Separation and Utilization of Rare Metal Fission Products in Nuclear Fuel as for Hydrogen Production Catalysts

Transcription

1 Third Information Exchange Meeting on the Nuclear Production of Hydrogen 7 th Sep., 2005 O-arai, Japan Separation and Utilization of Rare Metal Fission Products in Nuclear Fuel as for Hydrogen Production Catalysts Masaki OZAWA 1,3, Reiko FUJITA 2, Tatsuya SUZUKI 3 and Yasuhiko FUJII 3 Japan Atomic Energy Agency (JAEA) 1 Toshiba Corporation 2 Tokyo Institute of Technology 3 JAPAN 1

2 Head-Line Why P&T,U, now? ( Introduction ) Environmental-friendly R Wastes (Motivation 1) Utilization of RMFP (Rare Metal Fission Products) (Motivation 2) How to Separate RMFP? Catalytic Electrolytic Extraction (CEE) Method How to Utilize RMFP? Electrolytic H 2 Production by RMFP deposit Electrodes Outlook Advanced ORIENT Cycle Project Multi-Purpose FBR System Conclusion 2

3 Motivation 1 ; Decrease Radio-toxicity of HLLW Actinide and Fission Product Partitioning and Transmutation - Status and assessment Report, pp.196, OECD

4 Motivation 2 ; Utilization of RMFP 図 5 Mass yield curve for the fission of 235 U with thermal neutrons. Rare metal Ru Rh Pd Tc Te Se Note Amount (kg/hmt) FBR-SF;150,000MWd/t, Cooled 4 years. RMFP(FBR);ca.33Kg/t (PWR [4.5%,45,000MWD/t,4 years] ; ca.12kg) Hindrance FP during Vitrification Rare Metal Fission Products Sr Se Zr Mo Cs (Sn) Ce Tc Ru Rh Pd Te Nd Re Pt Au Mass yield curve for the fission of 235 U with thermal neutrons (by Choppin et al.,(1980)) 4

5 Properties of Special Interest VII family 4th 5th 6th Periodicity of Hydrogen Overpotential (Acidic Solution, Ic :1mA/cm 2 ) (Ref.) H.Kita, et al. Denkikagaku, 38,17 (1970) 5

6 1 C 4 H O 2 4CO 2 +5H 2 O 2 C 4 H 10 +2O 2 4CO+5H 2 1>2 2>1 Butane conversion Hydrogen generation Without Catalyst Catalytic effects of Metals on Conversion of Butane to Hydrogen K.Kendall and D.S.Williams Platinum Metals Review, 42,(4), (1998) 6

7 Filtrated LWR- HLLW from Tokai Reprocessing Plant Concentration(g/l) Analysis:LWR-HLLW Simulated HLLW H+Li B NaAl SiCaCrFeNi ZnSeSr Y ZrMoTc RuRhPd TeCsBa La Ce Pr Nd S Eu U Pu RMFP Element Elemental Composition of High Level Liquid Waste (HLLW) (H+ : mol/l) 76

8 How to Separate RMFP from HLLW? Reference Electrode Ag/AgCl Power Supply 50cc cathode 10mm 10mm Clamp Anode Cathode cell 40mm Nafion membrane Anode Cell Electrolytic Cell for Separation of RMFP from Simulated HLLW and for Generation of Hydrogen by Electrolysis 8

9 Bach-wise Pd 2+ addition (0.11g x 3) Pd (Initial:750ppm) Ru (Initial:1200ppm) Re (Initial:500ppm) 100 Deposition yield [%] Ru (Divided Pd 2+ addition) Ru (Pd 2+ addition) Re (Divided Pd 2+ addition) Time [min] Re (Pd 2+ addition) Ru (without Pd 2+ ) Re (without Pd 2+ ) Electrolytic Extraction of RuNO 3+ and ReO 4- ; Catalytic acceleration effect by addition of Pd 2+ Electrolysis condition ; H+ : 2.5M, Temp. : 50, CD : 500mA/cm 2, Pt cathode 9

10 Deposition of Tc or Re with Pd Deposition of Ru with Pd Interaction between TcO 4- or ReO 4- and Pd 2+ in the bulk solution Deposition of ReO 3 and Pd on the cathode No change of the deposition potential for Re from the mono ionic solution of Re No interaction between RuNO 3+ and Pd 2+ in the bulk solution Deposition of Ru-Pd alloy on the cathode Decrease of the deposition potential for Ru comparing to that in the mono ionic solution of Ru Mediator Pd 2+ - TcO 4 Interaction No interaction - 2O -O - ReO 4 RuNO 3+ Island state Promoter -NO Pd 2+ Struc tural Param eters from EXAFS Curve Fitting r (Å) coordinati on no. Solid solution C alc ulat ion wi th m etall ic bondin g radi us (Å) Pd - Pd Pd - R u Ru - Pd 10 R u - R u ReO 3 ReO 3 TcO 2 TcO 2 Ru Pd Pd Ru Pd Pd Ru Pd Pd Pd Pd Pd Pd Pd Pd Pd Ru Pd Pd Ru Pd Pd Pt (cathode) Pt (cathode) CEE Model 10

