Fukushima Daiichi Decontamination and Decommissioning : Current Status and Challenges. Alios Iwaki Performing Arts Center August 6, 2018.

Transcription

1 The 3 rd International Forum on the Decommissioning of the Fukushima Daiichi Nuclear Power Station Fukushima Daiichi Decontamination and Decommissioning : Current Status and Challenges Alios Iwaki Performing Arts Center August 6, 2018 Akira ONO Chief Decommissioning Officer, President of Fukushima Daiichi Decontamination and Decommissioning Engineering Company, Tokyo Electric Power Company Holdings, Inc.

2 Map of Japan and location of Fukushima Daiichi NPS (1F) Fukushima Daini NPS Fukushima Daini NPS Fukushima Daiichi 10 km Fukushima Daini From Tokyo 220 km J-Village 1

3 1. Current Status of Fukushima Daiichi NPS 2. Improving Work Environment 3. Contaminated Water Management 4. Fuel Removal from Spent Fuel Pools 5. Toward Fuel Debris Retrieval 6. Waste Management 7. Two-way Communications and Collection of Wisdom around the World 8. Fukushima Revitalization Activities T H E F U K U S H I M A F O R U M I V M A R C H , T O K Y O, J A P A N 2

4 1 State of Units 1-4 All reactors are in cold shutdown condition. Plant parameters including RPV and PCV temperatures are monitored continuously 24 hours/day. Reactor Building Spent Fuel Pool Reactor Pressure Vessel (RPV) Dome roof Fuel-handling Cover for fuel removal machine & Crane 構台 566 assemblies Blowout panel (closed) Shield Fuel debris Fuel removal completed ｸﾛｰﾗｸﾚｰﾝ 1535 /1535 Dec. 22, 2014 Pedestal Primary Contain ment Vessel (PCV) 615 assemblies 392 assemblies Building cover steel frame Windbreak fence Front chamber 安全第一福島第一 福島第一安全第一 Unit 1 Cooling water injection Unit 2 Unit 3 Unit 4 Values as of 11:00 am on July 23, 2018 Temperature at the bottom of the pressure vessel Temperature inside the containment vessel Fuel pool temperature Unit Unit Unit Unit 4 23 Reactor coolant volume 2. 8 /hour 2 8 /hour 2. 8 /hour 3

5 Compared to the situation just after the accident, the current level of radioactivity has been lowered to parts per hundred thousand, to per million. The concentrations outside the port are substantially below regulation limits. Concentration levels decreased further after closure of the sea-side impermeable wall. Regulation Limit Cesium 137: 90Bq/L Cesium 134: 60Bq/L Bq/l (2) Monitoring Level in the Sea North of Units 5&6 Discharge Outlet Completion of Sea-side Impermeable Wall Closure(Oct 26,2015) Bq/l Completion of Sea-side Impermeable Wall Closure(Oct 26,2015) Front of Shallow Draft Quay In Front of Unit 1-4 water-intake Sea-Side Impermeable Wall Near South Discharge Outlet 4

6 5 1. Current Status of Fukushima Daiichi NPS 2. Improving Work Environment 3. Contaminated Water Management 4. Fuel Removal from Spent Fuel Pools 5. Toward Fuel Debris Retrieval 6. Waste Management 7. Two-way Communications and Collection of Wisdom around the World 8. Fukushima Revitalization Activities

7 (1) Number of Site Workers and Change in Exposure Dose Level Currently about 4,000 people day are working on weekdays. The exposure dose climbed to 21.59mSv/m in March 2011 but it has plunged to somewhere between 0.3 and 0.4mSv/m in recent years. Changes in number of workers (TEPCO & Contractors) Average number of on weekdays engaged in work is 4,250 as of June Percentage of workers from local area is approx. 60% as of June Average number of workers/day on weekdays since FY2013 4,250 (June 2018) Trend of monthly exposure dose rate msv Average 0.30mSv 6

8 (2) Decreasing Site Radiation Dose As a result of radiation reduction measure, workers don t have to wear full-face respirator or half-face respirator anymore in most parts of the site. Distribution of dose level : Area below 5μSv/h (Mar. 2018) Area where people can work in general uniforms Zoning in the site May 2018) Area where people should work in protective gears 96 of the site 7

