July 21 st, Tomohiro ASANO Fukushima Environmental Safety Center Headquarters of Fukushima Partnership Operations Japan Atomic Energy Agency

Transcription

1 July 21 st, 2012 Tomohiro ASANO Fukushima Environmental Safety Center Headquarters of Fukushima Partnership Operations Japan Atomic Energy Agency

2 CONTENTS Evacuation and dose reconstruction Environmental radiation monitoring Legal frame work of decontamination Decontamination Pilot Project by JAEA 1

3 Great East Japan Earthquake and Tsunami Time: 2:46 pm on Fri, March 11, Place: Offshore Sanriku coast (northern latitude of 38 degrees, east longitude of degrees), 24km in depth, Magnitude 9.0 Tsunami: Earthquake generated a series of large tsunami waves that stuck the east coast of Japan, the highest being 38.9 m at Iwate pref. Tsunami estimated at m high stuck the Fukushima site Casualties: Dead over 15,800 Missing over 3,200 Injured over 6,000 (As of Feb.21,2012) Evacuees: over 342,000 (As of Feb.9, 2012) 2

4 Trend of Onsite Radiation Level On site dose rate measurement by TEPCO 3

5 Evacuation The government took measures such as sheltering or evacuation as follows : <2011> Fri, March 11 14:46 The earthquake occurred 19:03 Emergency Declaration by the Government 21:23 3 km radius evacuation 10 km radius taking shelter Sat, March 12 5:44 10 km radius evacuation 18:25 20 km radius evacuation Tue, March 15 11: km radius taking shelter Thu, April 21 11:00 20 km radius is designated as Restricted Area Fri, April 22 9: km radius taking shelter has been lifted Establishment of Deliberate Evacuation Area and Evacuation Prepared Area in Case of Emergency Thu, June 16 PM Establishment of Specific Locations Recommended for Evacuation Fri, September 30 18:11 Evacuation Prepared Area in case of Emergency has been lifted. 4

6 Zones of Evacuation Instruction Iitate Minami-soma Energency evacuation preparation zone Kawamata Deliberate evacuation zone Minami-soma Katsurao Namie Tamura Energency evacuation preparation zone Kawauchi Naraha Restricted zone Hirono Evacuation zones Population (thousand) Restricted zone 78 Deliberate 10 evacuation zone Emergency 58 evacuation preparation zone (Lifted on September 30. Total 150 5

7 Dose Reconstruction of Fukushima Residents Dose reconstruction of Fukushima residents, including evacuees, is implemented by Fukushima pref. government and Fukushima Medical University, assisted by National Institute of Radiological Sciences (NIRS). Fukushima pref. government sent questionnaire to 2,056,994 residents and received 465,041 answers (22.6%) as of May 31 th Questionnaire includes where you were, how you moved, how long you stayed etc., after earthquake. According to the preliminary assessment for 14,412 evacuees, excluding radiation workers, maximum effective dose was 25.1 msv, 94 % was less than 5 msv, and 99.3 % was less than 10 msv. According to the preliminary assessment for 10,143 Fukushima residents, excluding evacuees and radiation workers, maximum effective dose was 3.9 msv. Continuing efforts by Fukushima prefecture required for dose reconstruction. Information from Committee on Health of Fukushima Population 6

8 Environmental Radiation Monitoring Emergency environmental radiation monitoring has been continued by various organizations such as TEPCO, prefectural government, universities and JAEA. Results of the environmental monitoring is compiled as contamination maps. Wide-area radiation monitoring has been implemented by aircraft and unmanned helicopter. Comprehensive results of the environmental monitoring is compiled in web site of MEXT, Vehicle monitoring Dose rate map (µsv/h) Soil contamination map (Bq/m2) Aircraft monitoring 7

9 Results of Aircraft Radiation Monitoring Aircraft radiation monitoring has been implemented by JAEA and Nuclear Safety Technology Center(NUSTEC) Gamma dose rate Deposited radioactivity of Cs-134 and Cs-137 8

10 Bird Eye View of Contamination Level Bird view from north-east direction view from 170 km off-shore of Fukushima and 370 km above the sea level Sum of Cs deposited (Bq/m 2 ), as of November 5,

11 Estimated deposition of Cs-137 Deposition of Cs-137 was estimated by WSPEEDI model by comparison with measured surface soil concentration and meteorological data. Radioactive material deposited by wet and dry deposition processes depending on wind directions on each day. Mar Wet deposition Mar. 20 Wet deposition Mar. 12 Dry deposition Mar. 15 Dry deposition H.Nagai et al., Atmospheric dispersion simulations of radioactive materials discharged from the Fukushima Daiichi Nuclear Power Plant due to accident: Consideration of deposition process, The first NIRS symposium on reconstruction of early internal dose due to the TEPCO Fukushima Daiichi Nuclear Power Station accident, Chiba, Japan, July, 2012 Mar. 21 Wet deposition 10

