Typhoon threat at Fukushima reactor site

Typhoon Roke, the 15th typhoon of the season in the northwest Pacific, is passing in the vicinity of the Fukushima reactor site.  It has already left in its wake significant flooding in Nagoya (southwest of Tokyo) and on the western outskirts of Tokyo as it cut a path across central central Japan.  It made landfall with 130+ mph winds.  Video footage of the typhoon effects can be found here.

All work was suspended at the nuclear plant site (including work to cover reactor 1), where 10+ inches of rain and strong winds were expected at the plant as a result of the typhoon.  Leaking is occurring at the reactor site.

The 5 km resolution COAMPS-TC (Coupled Ocean/Atmosphere Mescoscale Prediction System-Tropical Cyclone) shows the path across central Japan at 9 PM Japan Standard Time (JST) on September 21, as the typhoon headed toward the Fukushima reactor site bringing 60 knot winds to the coastal zone.  The Naval Research Lab’s COAMPS-TC forecasts can be found here.

COAMPS-TC forecast for 9PM 21 September JST

The official trajectory forecast has the typhoon proceeding over the ocean and brushing Hokkaido then moving across other smaller northern islands, and can be found at the Japan Meteorological Agency site here.

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Contaminated areas and permanent evacuations

More details have emerged lately regarding assessments of measured levels of radioisotopes as well as the Japanese government’s strategy for a permanent evacuation zone.  Soil measurements of radioactive cesium are distributed in patches throughout six municipalities: Okumamachi, Futabamachi, Namiemachi, Tomiokamachi, Iitatemura and Minami-Soma (see map below from Daily Yomiuri story, August 31).  And it reinforces indications from the government that part of the 20 km no-entry zone will be closed permanently.

This is an important aspect of the evolving tragedy and comparisons with long-term evacuations in the case of Chernobyl are inevitable.  So there is much speculation on the levels of contamination that will be deemed off-limits.  There are 34 spots that meet the Chernobyl level for permanent evacuation (1.48 million becquerels of cesium 137 per square meter) – the white and red circles in the map below.  Note that about half the sites lie outside the 20 km zone, with 8 located outside the 30 km zone.

From Daily Yomiuri (August 31, 2011)

Clean-up plans are also being devised with the aim of reducing exposure (more details here and here).

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Scrutiny of evacuations continues

This week the Wall Street Journal published a cluster of frontpage stories (here and here, along with video content) about the evacuation mishaps and tragedies in the wake of the Fukushima Daiichi nuclear incident.  In “How Japan Stumbled in Forecasting Fallout in One Town“: ‘The fallout projections “could have been used as a guide for evacuation if they had been shared with people ahead of time,” says Yukio Sudo, president of Nuclear Safety Technology Center, the government agency that operates Speedi on behalf of the education and science ministry.’

The evacuations of Namie in the several days after March 11 were riddled with confusion and received no information on the projected path of the vented radiation-laced steam that the residents could so clearly see coming in their direction.  For several hours on the afternoon of March 12 the plume predicted by Speedi impacted the region as the local wind vector rotated clockwise throughout the afternoon.  This is visualized in the WSJ interactive graphics associated with this story.  This is a separate event from the one on March 15 when sustained winds blew toward the northwest again, with significant fires and explosions ongoing at the nuclear plant.  This event was covered in prior posts (here and here) and in this week’s WSJ story “Murky Science Clouded Japan Nuclear Response“.  The impact of delays in releasing plume forecasts is examined through the eyes of residents of Iitate, well outside the 30 km zone.

(from the Wall Street Journal)

“In the end, it took government officials more than a month to decide that Iitate was too dangerous to inhabit. And by then, many residents, particularly older ones, didn’t take the warnings seriously.

Confusion over what to do about radioactive contamination is playing out in various forms all over Japan. Officials are struggling to figure out where it is safe to live, what is safe to eat and how farmers decontaminate their fields. At present, 116,000 people remain unable to return to their homes due to the radiation threat. Even as the government continues to ask more people to evacuate, it is mulling allowing others to return to towns where contamination is relatively light.”

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Evacuations lacked key plume model input

A recent frontpage story in the New York Times explores in more depth an evacuation tragedy that plagued the Fukushima nuclear incident.  The event they focus on is the evacuation of Namie, first reported by the Daily Yomiuri on June 10 and described in this prior post.  In the absence of evacuation guidance from the government, the village of several thousand evacuated to the north and sheltered in an area that ended up receiving the most severe radiation impacts.  Specifically, on March 15 the winds directed radioisotopes to the northwest –  covering the area, Tsushima, where they sheltered.  The government’s radiation plume forecast system, SPEEDI, predicted this particular event (see prior post) but the information was never disseminated to local officials who could have used it to guide evacuation strategies.  By contrast, children played outdoors and evacuees consumed food and water from the contaminated region to which they had fled.

