This is an interesting presentation on dry electrorefining reprocessing
by CRIEPI in
Regards, Jim Muckerheide
Foreign and Domestic Trends
The Draft Outline of Nuclear Energy Policy that was recently compiled by the Atomic Energy Commission's New Nuclear Policy-Planning Council calls for considering a second reprocessing facility in 2010 or so and a fast reactor fuel cycle R&D project some time around 2015. A feasibility study on the next generation of fast reactor fuel cycle technology, which is expected to be commercialized around 2050, is also being conducted by the Power Reactor and Nuclear Fuel Development Corporation in cooperation with the Japan Atomic Energy Institute (JAERI) and universities, and the Phase 2 report is slated to be released by the end of this year.
Next-generation fuel cycle [technologies] are required to not only be economical but also to improve resistance against nuclear proliferation and to reduce environmental impact through the combustion and management of long-lived nuclides.
other hand, in the
Special Features and Goals for Dry Reprocessing Technology
Dry reprocessing methods involve methods of cathodically recovering uranium (U), plutonium (Pu), and minor actinide elements (neptunium, americium, and curium) by means of metal electrorefining; and methods of electrorefining spent oxide fuel (U, Pu) and recovering oxygen (O2). Here I will discuss dry reprocessing by means of metal electrolysis, which is expected to entail a variety of requirements.
Because the oxidation-reduction potentials of the targeted elements in the molten salt are similar in metal electrolysis, recovering plutonium alone is difficult, and the transuranic elements are recovered together. Consequently, while it is technology that can be a powerful deterrent against nuclear proliferation, it also offers an advantage in that at the waste disposal step there is no need to add a process for separating transuranic elements, and minor actinides, in particular, which would impact the environment. As a result, the process can be compact and is also thought to be effective economically.
Furthermore, because dry reprocessing does not use organic solvents or other such substances that are degraded by acid or radiation, it can be used to deal with a variety of fuels, including fuel that has a short half-life once removed from a reactor, and fuel that is recycled from spent fuel containing large amounts of transuranic elements. Metal electrolysis was originally developed for a metal fuel cycle (a metal fuel fast reactor fuel and its reprocessing technology), but CRIEPI is developing dry reprocessing not only as a recycling technology for fast reactors but also as a technology that can be applied in reprocessing MOX [metal-oxide] fuel, the generation of which from light water reactors is anticipated, and in the dry separation of transuranic elements from high-level [radioactive] waste liquid generated from PUREX reprocessing.
CRIEPI has been engaged in the development of metal fuel cycle technology since 1986. Since 1989 it participated in the IFR (Integral Fast Reactor) project that the US Argonne National Laboratory is implementing. Although the IFR project was halted in 1994 under the Democratic administration's policy of not using plutonium, we have been conducting R&D in cooperation with the EU Institute for Transuranium Elements, JAERI, the Power Reactor and Nuclear Fuel Development Corporation, universities, and manufacturers.
we have obtained basic measurement data, e.g., thermodynamics data and separation
coefficients, on actinide elements and rare Earth elements in molten salt, and
we have finished demonstrating the principles of the process. We are now
verifying a series of processes using plutonium, and we are tackling the
demonstration of each process using irradiated fuel, though those
demonstrations are small in scale. We are now planning tests using not
only spent MOX fuel but also metal fuel containing transuranic elements that
was irradiated by
The actinide elements recovered in electrorefining become a product after salt and cadmium are distilled from the fuel, and in a joint effort with JAERI and the Power Reactor and Nuclear Fuel Development Corporation we have succeeded so far in recovering U-Pu alloys by means of post-electrorefining distillation. In addition, the idea in the dry method is that the molten salt that is used will solidify into sodalite, an artificial mineral, and through tests using dummy salts we have confirmed that a good solid can be produced. Furthermore, based on those results we are carrying out the design of 50-ton-per-year and 200-ton-per-year processing facilities, including the equipment design, and the results of that are reflected in the Feasibility Study on a Commercialized Fast Reactor Cycle System mentioned above.
The roadmap for CRIEPI's development of a dry method is shown in Figure 1 [omitted]. By the end of 2005 we will have completed the process verification, and by 2010 we plan to use spent MOX fuel and metal fuel that was irradiated by the Phenix reactor to conduct process demonstrations. And we are now producing metal fuel pins for the objective of Joyo irradiation tests from 2007. By about 2015 we plan to use those after they are irradiated to demonstrate the recycling technologies. Furthermore, in the engineering equipment development we will develop an electrolysis tank, distillation system, a device for extracting transuranic elements from molten salt, and a salt waste solidification system, among other things, by about 2015.
On the other hand, remaining issues we plan to tackle are the development of engineering equipment and the development of nuclear substance measurement and control methods that will enable remote operation of equipment, and which have not yet been established for the dry method.
According to that roadmap, CRIEPI aims to establish dry reprocessing technology based on electrorefining by about 2015. Incidentally, we think that this effort needs to be promoted as a national project in future developments after 2015.
on we hope to do all we can so that these efforts will contribute to