Current Status of Fukushima Daiichi Nuclear Power Station-Efforts for Decommissioning and Contaminated Water Management
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Current Status of Fukushima
Daiichi Nuclear Power Station
-Efforts for Decommissioning and
Contaminated Water Management-
Agency for Natural Resources and Energy, METI
April, 2020
＜ Outline ＞
１．Progress on Fukushima Daiichi Decommissioning
２．Overview of Water Management
- Countermeasures for contaminated water
- Issue of “ALPS treated water”
３． Environmental Monitoring
４． IAEA review mission
５． Information Portal site
1
Introduction: Where is Fukushima Daiichi?
Approx. 250km
from Tokyo
Approx. 2km
Unit 1-4
2
Overview : Current status of Fukushima Daiichi NPS
• The reactors of Fukushima Daiichi NPS are being kept in stable condition.
• “significant progress has already been accomplished to move Fukushima Daiichi from
an emergency situation to a stabilized situation.” (IAEA review mission report,
January 31, 2019)
At the time of the nuclear accident Today
The accident cut off the water supply to the Reactors are being kept stable.
reactors. As a result, the fuel generated heat, and
hydrogen explosions occurred.
3
1-1. Decommissioning of TEPCO Fukushima Daiichi NPS (FDNPS)
◇ Fukushima Daiichi Decommissioning is a continuous risk reduction activity to protect
the people and the environment from the risks associated with radioactive substances by:
Removing spent fuel and fuel debris from the Reactor Building
Reducing the risks associated with contaminated water and radioactive waste
◇ Safe and steady decommissioning is a prerequisite for reconstruction of Fukushima
Spent fuel Fuel that remains after its usage for power generation.
(Spent fuel pool) Continuous cooling is needed to suppress the heat
Water
Fuel that has melted and solidified by the accident.
Fuel Debris
Continuous cooling is needed to suppress the heat
Contaminated Water Radioactive Solid
Management Waste Management
Units 1 and 2 Unit 3 Unit 4
Removing fuel from Installation of fuel removal Storage/Tra
Rubble removal Fuel removal nsportation
the Spent Fuel Pool equipment
Units 1,3 Units 2
Fuel debris Ascertaining of the situation inside the Storage/
Fuel debris retrieval
Current retrieval PCV/ consideration of fuel debris retrieval etc Transportation
progress
Consideration of Dismantling
Disassembly of scenario and
Design and construction
and other
of equipment
reactor facility, etc technologies tasks
4
Extended to 30-40 years
[Ref. 1] Current status of Unit 1-4 of Fukushima Daiichi NPS
Unit 1 Unit 2 Unit 3 Unit 4
Removed fuel Removed fuel assemblies
Spent fuel assemblies 119/566
1535/1535
(Spent fuel pool) （As of 2020/3/26） （Completed in 2014/12/22）
Front Roof dome
前室
chamber Cover for fuel
Fuel handling retrieval
Hydrogen Hydrogen machine Hydrogen
explosion explosion crane explosion
392 Water injection 615
Water injection Water injection
安全第一
福島第一
Core melt Core melt Core melt
Confirmed that Started fuel
Dismantling Local the deposit
equipment removal from the
company
likely to be the spent fuel pool by
joins as a
fuel debris was remote control,
prime
able to be for the first time
constructor.
gripped and from a nuclear
[started
moved. reactor with core
Aug. 2019]
Top of exhaust (Unit 2) melt (Unit 3)
stack [Feb. 2019] [Apr. 2019] 5
[Ref.2] Impact on the surrounding Environment
• The environmental impact on the site and surrounding area have been
significantly reduced.
(Bq/L)
10,000 over Sea
200
180
N 160
140
120
100
80
60
Guidance value recommended in the WHO
40 Guidelines for Drinking water quality (10Bq/L)
20
0
Evaluation of annual exposure dose at the site
Radiation dose rate ( mSv/year)
boundary due to radioactive materials (cesium)
Air
from the reactors buildings of Units 1-4
Near the south There has been no effect of the radioactive
discharge material (dusts etc.) to the outside in the
course of decommissioning work.
channel
Whole map of Fukushima Daiichi Nuclear plant
20
1-2. The Mid-and-Long-Term Roadmap
• Decommissioning of Fukushima Daiichi NPS will be done by TEPCO in its responsibility.
