We found out what happened about the explosion of Fukushima Daiichi nuclear power plant Unit 1

Chief cabinet secretary,The explosion of Fukushima Daiichi nuclear power plant Unit 1, Although the outer wall portion of the nuclear facility was blown out by a hydrogen explosion, it was announced that the containment vessel of the nuclear reactor is safe.

Details are as below.
2011/03/12 20: 42
Chief Cabinet Secretary will meet.

"Nuclear power facilities are covered with steel containment containers, and the outside is covered with concrete and rebar buildings, this building is an explosion and the contents are not explosive.

The reason for the explosion was that the steam generated by the lack of water in the core entered the gap with the building, became hydrogen in the process, exploded together with oxygen.

Since there is no oxygen in the containment vessel, explosion does not occur even if it is combined with hydrogen.

TEPCO received reports that containment containers are not affected.

Therefore, radioactive substances do not leak out in large quantities.

The monitoring of radioactivity was also confirmed, but the concentration did not rise compared to before the explosion.

For the numerical value of 1015 microSievert at 15:29, there was an explosion at 15:36 after that, the numerical value at 15:40 was 860 microsievert, at 58 minutes it was 70.5 microsie It has become a belt, rather it is getting less.

Other points have also said that since the early days of the day, water vapor in the container called "vent" is brought out to suppress the pressure from rising around 14 o'clock, but this was done around 15 o'clock, Although it has been raised once before and after the vent, it has declined even after the explosion at 15:36, staying at a low level.

Therefore, it is recognized that there is no big change in the way out of the radioactive substances to the outside from the time of the explosion at the present time, so I would like you to be calm.

Based on these circumstances / current situation, in order to prevent the damage caused by breakage of containment containers of concern in the future, we decided to take measures to fill the container with sea water and instructed it at the Minister.

In that case, we also confirmed that it is devised so that event such as re-criticality will not occur as a precaution by using boric acid together.

The government confirms that such preparations and procedures are appropriate and evaluates it as valid.

We have already started this procedure at 20:20.

With regard to evacuation instructions, we expanded to have them evacuate from the 20 km range as a way to deal with them in the stages when directions and contours such as the situation of such explosions and countermeasures to be taken by them were visible.

As in previous countermeasures policy, there is no specific risk to the residents between 10 kilometers and 20 kilometers, but we decided to expand to 20 kilometers from the point of view to make sure more thoroughly, just in case.

Because the residents are accompanied by these circumstances and circumstances, we want you to respond calmly according to the instructions of the police and municipalities. "

"There is a nuclear reactor in the containment vessel, there is no damage to the containment vessel"

"The one who is better than the building is safe, I judged the countermeasure to fill the container with seawater"

2011/03/12 21: 01
"It is not an explosion of containment vessel" NHK News

Chief Cabinet Secretary Edano mentioned at the press conference that there was some kind of explosion at TEPCO · Fukushima Daiichi Nuclear Power Station in Fukushima Prefecture, "The nuclear facilities are covered with steel storage containers, It is covered with a building of reinforcing bars and it is confirmed that the explosion of this time is that the wall of the building collapsed and that the containment container was not exploded, "the explosion of the containment vessel It was made clear that it was not.

East Japan Great Earthquake: Minato Minano, Explosion "No Damage to the Reactor" - Everyday jp (Mainichi Shimbun)

Prime Minister Naoto Kan and Chief Cabinet Secretary Yukio Edano were holding a press conference on the evening of December 12 on the Great East Japan Earthquake that caused serious damage. For the explosion accident at Fukushima Daiichi Nuclear Power Plant, Minami Edano stated, "The explosion is the explosion of the wall of the building, it is not a containment vessel inside, it does not leak large amounts of radioactive material, the concentration of radioactive material rises The cause was that water in the core was exhausted, water vapor went out to the space with the building, hydrogen and oxygen exploded and exploded, I confirmed that the containment vessel was not damaged. "

It is not an explosion of the containment containers ... Chief Cabinet Secretary: Society: YOMIURI ONLINE (Yomiuri Shimbun)

On Friday night, Chief Cabinet Secretary Chief Edoko told a press conference at the prime minister's official residence and said about the explosion that occurred at Unit 1 of Fukushima Daiichi nuclear power plant, "Although the containment vessel of the nuclear reactor was not exploded, hydrogen got up together with oxygen outside the containment vessel He said. An explosion says the building's outer wall has broken.

2011/03/12 21: 08
I can understand exterior walls blown away by hydrogen explosion this time by looking at the figure below.

2011/03/12 21: 13
Asahi.com (Asahi Shimbun): Start seawater injection at Fukushima Daiichi nuclear power plant Unit 1 Pressure vessel cooling - Society

TEPCO began work to put sea water inside the container to cool the pressure vessel of Fukushima Daiichi Nuclear Power Station Unit 1 at 8:20 pm on 12th. When seawater is put in, it will be difficult to restore the facility, but the possibility of core melting can not be denied, so we decided to give priority to safety. Akira Komori, managing director of the same day, said at a news conference on the evening, "I am deeply concerned that the power is not enough and I thought about such means (damage to the nuclear reactor)," he said.

