session 12 korea by 6DJgJytp

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									The Korean Strategy for Nuclear
          Fuel Cycle



             2010. 6

           Do-Hee Ahn
                       Table of Contents



    Ⅰ     Spent Fuel Management

    Ⅱ     Recent Pyroprocessing Research Activity

           II-1.   Electrolytic Reduction
           II-2.   Electrorefining
           II-3.   Electrowinning
           II-4.   Waste Salt Treatment


    III   Summary




1
                             Spent Nuclear Fuel


  Attribute
      High radioactivity and heat : emits about 12 kW/ton after 1 yr cooling
      High radiotoxicity : 300,000 yrs will be taken to be natural uranium level
      Energy resource : contains 1% Pu and 93% Uranium


 Annual Spent Fuel Generation 700t/yr        Projection of Spent Fuel Generation
                                                                                90




                                               Spent Fuel Accumulation (ktHM)
                                              Accumulated SF Arisings (ktHM)
                                                                                80

       CANDU                     PWR                                            70

                                                                                60

                                                                                50                           PWR
                                                                                40

                                                                                30
                                                                                     10,0761 t, 2009
                                                                                20                                     CANDU
       95 t/yr,unit      20 t/yr, unit
                                                                                10
       4 units           16 units
                                                                                0
       380 t/yr          320 t/yr
                                                                                           톤/년
                                                                                      700 2025 2035
                                                                                 2005 2015             2045 2055   11,500 톤/년
                                                                                                                    2065 2075 2085 2095

                                                                                                          Year

 2
                  Status of Spent Fuel Storage

       On-site SF storage limit will be reached from 2016
       Decision making process for interim SF storage

                As of end of 2009                    Expansion Plan
                Cumulative   Storage                 Storage
    NPP                                 Year of                 Year of
                Amount       Capacity                Capacity
    Sites                               Saturation              Saturation
                (MTU)        (MTU)                   (MTU)

    Kori        1,762        2,253      2016         2,253      2016

    Yonggwang   1,704        2,686      2016         3,528      2021

    Ulchin      1,401        1,642      2008         2,326      2018

    Wolsong     5,894        5,980      2009         9,155      2017

    Total       10,761       12,561                  17,262
3
         Promising Fuel Cycle Concept (KIEP-21)

  Korean, Innovative, Environment-Friendly, and Proliferation-Resistant System for the 21st C (KIEP-21)



         Volume Reduction                                 FR Closed Fuel Cycle


                                                     Recycling
                                                                                                    Secondary
                                                                                                    EM Pump



                                                                 FR Metal Fuel
                                                                                                                                        IHTS Piping
                                                                                                             Reactor Head
                                                                                                                                               S/G



                                Pyroprocess
                                                                  (U-TRU-Zr)                      DHX

                                                                                                  IHX



PWR                                                                                        Primary Pump



                                                                                                        Reactor Core            Containment Vessel
                                                                                                                       Reactor Vessel




                                                                                                  GEN-IV
 Dupic                                                         (Cs, Sr)                           FR(SFR)
                                    Wastes                  Decay Storage



          CANDU                                             Benefits
                                                             Saves disposal space by a factor of 100
                                                             Shortens the management period to a few
                                                              hundred years
                                  Disposal                   Increases U utilization by a factor of 100
                                                             Ensures intrinsic proliferation resistance
              Flow Diagram of Pyroprocessing (KAERI)

                                                                                    Electrowinning
                                    Off-gas
                                    treatment
                                                                                                          TRU fuel
                                                                                                         fabrication
                           Fission gas



    PWR spent fuel    Decladding & Voloxidation                  Electrolytic
                                                                 reduction          Electrorefining



                                                                                                      Sodium-cooled
                                                      U3O8+                (U+TRU+FP)                 fast reactor
                                                      (TRU+FP)             metal
                                                      oxide




                            Air
                                                            Molten salt                 Uranium
                                                            waste treatment             recovery
                                  Cladding material


                              Low level waste

      TRU : Transuranic elements                                                        Recycle
      NM : Noble metal elements
                                                                 Recycle
                                                                 or treatment           or LLW
      FP : Fission products



5
                    R&D Issues of Pyroprocessing

 Purposes
      Increase throughput
      Simple and easy remote operability
      Enhance interconnection between unit processes
      Reduce waste volume

 Improvement
      High performance electrolytic reduction process
      Graphite cathode employment to recover U in electrorefining system
      Application of residual actinides recovery (RAR) system
      Crystallization method applied to recover pure salt from waste mixture