• The decommissioning is an unprecedented work with technical challenges. The Government
of Japan has been taking initiative based on the Mid-and-Long-Term Roadmap, with the
target of the completion of decommissioning in 30-40 years in a safe and steady manner.
Time flame for Fukushima Daiichi Decommissioning
December November 2013
2011 (Started fuel removal at Unit 4) Now
December End of 30-40years
2021 2031 from cold shut down
Efforts for stabilization Phase 1 Phase 2 Phase 3-(1) Phase 3
Achieved cold shut Period until start of
Period until the completion
down state Period until start of fuel debris retrieval of decommissioning (30-40
spent fuel removal
・drastic suppression in (within 10 yrs.) years from the cold shut
(within 2 yrs.)
release of radioactive down)
materials
Role of the Government of Japan
• GOJ sets the Roadmap • Based on the “Roadmap”, mid-and long-term
₋ The Inter-Ministerial Council for Contaminated Water and measures has been undertaken while giving top
Decommissioning Issues has set out the Roadmaps.
priority to the safety and keeping the attitude to
(Chairman: Chief cabinet secretary, First version: Dec. 2011)
value the risk reduction.
- Revised for five times to date
(Revised in Jul. 2012, Jun. 2013, Jun. 2015, Sept. 2017, and
Dec. 2019)
6
[Ref.3] Major milestones of Mid-and-Long-Term Roadmap (Dec. 2019)
30～40 years after cold
Dec. 2011 Nov. 2013 Now Dec. 2021 End of 2031 shutdown
Hold Hold
Phase 1 Phase 2 Phase 3-(1) Phase 3
Period until start of fuel Period until start of fuel debris retrieval Period until completion of decommissioning
removal (within 2 years） （within 10 years） （30-40 years later）
Major milestones Roadmap (Sept. 2017) Revised Roadmap
Contaminated Reduce to about 150 m3/day Further reduction Within 2020 Within 2020
water Reduce to about 100ｍ3/day or less of generation ー Within 2025 NEW
management
Stagnant water Complete stagnant water treatment in buildings* Within 2020 Within 2020(*)
treatment
Reduce the amount of stagnant water in buildings to ー FY2022 - 2024 NEW
about a half of that in the end of 2020
Complete of fuel removal from Unit 1-6 ー Within 2031 NEW
Complete of installation of the large cover at Unit 1 ー Around FY2023 NEW
Fuel removal
Start fuel removal from Unit 1 Methods have changed Around FY2023 FY2027 – 2028 REVISED
Start fuel removal from Unit 2 to ensure safety and Around FY2023 FY2024 - 2026 REVISED
prevent dust scattering
Fuel debris Start fuel debris retrieval from the first Unit Within 2021 Within 2021
retrieval
（Start from Unit 2, expanding the scale gradually）
Technical prospects concerning the processing/disposal Around FY2021 Around FY2021
Waste policies and their safety
management
Eliminating temporary storage areas outside for rubble ー Within FY2028 NEW
and other waste
* Excluding the reactor buildings of Units 1-3, process main buildings, and High temperature incineration building. 7
1-3. Essence of fuel removal from pool and fuel debris retrieval
Fuel removal from pools Fuel debris retrieval
(Adoption of method for suppressing dust scattering) (Determination of method for
retrieval from Unit 2*)
Unit 1 Unit 2
Installation of Fuel handling
Installation
machine Robot arm
large cover of stand for
removal for retrieval
• Review the method and staring time of fuel removal in order to • Robot arm has been developed for
prioritize safety such as suppression of dust scattering. retrieval work.
• Aim the completion of fuel removal from all Units, including Unit 5 • Present detailed method for
and 6, within 2031. retrieval
• Retrieval will be started in 2021,
carefully, and will gradually expand
its scale.
* first implementing Unit
8デブリ取りだしに向けて
1-4. Towards fuel debris retrieval
In the “Mid-and-Long-Term Roadmap” revised in December 2019, it was
described that the trial retrieval will start at Unit 2 within 2021 and then the
scale of the retrieval will be gradually enlarged.
Unit 1：Investigation of the distribution situation of deposits including small amount sampling will
be done in the last half of FY2020.
