ハイる知をMarch 15,

Steps for decommissioning at Fukushima Daiichi NPSロ2020

Vol. 11

Next issue schedule: June 15, 2020

Fukushima PrefectureNuclear Safety
Management DivisionL earn abo u t deco mmi ssi o n i n g

http://www.pref.fukushima.lg.jp/sec/16025c/

What is happening NOW in Fukushima.

Mid-and-Long-Term Roadmap revision
In the Mid-and-Long-Term Roadmap, the government has established basic concepts and major
target processes for the decommissioning of the Fukushima Daiichi Nuclear Power Station. The
official name is "Mid-and-Long-Term Roadmap towards the Decommissioning of TEPCO's
Fukushima Daiichi Nuclear Power Station". This was the fifth revision since it was formulated inDecember 2011, and was approved by the Inter-Ministerial Council for Contaminated Water andDecommissioning Issues on December 27 last year.

Mid-and-Long-Term Roadmap

The revised Mid-and-Long-Term Roadmap and the changes from the last revision are shown below.
Phase 12011

Phase 22013◆FY2015 490 m /day
◆September 2018 Completion offrozen-soil wall

Contaminatedwatermanagement◆March 2017 Investigation inside PCV starts ◆Examination of retrieval, treatment,
and disposal methods◆Examination of retrieval method

Unit 2◆February 2019 Contact with fuel debris in PCV◆By end of 2021 Trial retrieval (target)

Unit 3◆Mach 2016
Establish solid waste storage management plan

1Stored fuelassemblies

assemblies

As the radiation dose inside theFuel debris building is extremely high, noretrieval
access route to fuel debris has
been established. We willcontinue to examine theretrieval method throughinvestigation.

PCVRPV

As an installation of a large
Spent fuel cover (see below) has been
removaldecided to be needed in orderto prevent the scattering ofradioactive materials during
removal of large rubble, theprocess is expected to bedelayed by 4 to 5 years.

Top floor (Operating floor)ⒸTEPCO

Waste
management

Fukushima
DaiichiNPS

2Stored fuelassemblies

Reactor building
Turbine building

assemblies

Top floor (Operating floor)

An internal investigation
Spent fuel revealed that the radiation dose
removal was lower than expected, and afuel removal work platform (seebelow) will be installed on thesouth side without dismantling
the building. The construction
period is expected to bedelayed by one to three years.

Frontchamber

PCV●Reduce generation amount of contaminated water

Main changes from 150 m3/day to 100 m3/day or lessfrom
●In FY2022 - FY2024, amount of stagnant water
will be reduced to half of that in the end of 2020
last revision

Fukushima
Daiichi
NPS3Stored fuel

Crane



assemblies

It is expected that all
spent fuel will be
removed from the spent
fuel pool by end of FY
2020 as scheduled.

Spent fuel
使用済燃料
removalの取り出し
Dome roof

As the radiation dose inside
the building is relatively highand the airtightness of PCV islow, it is necessary to retrieve
the fuel debris while confining
the gas inside. The retrieval
method is being examined.

Fuel debris
retrieval

Spent fuelpoolⒸTEPCOⒸTEPCO

RPV: Reactor Pressure Vessel

Changesfromlast revisionChanges from last revision

ShieldFirst contact with fuel
Fuel debris debris in February 2019.
retrieval
The radiation dose inside
the building was relatively
low, so it was decided tostart fuel debris retrieval
with Unit 2.

Melting fuelassemblies

Unit

Spent fuelpool

Robot arm

Sea-sideimpermeable wall

Ocean

Layout of Fukushima Daiichi NPS
building site

Melting fuelChanges from last revision

Unit

RPV

Spent fuelpool

PCV: Primary Containment Vessel

Groundwater drain

Sub drain

Fuel debris
retrieval starts
at Unit 2.

◆Around FY 2021 Technical prospect ◆By end of FY 2028 Eliminate temporaryof treatment/disposal methods
storage areas outside for rubble and other waste

Melting fuelChanges from last revision

Unit

Groundwater bypass

Land-side impermeable wall
(Frozen-soil wall)◆July 2017 Investigation inside PCV starts ◆Examination of retrieval, treatment
and disposal methods◆Examination of retrieval method

Waste management

Fukushima
DaiichiNPS

Groundwater flow from the mountain side (image)◆February, March 2018 Install covers, cranes, etc.
◆April 2019 Start removal of spent fuel (completion planned in FY 2020)

Unit 1
Fuel debris
retrieval◆By end of 2025 100 m3 /day or less (target)◆June 2018 Completion of preparation construction for internal investigation ◆FY 2024-2026 Start removal of fuel (target)◆November 2018 Start internal investigation on the top floor (on going)

