P and T: An option for spent fuel and waste management using a double strata fuel cycle with a dedicated waste burner reactor

The present commercial reactors (LWR, CANDU, etc.) operate in a Once Through Fuel Cycle OTC, and based in a feed of uranium. From around 400 operating reactors a large stock pile of radioactive waste are being produced, mainly long lived TRU- Plutonium, MA( Am, Np, Cm), and Long Lived Fission Products, LLFP, such as I-129, Tc- 99, Cs-135 etc. It is estimated around 300,000 t of the spent fuel be produced in this decade, with 1% of Pu (3,000 tons), 0.1% MA, 300 t, and 400 tons of LLFP. The build up of radioactive stock piles, besides the concern of waste disposal, also brings the issue of proliferation. To overcome these issues, the next generations of nuclear reactors are considering concepts that coupled with a closed fuel cycles in many new initiatives, such as GIF and INPRO. This is the main point to note, that is P and T is sustainable option for spent fuel and HLW management, considering the renascence of Nuclear Energy for the next decades. Some issues such as safety, economics had already been almost solved. The contribution of nuclear energy to avoid the threat of global warming due to CO2 emissions in short term is also a positive point. So the only point which still remains as a controversy issue for a complete acceptance of Nuclear Energy, is what is going to be done with the HLW (long term hazard). There is a need to give answers acceptable for the public, and as established in the Joint Convention for Safety Spent Fuel Management and Radioactive Waste Management to protect the people, the society, and the environment presently and in the future in such way that the needs from present generation be satisfied without compromising the future needs of the future generations. The scheme shown in this presentation, summarizes almost all possibilities of waste and spent fuel management. At present OTC cycle, only uranium is being used as fuel. The first point is that the utilization of thorium fuel cycle is an option to reduce long lived radio toxicity and constrain plutonium even in a present time reactors (LWR, CANDU), or in the concepts under development (Molten Salt Reactors, Gas Cooled Fast Reactors, HTR, considered in INPRO and GIF initiatives). The IAEA has promoted several technical meetings, coordinated research projects related to Thorium utilization (TECDOC-1319 and TECDOC-1349. The second point is that OTC assumes that the final solution for HLW is the geological repository for thousand of years(>10,000 y). Although this looks most attractive and economically competitive, there is still a lot of controversies and unsolved issues (possibility of physical control by engineering design and natural barriers for such long period of time (10,000-100,000 y), and security). The second fuel cycle option, already implemented or in planning by countries like France, Japan, Russia, etc. Is the aqueous reprocessing fuel cycle with vitrification of HLW. In fact LWR-MOX is already in use in Western in Europe in LWRs, and are a first step in a global losed fuel cycle scenario. The PUREX aqueous process is well established, and reprocessing of Plutonium and uranium is available in France, UK, Japan, India, Russia, and China., and the recycling of these major actinides(U,Pu- 99.9% are extracted). For the innovative reactors under consideration RFC is an option, and if we include in cycle the possibility to separate MA (pyroreprocess), and burn in fast reactors than the goal to reduce the requirement in the repository by a hundred fold could be achieved. On should add, the possibility to use thorium in a closed fuel cycle with aqueous reprocessing (THOREX), with Fast Reactors, as also an option to reduce the burden in the repository, besides to increase the utilization of natural resources (thorium is 3 times more abundant than U in the earth crust, 6.000 ppb), in a sustainable nuclear energy scenario. Finally, the Advanced Fuel Cycle with Partining of MA could be a sustainable option for spent fuel and HLW management. So P and T objective is to reduce the Long term hazard of spent fuel or HLW by transforming long lived radionuclides (MA, LLFP) into short lived nuclides and reduce the radio toxicity by a factor of 100. Of course P and T demands a lot of development in dry processing (pyro), fuel fabrication, and new innovative dedicated transmute reactor. Accelerator Driven System (ADS), Thorium fueled(Th-TRU), Helium or lead bismuth cooled could be such reactor. In fact a lot of R and D effort are being put in P and T in all technical aspects, pyro processing, fuel fabrication, ADS concepts using solid or fluid fuels( MSR). The European Community, the USA, Russia, China, Republic of Korea, France etc. are involved in P and T, and have programs in it. The IAEA through the technical Working Group of Fast Reactors have reported several technical documents related with P and T, such as IAEA TECDOC 1365 - Review of National ADS programs for P and T. A NEA OECD 2003 report (Comparative Study on ADS and FR in Advanced Nuclear Fuel Cycles), made an excellent and consistent study comparing the sustainability (cost effectiveness, environmental friendly, resource efficiency) of several fuel cycles scheme(Pu Burning in LWR-FR, Heterogeneous MA recycling LWR-FR, TRU burning in FR , TRU burning in ADS, MOX recycling LWR-ADS, Double Strata LWR-FR-ADS, only FR), using U-Pu-MA solid fuels, and compare with OTC. The main conclusions were that: P and T will not replace the needs for appropriate geologic disposal of HLW; the closed fuel cycle with P and T using ADS or FBRs, will reduce in a hundredfold the time requirement for the repository; the cost of electricity in such cycles will increase 10-20%; the need of R and D efforts remain for the development of the necessary technology