The NYT story probes the possible contributing factors to this lapse in emergency response – including distrust of the forecasts and fear that the forecasts were wrong, given the uncertainty about the source term.
“Mr. Kosako and others, however, say the Speedi maps would have been extremely useful in the hands of someone who knew how to sort through the system’s reams of data. He said the Speedi readings were so complex, and some of the predictions of the spread of radiation contamination so alarming, that three separate government agencies — the Education Ministry and the two nuclear regulators, the Nuclear and Industrial Safety Agency and Nuclear Safety Commission — passed the data to one another like a hot potato, with none of them wanting to accept responsibility for its results.”

“Mr. Hosono, the minister charged with dealing with the nuclear crisis, has said that certain information, including the Speedi data, had been withheld for fear of “creating a panic.” In an interview, Mr. Hosono — who now holds nearly daily news conferences with Tepco officials and nuclear regulators — said that the government had “changed its thinking” and was trying to release information as fast as possible. ”

In a Nature Newsblog analysis of the NYT story the chronic failure in communication with the public during the crisis is cited as another contributor to the evacuation tragedy.

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Special scientific session on “Fukushima Crisis: Air & Sea Transport Modeling”

An upcoming special session at the 15th Annual George Mason University Conference on Atmospheric Transport and Dispersion Modeling will focus on the Fukushima nuclear power plant crisis.  On the schedule are scientists from NRC, DTRA, NRL, NOAA, Japan Atomic Energy Agency, Japan Agency for Marine-Earth Science and Technology, University of Toulouse, French Institute for Radioprotection and Nuclear Safety, and Joint Research Centre/European Commission, among others.  The scientific content will mainly concern the modeling of local (Japan) pathways of transport and dispersion of radioisotopes.  The morning will address the coastal ocean and groundwater while the afternoon will cover the atmosphere.

Update: The special session was successful and highly informative.  We are currently writing up a summary of the special session for the Bulletin of the American Meteorological Society.

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Scientific source term estimation of radiation release

Researchers at the Japan Atomic Energy Agency have just published a scientific paper reporting on detailed source term estimation for the airborne release from the Fukushima Daiichi Plant.  The paper in “Journal of Nuclear Science and Technology” can be found here.  The authors utilize the SPEEDI predictions with unit release rate in combination with a source term inversion, similar to the methodology they have employed for Chernobyl.  Their analysis reveals that the greatest release from the Fukushima reactors occurred in the late morning/early afternoon of March 15.  Later that afternoon and early evening, rain deposited cesium and iodine in a plume created by winds directed toward the northwest.  (See SPEEDI prediction of this event).  The authors estimate a 6-hour release on March 15 (from  9 AM to 3 PM JST) of 10^(16) Bq/h of radioactive iodine occurred.

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International entities take steps to encourage data release

Several recent developments related to data sharing have elevated the topic on the international stage.  Wednesday June 23 at an International Atomic Energy Agency meeting the members agreed to share more information in the event of a nuclear crisis, and will set up mechanisms to do so.  Furthermore, “A Japanese official quoted an expert from the World Meteorological Organization as saying the group was unable to obtain necessary information from Japan. He said this led to difficulties in projecting how radioactive materials would spread around the world.”

A meeting June 8-10 of scientists working with the Comprehensive Test Ban Treaty Organization (CTBTO, an international entity established to monitor nuclear weapons test) resulted in an initiative to encourage more widespread dissemination of data from their radiation monitoring sites.  As the Fukushima crisis unfolded, disclosure of the CTBTO data was restricted to participating member-state designated scientific institutions.  This restricted release of data was criticized by the wider scientific community.  A June 15 editorial in Nature urged open access to the data: “…the CTBTO data are valuable in times of both calm and crisis. Contrary to the concerns of some, the more people who see them, the more valuable they will become.”

Citizens and scientists in Japan continue to monitor radiation and map areas of contamination up to ~100 miles from the Fukushima site – reaching the edges of Tokyo.  The comprehensive dataset is attracting the attention of the international scientific community, as described in the June 17 issue of Science magazine.   The compiled “citizens’ map” is shown above and here, along with details about each station measurement.  Radiation values in the zone to the northeast of Tokyo are 0.4 microsievert/hr (~3.5 millisievert/yr) – exceeding the Japanese limit of 1 millisievert/yr. Evidence of more widespread (150-200 km north of the nuclear plant) radiation contamination of cattle grazing lands is emerging.  This region is shown on the map above.

Depth contours and cruise track from WHOI research cruise blog (Image: Steve Jayne, Woods Hole Oceanographic Institution)

The Woods Hole Oceanographic Institution conducted a research cruise June 3-17 (see above cruise track) to sample the waters in the vicinity of the Fukushima plant and through the Kuroshio current.  The cruise maintained a blog and is committed to the public dissemination of results:  “The larger questions—those that we are working towards with this cruise—include the full range of isotopes that were released from the reactor that and may yet be released, how fast and by what paths cesium and other isotopes are being diluted into and removed from the North Pacific, and how these different substances might be assimilated into different levels of the food chain.”

Other relevant sources of consolidated data include current and forecast wind and rain from the Japan Meteorological Agency 2 km resolution GPV model.

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