Unit 3

Contaminated water management◆By end of 2020 150 m3/day (target)◆November 2016 Building cover dismantling◆Around FY 2023
◆FY 2027-2028 Start removal of◆January 2018 Start removal of small rubbles (on going) Large cover installation spent fuel (target)

Unit 2

Removal ofspent fuel◆Stagnant water in the reactor building will be decreased
to half of what it is in end of 2020 by 2022 - 2024. (target)◆FY2018 170 m3/day

Unit 1

Phase 32021

3ⒸTEPCO*Numbers●Establish a technical prospect on treatment and disposal●Eliminate the storage of solid waste (trimmedmeasures and safety around FY 2021. Specifically, develop atrees, rubble, contaminated soil, protective
method to reduce the amount of solid waste generation andclothing, etc.) that is temporarily stored outside
an efficient analysis method for its properties, etc., andby the end of FY 2028 by installing solid waste
create a mechanism that can compare and examine multiple
incineration facilities and waste volume
methods for safely treatment and disposing of solid waste.
reduction facilities.

Additional
miscellaneous
solid waste
incineration
facility

Additional solid waste
storage facility
10th - 13th buildings

toare as of February 25

Contaminated soil Miscellaneous solid
waste incineration
temporaryfacilitystorage facility

ncinerator
pre-treatment
facility

Unit 6Unit 5

Large waste
storage facility
Volume reduction
facility

Waste-related facilities planned for construction ⒸTEPCO

Voices from the Fukushima prefecture regards to the Mid-and-Long-Term Roadmap

Inter-Ministerial Council for Contaminated Water and Decommissioning Issues

Safety Monitoring Council* on the Decommissioning of the Fukushima Daiichi NPS was held on Main opinions submitted
December 5 last year, and after receiving an explanation from the Agency for Natural Resourcesand Energy, Ministry of Economy, Trade and Industry (ANRE, METI) regards to the revision of the •While the return of residents is progressing, the highest
should be given to ensuring safety so that
Mid-and-Long-Term Roadmap, many questions, requests, and proposals were received from priority
radioactive materials will not be scattered again in thethe Expert Committee during the Q&A session. The prefecture
process of decommission. And the appropriate method
gathered the opinions of these expert committee members
should be selected through the consideration of theand submitted their opinions to the METI on December 17
process and the risks that might be generated.
after a meeting of the governors with the related directors.
•The contaminated water generation amount target

The safe and steady decommissioning of the Fukushima Daiichi Nuclear Power Plant is amajor prerequisite for the reconstruction of Fukushima. To ensure the decommissioning iscarried out as expected, we strongly request that the relevant ministries and agencies,
TEPCO, will continue to take measures against decommissioning and contaminatedwater in a steady manner based on the Mid-and-Long-Term Roadmap.

*About Safety Monitoring Council

An organization consisting of 19 experts and a group of employees from
Fukushima prefectural government and related municipal, who monitors
on-going decommissioning activities and response status to troubles throughon-site inspections and meetings, and makes proposals to the government
and TEPCO based on the results.

should be further reduced from 150 m3/day.
•Gather the wisdom from around the world to select themost appropriate method, and to show a detailed plan
regards to the temporary storage and management
plan of the retrieved fuel debris.

Fukushima Prefecture

Chair's remark (Chief Cabinet Secretary Yoshihide Suga)

Governor's remark

Representing the voices of the citizens in the Fukushima prefecture, we ask thegovernment and TEPCO to call forward to build trust with the local community, carry out
the decommissioning in a safe and steady manner, work to avoid harmful rumors andhelp gain confidence in the region, and lead to a full recovery of Fukushima .

ハイLearn about decommissioning

を 知るロ1１Vol.●Steps for decommissioning at Fukushima Daiichi NPS

Fukushima Daini Nuclear Power Stationdecommissioning decided.

Last year, on September 30, TEPCO Holdings submitted the notification of a power generation
business change based on the Electricity Business Act to the METI regards to decommissioningof all reactors, Units 1 to 4 of Fukushima Daini Nuclear Power Station, and it was decided.
At the time of the Great East Japan Earthquake, all four reactors of the Fukushima Daini NPS
were in operation. Although some cooling equipment for Units 1, 2, and 4 were damaged by thetsunami, the power supply was secured and the reactor water level was maintained by water
injection, therefore the units escaped a severe accident, and have served as a logistics support
base in the Fukushima Daiichi accident, such as receiving injured persons and resting workers.

