Fukushima nuclear power plant damaged by M9 Earthquake with some focus on ocean

Transcription

1 Fukushima nuclear power plant damaged by M9 Earthquake with some focus on ocean Moto Ikeda (Hokkaido Univ. & JAMSTEC) Oceanographic Society of Japan, Earthquake Disaster Working Group

2 Magnitude-9 earthquake off East Japan March 11, 2011 Horizontal slide in sea floor: Max of 30m Vertical shift: 1.2m down

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5 Tsunami Total death exceeding 15,000 Sendai-city Height: 15m Running up to altitude of 35m

6 Fukushima-I Nuclear Power Plant Electric power lost Nuclear fuel melt down Hydrogen explosion Radionuclide coming out to air & Polluted Water flowing out Flooding Damage on power plant

7 Components of radionuclide (1) Atmospheric fallout to the ocean Quickly (in a week) spread in mid-march to the Eastern Pacific Ocean, large amount but low concentration (2) Polluted water flowing out In April flowing southward due to northerly winds and northward due to southerly winds, in May entrained into the Kuroshio (3) River & ground water (underground of power plant) Accumulating on the ocean floor? Pollutant fish in June?

8 Main questions Distribution of radio-active materials (radionuclide) Processes of the materials emitted to the atmosphere falling out to the ocean Processes of the polluted water flowing into the ocean Ocean currents and mixing around Fukushima-I Interactions with plankton, behavior in food web, sedimentation Impacts of the materials on marine ecosystem

9 Radionuclide emitted to air, and fallout Cs-134 & 137 fallout to land surface Exploded, carried in air and fell out with rain About 200,000 people are still evacuated.

10 In the case of Chernobyl Much larger area received impacts Plutonium and Strontium as well

11 From the era of nuclear bomb experiments 1Bq/liter to the present Western North Pacific

12 Statement: Our action plan for East Japan Magnitude-9 Earthquake and Fukushima nuclear power plant disaster Oceanographic Society of Japan Monitor and research continuously pollution caused by radio-active materials Collect and send information, organize observations and contribute to society through suggestions Set up working group

13 Function of Earthquake Disaster Working Group Objectives Promote monitoring of coastal regions Promote observations of North Pacific and fulfill responsibility for neighborhood countries Transmit information of marine environ. Prepare suggestions for policy makers Collaborate with foreign res. groups Collaborate and exchange information with Related disciplines Atmos., Limnology, Soil, Radiology, Nuclear physics, Atomic Energy Research organizations JAMSTEC, MRI, Fisheries, Universities, Local Gov. Inst., WHOI, NOAA National and local government Private sectors and citizens Observation Monitoring Sampling Analysis Modeling Simulation Ecosystem Public info. Outreach Suggest and coordinate Cruise plans Observation lines and Argo float deployment Collection items Suggest and coordinate Sampling protocol Analysis team Suggest and coordinate Model and Key mechanisms Model intercomparison Prepare and describe model results Coordinate research plans for Impact of Tsunami wash away Food-web condensation of radionuclide Verify new information Collect existing information Talk to citizen Prepare web Organize symposium

14 Observed distribution 10Bq/liter Cs-137 for a couple of weeks, Log[Bq/L], with data collected at black dots

15 100 X background JAMSTEC cruise (Apr.-May) : Cs-137, atmospheric fallout

16 Model simulation Powerful tool for forecast, and also for better understanding of processes Use both coastal models and Kuroshio-Oyashio model Coastal currents forced by winds and riverinduced buoyancy Kuroshio-Oyashio with mesoscale eddies

17 Kuroshio-Oyashio Model (from Miyazawa)

18 5 models of 4 groups on May 1st Cs-137 Red broken line Kuroshio axis from reanalysis data Coastal model +Kuroshio-Oyashio model Modeler JCOPE-T +JCOPE2 Miyazawa MSSG +JCOPE2 Choi

19 Main progressions well simulated Some details still under verification (more northward or southward spread) Kyoto-U +Kyoto-U Kobayashi (JAEA) ROMS +JCOPE2 Tsumune (CRIEPI) ROMS-L2 +ROMS-L1 +JCOPE2 Uchiyama (Kobe U.)

20 Evaluation Alongshore currents are reproduced qualitatively. Radionuclide concentration is consistent with near-shore data off Fukushima. Eastward flux is now consistent among models. Shelf waves driven by wind forcing along Japan coast are effective to transport radionuclide northward or southward, and variable among models. Sediment data could be useful by showing high water concentration in the early period (April-May) or continuous outflow from rivers and ground water. We should use available data for evaluation.

21 Experimental development of ocean prediction system for accidental radionuclide dispersion Funded by Sumitomo Foundation Prof. Masumoto and seven others Several NPPs in Japan (Fukushima, Ikata, Hamaoka) Forecast experiments for 1-month in each season of km resolution, ocean reanalysis, atmospheric forcing Model inter-comparison project

22 Following work Radionuclide: focus on Cs-137, and estimate adherence on phytoplankton, condensation through food webs and accumulation with sediments Estimate inflow of radionuclide through rivers and ground water Taking the information of atmospheric fallout, simulate radionuclide in the Pacific Ocean and explain pollution in fisheries products so that we may take some of international responsibility

23 Additional point to be clarified Bottom Sediment Cs monitored by Tokai Univ. ( ) Spreading along-shore Gradual decline after the half-year period

24 Five important processes (1)Adsorption to & uptake by phytoplankton (2)Detritus of zooplankton (3)Materials (soil, sand and sediments) resuspended by earthquakes (4)Direct adsorption to bottom sediments at ocean floor (5)Carried with river flow from land Order estimates have been carried out.

25 Cs monitored by Fish. Res. Agency (July, 2012) Higher near the coast but gradually sliding down (by T. Ono)

26 Middle-to-long term prediction in the wide area Low-level pollution is spreading along the Kuroshio Extension and is expected to distribute along the subduction areas for longer than ten years. Japanese experts should take responsibility of exploring the pollution and giving information to the international community.

27 Experts of ocean sciences ought to try to give more information beyond the non-regret policy, pursue to clarify mechanisms of behaviors and impacts of radionuclide, not try to oversell their own research areas and projects, give uncertainty in risk assessment, send accurate information in understandable words to citizens and rely on their decision. Analogous to climate change!

28 How should we deal with nuclear power generators? 3 different opinions in Japan Improve technology of nuclear reactor Shift to renewable energy Forget about global warming, and use fossil fuels Assess each and give correct information to public, avoiding conflict of interests However, one of the plants has restarted in last month, following the new assessment policy.