In June 1997, one of the first actions of Lionel Jospin on becoming Prime Minister was to announce the closure of the plant

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critics have argued that Jospin's decision was motivated by political motives (i.e. please his unwieldy Green political allies) rather than rational considerations.

I guess I am one of those critics. ;)

Peak oil is not an energy crisis. It is a liquid fuel crisis.

That shutdown was really infuriating. At long last, in 1996, SuperPhénix had reached sustained high power generation and was operating glitch-free in a very satisfactory manner. And Jospin cowered and took the opportunity of a planned maintenance to shut it down for good, junking a 9 billions euros investment and a very interesting technology just to placate his Green allies. A lot of good that did him in 2002. The cost argument (~1.3 billions euros budget overrun) was so stupid and fraudulent. A good 75% of those overruns were induced by the judicial guerrilla and administrative delays, not by the technical problems.

The worst offenders in this mess are clearly the so-called political ecologists (as opposed to actual ecologists, who know their science) and their facilitators, feckless socialist politicians. On them, case closed, so I'm not going to pile on.

But, as much as I like to heap my scorn on the Greens, SuperPhénix's supporters are not blameless. They sold this project as a slam dunk, a simple up-scaling of a mature technology demonstrated by the Phénix demonstration reactor, which would quickly become profitable.

Well, no. FNRs are not trivial and changing the scale changes a lot more than mere size. SuperPhénix was a complex beast, a full scale prototype of an entirely new design and it was completely predictable that it would have its share of glitches and problems. Also, the main argument of the 1992 Curien report to justify the continuing operation of SuperPhénix, using FNRs as waste incinerators, was at best disingenuous without significant advances and investments in reprocessing. Yes, FNRs can be used to burn some wastes but not all of them and advance separation and waste management is required.

Then, there is the problem of sodium chemical reactivity with oxygen and water. Overall, a sodium-cooled FNR is at least as safe as a PWR. No high pressure vessel, much better thermal behavior, excellent safety under LOCA (as demonstrated by EBR-II), inherent safety by doppler broadening, and so on. Plus add the intrinsic benefits of FNRs for fuel efficiency and fast flux applications. But sodium remains a concern and is just an stepping stone towards better coolants at higher core temperature.

SuperPhénix should have been sold for what it was: a full-scale prototype and a long term investment to master an important technology. An opportunity wasted.