Upload
others
View
1
Download
0
Embed Size (px)
Citation preview
Outcome of the Japan Power Demonstration Reactor Decommissioning Project
Satoshi Yanagihara柳原敏
Research Institute of Nuclear EngineeringUniversity of Fukui
2019 Sino-Japanese Workshop on NPP Decommissioning TechnologyOctober 29-30, 2019 @ Atomic Energy Council 3F
1
JPDR拆除實地試驗的成果— 輻射調查、拆除工法與廢棄物處理
Contents
⚫Outline of the Japan Power Demonstration Reactor decommissioning project
⚫ Dismantling activities: remote / hands-on / building demolition
⚫ Project management data
⚫ Study on project planning and evaluation
⚫Outcome of the project
2
Plant Characteristics
⚫ Reactor type & power : BWR, 45/90 MWt
⚫ Facility operation period : 1963-1976
⚫ Total output power : 21,500 MWD
Objectives⚫ to gain actual experience of nuclear power plant dismantling⚫ to verify the developed techniques in actual dismantling activities⚫ to collect data on JPDR dismantling activities
Dismantling Project Overview
⚫ Project period : Dec. 1986 - Mar. 1996
⚫ Project cost : 23 billion yens (including R&D)
⚫ Waste arising : 3,770 tons (Radioactive)
⚫ Worker dose : 306 person-mSv
The JPDR Decommissioning Program
The first experience of dismantling reactor facility in Japan.
before
after
3
Brief Biography of the JPDR Decommissioning Program
1979 Oct.
1980 Mar.
1981 Apr.
1982 Jun.
1982 Dec.
1985 Dec.
1986 Jul.
1986 Dec.
1996 Mar.
2002 Oct. Approval of JPDR decommissioning completion by regulatory body
Setting Committee for JPDR(1976: cessation of operation )
Decision of starting the JPDR decommissioning program
Start of R&D program for decommissioning
Atomic Energy Commission: Announcement on demonstration of decommissioning technology by
using JPDR
Notification of JPDR decommissionig by submitting the decommissioning plan (First stage)
Nuclear Safety Commission: Basic concept of the safety assurance on the dismantling of nuclear
reactor facilities –for JPDR Decommissioning-
Amendment of JPDR decommissioning plan( Second stage)
Start of JPDR decommissioning program
Completion of JPDR decommissioning activities
4
Management of Dismantling Activities
Basis of dismantling project
⚫ The plan of dismantling activities was made based onthe guideline issued by Nuclear Safety Commission.
⚫ The key principles of the JPDR dismantling plan are;✓safety of workers, and✓prevention of radioactive materials being released.
Organization (1986-1992)
⚫ Administrative division
⚫ Decommissioning program management division
⚫ Decommissioning operating division
⚫ Waste management division
⚫ Technology laboratory
Waste management
⚫ Classification for effective waste storage
⚫ Transport of radioactive waste to storage facility
⚫ Near surface burial in JAEA's site (extremely LLW)
⚫ Radiation control division( Dep. Health physics)⚫ Reactor control laboratory (Dep. Reactor engineering)⚫ Quality assurance committee
Support organization
5
Timeframe of Dismantling Activities
Preparatory activities
Reactor Pressure Vessel
Reactor internals
Biological shielding
Reactor building
Decontamination and final survey
Landscaping
Components around core region
1986 1987 1988 1989 1990 1991 1992 1993 1994 1995
Pipes connected to RPV
Building demolition
Dismantlement of components in auxiliary buildings
6
Research and Development for the JPDR Decommissioning
1. Systems engineering for reactor decommissioning
2. Non-intrusive measurement of radioactivity inside pipe
3. Radioactive inventory estimation
4. Dismantling techniques and systems
5. Decommissioning waste treatment, storage and disposal
6. Decontamination for reactor decommissioning
7. Radiation control
8. Remote operation technique
7
Area Classification and Applied Techniques to Dismantling Components