9 1. Current Status of Fukushima Daiichi NPS 2. Improving Work Environment 3. Contaminated Water Management 4. Fuel Removal from Spent Fuel Pools 5. Toward Fuel Debris Retrieval 6. Waste Management 7. Two-way Communications and Collection of Wisdom around the World 8. Fukushima Revitalization Activities 8

10 (1) Conceptional Diagram of Reactor Circulation Cooling Spent fuel pool Reactor bldg. Primary containment vessel (PCV) Reactor pressure vessel (RPV) Inflow of ground water Approx. 130m3/day Turbine bldg. Drawn from well-points etc. Approx.10m3/day Value in June * 5/31-6/28 Cesium absorption apparatus including rainy water 5/31-6/28 Contaminated water inside R/B Ground water Reactor cooling water Approx. 200m3/day Pump Cooling by recirculating cooling water KURION SARRY Added strontium removal function Approx. 340m3/day Treated water from multinuclide removal equipment Cooling water tank Stored volume 897,842 m3 (as of 12th July) Strontium-treated water Approx. 140m3/day Stored volume 173,941 m3 (as of 12th July) Storage tanks Remove 62 radioactive nuclides except of tritium Desalination Storage tanks Multi-nuclide removal equipment (ALPS) Reduced Strontumconcentration. 9

11 (2) Three principles for Measures to Counter Contaminated Water ① Three Principles ②Isolating fresh water from contaminated areas ①Removing source of contamination ①Treatment System (Multi-nuclide removal equipment) Water treatment facility for Subdrain & Groundwater drain ③Preventing leakage of contaminated water Temporary storage tanks ②Groundwater Bypass wells ②Subdrain wells ③Augmentation of tanks(replacement with welded tanks) ②Ice Wall (Frozen Soil wall) ②Paving ①Removing contaminated water from trenches ③Ground improvement with liquid glass ③Sea-side Impermeable Wall Water collecting tanks Groundwater drain

12 (3) Three Principles for Measures to Counter Contaminated Water ② Measure ① Removing source of contamination ② Isolating fresh water from Contaminated Areas ③ Preventing leakage of contaminated water Status Purification with multi nuclide removal equipment (ALPS) Completed RO concentrated water treatment in May, 2015 Removal of contaminated water from trenches Completed in December, 2015 Removal of contaminated water from buildings Completed water removal from the Unit 1 turbine building, Mar, 2017 Completed water removal from the Units 1-3 condensers, Dec, 2017 Continue operation Completed Continue removal Pump up of groundwater through groundwater bypass wells The accumulated amount of drainage to the sea : 392,000t (As of Jul. 23, 2018) Pump up of groundwater through subdrain The accumulated amount of drainage to the sea : 567,000t (As of Jul. 22, 2018) Including pumped up water through groundwater drain for pumping up groundwater dammed up by seaside impermeable wall) Ice Wall (Frozen soil wall) Almost all sections reached below 0 degrees Wall formation almost completed Paving to prevent rain water seepage into soil Completed 94% of planned area in July 2018 Continue work Ground improvement with liquid glass Completed in Mar Completed Installation of sea side impermeable wall Completed closure in Oct Completed Augmentation of tanks Implementing replacement of flanged tanks with more reliable welded tanks and additional construction of welded tanks Continue operation Continue construction 11

13 (4) Closure of the Ice Wall Freezing of the final section commenced last August. Judging from its temperature, TEPCO concluded in March that Ice Wall was completed except for a small part of the deep zone. Thanks to the closure of the Ice Wall, the groundwater from the landside is dammed up and makes a detour around the buildings, and eventually flows to the seaside. Landside Ｎ Outside of Ice Wall Water level difference Inside of Ice Wall as much as 4 to 5 meters in the landside area Seaside Electric Power Company Holdings, Inc. All Rights Reserved.Reserved Tokyo Tokyo Electric Power Company Holdings, Inc. All Rights 12

14 (5) Reduction of Contaminated Water Generation Generation of the contaminated water totaled 140m3/Day(Dec to Feb. 2018). Even though the record was during the drought season, that amount is below the target value of 150 m3/day set for 2020 in the Mid- and Long-term Roadmap. m3/day mm/day Below 150m3/Day Rainfall Day Contaminated Water Generation Day Will continue to take additional measures against the inflow of rainwater etc., and aim to reduce the generation to 150ｍ3/day on an annual basis within FY

