"There were two 8-square holes on the northwest side at Unit 4", Nuclear Safety and NISA Q & A session Summary

From 16 o'clock to 18:30Nuclear and Industrial Safety AgencyAnd a question and answer session was held.

Among them, about the explosion sound occurred today at 6:14 PM, the report from Tokyo Electric Power Company reported "Explosive noise from the Unit 4, so we confirmed that there were two 8 m square holes on the northwest wall at two places" It became clear that it was something like that, and it is highlighting the situation where accurate information does not appear promptly.

The contents of the interview are as follows. It does not cover all the question and answer, but on television it is not understood what kind of question is being done in the part being cut.
NISA:
Hydrogen explosion occurred in Units 1 and 3, but it may be difficult for hydrogen to accumulate in Unit 2 because the blowout panel is open. Chief Cabinet Secretary Hiroyuki Edano has asked about the figures announced at the press conference (the case of observing 400 mSv) that it was measured at the lower part of the building. Monitoring posts are 900 to 1000 m away from the furnace even if they are near the site, so the announcement and the figures are different.

Question from reporters (Q, below):
How long is the fuel rod immersed in water at Unit 4?

Answer by NISA (A):
Radiation dose is high and it can not be confirmed.

Q:
How did you confirm the fire of Unit 4? Did it really fire?

A:
Visual inspection of appearance from fire occurrence and extinguishment. At least now there is no smoke.

Q:
While troubled, trouble occurred in Units 1, 2 and 3, how did you monitor the Unit 4?

A:
Regarding the monitoring posture, we checked the temperature of the water.

Q:
Why is there no data (water temperature of Unit 4 spent fuel pool) after 14th? How did you monitor it?

A:
Confirm about it.

Q:
What is the pressure of Unit 2?

A:
The pressure of Unit 2 is going up and down, but basically I think that it is being cooled by the fact that water is pushed by the pump.

Q:
I heard that pressure control was difficult and I could not inject it last night. Even now it is difficult to control because the pressure is high as you look at the materials. I think, are you doing well now?

A:
I think that it is done, but I think that it is necessary to keep an eye on future.

Q:
Is there any abnormality other than pressure? Is the valve closed or not?

A:
It is not at 1 o'clock in the afternoon.

Q:
What kind of means can be considered for water injection into Unit 4?

A:
It is said that we are currently examining how to put in concrete water. Is the wall hole of Unit 4 a storage container? There was a question that it is a building.

Q:
If enough things happened to make a hole open. Do you think that damaging the outer wall might damage the spent fuel pool?

A:
At the moment it has not been confirmed whether there was some influence on the pool

Q:
What about the dangers of re-criticality?

A:
Since spent fuel is placed in a rack and managed at a distance, it is considered that there is no danger of re-criticality. Even if there is no water, it will not have any problem as long as it is in the rack. Rather, it is generally easier to reclose if there is water. Whether or not there is water in the pool, although there is no water temperature data, there is information that the operator confirmed the information that there is pool water on site. Today 's 13 o'clock (Correction later, confirmation at 4 o'clock March 14th is the last).

Q:
Is there enough water to fill the fuel?

A:
It is the same as the situation patrolled from before.

Q:
Although it will generate fever without water, it was said that there were plenty of water after the patrol. Is it not the cause of the fire of Unit 4 spent fuel?

A:
We do not grasp detailed information such as fire occurrence situation, but since we are checking at the time of patrol, we think that a certain degree of safety is secured. If there is something I have contact with NISA.

Q:
Can we think that hydrogen is not generated in Unit 4?

A:
I want to think so. At 13 o'clock today there is no such thing. Since the cause of the fire has not been investigated, we can not affirm at this place.

Q:
Why is this phenomenon prolonged so much?

A:
The accident this time was affected by the tsunami, many equipment can not be used. Especially power supply equipment, external power supply (power supply from transmission line), emergency power supply ...... The function of pumping up the seawater and cooling various things is stopped. It is necessary to restore the power supply of such functions. However, with regard to Fukushima Daiichi Nuclear Power Plant, many facilities have yet been damaged, and such a thing has not yet been recovered. We will continue to watch gazing at the cooling of the core

Q:
It is said that IAEA experts will respond to the accident.

A:
It is said that we are receiving an offer at the moment but we do not grasp it. If we can collect wisdom from all over the world at the joint headquarters, we think that is also natural. I am exploring the best path among them. There may be places dependent on overseas knowledge and equipment in the future, but I do not know exactly at the moment that "I am being helped with this kind of thing" now. Current situation, the situation inside is not understood, but the fuel is broken, but I do not know if it is melt down.

Q:
"400 thousand micro sievert (400 mSv)" that came out at 11 AM arrived from Unit 4? Since it has become this figure after the explosion of Unit 3 and since I heard that the original number before that was low,

A:
Perhaps the cause was that the explosion caused scattered substances.

Q:
It is a story about explosion sound at Units 2 and 4, but did both explosions occur?

