March 15 2011 Fukushima Diiachi (again)

See also https://nuclearhistory.wordpress.com/2013/03/19/iaea-fukushima-nuclear-accident-update-15-march-2011-1410-utc/

http://www.google.com.au/url?sa=t&rct=j&q&esrc=s&source=web&cd=8&ved=0CGgQFjAH&url=http%3A%2F%2Fmeetingorganizer.copernicus.org%2FEGU2013%2FEGU2013-3793-3.pdf&ei=U7lRUZWFHoiZiAfro4HwDA&usg=AFQjCNFIEWYwolYGu-MDsgOsRsvpvGK_QQ&bvm=bv.44158598%2Cd.aGc&cad=rja

Geophysical Research Abstracts
Vol. 15, EGU2013-3793-3, 2013
EGU General Assembly 2013
© Author(s) 2013. CC Attribution 3.0 License.
The time series analysis of the radionuclide emissions from Fukushima
Daiichi nuclear power plant by online global chemistry transport model
and inverse model

Takashi Maki, Taichu Tanaka, Mizuo Kajino, Tsuyoshi Sekiyama, Yasuhito Igarashi, and Masao Mikami
Meteorological Research Institute, Japan (tmaki@mri-jma.go.jp)

The accident of the Fukushima Daiichi nuclear power plant that occurred in March 2011 emitted a large amount of radionuclide.

The important feature of this accident was that the source position was evidently clear, however, time
and vertical emission variations were unknown (in this case, it was known that the height of emission was not so high in altitude). In such a case, the technique of inverse model was a powerful tool to gain answers to questions; high resolution and more precise analysis by using prior emission information with relatively low computational cost are expected to be obtainable. Tagged simulation results by global aerosol model named MASINGAR (Tanaka et al., 2005) were used; the horizontal resolution was TL319 (about 60 km). Tagged tracers (Cs137) from lowest model layer (surface to 100m) were released every three hours with 1Tg/hr which accumulated daily mean. 50 sites’ daily observation data in the world (CTBTO, Ro5,Berkeley, Hoffmann and Taiwan) were collected.

The analysis period was 40 days, from 11 March to 19 April. We tested two prior emission information. The first information was JAEA posterior emission (Chino et al., 2011) and the second was NILU prior emission (not posterior) (Stohl et al.,2011) as our observation data were almost similar to their study.

Due to consideration for observation error and space representation error, the observation error was set as 20%. Several sensitivity tests were examined by changing prior emission flux uncertainties. As a result, Cs137 estimated the total emission amount from 11 March to 19 April as 18.5PBq with the uncertainty of 3.6PBq.

Moreover, the maximum radio nuclei emission occurred during 15 March, which was larger than prior information.

The precision of the analysis was highly dependent on observation data (quantity and quality) and precision of transport model. Possibility to obtain robust result by using multi-model ensemble results with inverse model was also considered. The results of this study are available for
modification of many processes of aerosol transport models. In the future, the combination of regional chemistry transport model and higher time resolution observation data in order to obtain robust emission time series of radionuclide is being planned.” end quote.

recap

http://www.iaea.org/new
scenter/news/2011/fukushima150311.html

Fukushima Nuclear Accident Update (15 March 2011, 14:10 UTC)

The IAEA continues to seek details about the status of all workers, reactors and spent fuel at the Fukushima Daiichi plant.

An evacuation of the population from the 20-kilometre zone around Fukushima Daiichi is in effect. The Japanese have advised that people within a 30-km radius shall take shelter indoors. Iodine tablets have been distributed to evacuation centres but no decision has yet been taken on their administration.

A 30-kilometre no-fly zone has been established around the Daiichi plant. Normal civil aviation beyond this zone remains uninterrupted. The Japan Coast Guard established evacuation warnings within 10 kilometres of Fukushima Daiichi and 3 kilometres of Fukushima Daini.

ukushima Nuclear Accident Update (15 March 2011, 22:30 UTC)

Japanese authorities have informed the IAEA that the evacuation of the population from the 20-kilometre zone around Fukushima Daiichi has been successfully completed.

The Japanese authorities have also advised that people within a 30-km radius to take cover indoors. Iodine tablets have been distributed to evacuation centres but no decision has yet been taken on their administration.