15 (6) Efforts to Reduce Contaminated Water Generation during Heavy Rain Various measures are being taken for areas that may become the route of rainwater into the buildings. Will continue to search other routes of the inflow and take steps. ① Prevention of backflow in the drainage pipe A check valve was installed in June 2018 to prevent rainwater from flowing back from the drainage pipe into the building ②Prevention of inflow from the trench on the east side of Units 1 and 2 Scheduled to block water leaks in the penetration area inside the trench and fill the trench ③Prevention of inflow from the damaged roof of the Unit 3 bldg. Rainwater surpassing the capacity of roof drain flows into the building. Countermeasures are being prepared. Damaged roof Inflow of rainy water Ground level Inflow of ground water Check valve Stagnant water 14

16 1. Current Status of Fukushima Daiichi NPS 2. Improving Work Environment 3. Contaminated Water Management 4. Fuel Removal from Spent Fuel Pools 5. Toward Fuel Debris Retrieval 6. Waste Management 7. Two-way Communications and Collection of Wisdom around the World 8. Fukushima Revitalization Activities

17 (1) Overview of Fuel Removal from the Spent Fuel Pools After the completion of removal at Unit 4 in December 2014, preparation at Units 1 through 3 is underway Units 1 & 2 瓦礫撤去 除染 Removal of rubble & Decontamination Unit3 燃料取り出し設備の設置 Installation of 燃料取り出し Fuel removal fuel removal facility Fuel removal cover Large cranes and Removing & transporting (or container) and heavy machinery used Fuel Handling Machine fuel to common pool etc. installed Unit 1 Jun Unit4 保管 搬出 Storage & Transportation -Storing fuel in common pools - If necessary, fuel to be transported to dry cask temporarily storing facilities in order to secure the capacity of pools Unit 2 Unit 3 Sep Sep Suction device Jan Windbreak fence was installed (Dec. 2017) Removal of rubble started. (Jan. 2018) Dec The front chamber was installed. (Feb. 2017) The opening was formed in the west. (Jun. 2018) Feb Removing large pieces of rubble was completed (2015) The installation of fuel removal cover was completed (Feb. 2018) 16

18 (2) Toward Fuel Removal from Spent Fuel Pool at Unit 1 Protective work for the spent fuel against the falling rubble is being planned. Outer frames including X braces will be removed which may interfere with the protective work. Nozzle for sprinkler E Work floor Windbreak fence Beam Unit 1 Reactor Bldg. S Removal place Work floor W Range of X braces removal Before removing obstacles Example of X braces to be removed After removing obstacles Removal of obstacles interfering with X braces removal 17

19 (3) Toward Fuel Removal from Spent Fuel Pool at Unit 2 Survey on the refueling is planned prior to the dismantling of the upper part of the building in preparation for fuel removal. After the formation of the opening in June, the survey using remote-controlled robots was conducted in July. Air dose rate, etc. was measured. As the obtained data shows no challenges for activities of remote-controlled robots, decluttering work will be implemented as planned. Completed in Jun. Formation of opening on the west wall Work flow on the refueling floor Completed in Jul. Survey Decluttering Survey Survey results on the refueling floor Air dose Gamma ray dose rate* measured at 1.5m above the floor Photography direction Planning Measurement by the robot Measurement Survey locations msv/h area N ① Formation of Opening 59 Well plug ② Maximum values measured SFP 26 *: 1cm dose equivalent rate 18

20 (4) Toward Fuel Removal from the Spent Fuel Pool at Unit ３ Removal of large pieces of rubble was completed in Decontamination work was completed in Jun and shielding was completed in Dec Installation of a dome roof was completed In Feb The fuel removal will take place in November After removal of large Immediately after the Installation of pieces of rubble earthquake a dome roof Feb Feb Sep Major Tasks in the process ①Removal of rubble (complete) ②Decontamination complete ③ Shielding (complete) ④Installing Cover & Fuel Handling Machine complete ⑤Undertaking Fuel Removal (mid FY2018) 19

