Nuclear Damage Compensation and Decommissioning Facilitation Corporation

Approaches to the decommissioning andcontaminated water management forFukushima Daiichi Nuclear Power Station
1st International Forum on Decommissioning ofFukushima Daiichi Nuclear Power Plant

April 10th, 2016

Hajimu Yamana
President, Nuclear Damage Compensation andDecommissioning Facilitation Corporation
無断複製・転載禁止 原子力損害賠償・廃炉等支援機構©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

Review of the Fukushima Daiichi Nuclear Power Station Accident
Difficult-to-return

Regulated area
as of Sep. 5, 2015

Restricted residence
Evacuation cancellationpreparation
BBC World News

Photo: Air Photo Service Co. Ltd

Released radioactivity
FukushimaDaiichi [2][3]PBq

NuclideHalf-life

Chernobyl [1]PBq

As of Oct.2015

Xe-1335.25h

6, 50014, 000

Difficult-to-return24, 000

I-131

8.03d

1, 760150

Restricted residence

23, 000

I-133

20.8h

910

146

Evacuation cancellation
preparation

24, 000

Cs-134

2.07y

47

11.8

Cs-137

30.1y

85

12

Restricted area

Evacuees[1] UNSCEAR (2008), [2] Chino et al. (2011, 2013),[3] Steinhauser et al. (2014)

2Changes in five years since the accident
20112012

Government
Nuclear Emergency Response
Headquarters 2011.03.11
Local nuclear emergency response
headquarters 2011.03.11

Roadmap

Roadmap
1st issue
2011.12.26

20132014

2015

Council for the Decommissioning ofTEPCO's Fukushima Daiichi NPS
2013.09.03
Team for Countermeasures forCommittee on Countermeasures
Decommissioning andfor Contaminated Water Treatment
Contaminated Water Treatment
2013.04.19
2013.09.10

Roadmap
1st revision
2012.12.26

Roadmap
2nd revision
2013.06.27

Roadmap
3rd revision
2015.06.12

Strategic Plan

Emerging entities

StrategicPlan2015
2015.04.30

NDF
2014.08.18

IRID
2013.08.01

2011.03.11

Coldshutdown
2011.12.16

TEPCO D＆D Co.
2014.04.01

3

Update of Units 1-4

Unit1

Removal of last one roof panel

Unit2

Policy decision for the overall
disassembly of storage shed

Unit3

Unit4

During preparation ofretrieval/decontamination

Completion of spent fuelSource :Meeting material from Team for Countermeasures for Decommissioning and Contaminated Water Treatment

4

Retrieval of fuel debris from Unit3
 The removal of the spent fuels stored in the pools of Unit-1,2, and 3 is urgently required operation.
 They are planned to be taken out after clearing off theradioactive rubbles existing on the operation floor.
 The decontamination and clearing off of the operation floorof Unit-3 has progressed, and the removal of rubbles fallen
down into the pool has started.

 After the decontamination, a building cover will be installed
to remove the fuels with newly installed Fuel Handling
Machine.

Building cover to be installed

Removal of rubles from SF pool of U-3

Building covers under fabrication

Source： TEPCO website and photo archive

Rubble removal operation5

Improvement of site condition
Unit-4 Aftermath 2011)

Rubbles Aftermath (2011)2015

After2015

Improvement of radiological safety
Dose ave./month mSv

20G-Zone

Source： Courtesy by TEPCO

100%
Individual dose
個人被ばく線量
Full face mask area
全面マスクエリア

Full facemask area

1050%

00%

2014
2011.322011
011.92012.322012
012.92013.322013
013.9
2014.322014
014.92015.3
2015

6

Approaches to the contaminated water purification
 Contaminated water is generated by the inflow ofground water into the reactor buildings. The total
amount of the accumulated water exceeds 800 k
m3 to date.
 It has been treated by using ALPS, Advanced
Liquid Processing System, and Mobile SrRemoval system to remove major radio-nuclides,
and residual tritiated water is stored in tanks.