2011/03/12 21: 16
Nikkei's "Structure of Fukushima nuclear power plant (boiling water type) and mechanism of core meltingThe figure of

2011/03/12 21: 23
Asahi.com (Asahi Shimbun): Prime Minister Kan 's remark after visiting the disaster area "All rescued with maximum power" - Politics

2011/03/12 21: 24
Seawater injection by containment vessel safety measures NHK News

According to Chief Cabinet Secretary Edano, TEPCO has decided to fill the container with sea water in order to prevent the reactor vessel and containment vessel from being broken. At that time, we are planning to add boric acid that absorbs neutrons so that nuclear fuel does not become critical again. According to Tokyo Electric Power Company, according to Tokyo Electric Power Company, Nuclear Power Safety and NISA confirmed this procedure, including preparations, and evaluated it as reasonable. According to the TEPCO, he started work such as putting seawater in a container at 8:20 pm It is that.

2011/03/12 21: 30
Explain the explosion of Chief Cabinet Secretary No. 1 NHK News

And the explosion revealed that it was not an accident that the radioactive substance leaked out to the outside in large quantities. In addition, Secretary Edano explained that TEPCO began work to put seawater in a storage container from 8:20 pm to cool down the nuclear reactor of Unit 1. Finally, to mention about expanding the range of evacuation around the Fukushima Daiichi nuclear plant from 10 kilometers to 20 kilometers, "Although we did not cause any specific dangers, we took measures for completeness. I want you to correspond calmly. "

2011/03/12 21:38
Asahi.com (Asahi Shimbun): Start seawater injection at Unit 1 of Fukushima Daiichi nuclear plant to cool storage containers - Society

Akira Komori, executive director of TEPCO, said at a press conference on the evening of 12th, "With regard to the first nuclear power plant, we can not grasp the state of the nuclear reactor at the moment, but the possibility of releasing (radioactive material) per hour is high and it is a tough situation."

The National Institute of Radiological Sciences and TEPCO confirmed cesium and iodine, which are fission products contained in the fuel, within the plant site. Both are substances that can be created after uranium has undergone nuclear fission.

For these reasons, both NISA and TEPCO assume that the possibility of core melting is high. It is the worst situation in the assumed nuclear accident. As this progresses, it may cause explosive reactions and spread the radiation to the outside widely.

2011/03/12 21: 43
Fukushima nuclear power "I resembled Chernobyl" remark: International: YOMIURI ONLINE (Yomiuri Shimbun)

UK BBC broadcast said, "Japan's first nuclear emergency situation that boasts high-level nuclear technology." He introduced a remark by the expert who says the news video on the occasion of the former Soviet Union's Chernobyl nuclear accident (1986) and the US Three Mile Nuclear Power Plant Accident (1979), which is similar to the situation of the Chernobyl accident.

Asahi.com (Asahi Shimbun): expansion of evacuation range, target residents to tens of thousands people Fukushima Daiichi Nuclear Power - Society

Following the explosion of the Fukushima Daiichi Nuclear Power Station, the target of evacuation orders of the country was expanded to within 20 kilometers on the evening of 12th. The number of municipalities that need evacuation increased to 2 cities, 5 towns and 2 villages, the target residents reached more than ten thousand people, and staff of each government office were forced to deal with it.

According to the Tokyo Fire and Disaster Management Agency, 28 eight hyper rescue teams specialized in radiation measures, etc. who left Tokyo in the afternoon at 3 p.m. on the same day and headed for the first nuclear power plant began to turn back at 6 pm. It is said that because of the explosion, the task of cooling the reactor was changed, and the situation became dangerous.

2011/03/12 22: 01
Asahi.com (Asahi Shimbun): Fukushima Daiichi nuclear power plant Unit 1 explosion, three persons exposed prefecture Presentation - Society

On Friday, Fukushima Prefecture announced that three people waiting on the roof of a nearby hospital were exposed to this explosion (hibakusha).

2011/03/12 22: 05
Three of the 90 people waiting at a high school near 3 kilometers were examined and found to have been exposed.

2011/03/12 22: 13
Residents around Fukushima Daiichi Nuclear Power Plant, at least three people exposed to radiation: Prefecture Nihon Keizai Shimbun

At 9 p.m. on 12th, Fukushima prefecture, at least 3 out of 90 general residents who had been transported from Futaba area located by Fukushima Daiichi Nuclear Power Station to Futaba Welfare Hospital, were exposed to severe exposure requiring decontamination treatment He announced that he was a patient. There is a possibility of radiation exposure for the remaining residents, and inspection is necessary.

2011/03/12 22:23
According to FNN, there are a maximum of 190 people exposed to radiation.

2011/03/12 22: 30
Wind direction prediction by FNN. This is tomorrow. In the unlikely event that radiation leaks, it is predicted that it will not come into the metropolitan area.

2011/03/12 22: 34
On the influence of radioactivity on the human body.