21 (5) Remote technology for Fuel Removal at Unit 3 Cover completed February 2018 after fuel handling machine and crane installed. Commissioning started March 15 and actual removal from this November. Top of Unit 3; Overview Cover Fuel removal procedure Fuel removal cover Crane Fuel handling machine FHM Crane FHM girder Spent Fuel Pool Fuel Transport cask Unit 3 Reactor Bldg. Control panel container Remote control room 20

22 (6) Remote Control Technology for Dismantling the Exhaust Stack of Units 1 and 2 The upper parts of the exhaust stack of Units 1 and 2 to be dismantled prior to the fuel removal at Units 1 and 2 to further reduce risks because it has damaged or fractured parts. Plan to carry out performance verification of dismantling equipment using a simulated stack from August, and verification of the work execution plan simulating actual dismantling work from October. Preparatory work to commence in December Range of Dismantlement Dismantling of cylinder Installation of crane Installation of dismantling equipment Steps to prevent scattering Cylinder grip Cylinder Cutting Lowering Dismantling of steel tower Steel tower grip Steel tower cutting Lowering 18 m Repeat Preparation Dismantling of cylinder Steps to prevent scattering Cylinder grip Cylinder Cutting Lowering Dismantling complete Installation of lid on the top part Simulated facility Demonstration test 21

23 1. Current Status of Fukushima Daiichi NPS 2. Improving Work Environment 3. Contaminated Water Management 4. Fuel Removal from Spent Fuel Pools 5. Toward Fuel Debris Retrieval 6. Waste Management 7. Two-way Communications and Collection of Wisdom around the World 8. Fukushima Revitalization Activities

24 (1) Assumed Distribution of Fuel Debris Investigations suggest that almost all of the fuel in Unit 1 melted and dropped to the bottom of the PCV and most of it was no longer in the reactor s core. As for Unit 2, it is assumed that some of the molten fuel dropped to the bottom of the RPV or to the lower portion of the PCV, while some still remain within the core. As for Unit 3, it is thought that most of the molten fuel dropped to the bottom of the PCV, but some is also present at the bottom of the RPV. Reactor Building Unit 1 Unit 2 Unit 3 Confirmed that CRD X-100B penetration X-53 penetration CS Approx. 1.9ｍ ＦＷ X-6 penetration Muon measurement suggests that most of the fuel debris is at the bottom of the RPV. supports have fallen off or are deformed. Confirmed that materials thought to be solidified molten materials were attached to CRD housing supports. ＦＷ CS X-6 penetration Confirmed leak from sand cushion drain & s/c vacuum break line bellows. Based on muon measurement/an alysis and that water level cannot be determined, it is assumed most of the fuel has melted Muon measurement suggests that there is fuel on the outer periphery of the core It is assumed that leakage is from S/C shell or submerged part of connection system RPV RPV Lower Part X-53 penetration CS X-6 penetration Approx. 0.3ｍ Internal investigation of the PCV found that there were deposits on the D/W floor PCV Drywell No serious damage found in CRD housing. Solidified molten material and fuel assembly components were found in lower part of pedestal. Approx. 6.3ｍ ＦＷ Pedestal Suppression Chamber Sediments thought to be solidified molten materials etc. were identified at the bottom of the pedestal and on structures inside the pedestal. Confirmed leak from bellows in the MSIV on the 1st floor. 23

25 (2) Internal Investigation of Unit 2 PCV (Jan. 2018) An investigative device was lowered through distortion of the grating to the bottom of PCV inside the pedestal Deposits thought to be including fuel debris as well as fuel assembly components which were located in RPV before the accident were identified at the bottom. CRD Housing CRD exchanger Telescopic guide pipe Grating distortion ① Platform Grating distortion ② PCV Bird s eye view camera Cradle Cable CRD exchange rail Investigative Device Cable tray RPV Overview of the investigative device edge SOURCE: IRID Basement CRD Housing (above the grating distortion) Workers entrance 堆積物の付着 Basement Fuel Assembly Component Pedestal Deposits engraved letters (F 2 X N) 24