ReactorDemineralized
water storage

Csremoval
Reverse osmosis
membrane
Desalinization unit

Mobile Sr-Removal

RO (Reverse Osmosis)

2nd Cs removal system

Concentrated salt
water tank

Tritiated waterstorage

Multi-radionuclide
removal system(ALPS)

Adsorption
vesselSource： Released material from TEPCO

ALPS

2nd ALPSHigh Performance ALPS

7

Approaches to the contaminated water
2014/5
Discharge started
2015/9Pumping-up started
2015/3Operation started

2015/7Water
removalcompleted2016/2
Closingcompleted

Cooling pipe installation

Sub-drainage
treatment

Frozen wall

Source： TEPCO website and photo archive

Refrigeration facility

8

Accumulated contaminated water

Inventory of treated water

Source： TEPCO photo archive

RO-concentrated salt water
ALPS processing water
Sr processing water

9

Organizational structure for decommissioning of Fukushima Daiichi
TEPCO

Government
Policy making andprogress management(D＆D Engineering Company)

Formulation of Mid- andLong-term Roadmap

Implementation of decommissioning
operation and project management

Issue of the Strategic Plan

NDF
Formulate mid- and long-term strategy
Provide technical support

IRIDJAEA

Implementation of R＆D projects

NRA(Nuclear Regulation Authority)
Safety regulation

10Mid-and-long-term Roadmap and Technical Strategic Plan2015
Mid- andLong-term
Roadmap byGOJ

Strategic Plan
by NDF
Strategic Plan 2015：
Issued on Apr. 30, 2015
Strategic Plan 2016:
Scheduled for this summer◆Discussion through the close dialogue and exchange of information
between the Government and TEPCO.
◆Study mid-term technical strategy through the discussion with theexperts from various technical fields while receiving the advise fromDecommissioning Strategy Board, Expert Committee from multiple fields,
International Special Advisors.
◆"Risk reduction strategy" regarding mid- and long-term decommissioning◆In vessel inspection and study of the technical strategy for the fuel debris
retrieval method.

◆Develop an optimum technical strategy based on the Five Guiding
Principles. " Safe, Proven, Efficient, Timely and Field-oriented"

11Fuel debris retrieval• Operation floor largely damaged.
High dose rate
• Spent fuels stored in Unit1, 2 and 3• Fuel debris dispersed in both RPV andPCVProperties unknown• High radiation inside PCVInside PCV gradually known.
• Cooldown by water injection required.
• Building highly contaminated withhigh radiation (battle withdecontamination)• Leakage from PCV.
Generation of contaminated water.
• Leakage from the building.
Penetration of groundwater.
Needs of contaminated water leakage
prevention

Source： Courtesy of IRID

12

Internal inspection for reactor containment vessel Internal inspection for reactor containment vessel using robots and other remotetechniques are the keys to determine the fuel debris removal method.

Muon-tomography
adopted to Unit-1

Shape-changing
crawler robot

Measurement for 3 months

PCV inside (unit-1)

Simulation

CameraSource: Published materials by TEPCO and IRID

13

Fuel debris retrieval method

Submersion Top entry method

Partial submersion Top entry method

Partial submersion Side entry method

Assuming the in-core
structures above the fueldebris are removed

Assuming that the in-core
structures above the fueldebris are removed

Assuming that the equipment andother objects outside RPV pedestal in
PCV are removed

Source: Strategic Plan 2015, NDF14

Decommissioning as risk reduction

Risk defined in the Technical Strategic Plan 2015
by NDF, JapanFig. 3-5 shows the levels of risks for major risk sources in the Fukushima Daiichi NPS based on the“hazard potential” and “likelihood of loss of containment function”

Source: Strategic Plan 2015, NDF

15

Integration from basic research to practical application

16

Approaches to the decommissioning While accelerating the stabilization of the contaminated water management, risks which mat
be exposed in a short period of time should be eliminated as quickly as possible , such asremoval of spent fuels.
 Realize the stable state where the risks would not be exposed by promoting the fuel debris
retrieval and other "cleanup after the accident" and removing a shot- and mid-term risk
derived from the reactor building.
Study final decommissioning while continuing the inspection and monitor of the inside of thereactor.
 Securing the "Low risk state" that dose not have impact on the residents and environment anddeveloping reasonable decommissioning strategy so that the people in Fukushima can maketheir all effort to the restoration of hometown.

Reference：Concept of decommissioning defined by IAEA
Radioactive waste management

EmergencyresponseStabilization

Cleanup after
the accident

Occurrence of accidents
Source：IAEA Nuclear Energy Series NW-T-2.7“Experiences and lessons learned worldwide in the cleanup anddecommissioning of nuclear facilities in the aftermath of accidents”

Disassembly andsite restoration

Safety storing (Optional)

17

Thank you for your Attention!

Source: TEPCO photo archive18