ⒸTEPCO

Overview of Fukushima Daini Nuclear Power Station

The Fukushima Daini NPS was constructed in Naraha-machi and Tomioka-machi, and started operation in April 1982,
11 years after Daiichi NPS started operating in 1971. It has supplied electricity to the Tokyo metropolitan area for about
29 years until the Great East Japan Earthquake.

Fukushima Daiichi
Nuclear Power Station (Reference)

Fukushima Daini Nuclear Power Station

Plant Name

Unit
Spent fuel1

Unit2534

Spent fuelInner diameter 6.4 m

Spent fuelpool

assemblies

22482

assemblies

2544

Unit

4

Spent fuelassemblies

2516

Unit

Spent fuelassemblies

Inner diameter 6.4 m

Vent pipe

Spent fuelassemblies

Inner diameter 4.8 m

Spent fuelpool

Reactorpressure
vesselPrimary
Containment
VesselFuel debris
Diameter approx. 26 m
Reactor type
Power generation
outputOperation startdate

Diameter approx. 29 m

Diameter approx. 18 m

Boiling water reactor (Mark II)

Boiling water reactor (Mark II Advanced type)

Boiling water reactor (Mark I)

1.1 million KW

1.1 million KW

0.46 million KW

April 1982

Unit 2: February 1984 Unit 3: June 1985 Unit 4: August 1987

March 1971

Unit 2,3,4: September 2019

April 2012

Abolition date September 2019

Decommissioning of Fukushima Daini NPSTEPCO Holdings will submit an application toward the Nuclear Regulation Authority (NRA) regarding decommissioning
plans and changes to safety regulations, and then will start decommissioning work once the plans are approved. It is
expected to take more than 40 years to complete the decommissioning of all four units. In addition, all spent fuelcurrently being stored will be transported outside the prefecture by the time the decommissioning is completed. In orderto start the decommissioning work, based on new agreement concluded with the towns where plant is located, priorconsent must be obtained by the prefecture, Naraha-machi and Tomioka-machi.
Decommissioning process

Stage

1

Stage

2

Stage

3

400

assemblies

Building height approx. 59 m

Reactorpressure
vessel392

1Height approx. 20 m

Building height approx. 76 m

Vent pipe

PrimaryContainment
Vessel3

Spent fuelHeight approx. 23 m

Primary
Containment
VesselBuilding height approx. 76 m

Height approx. 23 m

Spent fuelpool
Reactorpressure
vesselUnitStage4

Conclusion ofagreement to ensure
safety fordecommissioning

Last year, on December 26, the Fukushima
prefecture, the towns where nuclear power
plant is located, and surrounding
municipalities have concluded new
agreements with TEPCO regarding theimplementation of the decommissioning of
the Fukushima Daini Nuclear Power Station.
The purpose of these agreements is toensure the safety of the surrounding local
residents by the safe and steady progressof decommissioning.
Main items ( Responsibilities of TEPCO)

Preparation for dismantling

Dismantling peripheral equipment● Contamination statusinvestigation● Dismantling of turbines(generators)● Contamination removal● Completion of removal of
spent fuel, etc.

● Start removing spent fuel, etc.

Dismantling of reactor body

Dismantling of reactor buildings● Dismantling of reactor pressure vessel● Dismantling of reactor buildings

Upper part ofreactor pressurevessel ( Unit 2)©TEPCO

There are fourstages indecommissioning.

Nuclear power Station where decommissioning is underway (boiling water reactor case)● Shizuoka Prefecture Chubu Electric Power Co., Inc.

Hamaoka Nuclear Power Station (Units 1 and 2)● Fukui Prefecture Japan Atomic Power Company

Tsuruga Power Station (Unit 1)● Shimane Prefecture Chugoku Electric Power Co., Inc.

Shimane Nuclear Power Station (Unit 1)● The decommissioning of the Fukushima
Daini Nuclear Power Station should becomprehensively proceeded together
with the decommissioning of theFukushima Daiichi Nuclear Power Station
which caused the nuclear accident.
● Regards to safety-related matters, it
should be notified in a timely manner.
● When trying to add, change, or abolishmajor facilities, it should be explained inadvance and the consent of the
Fukushima prefecture and the towns
where nuclear power plant is locatedshould be obtained. (Agreement withtowns where plant is located)
Municipalities involved in the conclusion
Towns where nuclear
power plant is located Naraha, Tomioka

Surrounding
municipalities“Nuclear Disaster Prevention Drill” which was announced in the paper, “Learn about decommissioning Vol.10” was canceled due to the Typhoon 19 and the December issue was not released.

Fukushima PrefectureIwaki, Tamura, Minamisoma,
Kawamata, Hirono, Kawauchi,Okuma, Futaba, Namie,
katsurao, Iitate