) via the Belgian counterpart Cellules Communistes Combattantes (CCC). On 18 January 1982, five missiles were fired against the Superphenix construction site (three other pieces of ammunition had been discarded prior to the attack). There was little material damage but significant political and media attention. The authors of the attack were never caught until the confession of the key person, Chaim Nissim, 22 years later.42

The internal incident database of the French Nuclear Safety Authorities only refers to a single event during the operational period of Superphenix: a sodium leak from the main fuel storage tank. The tank was a key element of the plant since it was intended to serve as a transfer and storage tank for new and spent fuel assemblies. The leak was detected on 3 April 1987 and led to a 10-month shutdown. Worse, it became evident that it would be impossible to repair the tank. The leak was determined to be the result of a design error (wrong material). An entirely new fuel loading and unloading scheme had to be developed. It is interesting to note that the original design of the transfer tank did not have double walls. The consequences of the leak would most likely have been much more dramatic if that design had been used.

The National Assembly’s Enquiry Committee on Superphenix and the fast breeder reactor line also discussed the three previously mentioned significant events: the sodium pollution of July 1990, the turbine hall roof collapse of December 1990, and the argon gas leak in December 1994.43

At present the Superphenix reactor is undergoing various decommissioning operations. The dismantling of its reactor block is planned to begin in 2014 and continue for a period of eight years. The entire installation is to be dismantled by 2025.

After four decades of R&D, design and operation of LMFRs, with no imminent new breeder project, CEA, EDF and AREVA agreed in 2000 to preserve the breeder knowledge-base.44