To call superfenix a "successful breeder" seems to me to be a big stretch. It ran for 10 years prior to being closed down, cost 6.8 billion USD to produce a total of 8 Billion KWH of electricity and as far as I know did not actually do much breeding (was not operated much in that mode AFAIK.

What sort of a fuel cycle do you have in mind to justify: "All a breeding regime needs for success is a breeding ratio of 1.0"?

Oak ridge labs gives the fuel doubling time for the MSBR design as between 13 and 21 years here

www.ornl.gov/info/reports/1966/3445602516436.pdf

and seems to see it as a constraint (see my post above) but maybe I'm missing something...

To call superfenix a "successful breeder" seems to me to be a big stretch.

Technically successful, economic failure. All breeders will be with so much cheap uranium unless the offer more than fuel efficiency. Any solid fuel breeding regime is going to be a failure.

What sort of a fuel cycle do you have in mind to justify: "All a breeding regime needs for success is a breeding ratio of 1.0"?

You breed enough fissile material to keep the reactor running. We have access to 20000 tons of fissile material easily, and thats all you need in a 1.0 breeding regime for 20000 reactors.

and seems to see it as a constraint (see my post above) but maybe I'm missing something...

Thats probably because the MSBR's ideal fuel is U233, and it would be nice to breed enough U233 to fuel other reactors in the fleet, but its hardly necissary. I find liquid chloride actinide incinerators as ideal breeders for U233 for MSR seed fuel myself; But you cold just as easily seed it with U235, just making sure to pay more attention to initial actinide inventory.

Technically successful, economic failure.

Superphénix in France was not a technical success. It never got near its design output and was plagued with corrosion problems and leaks from the liquid sodium coolant. For most of its last ten years it produced little electricity and was a net consumer of power as the sodium had to be heated to keep it molten even when no electricity was being generated.

The two fast breeder reactors at Dounreay in Scotland also suffered problems from liquid sodium and this was one of the factors in the abandonment of the British fast breeder programme although the economic arguments about fuel costs in the medium term were bigger factors. It is not an inherent feature of fast breeder reactors but the environmental safety management at Dounreay was a disgrace. An estimated 10,000 irradiated fuel particles are in the nearby sea. Intermediate waste was dumped in a 65 metre shaft without records being kept which has contaminated groundwater and is likely to be washed away by the sea in 300 years. Hydrogen generated in the shaft has lead to one explosion.

Although, as I have said they are not inherent in fast breeders, these and other safety failings mean that the political realities are that there is almost no chance of a new fast breeder programme in the foreseeable future.

Neither country has yet come up with an answer of what to do with the thousands of tonnes of radioactively contaminated sodium.

By no chance of a new fast breeder programme, I meant in the UK, perceptions elsewhere may be different.

the political realities are that there is almost no chance of a new fast breeder programme in the foreseeable future

That's so funny. Usually it starts with "we have only 50-60 years" of uranium left. When shown that the exact numbers are closer to hundreds of years and many thousands of years if we include breeders then it always goes to the breeders and their birth defects. And it ends with a statement like the one above, generously dismissing the whole nuclear industry because of several failures. What is for you a foreseeble future? 10 years? 50 years (when the proven, high-grade ores are expected to end? 1,000 years? Do you know how much natural gas we have in US? Just for 8 years. How much copper? For 30 years. Do we need to stop using those - you bet!!!

This is such a junk. I wish at least you came up with something new - it is a same old overused strawman over and over again.

the political realities are that there is almost no chance of a new fast breeder programme in the foreseeable future

That's so funny ...

LevinK:

Nick is simply stating a political truth for the British environment.

Insulting him doesn't change the truth of his message.

Fast breeder reactors are NOT coming back here in the UK anytime soon.

If "soon" means 20 to 30 years I agree. I just pointed out that arguing against the long term feasibility of a technology on political grounds, which change from the morning to the afternoon is a ridiculous thing to do. Anyway in this 20-30 years timeframe there is no pressing need to develop breeders - uranium supplies will be more then sufficient.

You arent going to get me to defend liquid metal breeder reactors. They are technically successful at being able to produce plutonium. That superfenix didnt meet all the public works promises is a different matter. We will never pursue liquid metal breeder reactors because they are inherently less safe than thermal reactors or liquid fuel reactors, and incur large costs with processing regimes that must deal with many transuranic actinides. They do illustrate a technology that does work, albeit with many engineering challenges and extra costs. We wont ever pursue them because uranium will allways be too cheap for them to be justified.

The MSBR however did meet all of its design goals, but it wasn't an excuse to produce more plutonium during the cold war either. It is potentially cheaper than LWRs because of issues entirely divorced from fuel costs; No fuel fabrication, much smaller waste streams, inherent safety, negative void and temperature coefficients, better thermodynaic efficiency, scalability in size, continuous uptime.

Although, as I have said they are not inherent in fast breeders, these and other safety failings mean that the political realities are that there is almost no chance of a new fast breeder programme in the foreseeable future.

Well, a liquid chloride reactor might make sense for actinide incineration.

Neither country has yet come up with an answer of what to do with the thousands of tonnes of radioactively contaminated sodium.

Stick it in concrete casks in a parking lot. Worry about it next century. This isn't a hard problem, despite peoples efforts to make it so.