efarmer wrote:Excellent data Tanada, so are we to expect abandonment of all other reactor types for the IFR designs or will other factors drive the next commercially deployed reactors and if so, why?
Fast reactors are all about fuel efficiency, at least in a civilian context. That means that unless fuel is very limited their main selling point of fuel efficiency is moot. However they do have a secondary selling point, they consume the long lived actinides as part of their fuel matrix and deliver energy as a side effect. In an ideal world we would build a fleet of IFR design fast reactors as we reprocess our once through LWR fuel spent fuel stockpiles which results in separated Plutonium and the potential for all actinides separation.
For clarity think of it this way, you build a dozen IFR reactors that will essentially refuel themselves indefinitely provided about two cores worth of material at start up. To start each of them you take depleted uranium, which we have tens of thousands of tons of on hand, and blend it with the chemicals Neptunium, Plutonium, Americium, Curium and on up the table through Nobelium. Americium is rare in this blend and the higher up the table you go the rarer each element is because they are progressively harder to make. You need about 20% of the fuel mixture to be these chemicals seperated from LWR fuel after it has been used for a year or more in producing power. You get roughly 1% from each LWR each year of these elements in the spent fuel, so for efficient use you could build one IFR for every 10 LWR's operating in any given year in the USA or elsewhere. The thing is the USA had over 100 reactors operating for about 30 years by this time, so we could fuel 300 IFR plants for life with just the spent fuel we already have stockpiled. And as each year goes by we could fully fuel another 10 next year, and the year after that, and the year after that, for another 20 years into the future at least.
Each IFR would regenerate Plutonium from the 80% depleted Uranium in its core as it consumed the chemical mix of Actinides in its start up core, and every few months some of the core would be exchanged for fresh fuel from the second core set on site. Once the extracted fuel has cooled for about 240 days it would be electro-refined to extract the fission fragments from it, then depleted Uranium would be added to the mix to replace the fission fragments and it would be put in the que of stockpiled fuel at the plant site. Over time the proportion of the fuel which are actinides other than Uranium 238 and Plutonium would decrease as they get consumed and very little more is made in the IFR to replace them. There would always be a little Americium and even a little Curium, but everything heavier than that is very rarely made by fast neutrons.
So short answer, fuel for LWR's is not going to be in short supply for any reasonable future, but the civilian Plutonium and higher Actinides stockpile will keep growing until it gets burned up in fast reactors at some point. Why not start building IFR's now and use up these stockpiles now while we can make the effort safely instead of leaving all that spent fuel laying around for our descendants to deal with? Anti-nuclear protesters often point to civilian Plutonium as the Achilles' heel of nuclear fission. IFR's remove that problem while providing energy in the process. Not only do they remove the problem directly they avoid all the Plutonium transportation issues once their 2 initial core loads are delivered on site, after that all they need is depleted or recycled Uranium to make up for the fission fragments extracted.