11 Deposition yield (%) Pd (LLFP) Te(LLFP) Se(LLFP) Rh Ru Mo Re H+ concentration (M) 10 Zr(LLFP) Time (min) Separation of RMFP from Simulated HLLW Galvanostatic Electrolysis ; 500mA/cm 2 (Cathode), Room temp. Cathode; Pt-Ti, 20cm 2, S/V: 1/15cm -1, Pd 2+ Addition; Continuously (2.53gPd 2+ /hr), Pd added /Ru=3.6, Pd added /Rh=16.0, Pd /Re=

12 How to Utilize RMFP? System Reduction ratio / % Composition of Pd Ru Rh Re Tc Electrode Surface Pd > Ru Rh - - > Re Tc Pd-Ru Pd Ru Pd-Rh Pd Rh Pd-Re Pd>Re Ru-Rh Ru Rh Ru-Re Ru>Re Rh-Re Rh>Re Pd-Ru-Rh-Re(1:1:1:1) Pd Ru Rh>Re Pd-Ru-Rh-Re(3.5:4:1:1) * Pd Ru Rh>Re Pd-Ru-Rh-Re(3.5:4:1:1) * Pd Ru Rh>Re *1:Pd block addition *2:Pd 5 divided addition 12

13 Pd 20 µm IMG1 20 µm Pd L Rh Ru 20 µm Rh L 20 µm Ru L Average diameter of individual particle ca.φ1000nm ( 2000) 20 µm Re Re M EDS(EPMA) of the deposits on the Pt Electrode from Nitric Acid Solution Soln. Composition : Pd-Ru-Rh-Re(3.5:4:1:1),Divided Addition of Pd 2+ 13

14 70 1M NaOH M NaOH 60 Current / ma Pt 100 Ru Rh Re 80 Pd Tc Potential / V vs.ag/agcl Current / m A The Initial Hydrogen Evolution Potentials at Ic=0 y = x R 2 = Potential / V vs. Ag/AgCl Cathodic Polarization Curves of Pd, Ru, Rh, Re and Tc deposit Pt Electrodes and Pt Electrode (left), and Pd-Ru-Rh-Re deposit Pt Electrode* (right) *Soln. Composition : 3.5:4:1:1, Pd 2+ Divided Addition 14

15 200 Active Cathode Current, I (ma) at ψe=-1.25v 100 Less Active Re Rh Pd-Ru-Rh-Tc (1:1:1:0.5) Pd Ru-Re Pd-Ru-Rh-Re(1:1:1:1) ψhinit. ( V vs. Ag/AgCL ) Relation between Cathodic Current Corresponds to Hydrogen Evolution at -1.25V and Initial Hydrogen Evolution Potential (f Hinit. ) on each Deposit Electrode in 1M NaOH. Deposits from the quaternary ionic solution; *1, Pd:Ru:Rh: Re=1:1:1:1, *2, Pd:Ru:Rh:Re=3.5:4:1:1(Pd 2+ bloc addition), *3, Pd:Ru:Rh:Re= 3.5:4:1:1(Pd 2+ divided addition) Pt Rh-Re Pd-Re Pd-Rh Ru Pd-Ru-Rh-Re(3.5:4:1:1) Ru-Rh Pd-Ru Tc Pd-Ru-Rh-Re(3.5:4:1:1) Sol. Composition Reduction Rate(%) Pd Ru Rh Re Tc Re Tc Pd-Ru-Rh-Re Pd-Ru-Rh-Tc

16 * Relative Energy Consumption* 電力源単位 ( for (Ni 電極基準 カソード Ni electrode) ) 水素発生電力エネルキ ー消費量比 ( カソード電圧で代表 ) I V V C Q 0 W = Iε F /Q 0 ε F 見掛けの水素発生開始電位 Initial Hydrogen Evolution ( V vs. Ag/AgCl) Potential ( V vs. Ag/AgCl) 見掛けの水素発生電位 [ V ] Relative 希少元素 Energy FP( Consumption 模擬 ) 析出電極の水素発生反応に関する電力消費 of RMFP deposit Ti Electrode for Electrolytic H 2 Production Ti cathode:10cm 2, Catholyte:1M NaOH, 50, CD cathode =100mA/cm 2 Ni Pt ワイヤ束 Ti Ru-Ti Rh-Ti Pd-Ti Re-Ti Ru+Re-Ti Pd+Rh-Ti Pd+Rh+Ru+Re- Ti 16