12 Comparison of Contaminated Area Contaminated land map around Fukushima NPP1 shown at the same scale Contaminated area over 1,480 kbq/m 2 : 3,100km 2 Contaminated area from 555 to 1,480 kbq/m 2 : 7,200km 2 Contaminated area from 37 to 555 kbq/m 2 : 125,000km 2 Surface ground deposition of Cs-137 in the vicinity of Chernobyl 100 km 11

13 Legal Framework of Decontamination Act on Special Measures concerning the Handling of Radioactive Pollution Promulgated: at the end of August 2011, Fully came into force: January 1, 2012 Basic Principles of the Act -Decided by the Cabinet: November 11, 2011 The Order and Ordinance -Promulgated: December 14, 2011 Waste-related regulations: Designation standards for Designated Waste, collection and transfer standards, storage standards and final disposal standards for decontaminated waste, etc. Decontamination-related regulations: Standards for decontamination and other measures, collection and transfer standards and storage standards for the removed soil, etc. -Designation of the target areas: December 28, 2011 Special Decontamination Areas: 11 municipalities* (20km radius from NPP + area with 20 msv of annual cumulative dose) Intensive Contamination Survey Areas:102 municipalities* (area with 1-20 msv annual cumulative dose) * 4 municipalities have been partially designated 12

14 Basic Approach of Decontamination Work Principles set by ICRP 100 msv/y 20 msv/y 1 msv/y Emergency exposure situation [Planned evacuation zone, Restricted zone] Those when require emergency activities such as nuclear accident. Aiming to reduce exposure dose to 20 msv/y or less. Existing exposure situations Long-term exposure after emergency situation Long-term goal Reducing additional exposure dose to 1 msv/y The national government will undertake decontamination work Long term efforts are needed in high dose area Municipalities develop and implement decontamination plans The national government provides financial and technical support 13

15 Basic Principles under the Act Targets of the Decontamination Additional * exposures over 20mSv/y - Aim at stepwise and rapid reduction of those areas based on the ICRP Recommendation (2007). * additional means beyond natural background and medical exposure Additional exposures < 20mSv/y - As a long term goal, aim at reducing to 1 msv/y or less General Public Children - Reduce estimated annual exposure of the general public by 50 % in 2 years (by Aug 2013) by radioactive decay, decay by natural factors and by decontamination - Reduce estimated annual exposure of children by 60 % in 2 years (by Aug 2013) by thorough decontamination of their living environment. by radioactive decay, decay by natural factors and by decontamination - The goals will be reviewed periodically 14

16 Decontamination Roadmap for the Special Decontamination Areas - Released by MOE on January Decontamination Plan including specific plan for each of 11 municipalities will be developed by around the end of March 2012* * Plans of 4 municipalities have been developed as of the end of April. Plan should correspond to new evacuation instruction and zoning Advance decontamination work for public facilities (e.g. city and town halls) and infrastructures (e.g. highway, water facilities) Priorities of Full-scale decontamination should be given to areas with < 20mSv/y and areas with msv/y with an aim of realizing earliest possible return of evacuees In Areas with >50mSv/y, demonstration projects will be implemented Implementation policies for each of new evacuation zones (priorities and goals of decontamination etc.) 15

17 Rearranging Zoning of Restricted Area Basic Definition of the Areas Area 1 Areas to which evacuation orders are ready to be lifted Area 2 Areas in which residents are not permitted to live Area 3 Areas where it is expected that residents will face difficulties in returning for a long time Areas where it is confirmed that the annual integral dose of radiation will definitely be 20mSv or less Areas where the annual integral dose of radiation is expected to be 20mSv or more and where residents are ordered to remain evacuated in order to reduce the risk of radiation exposure. Areas where the annual integral dose of radiation is expected to be 20mSv or more within five years and the current integral dose of radiation per year is 50mSv or more. 16

18 Full-scale decontamination Areas not more than 20 msv/yr Areas with msv/yr Areas >50 msv/yr Decontamination Policy for New Evacuation Zones FY 2011 FY2012 FY2013 Jan -Mar April July Oct Jan April July Oct Jan Areas with msv/yr (Schools with 5-20 msv/yr) Demonstration Works Areas with 5-10mSv/yr Areas with 1-5 msv/yr Areas with msv/yr Verification of the results FY Temporary storage Design Surveys and preparation Delivery and management (in the order agreed by the community) 17