 Spent Fuel    Voloxidation Electroreduction Electrorefinning Electrowining Fuel Fabrication   SFR

     HM




 6
        Electrolytic Reduction Process – Flow Diagram

Pre-               Electrolytic Reducer                   Cathode Processor              Electro-
treatment            (650 oC, 120 kW)          Metal U     (725 oC, 120 kW)              refining
                                               + MS
 UO2                                           + Cs, Sr                                      Metal U




                       Electrode Handling Apparatuses




                                                                     LiCl      MS + Cs, Sr
       MS: LiCl-Li2O molten salt
                                                                 Waste Salt Treatment
   7
     Development of Electrolytic Reduction Process

    Bench Scale ER              Lab. Scale ER                Eng. Scale ER
    (~g UO2/batch)            (~20 kg UO2/batch)           (~50 kg UO2/batch)




Year 2008                Year 2009                     Year 2010
→ Change of Ceramic      → Successful Demonstration    → Construction of Eng-scale
  Cathode Basket to        of Lab-scale Electrolytic     ER focusing on the High
  Metal Cathode Basket     Reducer                       Speed Reduction
8
                    Electrorefining System – Flow Diagram

22.5 kg UCl3/batch
                              CERS (Continuous Electrorefining System)
Height: 2 m
OD: 0.9 m                                                             71.43 kg U-deposit/batch
                              U chlorinator
                                                        Salt recycle   Height: 2.7 m
                               UCl3                                    OD: 0.9 m




                                          Uranium deposit                 Salt distiller Uranium deposit
Electro-
reducer      Impure U mixture



              Continuous
             electrorefiner

        Continuous                                                                                         Melting furnace
         recovery
                                                                                                     50 kg U/day
     50 kg U/day
                                                                                                     Height: 2.7 m
     Height: 2.3 m
                                               Residual salt                                         OD: 4.9 m
     OD: 1.2 m                                                           Electrowinner



 9
                 Development of Electrorefining Process

      HTER Design                            HTER Construction/Test                Eng.-Scale HTER
     (~20 kg U/batch)                           (~20 kg U/day)                      (~50 kg U/day)

        Double layer cathode




                               167 mm




  Inner layer


   Outer layer       Back side of
                     outer layer
Double layer cathode
module
Year 2008                               Year 2009                              Year 2010
→ Lab. Scale HTER Design                → Construction of Electrorefiner       → Construction of Eng.-scale
  Electrohydrodynamic Anal.               Design of Eng. Scale Melting Furn.     HTER System
  Cu-recovery Test
10
                Electrowinning Process – Flow Diagram

                       Salt To
                    electrorefiner                                           Cleaned salt
                                                                           To electrorefiner
                       LCC                    Residual Actinide
                  Electrowinning                 Recovery
  Salt from
electrorefiner                                                                        Salt
TRU/U/RE/Salt                           RE/                           RE/Salt     purification   RE
- Pu/U>3.0                             TRU/                        (TRU<100ppm)
                                       Salt




                             TRU/U/RE/Cd
                   Cd        - HM>10wt%
                             - RE/TRU<0.25

                     Cd-TRU
                    Distillation

                                                   TRU               Fuel                Metal
                                      TRU/U/RE    Product         Fabrication            Fuel
                                     (Cd<50ppm)




11
                                               Development of Lab-scale LCC Electrowinners

  LCC assembly tests  8.4wt% U/Cd deposition by mesh-type LCC assembly (manual operation)
  Set-up of mesh-type LCC assembly to be installed in PRIDE (pneumatic operation)


                                                                                                        [Mesh]




                                                                                          Paddle                  Harrow



                                                                                                                                                                                            Mesh-type LCC by pneumatic operation




                                                                                                                              Cathode Voltage(V. vs. Ag/LiCl-KCl-1% AgCl)
                                       -1.35                                    [ 5 wt%U/Cd )                                                                               -1.5                            [ 8.4 wt%U/Cd )
 Voltage(V. vs. Ag/LiCl-KCl-1% AgCl)




                                                                                                                                                                                                2
                                                                                                                                                                                       100 mA/cm
                                                           0rpm                                                                                                             -1.6
                                       -1.40               100rpm-paddle
                                                                                                                                                                            -1.7
                                                           200rpm-harrow
                                       -1.45
                                                                                                                                                                            -1.8

                                                                                                                 (a) paddle
                                                                                                                                                                                                                                   Clean Cd surface
                                       -1.50                                                                                                                                -1.9


