A realistic plutonium elimination scheme with fast energy amplifiers and thorium-plutonium fuel

In a previous report [1] we have presented the conceptual design of a subcritical device designed for energy amplification (production). The present note further explores the possibilities of the Energy Amplifier (EA) in the field of the incineration of unwanted actinide "waste" from Nuclear Power Reactors (PWR) and from the disassembly of Military Weapons. The key idea which is developed is the one of using a Thorium-Plutonium mixture which is much more effective in eliminating Plutonium at acceptable concentrations (less than or equal to 20%) than the conventional mixture of Uranium-Plutonium. The device operates as an effective Plutonium to U-233 converter. The latter can be later mixed with ordinary or depleted Uranium and it constitutes an excellent fuel for the PWRs. The EA sub-critical mode is preferred over the conventional Fast Breeder Reactor, because of the much smaller risks associated to the narrow criticality window (approximately +/- 0.15 % in Delta k) of a Fast Reactor, the negative void coefficient related to the presence of Plutonium and the inevitable presence of large amounts of highly toxic Plutonium. It is shown that a cluster of EAs operated in conjunction with existing PWRs is a very effective and realistic solution to the ultimately complete elimination of the accumulated Plutonium and Minor Actinide stockpiles and it greatly alleviates the problem of definitive geologic disposal. Preliminary economical considerations show that Plutonium incineration when compared to direct geological disposal is not only environmentally more acceptable but also an economically profitable alternative.