2011/03/12 23: 01
Reactor cooling started by seawater injection TEPCO, Unit 1 waste furnace also viewed: Nihon Keizai Shimbun

Because it becomes easy to rust with seawater injection, we have taken safety measures in view of the waste furnace as well. Detects cesium and iodine from the nuclear fission due to nuclear fission of fuel. It became the worst nuclear accident on the history of Japan's nuclear power in nearly half a century.

2011/03/12 23:14
Three patients exposed to Fukushima Futaba Town NHK News

In Fukushima Prefecture, a hospital in Futaba Town, about 3 kilometers north of Fukushima Daiichi Nuclear Power Station, we extracted three patients out of 90 patients and staffs and found that all 3 people were exposed Did. Fukushima prefecture says, "Although the exposure of these three people is a level that requires decontamination to wash down radioactive materials, there are no abnormalities in the physical condition of the three people." According to Fukushima prefecture, three patients are extracted among 90 bed-bed patients and staff at Futaba Welfare Hospital located in Futaba Town located in the range of evacuation instructions within 10 km radius from Fukushima Daiichi Nuclear Power Station I examined the exposure. As a result, all three patients were exposed, and three people were at a level requiring "decontamination" to wash radioactive substances, but Fukushima prefecture says "There is no abnormality in the three people's physical condition." According to Fukushima Prefecture, 90 people who were in the hospital were waiting to be carried by the helicopter of the SDF at the high school ground when an explosion occurred at Unit 1 of Fukushima Daiichi Nuclear Power Station at around 3:30 pm on December 12 about it.

2011/03/12 23: 15
Cooling in sea water Ending at around 1 AM NHK News

At the TEPCO Fukushima Daiichi Nuclear Power Station in Fukushima Prefecture, where explosion seems to have occurred, the Self Defense Force uses a pump car or the like to fill the vessel with seawater and cool it in order to prevent the reactor vessel and containment vessel from being destroyed I am working. According to the Ministry of Defense, this work will start at 8:00 pm and is expected to end around 1 a.m. on 13 th.

2011/03/12 23: 23
Asahi.com (Asahi Shimbun): explosion of reactor building, exposed fuel rods react with water vapor - Science

Direct contact with high temperature steam produces hydrogen. This reaction can be predicted when the water level goes down, and it seems to be asked whether TEPCO had taken measures to remove hydrogen.

2011/03/12 23: 27
Asahi.com (Asahi Shimbun): Tension national tension IAEA to 'explosion sound', ready to respond - international

The International Atomic Energy Agency (IAEA, headquarters Vienna) had received reports from the Japanese government on the situation of the Fukushima Daiichi nuclear power plant, "It is highly probable that fuel melting is advanced" by 12th. The explosion on the 12th was also reported from the Japanese side, but it says "details are not available".
On 11th the day the earthquake occurred, the IAEA announced that "Japan is ready to provide any technical assistance if requested." Amno Yuniya (Yukiya) secretary general is gathering information and analyzing the information, and if there is a request from the Japanese side, it is preparing to instantly respond by dispatching experts etc.
However, in the current situation where the situation changes every moment, "the fact that IAEA can do as well is limited" (relationship source). While watching Japan's response, he said he is devoting her full efforts to share information gained from the Japanese side with member countries.

A spokesperson for Russian state-run nuclear company Losuatom said, "(This explosion is fundamentally different from the Chernobyl accident, and the risk is far less."

2011/03/13 00: 03
【East Japan great earthquake】 "Three people exposed" and pollution of radioactive materials in Fukushima prefecture clothing - MSN Sankei News

East Japan great earthquake: Three people evacuated from near the Fukushima Daiichi nuclear plant - Everyday jp (Mainichi Shimbun)

2011/03/13 01:35
An interview by Nuclear and Industrial Safety Agency was held. "The sea water injection work that began at 20:20 is still ongoing and seawater is being injected." The medical team said, "When an explosion and smoke evolved around Unit 1, four people were injured outside the controlled area near the turbine building, we are still receiving reports that medical treatment is in progress."

At the Fukushima Daiichi nuclear power plant Unit 1 that the building exploded, the current reactor pressure is 3.75 kg / cm 2 = 0.375 MPa (that is, about 4 atmospheres). The water level of the nuclear reactor is one downscale (the state is shaken down to the bottom of the memory), and the other 1750 mm from the top of the fuel (the fuel rod is exposed 1 m75 cm from the cooling water).

2011/03/13/02: 06
Cool down at Fukushima Daiichi nuclear power plant Unit 1 seawater NHK News

At the Fukushima Daiichi Nuclear Power Station, in order to prevent nuclear reactors and containment vessels from being damaged, the Self Defense Force used a pump car or the like to fill the containment with sea water and work to cool it. The work is that boric acid which absorbs neutrons was added to prevent nuclear fuel from reacting again.

· Continued
The explosion accident occurred at Fukushima Daiichi Nuclear Power Plant is over the International Atomic Energy Evaluation Scale "Level 4"

in Note, Posted by darkhorse