Unit 2：The trial retrieval of fuel debris and internal investigation will start within 2021.
* In February 2019, the contact investigation inside PCV was conducted. Information such as
hardness was acquired and it was confirmed that the deposit likely to be fuel debris was able to
be gripped and moved.
Unit 3： Measures to reduce water level in the PCV and detailed investigations are under
consideration.
-FY2019 FY2020 FY2021 FY2022 FY2023-
Investigation at the bottom of PCV
(including small amount sampling)
Unit
1
Metallic brush Vacuum vessel
Contact investigation
（Feb. 2019） Trial retrieval/Internal investigation
Fuel debris retrieval
Unit
（Gradual enlargement of the
2 retrieval scale）
Unit Detailed investigation
3 at the bottom of PCV
92-1 Generation of contaminated water, purification process and tank storage
◇ Water gets contaminated when it touches the damaged reactors and fuel debris in buildings.
The level of groundwater outside is controlled to be higher than that of contaminated water
inside the buildings to prevent the water flowing out of the building.
Groundwater keeps flowing into the buildings
◇ TEPCO has been successful in removing most of radionuclides except tritium from contaminated water.
ALPS (Multi-nuclide retrieval equipment) and the other equipment have been used. See more at P13
It is ALPS treated water, NOT -contaminated water, that is stored in the tanks.
Radioactive materials in ALPS treated water are reduced to about 1/1,000,000 (one millionth).
ALPS
② Most of the nuclides
except tritium are
removed in this process.
ALPS-treated water
Continuous injection
③ Treated water is of cooling water ① Contaminated water
stored in tanks. is sent to purification
equipment such as ALPS.
Fuel Debris
Damaged
Reactors
Flow of groundwater at FDNPS
Contaminated Water
Sea-side
Sub-drain Impermeable
wall
Land-side Impermeable wall
(frozen-soil wall) 10[Ref.4] Overview of water management
*3 Basic Principles for water management
1. “Redirecting” groundwater from the
contamination source 8) Removing radionuclides from
Flow of groundwater
1) Pumping from Groundwater-bypasses and sub-drains contaminated water
2) Installation of Frozen-soil impermeable walls
3) Waterproof pavement to prevent rainwater seeping; and others 5) Prevent leakage from
the tanks
2. “Preventing leakage” of contaminated water
3) Waterproof pavement to prevent
4) installation of sea-side impermeable walls rainwater seeping
5) Prevent leakage from tanks (installing welded-joint tanks etc.)
6) Pumping from Groundwater-drains 1) Pumping from the Groundwater-
7) Ground Solidification by Sodium Silicate; and other measures bypasses and Sub-drians
Ａ
3. ”Removing” the contamination source
2) Installation of Frozen- soil
8) Removing radionuclides from contaminated water
impermeable walls
9) Removing water in the trenches; and other measures
４ ３ ２
１
9) Removing water in
the trenches
1)Groundwater-
Ａ´
bypassing 6)Groundwater-
drains 4) Installation of Sea-side 6) Pumping from
1) Sub-drains
impermeable walls Groundwater-drains
2) Frozen-soil walls 4)Sea-side walls
7) Ground solidification by
Sodium Silicate
Ａ Ａ´ 112-2. Key figures of ALPS treated water
Key Figures for ALPS treated water at the site
(As of March 12, 2020)
Number of tanks 979
Tank Storage volume About 1.19 million ㎥
Planned capacity About 1.37 million ㎥
(Under current plan) (by the end of 2020)
Annual increase of
About 50,000～60,000㎥/year
ALPS treated water
※ About 2 years will be needed for preparation and
permission for disposal. Time to reach its full capacity (forecast):
※There is a limited room for further tank construction
around summer of 2022
Amount of Tritium (tritiated Approx. 860 TBq* (16g)
water) in tanks (*TBq = 1×1012 Becquerel)
Average Concentration of 0.73 MBq/L
Tritium (*MBq = 1×106 Becquerel)
※Currently, several kinds of radionuclides other than tritium are found
in ALPS treated water in tanks. → See page 13
※ If the treated water is discharged into the environment, it will be re-
purified and diluted to meet the standards for discharge.
