Decommissioning and Reutilization of the Musashi ??文/ and Reutilization of the Musashi Reactor Tomio Tanzawa, Nobukazu Iijima, Norikazu Horiuchi, Tadashi Yoshida, Tetsuo

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  • Decommissioning and Reutilization of the Musashi Reactor

    Tomio Tanzawa, Nobukazu Iijima, Norikazu Horiuchi, Tadashi Yoshida, Tetsuo Matsumoto,

    Naoto Hagura and Ryouhei Kamiya

    Musashi Institute of Technology

    MI-TECH 1

    4th WORLD TRIGA USERS CONFERENCE September 8 to 10, 2008


    1. Outline of the Musashi Reactor2. Planning of Decommissioning3. Progress of the Decommissioning

    and Issues Remained4. Reutilization of the Installations for

    Musashi Reactor Simulator5. Department of Nuclear Safety

    Engineering Newly Established

    MI-TECH 2

  • Key Notes on Research Reactors in Japan

    Many Research Reactors with Long Term Operation

    What are Ageing Issues ?

    Keep Operation or Decommissioning ?

    New Regulations

    Introduction of Periodic Safety Review in 2004.

    Establishment of Decommissioning Stage Regulation in 2005.

    MI-TECH 3

  • Research Reactors in Japan (15 Reactors In Operation)FacilityName

    Operator Power(kW)

    Type First Criticality

    HTTR JAERI(JAEA) 30,000 High temp. gas cooled 1998

    JMTR JAERI(JAEA) 50,000 Tank(material test) 1968

    JRR-3M JAERI(JAEA) 20,000 Pool 1990

    JRR-4 JAERI(JAEA) 3,500 Pool 1965


    FCA JAERI(JAEA) 2 CA(fast reactor) 1967

    TCA JAERI(JAEA) 0.2 CA(light water reactor) 1962

    STACY JAERI(JAEA) 0.2 CA(homogeneous) 1995

    TRACY JAERI(JAEA) 10 CA(pulsing) 1995

    JOYO JNC(JAEA) 140,000 Fast reactor 1977

    YAYOI Tokyo Univ. 2 Tank 1971

    KUR Kyoto Univ. 5,000 Tank 1964

    KUCA Kyoto Univ. 0.1 CA 1974

    UTR-KINKI Kinki Univ. 0.001 Argonaut 1961

    NCA Toshiba Corp. 0.2 CA(light water reactor) 19634

  • Research Reactors in Japan (Decommissioned and under Decommissioning)


    Operator Power(kW)

    Type Decommissioning Start Completion

    AHCF JAERI(JAEA) 0.01 CA(homogeneous) 1967 1979

    JRR-1 JAERI(JAEA) 50 Water boiler 1969 2003

    SCA Sumitomo Corp. 0.1 CA 1970 1971

    MCF Mitsubishi Corp. 0.2 CA 1973 1974

    OCF Hitachi Corp. 0.1 CA 1974 2003

    JPDR JAERI(JAEA) 90,000 Prototype of BWR 1982 2002

    JMTR-C JAERI(JAEA) 0.1 CA(for JMTR) 1995 2003

    HTR Hitachi Corp. 100 Pool 1975

    Mutsu JAERI 36,000 PWR 1992

    JRR-2 JAERI(JAEA) 10,000 Tank 1997

    VHTRC JAERI(JAEA) 0.01 CA 2000

    TTR Toshiba Corp. 100 Pool 2001

    DCA JNC(JAEA) 1 CA 2002

    Rikkyo Rikkyo Univ. 100 TRIGA Mark 2002

    Musashi Musashi Inst. 100 TRIGA Mark 2004 5

  • The Musashi ReactorTRIGA-(Training, Research and Isotope

    Production Reactor designed by General Atomic)

    Max. Thermal Output : 100kW

    Moderator : Zirconium-Hydride

    Coolant : Light Water

    Reflector : Graphite

    Fuel Element : 20% Enriched Uranium Zirconium Hydride Alloy, Stainless Steel or Aluminum Cladding

    Control Rod : Boron-Carbide MI-TECH 6

  • Vertical Cross-sectional View of Reactor


    Spent Fuel Spent Fuel Storage PoolStorage Pool


    Reactor Tank

    Irradiation Irradiation RoomRoom

    MI-TECH 7

  • Core and Reflector

    Fuel Elements


    Reactor Tank

    Neutron Detectors

    Control Rods

    Pneumatic Tube

    Experimental Tube

    MI-TECH 8

  • Fuel Element of Musashi Reactor (TRIGA-)

    Fuel 20%Enriched UraniumZirconium Hydride

    CladdingStainless Steel orAluminum

    Dimension SS-Clad Al-Clad

    Length ~75cm ~72cmDiameter ~38mm ~37mm

    Fuel Diameter ~36mm ~36mmFuel Length ~38cm ~36cm

    MI-TECHFuel Element (unit:mm) 9

  • History of the Musashi Reactor

    Oct., 1959 : Permission for Establishment by Competent Authority Jan., 1963 : First Criticality