17 MNaOHSoln. ; per mg of deposit Artificial Sea Water Cathode Current (ma) Pt Pd Ru Rh Re Pd-Ru Pd-Rh RMFP-deposit Pt Electrodes Pd-Re Ru-Rh Ru-Re Rh-Re Pd-Ru-Rh-Re(1:1:1:1) Pd-Ru-R-Re(3.5:4:1:1)*1 Pd-Ru-Rh-Re(3.5:4:1:1)*2 Cathodic Currents of RMFP deposit Pt Electrodes at -1.25V(V vs. Ag/AgCl) in 1M NaOH and Artificial Sea Water Deposits from the quaternary ionic solution; *1, Pd:Ru:Rh:Re=3.5:4:1:1(Pd 2+ bloc addition), *2, Pd:Ru:Rh:Re= 3.5:4:1:1(Pd 2+ divided addition) 17

18 1 in HNO H ad H + + e Current / A in NaOH Sweep 50mV/s H + + e - H ad M NaOH Potential / V vs. Ag/AgCl Pd in NaOH Pd in HNO3-0.8 Pd:Ru:Rh:Re=3.5:4:1:1 *1 Pd:Ru:Rh:Re=3.5:4:1:1 *2 Rh Pd-Rh Ru-Rh Pd:Ru:Rh:Re=1:1:1:1 Pd Pd-Ru Pd-Re Pd-Pt *1 Pd:Ru:Rh:Re = 3.5:4:1:1 ; Pd/(Ru+Rh+Re)=1.6 Block Addition of Pd 2+ *2 Pd:Ru:Rh:Re = 3.5:4:1:1 ; Pd/(Ru+Rh+Re)=1.6 Divided Addition of Pd 2+ Cyclic Voltammograms of RMFP deposit Pt electrodes 18

19 Salt-Free Radio Activity Separation (Partitioning) Transmutation Utilization Green Chemistry Outlook Environment Isotope Sptn. Spent Fuel 19 Non Proliferation Functional Material Nano-tech

20 133 Cs Application for Heat source and/or Radiation Source Isotope Separation 135 Cs (Transmutation) Zeolite Solidification 93 Zr (Transmutation) 137 Cs Application for Functional Sorbent Removal of Cs by Inorganic Cs Ion Exchanger Elution Ion Exchange Separation Zr Isotope Separation Zr Mo Other FP (Near Surface Repository) Advanced ORIENT Cycle Project ORIENT: Optimization by Removing Impedimental Elements Optimization by Removing Instructive Elements Adsorption Separation bu Ion Exchange Filter Main Separation Process by Ion Exchange Chromato -graphy Sr Spent fuel Am, Cm Reuse of Filter RE Electrolytic Extraction (Regeneration of Filter) Pd, Ru, Rh,Tc, etc U, Pu, Np Am, Cm Separation Am Fuel Nuclear Fabrication Fuel Cm (Cm Pu) Ru,Rh,Pd,Tc,etc Zeolite Solidification Application of RE Application for Heat Source for various Quantum Materials (Sr battery) and/or Radiation Source Investigation of Irradiate Am fuel Fast FBR Reactor Pd Tc Solid State Physics for Nuclear Fuel Cathodic Deposition Isotope Separation Pd Application for Catalysts for Hydrogen Generation and Fuel Cell 107 Pd (Transmutation) Tc battery Application for Catalyst After Transmutation 99 Tc(n,β - ) 100 Ru 20 Suzuki/Ozawa

21 FBR Cycle in Future UO 2 Recycle Facilities Fuel Fabrication (Nuclear Fuel) FBR Electricity Generation with Transmutation of LLFP Power Utilization Natural-U Saving Effect Effect Actinides Tc, I (as LLFP) Ad. Reprocessing (Target LLFP) (Spent Fuel) Hydrogen Generation Nuclear-H 2 Society 2 Artificial Resources Generation 99 Tc (n,γ) 100 Tc β Ru Tc, RMFP, etc Material Utilization Decreasing Amount and Radio-Toxicity of HLLW Advanced Separation will be Key Technology! S/MLFP ; Non Actinides Non LLFP, Non RMFP Environmental- Friendly 21

22 Separation Catalytic electrolytic extraction (CEE) method for d- element utilization. CEE process is merged into tertiary pyridine-based IX process. The both will be key technologies of advanced ORIENT process. Nonα, non RMFP and non LLFP (Tc, Pd, Se, etc) contained HLLW will be highly expected. Utilization Conclusions RMFP as catalysts of H 2 production. Excellent ability of quaternary, Pd-Ru-Rh-Re deposit Pt or Ti electrodes for electrolysis of either alkaline or sea water. Will continue parametric study and hot experiments (Japan-Russia collaboration). Strategic View and Future R&D Program Enhanced separation can decrease wastes, and change them into resources. Advanced ORIENT Cycle project will be initiated in the next year for multipurpose FBR system. 22

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