122-3. Characteristics of ALPS treated water
Two regulatory standards:
1) Applicable to storage: to keep site boundary dose levels less than 1mSv/year Goal currently achieved through ALPS
2) Applicable to release to the environment: to keep radionuclides concentrations of treated water less than the regulatory limit.
There are various concentration of ALPS treated water in the tanks, because:
Concentration of ALPS treated water depends on the attributes of water to be treated and operation management of ALPS
such as frequency of absorbent exchange; and
Especially in the first few years after the accident, which was before improvement of ALPS performance, concentrations of
tritium in ALPS treated water was relatively high.
In case of releasing ALPS treated water to the environment, the water needs to satisfy standard 2).
TEPCO announced to re-purify ALPS treated water, to meet standard 2) for radionuclides other than tritium.
After the re-purification, the water will be diluted to meet the standard 2) for tritium.
9.76 Site Boundary dose levels
Direct rays from tanks/skyshine
Direct rays from sources other than
tanks/skyshine
Other (Groundwater bypass/sub-drains,
etc.)
1.44
0.96 0.92 0.90
*These drawings are quoted from “Treated water `portal site（TEPCO HP）”
132-4. Process ahead
Role of the subcommittee:
1) to examine in a comprehensive manner, such as countermeasures for reputational damage,
and
2) to compile report for the government
GOJ will decide its basic policy, after receiving report of subcommittee and discussing with
parties concerned.
Report
Feb. 10, 2020 Share the discussion at subcommittee
The Subcommittee
１ Stakeholders
on handling of Government ２ (community people etc.)
ALPS treated water
Discuss from experts’ Decide on basic policy Listen to opinions of parties concerned
point of view Request for Since April, 2020
Nov. 2016 – Jan. 2020 Examination
Nov. 11, 2016
Approve
３
Nuclear Regulation TEPCO
Authority Measures for handling
Apply Decide on engineering
142-5.The key points of the report (1): Basic approach
Reputational damage still remains and affects reconstruction of
Fukushima.
"Coexistence of reconstruction and decommissioning" is a basic
principle:
- Returning of residents and reconstruction efforts in the surrounding area have been
proceeding.
- Additional reputational damage should not be caused by a hastened disposition of ALPS
treated water.
Disposition of ALPS treated water needs to be completed until the
completion of the decommissioning:
- with necessary storage, and
- with due consideration to the minimization of the impact on reputation
In deciding the disposition of the ALPS treated water, the
government must also compile a policy for countermeasures against
17
reputational damage.
152-6. The key points of the report (2): disposal methods
Vapor release and Discharge into the sea have been conducted and recognized as feasible
methods.
There are precedents for discharge into the sea in Japan and it is easy to operate necessary
facilities. Thus this can be conducted with certainty.
Radiation impact of both methods is considerably small compared to natural exposure to radiation.
Vapor release Discharge into the sea
Precedent in case of accident at NPP overseas Precedents exist world-wide
* Vapor is also released from reactors in normal operations
at the time of ventilation. More reliable option
In Japan, there is no example of vapor release * precedents in Japan and easiness of operating facilities
Technical in order to dispose liquid waste. Relatively easy to predict how discharged
Issues Difficult to predict how the released vapor is water is diffused in the ocean
diffused into the air
Easy to examine proper monitoring method
Difficult to establish proper monitoring
methods
Difficult to compare the social impacts of two methods
* Social impact is greatly dependent on consumer psychology.
Social
issues May attract significant social concern May attract particularly large social concern if
no countermeasure for reputational damage
is taken
The following three options have many insurmountable issues (regulatory, technological, and timewise)
Geosphere injection：Need to seek for appropriate sites, and monitoring methods have not been established
Hydrogen release ：Further technological development would be required for pretreatment and scale expansion.
Underground burial ：In solidification process, water including tritium will be evaporated. New regulations may be necessary.
Area for disposal yard will be needed. 16[Ref. 5] Impact assessment for environmental release of ALPS treated water
[Conditions]
Using UNSCEAR*1 assessment model*2 and precondition that all the treated water stored in tanks
(containing 860TBq of tritium) is discharged in one year.