19 Temporal storage: about 3 years Interim Storage Roadmap Placed In each municipality or community In Special Decontamination Areas: MOE builds facilities Other areas: municipalities builds ones with financial and technical support from MOE Operation of Interim Storage Facilities: (start in 3 years, for less than 30 years) Placed in Fukushima Pref. (for waste and soil generated in the pref.) Select site in FY 2012 Negotiation has started with 8 municipalities since January Final disposal: outside Fukushima Pref. Other pref. : use existing waste disposal facilities in each pref. Released by MOE on Oct 29, 2011 Treatment flow in Fukushima prefecture 1. Generation of waste 2. Temporal storage site 3. Intermediate storage site 4. Final disposal (outside) 18

20 Implementation of Decontamination Pilot Project by JAEA Before the implementation of full scale decontamination, the Cabinet Office commissioned Decontamination Pilot Project to JAEA. The purpose of the project is to acquire technical data and knowledge, and provide integrated expertise for full-scale decontamination projects ; Check the availability and efficacy of proven and new techniques Investigate cost, work period, workforce, waste generated, and radiation exposure of workers Establish waste management including volume reduction of wastes and treatment of the secondary waste Secure workers safety under radiation protection Establish optimal radiation monitoring Record the public communication 19

21 Decontamination Area of the Project Demonstration of wide area decontamination The model areas, totaling 209 ha in size within or close to restricted area and deliberate evacuation area, include; various components such as forest, farmland, building, road and playground various dose rate levels; high (> 100 msv/y) intermediate (20 100), and low (5 20) R&D of decontamination technologies 25 proposals funded for R&D of decontamination technologies In situ operation 20

22 Clean-up of Pavement high pressure water road cleaner surface stripping blasting Iron shot blasting Ice blasting 21

23 Clean-up of Housings 22

24 Clean-up of Farmland plow turf stripping topsoil removal fixation 23

25 Clean-up of Trees and Forest weeding removal of leaf mold clipping water horsing clipping clipping curing removal of leaf mold Water jet 24

26 Volume Reduction of Waste water treatment chipping pruning and sticks flocculation-precipitation column adsorption 25

27 Clean-up of Ohkuma area 26

28 Temporary Storage for Waste Embankment or sandbags for shielding Gas discharge Impermeable layer or liner sheet Flexible container bags Impermeable layer or liner sheet Drainpipe Protective layer (Supplemental layer for water collection) Tank for checking of radioactivity concentration of seeping water Temporary storage under construction 27

29 Results of Dose Reduction by Wide Area Decontamination Estimated annual dose reduced to less than 20 msv/y, for the areas of estimated annual dose corresponding to msv/y before decontamination. Estimated annual dose could not reduced to less than 20 msv/y, for the areas of estimated annual dose exceeding 40 msv/y before decontamination. In case of agricultural and residential area of Ottozawa, Ohkuma, the dose rate reduced by 70 %. However, estimated annual dose could not decreased to less than 50 msv/y. The dose rate reduction was smaller in the areas of relatively low dose rate, compared with high dose rate areas. 28

30 Dose Reduction by Wide Area Decontamination (1/3) (Dose rate at 1 m height) Decontamination area Usage Average dose rate before clean up (μsv/h) Average dose rate after clean up (μsv/h) Dose rate reduction factor (%) Waste gererated Residential area % Ottozawa, Ohkuma Town Estimated annual dose before decontamination : 344 msv/y Area : 16.9 ha Residential area Agricultural area % Forest % Paved road % Unpaved road % Amount of waste generated per unit area : 795 m3 /ha Vicinity of Town Office, Ohkuma Town Estimated annual dose before decontamination : 65 msv/y Area : 5.1 ha Townl area Outside clean up area Residential area % Parking, Road % Park % Outside clean up area Residential area % Amount of waste generated per unit area : 326 m3 /ha Tsushima, Namie Town Estimated annual dose before decontamination : 48 msv/y Area : 5 ha Residential area Housings % Agricultural area % Forest % Road % Amount of waste generated per unit area : 345 m3 /ha Outside clean up area Residential area % Yonomori, Tomioka Town Estimated annual dose before decontamination : 43 msv/y Area : 8.65 ha Townl area Housings % Road % Forest % Ground % Amount of waste generated per unit area : 353 m3 /ha 2 nd junior high school, Tomioka Town Estimated annual dose before decontamination : 32 msv/y Area : 2.54 ha Town area Outside clean up area Ground % Outside clean up area Amount of waste generated per unit area : 514 m3 /ha 29

