Radioactive Nuclides in Japan Eighth Information Exchange Meeting on Actinide and Fission Product Partitioning & Transmutation Las Vegas, Nevada, USA 9-11 November 2004 Resent Research and Development Activities on Partitioning and Transmutation of Radioactive Nuclides in Japan　 Kazuo Minato Japan Atomic Energy Research Institute, Japan Tetsuo Ikegami Japan Nuclear Cycle Development Institute, Japan Tadashi Inoue Central Research Institute of Electric Power Industry, Japan

OMEGA Program in Japan In Japan, the spent fuels from nuclear reactors are to be reprocessed A long-term program for research and development on partitioning and transmutation (P&T) technology Reduction of the burden of the backend of the nuclear fuel cycle The Atomic Energy Commission of Japan (AEC) began the program in October 1988. Advisory Committee of AEC reviewed the progress in 1999. The Committee issued the report in March 2000. OMEGA: Options for Making Extra Gains from Actinides and fission products generated in nuclear fuel cycle

OMEGA Check and Review in 2000 In P&T technology, there is a possibility to reduce the burden of waste disposal and to utilize waste as resources. P&T technology is still on the fundamental stage. It is appropriate to steadily promote the research and development (R&D) and to demonstrate its feasibility. Then engineering tests are to be performed to obtain various knowledge such as safety data... Three main institutes should promote their R&D steadily and effectively by collaborations with other institutes and universities in Japan and in foreign countries. Innovative idea is required in the development of P&T technology. It is necessary to prepare attractive condition for young researchers and engineers where they can exert their full ability.

P&T Technology in Japan In Japan, P&T technologies are studied mainly at three institutes: JAERI (Japan Atomic Energy Research Institute) JNC (Japan Nuclear Cycle Development Institute) CRIEPI (Central Research Institute of Electric Power Industry) JAERI is studying P&T technology using Accelerator Driven System (ADS) and dedicated transmutation fuel cycle. JNC and CRIEPI are studying P&T technology using critical fast reactor fuel cycle. Their activities are now organized as the “Feasibility Study on Commercialized FR Cycle Systems”.

Other Remarks to P&T in Japan Long-term Nuclear Program (2000) “…… Although P&T is still on the fundamental stage of R&D, there is a possibility to reduce the burden of waste disposal and to utilize waste as resources……” Fundamental Policy for Specified Radioactive Waste Final Disposal (2000) “…… Government and relevant institutes are required to steadily promote the research and development of P&T technology to reduce burden of final disposal, where viewpoints of international collaboration and periodic evaluation are important……”

JAERI’s Concept on P&T Dedicated Transmutation Cycle with ADS Commercial Fuel Cycle Partitioning & Transmutation Fuel Cycle (1st Stratum) (2nd Stratum) Proton Beam (1.5GeV-30MW) Superconducting LINAC 30% U, Pu Electric Power 70% Spallation Target (Pb-Bi) Grid Nuclear Power Plants MA, LLFP (Nitride Fuel) Spent Fuel Fuel Manufactiring Reprocessing Pu, MA, LLFP Recovered N-15 MA, LLFP High Level Waste Spent Fuel Partitioning Pb-Bi cooled Subcritical core (k-eff=0.95~0.93) Radioactive Waste without Long-lived Nuclides Pyrochemical Reprocessing Final Geological Disposal

R&D on Partitioning Process JAERI 4-group Partitioning Process For HLLW TRU, Tc-PGM, Sr-Cs, Others The process was tested with concentrated real HLLW ARTIST Process For spent fuel Phosphorus-free agents consisting of C, H, O and N (CHON principle) BAMA & DOHA : Separation of U, Pu TOGDA : An, Ln recovery N-donor ligand : An/Ln separation ARTIST Process Amide-based Radio-resources Treatment with Interim Storage of Transuranica

R&D on Transmutation Fuel Cycle JAERI Nitride Fuel Fabrication of (Pu,Am,Cm,Zr)N Property measurements Irradiation test of (Pu, Zr)N and PuN+TiN fuel pin in JMTR Irradiation: 2002-2004, PIE: 2005 Pyrochemical Process Electrolysis of UN, NpN, PuN, (U,Pu)N in LiCl-KCl eutectic melt Recovery of Pu, U+Pu into liquid Cd cathode (Joint Research with CRIEPI) Nitride formation behavior of U, Pu in liquid Cd (Pu,Zr)N PuN+TiN Liquid Cd cathod after recovery of Pu