A:
We recognize that it is only Unit 2. Unit 4 started from confirming smoke.

Q:
So why is the roof of Unit 4 damaged? Did it break by the explosion of Unit 2?

A:
Information came in after the explosion of Unit 2 and thought that it was time correction of Unit 2, but in fact it seems there was an explosion sound around 2 times, there was an explosion in Unit 2, even in Unit 4 It seems that there was. The explosion of Unit 2 was today at 6:10, and at 6: 14, the wall of Unit 4 was reported to be dented

Q:
Is the wall recessed? It is said that TEPCO's announcement is on the 5th floor roof?

A:
We are reported that the wall is dented from TEPCO, we do not know the roof.

Q:
At this time, we received a leave at seven o'clock in the morning, but I heard about Unit 2, but did not you tell us that there were various testimonies about Unit 4?

A:
In our mistransmission of information, I thought that it was a time correction of Unit 2 exploding without thinking about what was received at Unit 4.

Q:
Toden reported properly, but did NISA make mistakes in interpretation?

A:
That's it.

Q:
After all, is the pressure suppression room of Unit 2 broken? Is not it in the morning and has not changed?

A:
Since there is not much variation in plant parameters, the pressure of the suppression chamber remains low and there is no change in other data, so there is still no clear places.

Q:
I heard that the morning stage and the contents of the presentation have not changed

A:
That's right.

Q:
According to "TEPCO's report" there are many things, but NISA should have dispatched inspectors etc. to the site. What are those people doing? Are not you going to the scene?

A:
In the power station there are places where there are many TEPCO staff called the emergency response room, and there is a situation where it is managed mainly by the central control room there. In the Countermeasure Room, with the knowledge several days ago, four inspectors from NISA reside and check the activities there as regulatory authorities.

Q:
There is little information directly taken by NISA?

A:
I think that it is unavoidable that nuclear power will be operated directly by the business operator, and that beyond that, regulators will not be able to go to driving.

Q:
Yesterday was the explosion of Unit 3, the morning of today was Unit 2 Explosion and Unit 4 Building Fire, 400 mSv was observed at 10:22 today. Although this numerical value is not convinced that "Thinking in a time series and influence of Unit 3".

A:
Originally thought that way, but certainly when looking at time series events may have occurred next to (eg Unit 2), so it may not be possible to conclude. Considering that the numerical value was high next to Unit 3, I thought that Unit 3 was the cause.

Q:
Well then it's not a time series

A:
I agree with you.

Q:
The public worried about the influence of radiation because the containment vessel of Unit 2 has been damaged, but can also be considered the influence from Unit 2 even in cases where high numbers were detected in the village?

A:
It is a stage where there is a possibility, but it is difficult to specify whether it is Unit 3 or Unit 2.

Q:
If we consider the time of arrival at Tokai village, can we guess whether it is the day before or today?

A:
I think that you can identify it by calculating the wind direction etc, considering the approximate time to reach. Since Unit 2 is this morning, it seems that the possibility of reaching Tokai Village is low. To that extent the members have no knowledge.

Q:
Were not the manpower required for Unit 4's delay (such as fire) to be delayed?

A:
We have also made plans based on the fact that the temperature of the pool of Unit 4 is high, but we are concentrating on the most important things at that time, such as the difficulty of injecting water into the nuclear reactor, and as a result sufficiently early ( I think that water injection into the pool has not been done.

Q:
Did not the temperature be measured?

A:
As of the 14th, I keep it as 84 degrees Celsius, I know that this is considerably higher than usual.

Q:
Was it not enough to grasp what I was not in time, did not my hands turn different from the plan?

A:
Since there are developments of severe events, we have planned variously, but it is supposed to be impossible as a result.

Q:
Do you have the idea that people are not enough, that personnel should be increased? Why is that?

A:
We are looking forward to TEPCO for the procurement of materials and securing human resources as soon as possible. Actually the problem is that the pump does not work, and somehow it has taken measures, but both events have come to that sort of thing

Q:
Whether it is a problem of people or because engineers are missing from the beginning, how do you think as a regulatory agency?

A:
While checking the actions of TEPCO every day, I'd like to mention the need to prioritize and adopt an excellent method. In this time, the progress of the situation is fast and I am trying my best with all my efforts. Regarding the number of people, there are places where it is inevitable for the situation of the workplace and persons who can be hit, but we would like to consider whether we can not talk about it.

Q:
Rather than seeking TEPCO's staff recruitment as a regulatory authority, asking for dispatch to another electric power company, is there no plan to actively act as NISA?

A:
We also have a joint headquarters announced by Prime Minister, including that, so I think that they will be examined among them and give us the necessary instructions

Q:
Is there a shortage of transportation power or is there a missing technician? How do you grasp as authorities? If you know that, you can take measures?

A:
Currently, it is only necessary to bring such a person here, there is nothing immediately there is no need to take such measures. We will give directions as soon as possible.

Q:
How many times is it usually that pool temperature is high?

A:
I think that it is around 40 to 50 ° C.