* shaped explosive cutting was applied to core
spray and emergency condensation system pipes in addition of these pipes
** incore monitor tube
Biological shield (III)
radioactivity : 4,000- 4Bq/g
dismantling by controlled blasting
Biological shield (IV)
radioactivity : less than 4Bq/g
dismantling by controlled blasting
Biological shield (II)
radioactivity : 40-7,000 Bq/g
dismantling by water jet cutting
Biological shield (I)
radioactivity : 40-7,000 Bq/g
dismantling by mechanical cutting
Reactor pressure vessel
radioactivity : 1.6×105 Bq/g (Max)
dismantling by arc saw
Feedwater system pipe
radioactivity : app. 2,000 Bq/g (Max)
dismantling by rotary disk knife
Water level monitoring
radioactivity : app. 2000 Bq/g (Max)
dismantling by shaped explosive (in air)
Forced circulation system pipe
radioactivity : app. 6,000 Bq/g (Max)
dismantling by rotary disk knife
Reactor internals
radioactivity : 2×108 Bq/g (Max)
dismantling by plasma arc
Control rod guide tube
radioactivity : 6,000 Bq/g (Max)
dismantling by shaped explosive (in water)
8
Schematic Diagram of Underwater Plasma Arc Cutting System
Spent Fuel Storage Pool
Water Cleanup System
Reactor Internals
Reactor Pressure Vessel
Camera
Plasma Torch
Plastic Envelop
Primary Cutting System
Control Panel
Dross Collection
System
Secondary Cutting SystemTo Ventilation
System
Cutting work of control rod
guide tube
9
Dismantling of Reactor Pressure Vessel
Work period : Sep. 1989 – Oct. 1990Component weight : 62 tonsCutting techniques : Arc saw ( underwater)Handling technique : Mast-type manipulatorWorker dose : 108 person・mSvManpower expenditure : 10,176 man・days
10
Dismantling of Inner Part of Biological Shielding
Work period : Sep. 1990 – Sep. 1992Component weight : 260 tonsDemolition techniques : Mechanical cutting ( 24.4 tons)
: Abrasive water-jet ( 29.4 tons): Controlled blasting (205.6 tons)
Handling technique : Mast-type manipulatorWorker dose : 28 person・mSvManpower expenditure : 13,573 man・days
Mechanical cutting
Abrasive water-jet
11
Dismantlement of Components using Conventional Technology
Dismantlement of components
⚫ Turbine, Piping, Pumps, Heat exchangers, etc.
⚫ Liner of spent fuel pool
Decontamination of Building
⚫ Evaluation of contamination characteristics
⚫ Removal of embedded piping in building structure
Building Demolition
⚫ Demolition(under 1m below surface)
⚫ Reuse of concrete debris
Removal of heat exchanger
Removal of pool lines (cutting)
Removal of pool lines (removal)Demolition of reactor bldg. Decontamination of floor surface 12
⚫ Facility characterization using past operation data✓Specify contaminated areas
⚫ Characterization of contamination✓Area and depth (Scoping and detailed)
⚫ Decontamination✓Surface contamination: removal of surface✓In-depth contamination: removal of penetrated
plus 5mm in depth
⚫ Confirmatory survey✓Measurement by health physics workers✓Confirmation by regulatory body
⚫ Revise of safety regulation
⚫ Demolition of building
Process for Building Demolition
Measurement of radioactivity on
building surface
Decontamination on flow
surface
13
Characterization of Building Surface Contamination
Characterization of contamination
(Depth and intensity)
Mapping of contamination
Planning of decontamination
Measurement of
Contamination
Refer of historical record
on contamination
No contamination
Contamination
Wall Floor
Sampling Points
14
Near Surface Disposal Facility for Very Low-Level Radioactive Waste
3.5m
2.5m
45m
7m
▼
Water Level
Monitoring WellCover Soil
Radioactive Waste
Low-Water-Permeability SoilRadiation Monitoring Post
GrassWaste: 1,310 tons (Bio-shield)
360 tons (Building decontamination)
Radioactivity: ~230MBq
Institutional control (30 years)
Monitoring, Surveillance, Land use control, etc.