(*1: UNSCEAR: The United Nations Scientific Committee on the Effects of Atomic Radiation)
(*2: re-assessed with Japanese food consumption)
[Ref. UNSCEAR 2016 Report, Annex A “Methodology for estimating public exposures due to radioactive discharges”]
[case 1] Vapor release ------- Approx. 0.0012 mSv/year (1.3 μSv/year)
[case 2] Discharge into the sea ---- Approx. 0.000071 to 0.00081 mSv/year (0.071 to 0.81 μSv/year)
In both discharge methods, the impact of the radiation from the discharge is considerably small,
compared with annual natural exposure in Japan: 2.1 mSv/year (2,100 μSv/year).
Exposure dose [mSv/y] Vapor release※1 discharge into the sea※2
All radionuclides※3 0.0012※4 0.000071～0.00081
- tritium 0.0012 0.0000068
※1 Sum of external dose from the atmosphere and soils, and internal dose from inhaling the air and ingesting terrestrial life (at 5km points from the FDNPS)
※2 Sum of external dose from beaches and internal dose from ingesting marine life.
※3 Estimation was conducted on the two assumptions that “ND (Not Detected)” nuclides are 1) their ND value and 2) zero.
※4 For exposure dose for [case 1 (vapor release)], there is no difference between the results from two assumptions
Comparison of radiation impact between natural exposure and
discharging treated water containing 860 TBq of tritium
Vapor release 0.0012 mSv/year
Discharge into the sea 0.00081 mSv/year
Natural exprosure 2.1 mSv/year
0.05 2.05 2.1 2.15
0.1 0.15 mSv/y 172-7. The key points of the report(3):
Countermeasures against reputational damage
1) Well planned disposition process
2) Expansion and enhancement of countermeasures building on best practices
3) Continuous and flexible response
＜1. Well planned disposition processes ＞
Re-purify radionuclides other than tritium
Stop the disposition process in case of emergency
e.g. environmental situation, malfunction of facilities
Determine the details (starting time, volume, and period of disposition),
while listening to opinions of stakeholders
Disseminate information in a considerate and an easy-to-understand manner
Concentration of pre-disposition ALPS treated water
Monitoring results of surrounding environment
Explain safety of surrounding environment by utilizing diffusion simulation
182-8. The key points of the report(3): - continued
＜2. Expansion and enhancement of countermeasures building on best practices＞
< Risk communication> < Economic measures>
- to convey relevant information - for reputational damage
Disseminating information on the Constructing analytical framework
disposal method and scientific for:
knowledge in advance Environmental monitoring, and
Food sampling measurement
Providing information via:
Social media, mass media Utilizing third-party certification to
On-site lectures secure consumer trust, such as
GAP (Good Agricultural Practice)
MEL (Marine Eco-label)
Strengthening information
dissemination abroad Developing new market channels by
Basic information on Promotion events for Fukushima
decommissioning products
Disposition methods in the world Allocation of special sales staff in
as well as precedents outside of stores
Japan Opening of on-line stores etc.
193-1. Seawater radiation monitor near Fukushima Daiichi NPS
Regulatory Limit Specified by Reactor Regulation
Bq/l
① North side of units 5 and 6 discharge channel
・Cesium 137: 90Bq/L
・Cesium 134: 60Bq/L
N
② Real time monitoring
Sea-Side
Impermeable Wall ＜TEPCO’s website＞
http://www.tepco.co.jp/en/nu/fukushima-np/f1/seawater/index-e.html
Unit 1 - 4
③ Near South Discharge Channel
Frozen-soil Wall
Fukushima Daiichi NPS 213-2. Seawater radiation monitor around Fukushima Daiichi NPS
～20Km from Fukushima Daiichi NPS
Seawater sampling points
① ②
④
Fukushima
Prefecture
Fukushima
Daiichi
NPS ② 30～100Km from Fukushima Daiichi NPS
① ③ ④
③
sampling points
(Source : NRA website)
https://radioactivity.nsr.go.jp/en/contents/8000/7742/24/engan.pdf
224.Summary of the 4 th IAEA Review
- November 2018 (final report: Jan. 31, 2019)-
Main findings
- “ IAEA teams said Japan has made significant progress since the accident in March 2011, advancing from an
emergency situation towards a stable situation now.”
