Role of Partitioning and Transmutation (P&T) in Nuclear Energy

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1 Role of Partitioning and Transmutation (P&T) in Nuclear Energy Kazufumi TSUJIMOTO Japan Atomic Energy Agency Nov. 6, 2013, Tokyo, Japan Topical Meeting embedded to INES-4 : International Nuclear Law Symposium

2 Partitioning and Transmutation (P&T) Spent fuel Reprocessing FP MA MA (Np, Am, Cm) U Pu Geological disposal (Glass waste form) Recycle Conventional scheme P&T technology Transmutation by ADS and/or FR Partitioning (Example) PGM (Ru, Rh, Pd) Heat generator (Sr, Cs) Utilization and/or disposal Geological disposal after cooling and/or utilization (Calcined waste form) MA: Minor Actinides FP: Fission Products PGM: Platinum Group Metal FR: Fast Reactor ADS: Accelerator Driven System Remaining elements Geological disposal (high-density glass waste form) 2

3 Benefit and Role of P&T Benefits of P&T on Management of High-Level Radioactive Wastes (HLW): Reduction of long-term radiological toxicity Reduction of dose for future inhabitants To mitigate difficulties caused by long-term nature of radioactivity Reduction of amount of HLW Reduction of repository size To extend capacity of a repository Recovery of valuable materials from wastes, and so on. Steady implementation of High Level Waste (HLW) disposal is one of the most important issues even though we select to reduce dependency on nuclear energy. Partitioning and Transmutation (P&T) will be a key technology to reduce the environmental burden of HLW. 3

4 1E+7 1E+6 1E+5 1E+4 1E+3 1E+2 Radiological toxicity (ALI Ingestion hazard index per one metric ton of fresh fuel) 1E+1 1E+0 (ALI Ingestion hazard index per one metric ton of fresh fuel) E E+10 1E E E E E U ore 7.5ton Spent fuel HLW (U, Pu 99.9% recovery) Reduction of Radiological Toxicity by P&T PT (U,Pu 99.9%, MA 90% recovery) PT (U,Pu 99.9%, MA 99% recovery) PT (U,Pu,MA 100% recovery) Natural uranium 7.5t 100% Transmutation of U, Pu, MA Spent fuel HLW(U, Pu 99.9% recovery) 90% Transmutation of MA 99% Transmutation of MA 1E Time after reprocessing (Year) Radiological toxicity can be reduced by 2 orders, if 99% transmutation is achieved. The time period to reduce the radiological toxicity below the level of natural uranium used as raw material: 10,000y 500y HLW : High Level Radioactive Waste MA : Minor Actinide 4

5 Coupling with Long-term Storage Conventional Concept 1.8 km 2 (Vertical emplacement in crystalline rock) MA transmutation + FP Partitioning 0.41 km 2 MA transmutation + FP Partitioning + Long-term storage of Sr+Cs km 2 Normalized by 32,000tHM of 45GWd/t spent fuel Low-heating wastes (0.13km 2 ) 40,000 pieces of glass waste forms (1.8km 2 ) (CT: 50 y) 5,100 pieces of Sr-Cs calcined forms (0.23km 2 ) (CT: 130 y) 8,300 pieces of highly-loaded glass waste forms (0.18km 2 ) (CT: 5 y) 8,300 pieces of highly-loaded glass waste forms (0.01km 2 ) (CT: 45 y) 5,100 pieces of Sr-Cs calcined forms (0.005km 2 ) (CT: 320 y) CT: Cooling time before disposal Ref. : K. Nishihara, et al., Impact of Partitioning and Transmutation on LWR Highlevel Waste Disposal, J. Nucl. Sci. Technol., 45(1), (2008). 5

6 Fuel cycle concepts for P&T Homogeneous cycle Commercial FBR Fuel Cycle Double-Strata (ADS) Commercial Fuel Cycle FR LWR Fuel fabrication FR Reprocessing Fuel fabrication LWR Reprocessing Partitioning I-129 Transmutation Cycle FR FR HLW (MA, FP) MA, LLFP U, Pu, MA HLW U, Pu Fuel fabrication Partitioning Dedicated transmuter MA, LLFP Geological disposal MA is recycled in the next-generation reprocessing plant. MA is homogeneously mixed to FBR fuel with small amount up to 5 wt.%. MA transmutation is performed in all electricity generating FBR plant. Geological disposal Dedicated (second) transmutation fuel cycle with Accelerator-Driven System (ADS) is added to commercial fuel cycle. MA recovered from commercial fuel cycle is confined in the compact transmutation cycle. The ADS fuel mainly consists of MA. R&D for both concepts are being implemented in JAEA. 6

7 Design Concept of ADS for Transmutation Proton beam : 1.5GeV ~20MW Spallation target : Pb-Bi Coolant : Pb-Bi Subcriticality : k eff = 0.97 Thermal output : 800MWt Core height : 1000mm Core diameter : 2440 mm MA initial inventory : 2.5t Fuel composition : (60%MA + 40%Pu) Mono-nitride Transmutation rate : 10%MA / Year (10 units of LWR) Movable support Bending magnet Proton beam Fuel exchanger Beam duct Primary pump Steam generator Spallation target Reactor vessel Subcritical core Beam window Core support Concept of JAEA s 800MWth ADS 7

8 Double Strata Fuel Cycle Concept UOX-LWR MOX-LWR Pu Am, Cm Homo. FR UOX-LWR Pu+Np MA < 1% Am, Cm Pu, Np Homo. FR MA < 1% Pu, (Np) Am, Cm ADS MA ~ 60% All TRU ADS MA ~ 60% All TRU ADS MA ~ 60% All TRU (1) MOX-LWR for Pu burning and ADS for MA transmutation (2) FR for Pu burning and ADS for MA transmutation (3) FR for Pu recycling and ADS for MA transmutation UOX-LWR Pu, Am, Cm ADS MA ~ 60% All TRU ADS is a dedicated system to transmute nuclear wastes. Therefore, Double-strata concept with ADS can flexibly deal with various situations of nuclear fuel cycle. It will assist the deployment of FBR. It will also suit for the final stage of nuclear era. (0) ADS for TRU transmutation 8

9 Concluding remarks P&T technology has potential to reduce the radiotoxic inventory, to reduce the requirement for geological disposal, and to enhance design options of nuclear waste disposal. Nuclear energy utilization for sustainable future Even though we select to reduce dependency on nuclear energy, steady implementation of High Level Waste (HLW) disposal is one of the most important issues. Partitioning and Transmutation (P&T) will be a key technology to reduce the environmental burden of HLW. Double strata fuel cycle with ADS The double-strata fuel cycle concept with ADS has potential flexibility with various situations of nuclear fuel cycle. However, the technical challenges for ADS spread over wide range. 9