Radioactive waste partitioning and transmutation within advanced fuel cycles: Achievements and Challenges
In the last decades, numerous studies have been performed in order to identify appropriate “Partitioning and Transmutation” (P&T) strategies, aiming to the reduction of the burden on a geological storage (see, among many others, Salvatores, 2005). P&T strategies are very powerful and unique tools to reduce drastically the radiotoxicity level of the wastes and to reduce the time needed to reach the reference level (from ~100,000 years to few hundred years, i.e. comparable to the period in which technological and engineering means allow reasonably to control the radioactivity confinement). Moreover, P&T allows, in principle, also the reduction of the residual heat in a geological repository, with a potential significant impact on the repository size and characteristics. The first requirement of P&T strategies is the deployment of spent fuel reprocessing techniques (aqueous or dry), which are both in the continuity of today technologies (e.g. as implemented at La Hague in France, where Pu is separated up to 99.9 %) or which represent innovative, adapted approaches (e.g. pyrochemistry). The requirement is to extend the performance of Pu separation to 99.9 % also to Np, Am and Cm kept together or separated and in any case decontaminated from the lanthanides as much as possible. The separated TRU should then be “transmuted” (or “burned”) in a neutron field. The essential mechanism is to fission them, transforming them into much shorter lived or stable fission products. However, the fission process is always in competition with other processes, and, in particular, with neutron capture, which does eliminate isotope A, but transforms it into isotope A+1, which can still be radioactive. Isotope A+1 can in turn be fissioned or transmuted into isotope A+2, and so on. The neutron field has to be provided by a fission reactor. The requirement for this (dedicated) reactor is to be able to privilege the fission process with respect to the capture process and to be able to be loaded with fuels with potentially very different mixtures of Pu and minor actinides (MA), according to the chosen approach and the objective of the P&T strategy, and this without affecting its safety or penalizing its operability. A major issue of any P&T implementation strategy is a detailed evaluation of the impact of each strategy on the different features and installations of the fuel cycle, and a discussion of this issue will be provided in chapter 6. Chapter 7 will tackle the problem of nuclear data uncertainties and their impact on the nominal performances of the different transmutation systems. Finally, in chapter 8 it will be discussed in more detail the role of the different types of fast reactors described in the previous chapters, according to the different P&T objectives and implementation scenarios.
- Research Organization:
- Idaho National Lab. (INL), Idaho Falls, ID (United States)
- Sponsoring Organization:
- DOE - NE
- DOE Contract Number:
- DE-AC07-05ID14517
- OSTI ID:
- 1007248
- Report Number(s):
- INL/JOU-10-17546; TRN: US1101298
- Journal Information:
- Progress in Particle and Nuclear Physics, Vol. 66, Issue 1; ISSN 0146-6410
- Country of Publication:
- United States
- Language:
- English
Similar Records
Objectives, Strategies, and Challenges for the Advanced Fuel Cycle Initiative
U.S. Plans for the Next Fast Reactor Transmutation Fuels Irradiation Test
Related Subjects
ACTINIDES
CAPTURE
CONFINEMENT
FAST REACTORS
FISSION
FISSION PRODUCTS
FUEL CYCLE
IMPLEMENTATION
MIXTURES
NEUTRON REACTIONS
NEUTRONS
RADIOACTIVE WASTES
RADIOACTIVITY
RARE EARTHS
REPROCESSING
SAFETY
SPENT FUELS
STORAGE
TRANSMUTATION
WASTES
Radioactive Waste Transmutation
Fuel Cycles