Trench-type for waste from JPDR* (Capacity:1670 tons of concrete debris)
15
Total Waste
24,400 tons
Radiation control area
Shallow land disposal
Storage in facilityNon control area
Secondary waste24,400
tons
Radioactive Waste Arising from Dismantling Activities
Secondary waste
440 tons (1.8%)
Shallow land disposal
1,670 tons (6.8%)
Storage in facility
1,660 tons (6.8%)
Non-radioactive
20,700 tons
(84.6%)
Radioactive
3,770 tons
(15.4%)
Radiation control area
17,500 tons (71.5%)
Non control area
3,190 tons (13.0%)
16
17
Radioactive Waste Management
17Storage of 200-liter drums
Evaporation Compaction
(Melting)
Shiraishi et. al., Decommissioning Database, JAEA-Data/Code 2005-002, Jan. 2006
Thermal insulatorMetal components
Pipe & valves
Cables & conduit
Concrete
Duct
Others
Total
Breakdown of Manpower Expenditure and Worker Dose in Dismantling Activities
145,000
man-days
Supervision of dismantling
activities (20.4%)
Reactor internals (6.8%)
Pipes connected to reactor
pressure vessel (1.9%)
Reactor pressure
vessel (7.0%)
Biological shield (12.8%)
Components in reactor building (27.4%)
Demolition of
buildings (9.8%)
Decontamination &
Radiation survey (13.6%)
Manpower Expenditure
306 man-mSv
Reactor internals (23.9%)
Pipes to RPV (20.7%)Reactor pressure
vessel (35.2%)
Supervision of
dismantling work (2.6%)
Biological shield (9.3%)
Components &
Building structure (7.8%)
Decontamination &
Radiation survey (0.5%)
Worker Dose
18
Evaluation of Project Parameters (by COSMARD)
input output
Dmaf
Rado/DoseComputing Data on Project
Management & Scheduling
Unit Productivity
Factors, etc.
database
Work Packages with
Breakdown Structure &
Computing Conditions
- Activity names
- Components to be
dismantled
- Operational conditions
- Relationships with other
activities
- etc.
Data for Project
Management
- Manpower needs
- Occupational dose
- Waste generation
- Costs
- etc.
Computing of
Radioactivity & Dose
Equivalent Rate
Scheduling Data
- Bar charts
- Histograms
- Network diagrams
- etc.
Dose Equivalent
Rate at Each Area
Plant Inventory
including
Radioactivity
Setting of Work
Packages Using
Knowledge Base
Expe
COSMARD:Computer Systems for Planning and Management of Reactor Decommissioning19
Decommissioning Database
7,500
2,600
500
2,500
2,500
3,800
1,100
0 2,000 4,000 6,000 8,000
man-hours
Preparation
Power setting
Cleanup activity
Manpower Need
Unit Productivity Factors
1.12
1.08
1.66
1.79
2.21
1.11
0.60
1.27
0.00 1.00 2.00 3.00
hours/operation
Cutting preparation
Primary cutting
Cut piece transfer (large)
Cut piece transfer (small)
Secondary cutting
Cut piece packaging
Cutting (manipulator)
Machine setting(mast-type)
Machine setting(manipulator)
Removal of machine(mast-type)
Removal of machine(manipulator)
Cutting preparation(manipulator)
Mast Type Plasma Arc Cutting System
Total weight of
reactor internals: 16.6 tons
Max. radioactivity: 2×108 Bq/g
Secondary Plasma Arc
Cutting Device
Gas Supply
Cooling Water Circulation
Control Panel for
Plasma Arc
Primary Plasma
Arc Cutting Device
Carriage
Cross Travel
Carriage
Plasma Torch
Plasma Torch
Cut Piece
Cutting Capability (stainless steel)⚫Max thickness 230mm, Cutting speed 50mm/min (in air)⚫Max thickness 130mm, Cutting speed 75mm/min (underwater)
Mast-type remote handling machine
Slave arm (manipulator)
Plasma arc cutting is a thermal cutting method in which arc andplasma gas heat are produced by electrical current between arcnode and object to be cut. By-product treatment is necessary forworker safety and proper waste management.