                                       -1.55
                                                                                                                                                                            -2.0                                                      U deposits
                                                                                                                                                                            -2.1
                                       -1.60                                                    2
                                                   U solubility in Cd
                                                                                50 mA/cm                                                                                    -2.2
                                                                                                                                                                                                    U solubility in Cd
                                       -1.65
                                               0       1       2        3   4     5   6    7        8                                                                       -2.3
                                                                                                                                                                                   0        2        4         6         8    10
                                                           Passed Electric Charge(Ah)                            (b) harrow                                                               Passed Electric Charge (Ah)


Fig. LCC deposition results using Paddle and Harrow                                                                                                                                  Fig. LCC deposition result using Mesh
       (U dendrite growth at salt-Cd interface)                                                                                                                                    (No U dendrite growth at salt-Cd interface)

12
               Development of Drawdown(RAR) System

 Target concentration of residual actinides in a spent LiCl-KCl salt : < 0.01 wt% (100 ppm)
(1) Recovery of Ans & REs by LCC electrolysis                           (2) Oxidation of parts of codeposited REs using CdCl2

 Features & Progress of RAR Study:
- Same equipment using a LCC electrowinning can be used for a RAR operation.
- RAR process has merits such as a compact equipment and a simple process application compared to a
  counter current multi-staged reductive extraction.
- Experimental results show that the residual concentration of uranium can be reduced to a value of less than
  100 ppm.
- Design of PRIDE-RAR equipment: 50 kg-salt/10 kg-LCC capacity & remote operation by MSM


                                                                                  2Ce(-U-Cd) + 3CdCl2  2CeCl3 + 3Cd + 2(-U-Cd)

                                                               [EW&RAR Reactor]
                                                                                                            (Interval: 30 mins)
                                                                                                  CeCl3                CdCl2
                                                                                                     Time                  Time
                                                                                                     intervals           intervals

                                                  CC
                                                [L Assembly]




 [Electrorefining & Electrowinning Schematic]

13
          Computational Model for LCC Electrowinner

                                                                                                                                                                                                                           12                                                 -1.0

 Simplified model development
                                                                                                                                                                                                                                                                     2
                                                                                                                                                                                                                                    Applied current denisity: 10mA/cm     U




                                                                                                                                                                                                                                                                                     Cathode potential(V vs. Ag/AgCl)
                                                                                                                                                                                                                                                       2
                                                                                                                                                                                                                           10             (i0=0.1mA/cm )                  Np




                                                                                                                                                                                                 Current density (A/cm )
                                                                                                                                                                                                 2
                                                                                                                                                                                                                                                                          Pu
                                                                                                                                                                                                                                                                          Am -1.5

 Half cell one-step reduction reaction:
                                                                                                                                                                                                                           8
                                                                                                                                                                                                                                                                          La
                                                                                                                                                                                                                                    Cathode potential                     Ce
                                                                                                                                                                                                                           6
                                                                                                                                                                                                                                                                          Pr


      An3+ + 3e-  Ano
                                                                                                                                                                                                                                                                          Nd
                                                                                                                                                                                                                           4                                              Gd -2.0
                                                                                                                                                                                                                                                                          Y
                                                                                                                                                                                                                           2

 Electro-transport is controlled by                                                                                                                                                                                       0
                                                                                                                                                                                                                                0           200         400         600
                                                                                                                                                                                                                                                                             -2.5
                                                                                                                                                                                                                                                                           800

 reduction potential and activation                                                                                                                                                                                                            Deposition time (hours)



 polarization (Butler-Volmer kinetics)
                                                                                                   Diffusion controlled electro-                                                                                            Partial current behavior of
 Diffusion limited mass transfer at LiCl-                                                               transport model                                                                                                   multi component simulation
                                                                                                                                                                                                                                               (Iapp=10 mA/cm2)
 KCl/Cd interface
   - Linear concentration gradient at
 diffusion boundary layer:                                                                         0.005                                               -1.0




                                                                   Concentration in LCC(mol/cm )
                                                                                                                                                2




                                                                   3




                                                                                                                                                              Cathode potential(V vs. Ag/AgCl)
                                                                                                         Applied current denisity: 10mA/cm          U
                                                                                                                            2
                                                                                                               (i0=0.1mA/cm )                       Np
                                                                                                   0.004
                                                                                                                                                    Pu
                       Cisalt  Cisalt               CiCd  CiCd                                               Cathode potential                    Am -1.5

     ii  ni FD salt     ,b       ,s
                                          ni FDCd     ,s     ,b                                   0.003                                            La
                                                                                                                                                    Ce
                           c                           Cd                                                                                                                                                                                                               Cathode
               i            Salt               i                                                                                                    Pr
                                                         c                                         0.002                                            Nd
                                                                                                                                                       -2.0
                                                                                                                                                    Gd
                                                                                                   0.001                                            Y                                                                                      LCC
 Electric field analysis
                                                                                                   0.000                                               -2.5
                                                                                                           0

