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 4 th WORLD TRIGA USERS CONFERENCE September 8 to 10, 2008
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Decommissioning and Reutilization of the Musashi Reactor
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Decommissioning and Reutilization of the Musashi Reactor
4th WORLD TRIGA USERS CONFERENCE September 8 to 10, 2008
CONTENTS
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
NSRR JAERI(JAEA) 300 TRIGA ACPR 1975
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)
FacilityName
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 Ⅱ 2002 -
Musashi Musashi Inst. 100 TRIGA Mark Ⅱ 2004 - 5
The Musashi ReactorTRIGA-Ⅱ(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
ConcreteConcrete
Spent Fuel Spent Fuel Storage PoolStorage Pool
Core
Reactor Tank
Irradiation Irradiation RoomRoom
MI-TECH 7
Core and Reflector
Fuel Elements
Reflector
Reactor Tank
Neutron Detectors
Control Rods
Pneumatic Tube
Experimental Tube
MI-TECH 8
Fuel Element of Musashi Reactor (TRIGA-Ⅱ)
Fuel :20%Enriched UraniumZirconium Hydride
Cladding:Stainless 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
(3)Implementation
①Detail Plan for Decommissioning Work
②Review 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) USDOE’s 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-TECH12
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 Facility]Disposal Site
USD O E
Phase 1 Phase 2 Phase 3
General Plan and Image of the Musashi Reactor Decommissioning
14
Decommissioning Plan of the Musashi Reactor and Its Progress
Year
Item
Phase 1 Phase 2 Phase
3
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~
15
Permanent Shutdown of Reactor
Cover over the Reactor TankMI-Tech
Seal Seal
Appearance of the Reactor Tank
Top of the Reactor Tank
16
Stop Operational Function of Reactor Control and Instrumentation System
・Control Rod
・Control Rod Drive Mechanism
・Neutron Detector
・Others
・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
MI-Tech
純化装置
熱交換器
電気伝導度計
圧力計
圧力計
ろ過器
流量計
流量計
流量計
温度計
温度計
圧力計
圧力計排水ピットへ
原子炉タンクル
タンク出口閉止弁
閉止蓋
タンク入口閉止弁
循環ポンプ
循環ポンプ
温度計
温度計
2-10
2-132-4
2-5
2-11
2-1
2-2
2-72-6
1-1
1-5
1-7
1-8
1-31-2
1-4
1-6
電気伝導度計
18
Radiation Measurements of Installations
MI-Tech
All of the Installations Removed
Surface Radiation Level
Over 0.1μSv/h
Store in Container
Record and Label
Store in Area withRadiation Shielding
Radiation Monitoring
Label
Max. 20mSv/h
19
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
MI-Tech20
Transportation Cask (JMS-87Y-18.5T)
Shock Absorber
Diameter;1.9m
Height;2m
Fuel BasketCask Body
Weight;20tonMaterial;SSNo. of Fuels;80
MI-Tech21
Fabrication of Fuel Baskets
MI-Tech
Fabrication was startedin April, 2005
Completed in October, 2005
Inspections;Dimension,Material,
Ultra Sonic,etc
Fuel Baskets
22
Acceptance of Empty Cask into Reactor Room
MI-Tech23
Loading and Inspection of Fuels
Fuel Storage Cask
・Outer Surface Appearance・Confirmation of Fuel ID・Weight Measurement
Fuel Inspections
Transportation CaskNeutron Measurement
Fuel Storage Cask, Transportation Cask and Fuel Handling Equipment
MI-Tech
Fuel Handling Console and Monitoring TV24
Inspection of Packages
MI-Tech
Smear Test Radiation Survey Temperature Measurement
Pressure Test Leak Test Lifting Test
25
Store Installations Stopped Their Operational Function and Maintain Following Facilities Inside the Site
o Gaseous, Liquid and Solid Waste Disposal Facilities,
o Radiation Measurement and Control Facility,
o Reactor Housing Facility
MI-TECH
Phase 2
26
Issues Remained
o It may take long term to complete decommissioning, still under site selection for undertaking plan of the waste disposal facility for research reactor.
o Safe guard regulation is not terminated. It may be issue to be discussed that “zero inventory facility” under decommissioning can be released from safe guard of nuclear material.
MI-TECH 27
Framework of the Musashi Reactor Simulator
Operation Console
Personal Computer
DIO Card
DIOInterface
Simulated Core
Control Rod
Drive
Fuel Element Identification
Neutron Counting
Reactor Operation Data Neutron Transport Calculation
MI-TECH 28
Reutilization of Installation for Education
29
Realistic Simulation of the Musashi Reactor
Control Rod Drive
Simulated Fuels and Core
30
N :
Number of Neutrons ∝
Reactor Powerkeff :
Effective Neutron Multiplication Factor
β:
Effectine Delayed Neutron Fraction = 0.008
ι:
Neutron Life Time = 0.0008
λi:Decay Constant (i:1~6)
Ci :
Precursor (i:1~6)
Reactor Kinetic EquationReactor Kinetic Equation
∑+−−
= iieff CN
lk
dtdN λ
β 1)1(
iiii CN
ldtdC λβ
−=• Control Rod Worth• Temperature Effect• Core Composition
31
Control Rod WorthControl Rod Worth
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0 20 40 60 80 100
Control Rod Position [%]
Rea
ctiv
ity[$
] SAFETY
SHIM
REG
32
)( 00 θθρρ −−= DT
)( wGNWdtd θθθ
−−⋅=
:Coolant Temperature25℃
:Initial Core Temperature25℃
wθ
0θ
D:Reactivity Coefficient of Temperature
0.785¢/℃
Reactivity Effect associated with TemperatureReactivity Effect associated with Temperature
33
Reactivity Change due to Substitution of Fuel Element by Water Element
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
B4 C7 D11 E15 F19
Reac
tivi
ty [
$]
Experiment
MCNP4C ENDF/B-VI
βeff:0.008
B4C7D11E15F19
燃料
グラファイト
水
FuelGraphiteWater
Location of Fuel Element 34
New Department of Nuclear Safety Engineering
Faculty of Engineering
Until 2007
Mechanical Eng.
Electric & Electronic Eng.
Energy Science Eng.
Graduate School
Energy Science and Nuclear Engineering
Atomic Energy Research Laboratory
From 2008
Mechanical Eng.
Electric & Electronic Eng.
Energy Science Eng.
Nuclear Safety Eng. Nuclear Safety Eng.35
エネ
ルギ
ー
政策
Design and Operation
Nuclear Fuel Cycle
Application of Radioactivity
Environment
Inspection and DiagnosticApplication
Atomic Energy Policy
Nuclear Safety Regulation
International Energy Policy
Nuclear Risk Management
Nuclear Experiment and TrainingJAEA
Utility and Plant Maker
Atomic Energy Research Laboratory
Nuclear Engineering
Three Courses and Collaboration
Maintenance
36
Engineers and Researcher for Nuclear Energy and Radiation Utilization
Professional Education
Knowledge of Nuclear Technology, Safety, Experience and Training
Bases of Nuclear Engineering
Bases for Engineering and Ethics
First
Second
Third
Fourth
■Curriculum
37
Concluding Remarks-Phased decommissioning was selected for the Musashi Reactor starting with permanent shutdown of the reactor in 2004.
-The first phase was finished with completion of spent nuclear transportation.
-Issues remains for the completion of the decommissioning.
-Remained installations such as control drive mechanism, operation console will be reutilized for education.
MI-TECH38
4th WORLD TRIGA USERS CONFERENCE September 8 to 10, 2008
Decommissioning and Reutilization of the Musashi Reactor