The Superphénix Fast-Breeder Reactor

Salahodeen Abdul-Kafi
March 30, 2011

Submitted as coursework for Physics 241, Stanford University, Winter 2011

Fig. 1: Exterior view of Superphénix main building. Source: Wikimedia Commons

In 1976, France broke ground on an exciting new reactor in southern France, dubbed the "Superphénix." This reactor was a commercial prototype, designed to solve all of Europe's energy problems, as it has the ability to product more plutonium fuel than it consumed (hence the name "fast-breeder"). However, the reactor faced massive delays, maintenance costs, numerous closures, and was eventually decommissioned 10 years after it was connected to the Grid. [1] To analyze the disastrous history of the Superphénix, we must first look at fast-breeder reactors in general and understand the aims of building such a plant. As with all nuclear projects, the Superphénix has military and civilian uses, so we will also go into this dynamic of the story. Let us start with breeder reactors in general.

The fundamental question here revolves around the utility of producing a reactor that produces more fuel than it consumes. Well, this question boils down to energy sources. Uranium is not in any way a renewable resource. It is finite, and most estimates predict worldwide uranium supply to run out in 230 years. According to Nature magazine, "Breeder reactors would make it possible to obtain some 50 times more energy from a given amount of natural uranium than can be obtained with present day light-water reactors." [2] We can clearly see that if breeder technology can be implemented well, it will be the best reactor technology to use when faced with a dwindling supply of nuclear fuel. At a basic level, replacing all current nuclear reactors with breeder-type reactors would add around 11,000 years to the current nuclear fuel supply. Obviously, this is a very strong motivator for breeder technology, and is one of the main reasons why the Superphénix project was met with such strong support from the across Europe (it was a joint project among several European countries). Now, the fuel consumption explanation is obviously the strong sell point of a reactor which promises greater fuel output than consumption, but what about the plant's ability to produce power? Can a breeder reactor create power at a reasonable cost, or does the initial investment far outweigh the potential power gains?

To answer this question, we look at two factors. First, what is the theoretical yield of the Superphénix reactor? Secondly, since we now know exactly how much power it produced, how does the net realized power production compare to that of any other reactor's lifecycle? In 1976, when France broke ground on the Superphénix, the announced power production was 1200 Megawatts. [2] Assuming that this number is correct, and that the plant was operating fully from 1986-1996, it could have produced 1200 MW × 24 hours/day × 3650 days of operation = 105,120,000 Megawatt-Hours of electricity, or 105,120 GWH of electricity. According to the IAEA, Superphénix produced a grand total of 7494.72 GWH of electricity before it was decommissioned in early 1997. [3] Most of the delays were due to the sodium coolant that was utilized in the design of the reactor. In the end, the Superphénix project cost about $10 Billion, and produced a measly 7.1% of its expected production (or an approximate production of 85 Megawatts of power over its lifetime). [4] Clearly, no one would pay $10 billion for 7500 GWH of electricity- this translates to a production cost of $1.33/KwH, a number which was never hit even during the California energy crisis! At the same time, even at peak production, the Superphénix would have created energy which costs $0.1/KwH, much higher than the current costs of producing electricity from Nuclear power plants. Thus, we can safely assume that the Superphénix did not demonstrate a very good commercial model for producing power effectively and thus failed at achieving the goal of convincing world leaders that breeder reactors are commercially viable. However, both the discussion of nuclear reserves and the discussion of power production do not take into account the military aspect of such a plant.

The Superphénix was designed hold an initial core of 5,550 Kg of Plutonium, and, operating at full capacity, has the ability to produce up to 200Kg of Plutonium per year. [5] This is the mere definition of a breeder-reactor - where more fuel is produced after a power production cycle. However, this does not tell the full story. The type of plutonium in the original core is mostly low-grade plutonium that has comes from reprocessing of Uranium from normal reactors around the world (considering the unique, collective effort behind the Superphénix, this "spent" fuel came from across Europe and the US). [2] This means that Superphénix is perfect for nuclear weapon manufacturing, allowing France to potentially build up to 60 nuclear warheads using "bred" portions of the fuel core. [5] Interestingly enough, at the time that the Superphénix was completed, France no longer had any plants that produced weapons-grade plutonium. Consider the following quote, from General Jean Thiry, advisor to the French Atomic Energy Commission:

"France will be able to build atomic weapons of all kinds and within every type of range. At relatively low cost, she will be in a position to produce large quantities of such weapons, with fast breeders providing an abundant supply of the plutonium required. Lucky Europe and Luck France - at long last in a position to engage in an enlarged nuclear deterrent of their own, thus guaranteeing their security." [3]

This quote shows the incredible military potential of this reactor. Considering the ease at which weapons-grade plutonium could be extracted from the blanket of such a reactor (Ecologist), we can safely assume that this reactor is strictly off-limits to any non-proliferation treaty. In fact, the mere presence of such large amounts of plutonium in one facility presents extreme proliferation risks that must be accounted for before the production of another breeder reactor.

Considering the information presented here, we can conclude that the Superphénix reactor was only really useful for its military capabilities during its lifetime, considering the huge costs associated with the project and the minimal power production of the reactor. In order for a breeder reactor to be viable, it requires significantly more research to avoid the costly delays and failures that plagued Superphénix's lifetime. In addition, the incredibly high proliferation risks place such a project at an extreme disadvantage compared to other reactors, which take significantly more effort to extract weapons-grade material from. In conclusion, it does not make sense for a country to pursue breeder technology like the Superphénix at this time, considering the relative ease of attaining uranium, as well as the uncertainty in both the technology and proliferation aspects of such a reactor.

© Salahodeen Abdul-Kafi. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.


[1] "Superphénix Operating History," International Atomic Energy Agency, Power Reactor Information System (PRIS Database).

[2] G. A. Vendryes, "Superphénix: A Full-Scale Breeder Reactor," Scientific American 236, No. 3, 26 (1977).

[3] M. Sene, "Superphénix: The Reality Behind the Myth," Ecologist 16, No. 4/5, 198 (1986).

[4] "France Says Goodbye to the Fast-Breeder as Superphénix Takes on New Role," Nature, 385, 104 (1997).

[5] D. Albright, "French Military Plans For Superphénix?" Bull. Atomic Sci. 40, No. 9, 30 (1984).