 Overall cell voltage drop                                                                                               Deposition time (hours)



     E Cell  Eohm   Anode  Cathode
                                                                                                   Deposition behavior of multi                                                                                               Electric field pattern &
 CFD based model approach                                                                           component simulation                                                                                                  current stream in molten-salt
                                                                                                                       (Iapp=10 mA/cm2)                                                                                                region
                                                                                                                                                                                                                                               (Iapp=10 mA/cm2)

14
                     Waste Salt Treatment – Flow Diagram

    PWR
  Spent Fuel                                                                                

                                                                                                                       U
                        U, TRU, FPs                                  U, TRU, FPs
Voloxidation                          Electrolytic Reduction             (Metal)
                                                                                       Electrorefining (Drawdown)
                         (Oxides)                                                                                      TRU



                                       LiCl Waste (Sr/Cs)                               LiCl+KCl Waste (RE)



               Waste Salt              Cs/Sr : Salt refining                                 RE : Oxidation
                                          (Crystallization)
          minimization                                                                        Distillation &
                                                            <Waste from unit process>
          (FPs Removal &                                                                      Condensation
                                                         Residual Salt              RE
               Salt Recycle)                              Cs & Sr/Ba               Oxides
                                            LiCl Recycle                                     LiCl-KCl Recycle



                                           Solidifying             Solidification                Solidifying
           High-integrity                  Agent                                                 Agent
                                                             Final                  Final
                                                            Waste                  Waste            Characterization
           Solidification                                   Form I                 Form II          of Waste Forms


                                                                                   Disposal
15
                                    Waste salt minimization
   Lab-scale LiCl waste salt treatment                  Lab-scale eutectic salt treatment
                                                    Oxidative precipitation              Pure salt phase




                                                                                       Precipitation phase




           Crystallization   Melting of crystal
                                                    Vacuum distillation/condensation   Condensed Pure salt




                                                                                       Remaining RE oxides

                                  Salt
                                 crystal


                                                  ▶ Oxidative precipitation : separation of RE FPs by
▶ Reuse of LiCl waste salt by separation (or
                                                    oxygen sparing process (←1st pure salt recovery)
  concentration) of Cs/Sr/Ba using layer
                                                  ▶ Vacuum dis./cond. : distillation /condensation of
  crystallization process
                                                    residual salt from precipitation phase(← 2nd pure
▶ About 85-90 % LiCl salt reuse rate                salt recovery)
  → 85-90 % FPs separation efficiency             ▶Total eutectic salt reuse rate : > 97%
             Wasteform Fabrication of Residual Waste
  Lab-scale wasteform fabrication                Eng.-scale waste salt treatment apparatus

                                                                             Distillation/condensation
                                                                            8kg/batch
                                                                            W2.0 X H2 X L1.5m




              SAP wasteform      ZIT wasteform
             (FPs concentrated    (RE oxides)
                   LiCl)                                                       Wasteform fabrication
  Waste          ~25wt%            25wt%~                                     20kg-waste/2 weeks
 loading
                                                                              80kg-waste form
Durability   wasteform: ~10-2     Wasteform:
                                    ~10-3                                     W2.0 X H2.5 X L5.0m
(g/m2day)       Cs/Sr: ~10-3      REE:   ~10-6
 Density
                   ~2.4              ~4.3
 (g/cm3)
                                      Low
               ~1/3 volume       temperature
                reduction        processing &
Remark                            high waste
              *Compared with        loading
               zeolite method
                                   (~1100℃)
     Process Layout in PRIDE




18
                             Summary


 Based on the national long-term R&D program,
 the pyroprocessing technology will be developed to
 achieve the milestones.

  Research activities on lab-scale unit processes will be kept on in
 terms of throughput, remote operability, process optimization, waste
 minimization, and so on.
  20 kg/batch scale experiments have been successfully conducted.
  Eng. scale unit processes have been designed based on the lab-
 scale research activity. An inactive engineering-scale integrated
 pyroprocess (PRIDE) facility with a capacity of 10 tons-U per year is
 planned to be constructed by the end of 2011.
  PRIDE should be open for international collaboration. KAERI
 welcomes collaboration for development of pyroprocessing technology.

19

								
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