    July., 1976 : Addition of Medical Use to Reactor Operation

    Mar., 1985 : Change Core from Al Clad Fuel Elements to SS Clad

    Dec., 1989 : Small Leakage of Water from the Reactor Tank

    Shutdown Reactor Operation

    Investigation of Leakage Causes and Planning of Repair

    Discussion of Restart or Decommissioning

    May, 2003 : Decision of Decommissioning

    Jan., 2004 : Submit Decommissioning Plan to Competent Authority MI-TECH 10

  • General Flow of Decommissioning

    (1)Basic Senario

    (2)Planning and Submission of Initial Plan to Competent Authority


    Detail Plan for Decommissioning Work

    Review and Update the Initial Plan

    (4) Completion

    MI-TECH 11

  • Planning

    Regulatory Requirements for Completion of Decommissioning

    (1) Removal All of the Spent Fuels from the Site

    (2) Appropriate Disposal of Radioactive Waste

    Key Factors or Conditions for Implementing Decommissioning

    (1) USDOEs Foreign Reactor Spent Nuclear Fuel Acceptance Program

    (2) Radioactive Wastes are Low or Very Low Level, and Large Part of Wastes might be Clearance Material

    (3) Under Site Selection for Undertaking Plan of the Waste Disposal Facility for Research Reactor

    (4) Under Development of Clearance Criteria for Waste from Research Reactor (established in December, 2005)

    MI-TECH 12

  • Basic Scenario of Decommissioning

    (1) Time period of the decommissioning would be long term.

    (2) So, the activities would be carried out in a series of discrete operations(i.e., phased decommissioning).

    During first phase, (3) most high priority activity would be delivering the

    spent nuclear fuels to USDOE, and(4) nuclear installations for the reactor operation would

    be released from regulatory control and would be being stored inside the reactor housing facility for long time period.

    (5) Dismantling the reactor tank and concrete shielding would be started on condition that the undertaking of the waste disposal facility would be established. 13

  • Perm anent Shutdow nStorage of Radioactive D isposal ofEquipm ents inside Facility Radioactive W aste

    Fuel Transportaition

    (In O peration) (Facility w ithout Reactor C ore) (No Radioactive W aste)

    Fuels C ore

    Rem oval from C ore Tank Store inside FacilityDisposal Site

    USD O E

    Phase 1 Phase 2 Phase 3

    General Plan and Image of the Musashi Reactor Decommissioning


  • Decommissioning Plan of the Musashi Reactor and Its Progress



    Phase 1 Phase 2 Phase


    Status of Facility Decision of Decommissioning

    Submit Initial Plan to Competent Authority

    Permanent Stop Reactor

    Shut Down Operational Function

    Spent Nuclear Fuel Preparation of Packaging

    Transportation Shipping Fuels to USDOE

    Pre-shipment Preparation

    Dismantling and Storage of Radioactive

    Waste Management Waste inside the Facility

    ; Actual Dismantling Installation and

    ; Planned Disposal of Radioactive Waste

    Future20042003 2005 2006 2007


  • Permanent Shutdown of Reactor

    Cover over the Reactor TankMI-Tech

    Seal Seal

    Appearance of the Reactor Tank

    Top of the Reactor Tank


  • Stop Operational Function of Reactor Control and Instrumentation System

    Control Rod

    Control Rod Drive Mechanism

    Neutron Detector


    Remove and Store inside Facility

    Open Power Supply

    Disconnect Cable

    Disconnected Cables inside ConsoleMI-Tech17

  • Stop Operational Function of Water Cooling System

    Pipe of Primary Coolant

    Circulation Pump of Coolant

    Close Pipe

    Open Power Supply for Circulation Pump

    Pipe Circulation Pump

















  • Radiation Measurements of Installations


    All of the Installations Removed

    Surface Radiation Level

    Over 0.1Sv/h

    Store in Container

    Record and Label

    Store in Area withRadiation Shielding

    Radiation Monitoring


    Max. 20mSv/h


  • Work Flow of Spent Nuclear Fuel Delivery from Preparations of Casks to Transportation of Packages

    Design & Fabrication of Fuel Baskets

    Accept of Cask Body to the Reactor Room

    Install the Baskets to Cask Body

    Design & Fabrication of Fuel & Cask Handling Equipments

    Inspection of Casks

    Loading & Inspection of Fuels

    Inspection of Packages

    Inland Transportation to Port Oversea Transportation

    USA Inland Transportation to USDOE Laboratory


  • Transportation Cask (JMS-87Y-18.5T)

    Shock Absorber



    Fuel BasketCask Body

    Weight;20tonMaterial;SSNo. of Fuels;80


  • Fabrication of Fuel Baskets


    Fabrication was startedin April, 2005

    Completed in October, 2005


    Ultra Sonic,etc

    Fuel Baskets


  • Acceptance of Empty Cask into Reactor Room


  • Loading and Inspection of Fuels

    Fuel Storage Cask

    Outer Surface AppearanceConfirmation of Fuel IDWeight Measurement

    Fuel Inspections

    Transportation CaskNeutron Measurement

    Fuel Storage Cask, Transportation Cask and Fuel Handling Equipment


    Fuel Handling Console and Mo