26 (3) Internal Investigation of Unit 3 PCV (Jul. 2017) Several fallen obstacles and sediments were identified inside the pedestal. Analysis of image data shows, in contrast to Unit 2, a larger amount of fuel debris dropped inside the pedestal. CRD CRDhousing housing supporting supporting X-53 penetration pipe X-6 penetration pipe Ref.) Bottom of the CRD housing Bottom of the CRD housing CRD Replacement Rail Pedestal Platform Slot Platform Basement CRDハウジング Bottom of the CRD housing Inside the pedestal of Unit 5 Grating Bottom of the CRD housing Fallen objects Deposits Inside the pedestal 25

27 (4) Future Plan In the Mid- and Long-term Roadmap revised in last September, Policy on fuel retrieval is shown. Prioritizing Partial Submersion Side Access Method Step by Step Approach from small scale The work flow will be PCV internal investigation (including sampling) Retrieval in a small scale Retrieval in a large scale. PCV internal investigation in the immediate future Unit 1 Sending a submarine type boat through X2 penetration hole (FY2019 Unit 2 Sending a guide pipe device through X2 penetration hole The latter half of FY2018) Sending a arm type boat through X2 penetration hole (FY2019 X-6 penetration hole Arm-type device during storage) Arm- type device during investigating) Pedestal Investigation by the Arm-type device PCV In the PCV internal investigation at Units 1 and 2 scheduled in FY2019, sampling of small amount of deposits at the bottom of the PCV is planned. 26

28 1. Current Status of Fukushima Daiichi NPS 2. Improving Work Environment 3. Contaminated Water Management 4. Fuel Removal from Spent Fuel Pools ７ 廃棄物処理 5. Toward Fuel Debris Retrieval 6. Waste Management 7. Two-way Communications and Collection of Wisdom around the World 8. Fukushima Revitalization Activities

29 (1) Secure Storage of Waste After incineration and volume reduction, waste will be stored appropriately based on Storage Management Plan Current Status Total storage volume 430,000m3 Storage of rubble as of Mar Rubble(combustible Trimmed trees Used protective clothing Temporary trimmed trees storage pool Outdoor accumulation 10 years from now: 770,000m3 290,000m3 Rubble concrete metal etc. Tentative storage tent Container storage 140,000m3 ~0.005mSv/h to (A) To start in FY2025) to (A) 1 legend 30,000m3 Solid waste storage facility Storage volume 190,000m3 10,000m3 Existing solid waste storage facility No.１ 8 NO.9 To start in FY2020) Shredding equipment Volume reduction 3 Volume reduction facility To start in FY2022) Concrete shredder 90,000m3 200,000m3 50,000m3 Ａ 70,000m3 Metal cutter 90,000m3 to (A) Additional solid waste storage facility NO Dedicated storage facility for 6contaminated soil ( Recycle considered to start in FY2020) Treatment method to be studied later 50,000m3 Treatment method to be studied later 7000 vessels Spent absorption vessel temporary storage 4 Ｂ Contaminated soil Storage of secondary waste from water treatment additional facilities 250,000m3 Storage & Management Ｂ Outdoor accumulation Incinerator Pretreatment systwm Sheet curing 1mSv/h~ Solid waste storage Temporary soil cover type storage building Incineration 2 Container storage mSv/h 10 years from now Miscellaneous solid waste incineration facility Additional miscellaneous solid waste incineration facility If there is difficulty in incineration, volume reduction, and recycle, the waste goes ｄｉｒｅｃｔｌｙ to solid waste storage facility 設備及び施設設置のイメージ Container type Box-culvert type Spent absorption vessel temporary storage waste storage 5 Large facility To start in FY2019) 28

30 (2) Blueprint Northwest side of Units 5 & 6 1 Additional incineration facility ４ Additional solid waste storage Facilities No. 10 through 13 6 Dedicated storage facility for contaminated soil Miscellaneous solid waste incineration facility (Mar Unit 6 Unit 5 ２ Incinerator pretreatment system ５ Large waste storage facility ３ Volume reduction facility system Solid waste storage facility No. 9 (started operation in February 2018) Southwest side of Units 5 & 6 Current Situation July 2018) Construction site for additional incineration facility 29

31 1. Current Status of Fukushima Daiichi NPS 2. Improving Work Environment 3. Contaminated Water Management 4. Fuel Removal from Spent Fuel Pools 5. Toward Fuel Debris Retrieval 6. Waste Management 7. Two-way Communications and Collection of Wisdom around the World 8. Fukushima Revitalization Activities