R&D on Dedicated Transmutation System JAERI Accelerator Superconducting LINAC High-intensity proton accelerator (J-PARC Project) Lead-Bismuth Eutectic (LBE) Material corrosion/errosion test Thermal-hydraulics test for the beam window Evaporation test of Po from LBE Sub-critical Reactor 800 MWth ADS Transmutation of 250 kg of minor actinides annually Conceptual view of 800 MWth LBE-cooled ADS

JNC’s Concept on P&T Fast Reactor Fuel Cycle Basic Standpoints Treatment of all TRU in the same manner without distinguishing between Pu and MA Homogeneous loading of TRU in fuel assembly Classification of fission products into four categories Transmutation (Tc, I) Storage for cooling (Sr, Cs) Utilization (Ru, Rh, Pd, etc.) Waste Advanced fast reactor fuel cycle

R&D on Radiotoxicity Reduction JNC Next Process New Extraction System for TRU Recovery Advanced aqueous reprocessing method developed by JNC TRU recovery of > 99% MA-bearing MOX Fuel Fabrication 2%Np-2%Am-MOX 5%Am-MOX Irradiation Experiment In fast experimental reactor JOYO In 2006 MA-MOX irradiation experiment in JOYO

R&D on HLW Reduction JNC ORIENT-cycle: Optimization by Removing Impedimental Elements New concept of fast reactor fuel cycle system Reduction of HLW: < 1/10

R&D on Utilization of Noble Metal FP JNC Noble metal fission products About 30 kg/t-spent fuel Electrolytic extraction of Ru, Rh, Pd, etc. Utilization as catalyst for hydrogen production by water electrolysis Fission products of Sr and Cs Utilization as radioactive source Heat source Experimental apparatus of electrolysis

CRIEPI’s Concept on P&T Fast Reactor Fuel Cycle Metal fuelled FR cycle LWR cycle Mining Fuel fabrication FP Pyrometallurgical process (Electrorefining) U, Pu, MA, FP U, Pu U U LWR Spent fuel (Oxide) Metal fuel FR Fresh fuel (Metal) Enrichment U, Pu, MA Pyro-process with electrochemical reduction and fuel fabrication U, Pu, MA, FP U, Pu, MA U Fuel fabrication Aqueous reprocessing MA ： Minor actinide FP ： Fission product

R&D on Partitioning Process CRIEPI Separation of U and TRU from HLLW Conversion of HLLW to oxides by heat-treating at 500oC Chlorination of the oxides by chlorine gas at 700oC in LiCl-KCl Reductive extraction of noble metals in LiCl-KCl/Cd at 500oC Multistage extraction in the same system to separate U and TRU from rare earth elements Most of solvents, molten salt, liquid metal and chlorine gas can be recycled after treatment H L W D e n i t r a o M u l s g - x c > 9 % f T R U E w 2 O , N A k m S d v C K b / = 1 ( h ) F Z Process flow of pyro-partitioning

R&D on Partitioning Process CRIEPI Measurements of electrochemical potentials and distribution coefficients of actinides and lanthanides Separation tests of actinides by reductive extraction With simulated waste Recovery of > 99% actinides Setup of caisson in hot cell facility (cooperation of ITU) Electrorefining test of Pu recovery from metal fuel Currently, the program proceeds to use the genuine HLLW to finalize the process flow External and internal views of the caisson U-Pu-Zr alloy before and after experiment

R&D on Transmutation CRIEPI Characterization of Alloy with MA Solubility of tri-valence species in U-Pu-Zr is less than 1 wt% Properties of alloys with MA and lanthanides up to 5% each are approximately the same as those of U-Pu-Zr No melting phase appears below 650oC in U-Pu-Zr/Fe couple (Pu/(Pu+U) < 25 wt%) Irradiation test of MA-containing Alloys U-Pu-Zr-MA-RE In core region of PHENIX METAPHIX-1: 2.4 at % (2004) METAPHIX-2: 7 at % (2004-2006) METAPHIX-3: 11 at % (2004-2008)

Concluding Remarks R&D activities for P&T technologies are summarized JAERI: ADS transmutation fuel cycle with nitride fuel and pyro-process JNC: fast reactor fuel cycle with MA-MOX and aqueous process CRIEPI: fast reactor fuel cycle with metal fuel and pyro-process Integration of JAERI and JNC is scheduled in 2005 Other activities in Japan Tokyo Institute of Technology Basic study for innovative separation / transmutation systems toward vanishing HLW within the framework of COE-INES Measurement and evaluation of nuclear data for MA transmutation in collaboration with JAERI, JNC, Kyoto University Kyoto University and High Energy Accelerator Research Organizatio (KEK) Construction of proton accelerator to couple with an existing critical assembly, though the purpose of this program is not only for study of transmutation but also for energy production