- “The team acknowledged a number of accomplishments since the 2015 mission, including
The repair of subdrains and construction of the frozen soil wall around reactor Units 1-4, which have
reduced groundwater ingress into the reactor buildings.
Improved site working conditions including a reduced need for full protective gear, and real-time
radiation monitoring easily accessed by the workforce.
Progress towards the removal of spent fuel from Units 1-3 as well as remote investigations of fuel debris
by robots.”
- “The team said the Government of Japan, in engaging all stakeholders, should urgently decide on a disposition
path for ALPS treated water. “
【Reference】 Ordinary clothing can be worn at 96% of the site
Areas where Protective clothing are required
Panorama image of the impermeable walls Areas where ordinary clothing can be worn Fuel Handling Machine
for the removal of spend fuel
Frozen-soil walls unit3
Reactor building
234.Summary of the follow-up mission of 4 th IAEA Review
- Feb-Mar 2020 -
Background, Scope
- The total tank storage capacity will amount to approximately 1.37 million m3 by the end of 2020 and the tanks
are expected to be full around the summer of 2022.
- The IAEA pointed out that “the Government of Japan, in engaging all stakeholders, should urgently decide on a
disposition path for ALPS treated water“ in the 4th peer review mission in November 2018.
- The Government of Japan had requested the IAEA review of the management of the stored water, including the
report by the Subcommittee on Handling ALPS Treated Water, issued on February 10, 2020.
Main findings
- “The IAEA Review Team positively notes that ALPS subcommittee report addresses technical, non-technical and
safety aspects necessary to make a decision. “
- ”The IAEA Review Team considers that the methodology and criteria used for the down selection from the
initial five options to two* are based on a sound methodology for the purpose of decision making.
* controlled vapor release, and controlled discharges into the sea, the latter of which is routinely used by
operating nuclear power plants and fuel cycle facilities in Japan and worldwide.
- “The two options selected are technically feasible and would allow the timeline objective to be achieved. “
- “The IAEA Review Team positively notes the efforts of the Japanese experts to adjust the well-established
UNSCEAR methodology to the specific case of Japan.”
【Reference】 Comparison of radiation impact between natural exposure and
discharging treated water containing 860 TBq of tritium
Vapor release
Discharge into the sea
Natural exprosure
0.5 1.0 1.5 2.05 2.1 2.2 mSv/y 245-1. Information Portal site （１） : Fukushima Daiichi NPS
Decommissioning and Contaminated Water Management
at TEPCO's Fukushima Daiichi NPS
https://www.meti.go.jp/english/earthquake/nuclear/dec
ommissioning/index.html
Film, Fukushima Today 2019
- Efforts to Decommission and Reconstruction
https://www.youtube.com/watch?v=v_PeSp--Wuk
Film, Fukushima Today
- 8 years after the earthquake -
https://www.youtube.com/watch?v=pKjsSAz5Kws
Treated Water Portal Site
http://www.tepco.co.jp/en/decommission/progress/watertreatment
/index-e.html
Observation Data, Fukushima Daiichi NPS
https://www7.tepco.co.jp/responsibility/decommissioning/1f_newsr
oom/data/index-e.html
255-2 Information Portal site （２） : Fukushima Daiichi NPS
Fukushima Daiichi Status Updates
https://www.iaea.org/newscenter/focus/fukushima/status-update
IAEA Review mission reports (Press release )
IAEA Team Completes Fourth Review of Japan’s Plants to Decommission Fukushima Daiichi
(November 13, 2018)
https://www.iaea.org/newscenter/pressreleases/iaea-team-completes-fourth-
review-of-japans-plans-to-decommission-fukushima-daiichi
IAEA Issues Final Report on Fourth Review of Fukushima Decommissioning (January 31, 2019)
https://www.iaea.org/newscenter/pressreleases/iaea-issues-final-report-on-
fourth-review-of-fukushima-decommissioning
IAEA Reviews Management of Water Stored at Fukushima Daiichi Nuclear Power Station
(April 2, 2020)
https://www.iaea.org/newscenter/pressreleases/iaea-reviews-management-of-
water-stored-at-fukushima-daiichi-nuclear-power-station
UNSCEAR 2016 REPORT
-Sources, effects and risks of ionizing radiation
hhttps://www.unscear.org/unscear/en/publications/2016.html
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