31 Dose Reduction by Wide Area Decontamination (2/3) (Dose rate at 1 m height) Decontamination area Gongendo, Namie Town Estimated annual dose before decontamination : 26 msv/y Area : 12.8 ha Town area Kainosaka, Kawauchi Village Estimated annual dose before decontamination : 20 msv/y Area : 23.0 ha Residential area Kusano, Iitate Village Estimated annual dose before decontamination : 19 msv/y Area : 17.3 ha Residential area Sakashita, Kawamata Town Estimated annual dose before decontamination : 15 msv/y Area : 11 ha Residential area Kamishigeoka, Naraha Town Estimated annual dose before decontamination : 11 msv/y Area : 4.0 ha Residential area Usage Average dose rate before clean up (μsv/h) Average dose rate after clean up (μsv/h) Dose rate reduction factor (%) Residential area % Train station % Agricultural area % Road % Outside clean up area Residential area % Agricultural area % Forest % Road % Outside clean up area Residential area % Housings % Agricultural area % Forest % Road % Outside clean up area Residential area % Agricultural area % Forest % Road % Outside clean up area Residential area % Housings % Agricultural area % Forest % Road % Outside clean up area Waste gererated Amount of waste generated per unit area : 175 m3 /ha Amount of waste generated per unit area : 190 m3 /ha Amount of waste generated per unit area : 282 m3 /ha Amount of waste generated per unit area : 262 m3 /ha Amount of waste generated per unit area : 446 m3 /ha 30

32 Dose Reduction by Wide Area Decontamination (3/3) (Dose rate at 1 m height) Decontamination area Usage Average dose rate before clean up (μsv/h) Average dose rate after clean up (μsv/h) Dose rate reduction factor (%) Waste gererated Residential area % Vicinity of Village Office, Katsurao Village Estimated annual dose before decontamination : 8 msv/y Area : 6.5 ha Residential area Schools % Village office % Forest % Road % Outside clean up area Amount of waste generated per unit area : 256 m3 /ha Residential area % Kanafusa, Minami-soma City Estimated annual dose before decontamination : 5 msv/y Area : 13.9 ha Town area Public house % Agricultural area % Forest % Road % Amount of waste generated per unit area : 296 m3 /ha Outside clean up area South Industrial Complex, Naraha Town Estimated annual dose before decontamination : 4 msv/y Area : 36.8 ha Industrial area Housings % Forest % Road % Outside clean up area Amount of waste generated per unit area : 60 m3 /ha Jikenjo, Tamura City Estimated annual dose before decontamination : 4 msv/y Area : 15.5 ha Residential area Residential area % Agricultural area % Road % Forest % Outside clean up area Amount of waste generated per unit area : 38 m3 /ha Chuodai and Nawashirogae, Naraha Town Estimated annual dose before decontamination : 3 msv/y Area : 33.0 ha Residential area Residential area % Housings % Agricultural area % Forest % Road % Outside clean up area Amount of waste generated per unit area : 182 m3 /ha 31

33 Radiation Control of CleanupWorkers Radiation monitoring before clean-up work Flow diagram of daily radiation control Dose prediction, protective equipment (before work) Restricted area Radiation control officer Entering restricted area via Screening point Decontamination work Resting area Screening point Monthly dose check Daily dose check 32

34 Radiation Dose to Cleanup Workers Radiation doses to workers were controlled within the dose limit for cleanup workers. Area Estimated dose assuming residence(msv) *1 Work period(day) Number of workers Average dose of workers(msv) Maximum dose for individual(msv) Hirono * *2 Tamura Industrial Complex, Naraha Minami-soma Katsurao Kami-shigeoka, Naraha Kawamata Iitate kawauchi Gongendo, Namie Junior high school, Tomioka 32 Yonomori, Tomioka Tsushima, Namie Town Office, Ohkuma Ottozawa, Ohkuma *1 Dose estimated by results of pre monitoring, assuming living in concerning area *2 Dose measured by glass badge, where dose for other area measured by pocket dose meter during working time. 33

35 Lessons Learned Integrated results of Decontamination Pilot Project is compiled in report and submitted to Ministry of Environment at the end of June, Lessons Learned : Proven techniques are available for cleanup of roads and buildings and improvement of the techniques are expected for higher efficiency. Roof tile cleanup depends on the materials. Cleanup of farmland requires considerations of its vastness, a large amount of removed contaminated soil, and reusability, in addition to decontamination efficiency A cautious and presumably long-term approach is needed for forest, in consideration of ecosystem conservation and disaster prevention R&D is needed for soil cleanup and waste volume reduction Radiation dose of clean-up workers is controllable by daily dose check. Stakeholder involvement in implementation of clean-up activities is essential 34

36 Summary Environmental Monitoring Continue environmental radiation monitoring Spatial and time-series distribution of radioactive concentration Study on environmental transfer of radioactive materials Clean-up and recovery work Clean-up work began last year in parallel with development of legal and technical framework, including Decontamination model project by JAEA. Full-scale clean-up work will be started soon by Ministry of Environment and each municipalities. JAEA continues technical support for full-scale clean-up. Dose Reconstruction Reconstruction of radiation dose to the evacuated people and Fukushima population Continue whole body counting and measurement of external dose Public relations Stake holder involvement in decision making and implementation of cleanup activities is essential, especially for waste temporary storage facilities Comprehensive radiological information should be provided to the public and discussed in open manner by risk communication sessions. 35