32 (1) Two-way Communications with Local Residents Invitation to Site Visits Explanation at public meeting Attendance at 2nd Decommissioning Forum (Jul. 2017) Aims to increase the total number Status Updates regarding of site visitors to 20,000/y by Providing answers to what Tokyo Olympics. decommissioning are given the local residents want to to the public at the regular Examples of comments received: know about decommissionpublic meetings hosted by I was able to sense the real ing Fukushima Daiichi. Fukushima Prefecture situation. There is an obvious The challenges regarding Opinions to TEPCO have progress and I think TEPCO is communication were also been reflected to discussed. decommissioning measures trustworthy In the follow-up workshop I want TEPCO to continue this held in last November, the activity which helps dispel importance of conveying harmful rumor messages in a way that leads to people s understanding The scene of the Units 1 to 4 while considering their buildings helps understand what reaction was recognized. progress has been made since the accident FY2017 Number of visitors: 12,489 TEPCO Employees Center left : Ohkura, Representative of the Fukushima Revitalization Headquarters Center right Ono, Chief Decommissioning Officer, President of Fukushima Daiichi Decontamination and Decommissioning Engineering Company Overseas 9% 6% From Fukushima Prefecture 26% 58% From Other Prefectures Held in Hirono Town, Fukushima Prefecture by NDF 31

33 (2) Two-way Communications and Collection of Wisdom around the World The latest information shared through website. Videos released where Risk Communicators respond to the interests of people. As for magazines, understandability and familiarity prioritized by featuring figures engaged in the decommissioning work. Open innovation platform TEPCO CUUSOO established in order to transmit the on-site needs, and gather knowledge and expertise. Information sharing through website Live footage An explanatory video Information Magazine １Ｆ Hairo Michi TEPCO CUUSOO Challenges Radiation measurement using drone Hydrogen accumulation evaluation Example Effective treatment of Iodine and Ruthenium in contaminated water Unit 1,2 Stack dismantling 32

34 1. Current Status of Fukushima Daiichi NPS 2. Improving Work Environment 3. Contaminated Water Management 4. Fuel from Spent Fuel Pools ７. Removal 産官学連携による福島復興に向けた取組み 5. Toward Fuel Debris Retrieval 6. Waste Management 7. Two-way Communications and Collection of Wisdom around the World 8. Fukushima Revitalization Activities 33

35 (1) Fukushima Revitalization Activities Bearing in mind that it is our mission and existential reason to carry through our responsibilities TEPCO owes to Fukushima, TEPCO is performing revitalization activities. Fukushima Revitalization Headquarters is continuing their activities in response to the needs of local residents. The cumulative number of those engaged in the activities reached 422,418 at the end of June Employees activities Contribution to Local Festivals Outdoor Cleaning & Clearing Weed Removal Before and After: Making a Difference (Decluttering toward a school reopening Setting up a park in preparation for a marathon in Kawauchi Village (April. 2018) 34

36 (2) Promotion of Local Produce and Products in Fukushima Announced Action Plan against Harmful Rumor in Jan to become more proactive in and responsible for dispelling harmful rumor. Various kinds of sales events are supported by TEPCO. O-EN Network : 122 Companies joined Sales Event at TEPCO HQ on Jul. 24 Promotion of Fukushima Produce at member company cafeterias Marche held by member companies Activities Using Fukushima products and produce as congratulation gifts and commemorative gifts Sales Promotion of Fukushima produce etc. in Tokyo Metropolitan District Fukushima Marche Sales event of Sales event of Fukushima Fukushima meat (May 2018 rice (December 2017 (June 2018) Members 35

37 In Conclusion For Fukushima Revitalization Move forward with decommissioning work safely, steadily and swiftly Dialogue with local people with integrity and humility while responding to their concerns in a respectful manner

38 Thank you for your kind attention T H E F U K U S H I M A F O R U M I V M A R C H , TO K Y O, J A PA N

39 Fukushima Daiichi NPS Map Sea-side Impermeable Wall Cesium Adsorption Apparatus 2nd Cesium Adsorption Apparatus (Sarry) K3 K4 New Administration Office Building Multinuclide removal Equiom System(ALPS) Partner company Office Building