Q:
At the interview by Secretary Edano it was that the temperature was high at Units 5 and 6, is there data?

A:
I will prepare it now because I do not have one. Although it is said that the water temperature tends to be high, we assume that Unit 4 is in the most severe situation. Unit 4 is undergoing construction of shroud replacement and puts all of the fuel in the core in the pool. Normally, the fuel put in the pool is 1/3 to 1/4, which is supposed to be relatively easy to raise the temperature. However, we do not have data until the other (Unit 5/6) has been on several occasions. Also, we have not confirmed (pools of) Units 1, 2 and 3.

Q:
Although it was said that Units 4 to 6 were under regular checkup, only No. 4 received the total fuel, Is No. 5 No. 6 only?

A:
→ Although we do not normally issue all the fuel, No. 4 was about to replace the facility called shroud, so we put out all of the fuel in the pool.

Q:
Although No. 5 No. 6 had left a part, No. 4 was left. Does that mean it was in a special condition? You should have known that TEPCO should be careful, do not you?

A:
Think like that. We are aware of the importance of temperature management, we are measuring until the 14th, today we have not been able to confirm the water surface etc today.

Q:
Is the water level confirmed once a day?

A:
I will confirm it.

Q:
Normally, the spent fuel pool is equipped with a monitor camera, right?

A:
Now I have no electricity ... ....

Q:
That means you do not understand. It is usually fresh water, what do you use to put in now?

A:
I am considering it including it now. I think there is (Seawater) as an option.

Q:
Does that mean that we do not go in a bad direction even if you put seawater in? Without inconvenience.

A:
I think that it can not take much heat because it can take heat as well as put it in the furnace (water injection).

Q:
It is good to think that it is OK because it is used.

A:
I think that there is an influence by salting into the used pool.

Q:
What kind of things did you hear about the report of Unit 4?

A:
About the contents reported by Tokyo Electric Power Company, we heard explosive sound from Unit 4 at 6: 14. When I went to check on the site, there were two falls of the 8 m square wall in the northwest of the building, there was a report that the hole was open.

Q:
There may be time misunderstanding with Unit 2, but this was supposed to have been at that time as it put paper in the interview. Why did not you explain the fall of the wall?

A:
As for this, it was explanation of Unit 2, so that thing about Unit 4 was missing. I'm sorry.

Q:
What part of the building is it?

A:
I heard that it is northwest.

Q:
Did you receive a report that smoke could be seen through the hole after the fire at 9:38?

A:
I received a report saying that smoke was coming out at 9:38 and that I realized that it was through a hole.

Q:
I heard that there was no smoke when looking at the hole

A:
In the fire of 9:38, smoke was visible through the hole.

Q:
Were there no fire or smoke at 6 o'clock?

A:
It is not confirmed at 6 o'clock.

Q:
Was the hole open, did the wall fall?

A:
"The hole was open".

Q:
Are there any updated information / reports a bit more?

A:
There was a report that there was a fire on the 3rd or 4th floor, not the fact that there was no information, and there was a report that the fire had disappeared at 11 o'clock.

Q:
I think that it is important, but that the hole in the building is open, that it can not be confirmed whether the pool is filled with water, is it acceptable to interpret that the spent nuclear fuel is exposed there?

A:
There is no neat information as to whether it is not in the water.

Q:
Is there a possibility of burning out to the outside?

A:
I do not know.

Q
What does it mean you do not understand? Does that mean that the possibility can not be denied?

A:
It means that there is no information.

Q:
Is there a lid in the pool?

A:
There is no cover in the pool

Q:
Why do you mean to assert whether 400 mSv can be asserted as Unit 3 explosion? The hole is open, there is fuel on bare?

A:
Expression is over, but expression is over ......

Q:
Originally, is it possible to touch the outside?

A:
You should not touch it ... but how is it? (I will be next to you)
Normally, there is a depth of about 10 m above the fuel, and it is considered that the poolside people are not exposed to radiation by water shielding.

Q:
How much radiation dose will be without water?

A:
I do not know.

Q:
Why did the wall blow? What is the reason for thinking? Is it a hydrogen explosion?
If the dose is high and it can not be measured without getting close to it, does it clearly indicate that the dose in it is high? If you are told that you do not understand it, it will only stimulate anxiety.

A:
It is as I mentioned before that there was damage on the wall, but I do not know what is clearly the cause

Q:
Does the northwest side face Unit 3?

A:
confirm.

Q:
About evaluation of INES?

A:
Now I am planning to think as evaluation 4, but first I think that it will be after confirming what kind of fuel state it has after calming down itself
The current situation proved to be a provisional assessment of 4, because it is a provisional evaluation at the stage when you do not know what kind of damage it is at the stage of evaluation. I am considering evaluating at the stage when the content of the situation is clearly understood by formal evaluation.

Q:
When did you decide to be 4?

A:
Saturday or Sunday, it is not certain. There is a good chance that the provisional evaluation will change at the stage when you know what kind of damage situation is going on in the future.