20
Unit Productivity Factors
Dismantling & packaging activities
⚫ Hands-on dismantling : related to component type and weight
⚫ Remote dismantling : related to machine capability
⚫ Decontamination & Radiation measurement : Related to area size
⚫ Demolition of structures : related to structure weight
Preparation & cleaning activities
⚫ No specific relationship to manpower need except work conditions
21
Unit Productivity Factors of Hands-on Dismantling Activities
3.2
13.2
14.9
17.2
19.7
26.3
26.9
27.3
29.6
35.0
38.9
62.7
63.0
85.6
98.1
5.1
22.5
0.5
4.9
7.4
21.7
21.8
49.1
57.3
115.7
0.0 20.0 40.0 60.0 80.0 100.0 120.0 140.0
Transformer power supply panelPump
Wall & baseSmall machinery
Control panelHeat exchanger
Air conditionerTank
DemineralizerPiping & valve
Base hungerDuct
Cable & conduitCleaning of sludgeThermal insulation
Control blasting (outer layer)Control blasting (inner layer)
Building structureCrane
Steel wall of reactor enclosureTurbine generatorDump condenser
Turbine condenserUpper & lower part of RPV
Fuel pool liner
man-hours/ton
Facility components
Large components
Relationship between manpower expenditure and components weight
Weight of components being dismantled (tons)
Ma
np
ow
er
ne
ed
s (
ma
n-h
ou
rs)
0 50 100 150
2,000
4,000
6,000
8,000
0
:Preparation
:Dismantling & packaging
:Post-dismantling restoration
▲●■
Data Collection and Analysis
22
Construction using wall or existing pipes
Typical size (3×4m)
Covering a large component
Level 1
2
3
4
5
30~50m2 of work area
Narrow work area less than 30m2,
partially covering of work area
Large work area more than 50m2
Larger than typical size, durable or
multiple or more than single
Same criteria as above
man-hours0 20 40 60 80 100
Level 1
Level 2
Level 2
Level 2
Level 3
Level 3
Level 3
Level 4
Level 4
Level 4
Level 5
Level 5
Level 5
Level 1
Level 1
Remove of
greenhouse
Greenhouse
preparation
Cover of floor and
wall by sheet
Level 1
2
3
4
5
Leve l -5
Man-hours
(standard case)
Survey of work area
Selection of components
Carrying-in of material
Power cut
Scaffolding
Equipment preparation
Cover of floor and wall by sheet
Greenhouse preparation
Remove of greenhouse
Remove of scaffolding
Carrying-out of material
Transfer of equipment
Remove of sheet
5
7
10
10
10
16
23
24
10
10
14
14
28
0 5 10 15 20 25 30
Preparation
Cleanup
A
B
C
A B C
Unit Productivity Factors of Preparation and Post-Cleanup Activities
23
Lessons Learned: Major Consideration For Future Decommissioning Projects
Systematical Consideration For Decommissioning Project⚫ Necessity of total decommissioning plan including waste management and
technology transfer program.⚫ Planning of effective use of land or buildings after dismantling completion.
Record Keeping and Data Collection⚫ Use of any records on dismantling activities and waste management. ⚫ Analysis of project management data such as manpower expenditure,
waste arising and costs.⚫ Application and keeping of lessons learned in various aspects.
Review of Regulatory Systems for New Application or Reformation ⚫ Safety evaluation, waste management systems.⚫ Adequate inspection systems.
24
Major Outcome of JPDR Dismantling Project
⚫ Completion of nuclear reactor decommissioning safely using suitable dismantling techniques and health physics practices
⚫ Verification of the guideline on securing dismantling activities prepared by Atomic Safety Commission
⚫ Demonstration of dismantling technology and characterization
⚫ Establishment of build demolition procedures (from building surface decontamination, survey of radioactivity to demolition)
⚫ Accumulation of project data and experience on dismantlement and waste treatment/disposal.
25
Thank you for your attention.