The IAEA continues to liaise with the Japanese authorities and is monitoring the situation as it evolves.

http://www.iaea.org/newscenter/news/2011/fukushima160311.html

Fukushima Nuclear Accident Update (16 March 2011, 22:00 UTC)

Temperature of Spent Fuel Pools at Fukushima Daiichi Nuclear Power Plant

Spent fuel that has been removed from a nuclear reactor generates intense heat and is typically stored in a water-filled spent fuel pool to cool it and provide protection from its radioactivity. Water in a spent fuel pool is continuously cooled to remove heat produced by spent fuel assemblies. According to IAEA experts, a typical spent fuel pool temperature is kept below 25 °C under normal operating conditions. The temperature of a spent fuel pool is maintained by constant cooling, which requires a constant power source.

Given the intense heat and radiation that spent fuel assemblies can generate, spent fuel pools must be constantly checked for water level and temperature. If fuel is no longer covered by water or temperatures reach a boiling point, fuel can become exposed and create a risk of radioactive release. The concern about the spent fuel pools at Fukushima Daiichi is that sources of power to cool the pools may have been compromised.

The IAEA can confirm the following information regarding the temperatures of the spent nuclear fuel pools at Units 4, 5 and 6 at Fukushima Daiichi nuclear power plant:
Unit 4
14 March, 10:08 UTC: 84 °C
15 March, 10:00 UTC: 84 °C
16 March, 05:00 UTC: no data
Unit 5
14 March, 10:08 UTC: 59.7 °C
15 March, 10:00 UTC: 60.4 °C
16 March, 05:00 UTC: 62.7 °C
Unit 6
14 March, 10:08 UTC: 58.0 °C
15 March, 10:00 UTC: 58.5 °C
16 March, 05:00 UTC: 60.0 °C

Fukushima Nuclear Accident Update (16 March 2011, 14:55 UTC)

Japanese authorities have reported concerns about the condition of the spent nuclear fuel pool at Fukushima Daiichi Unit 3 and Unit 4. Japanese Defense Minister Toshimi Kitazawa announced Wednesday that Special Defence Forces helicopters planned to drop water onto Unit 3, and officials are also preparing to spray water into Unit 4 from ground positions, and possibly later into Unit 3. Some debris on the ground from the 14 March explosion at Unit 3 may need to be removed before the spraying can begin.
Fukushima Nuclear Accident Update (16 March 2011, 03:55 UTC)

Japanese authorities have informed the IAEA that a fire in the reactor building of Unit 4 of the Fukushima Daiichi nuclear power plant was visually observed at 20:45 UTC of 15 March. As of 21:15 UTC of the same day, the fire could no longer be observed.

Fire of 14 March

As previously reported, at 23:54 UTC of 14 March a fire had occurred at Unit 4. The fire lasted around two hours and was confirmed to be extinguished at 02:00 UTC of 15 March.

IAEA Briefing on Fukushima Nuclear Emergency (17 March 2011, 14:00 UTC)

At the IAEA headquarters in Vienna, Graham Andrew, Special Adviser to the IAEA Director General on Scientific and Technical Affairs, briefed both Member States and the media on the current status of nuclear safety in Japan.

Current Situation

The situation at the Fukushima Daiichi nuclear power plants remains very serious, but there has been no significant worsening since yesterday.

The current situation at Units 1, 2 and 3, whose cores have suffered damage, appears to be relatively stable. Sea water is being injected into all three Units using fire extinguishing hoses. Containment pressures are fluctuating.

Military helicopters carried out four water drops over Unit 3.

Unit 4 remains a major safety concern. No information is available on the level of water in the spent fuel pool. No water temperature indication from the Unit 4 spent fuel pool has been received since 14 March, when the temperature was 84 °C. No roof is in place.

The water levels in the reactor pressure vessels of Units 5 and 6 have been declining.

3 Responses to “March 15 2011 Fukushima Diiachi (again)”

  1. CaptD Says:

    More No Information is available from The Japanese WHY?

    If it were any good news they would be having a news release…

  2. Bobby1 Says:

    “The important feature of this accident was that the source position was evidently clear, however, time and vertical emission variations were unknown (in this case, it was known that the height of emission was not so high in altitude).”

    Wrong. Radiosondes released from Fukushima University showed beta radiation levels off the chart at jet stream levels (30,000 feet or 10 km):

    http://optimalprediction.com/wp/radioactivity-in-the-jet-stream/

    Every one of these atmospheric simulations that do not include high-altitude measurements of radiation is invalid.

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