Thursday, May 19, 2011

#Fukushima I Nuke Plant: TEPCO Workers Entered Reactor 3

TEPCO announced that 2 TEPCO employees entered the reactor building of the Reactor 3 on May 18 in the evening. 4 TEPCO employees entered the Reactor 2 reactor building in the morning on May 18.

From Asahi Shinbun (in Japanese; 12:41PM JST 5/19/2011):

It was the first time that human workers entered the Reactor 3 reactor building since the accident started.

The radiation level was 160 to 170 millisieverts/hour at the maximum.

TEPCO is preparing for the nitrogen gas injection into the Containment Vessel of the Reactor 3 in order to prevent another hydrogen explosion. 2 TEPCO employees with radiation protection suits and oxygen tank entered the reactor building for 10 minutes, and inspected the pipes and valves to be used for the nitrogen injection and measured the radiation level. Near the valves, the radiation measured 50 millisieverts/hour.

10 minutes in 170 millisieverts/hour environment will result in 28 millisieverts radiation.

If I remember right, when TEPCO opened the double door of the reactor building of the Reactor 1 on May 8, the purpose was to reduce the amount of radioactive materials so that the workers' exposure is limited to less than 3 millisieverts. The radiation level didn't go down much at all, but the human workers entered the building anyway.

Now that they openly admit to the total core meltdown in all three reactors, the pretense seems to have gone at TEPCO. High radiation? So? They've got a job to do.


Anonymous said...

If you thought #3 was going to blow up again if you didn't pump in nitrogen, would you care that much about two workers getting 20-something mSv of prompt exposure?

Anonymous said...

How does one get a melted core to 'cool down', when it is an out of control fission reaction?

Their statements do not seem to make any sense, given the complete meltdown situation.

What happens if and when the blob of fission material melts all the way through the reactor and down onto the concrete inside the building, and then down into the ground?

These are the questions I would like answered, and I have not seen ONE thing mentioned about it.

Anonymous said...

To Anon @4:17 Please visit the PhysicsForum website and look for the thread on the Fukushima situation. There is a great deal of excellent information there, without any hyperbola or bias.

Anonymous said...

To Anon @ 5:21 If you take the time to read the Tepco provided materials you will find that they will be injecting nitrogen to the express purpose of avoiding another hydrogen blast. Where in my post do you see hyperbola or bias?

Ah, here, have a pre-digested version:

20 mSv is an utterly acceptable prompt dose in an emergency (it is about the upper limit for yearly exposure in normal conditions for a nuclear plant worker).

Don't like reality? Think it's scary? Do some drugs, chill out, tune out, drop out. Let adults discuss the troubles of the world.

Anonymous said...

I did not see any reports on the radiation levels inside Reactor building #2. Did TEPCO release that data? Wasn't mentioned by NHK or the English language news of Asahi or Mainichi Shimbun.

While Reactor Building #1 radiation levels were very high, the fact that the atmosphere inside building #2 was so 'steamy' robotic cameras were rendered useless might lead one to believe that it could be even worse but, again, I have not seen any data on that.

Once again I am very concerned for the workers who must enter these buildings. A 10 minute examination as done in building number 3, while useful, would not seem to be near sufficient to give a complete picture of the radiation hazards follow on workers will face. Even if no 'hot spots' are found just how TEPCO is going to be able to maintain its work force AND do the necessary work while keeping everyone below the radiation limits seems a dilemma to me.

doitujin said...

"The utility said the 2 workers were exposed to radiation of 2 to 3 millisieverts."

maybe they used those vests mentioned earlier?

("Tokyo Electric Power Company says 2 workers in protective suits and carrying air tanks went inside for about 10 minutes from 4:30 PM Wednesday to check radiation levels.")

and 20mSv in such a short time, well... it's still much... as every human life is a person beloved by some people, these working conditions cause so much worry and pain... "emergency" still does not change people into machines... I wish there were more remote-controlled robots with high ability there...
NHK says "for about 10 minutes"... let it be 15 min at 160 mSv, then it's already 40 mSv and that only added to the amounts of previous and following days... from what I've read so far, it seems, around 2 mSv a day is really common and they're even exposed when not at work, staying so nearby... and the eating places etc. are also polluted (i.e. ... it's not Chernobyl, so they should not repeat the same mistakes alleviated, but the current developments, i.e. the big internal exposure danger are just the same as back then.

Anonymous said...

The work force is two- or even three- tiered. You have jumpers at the bottom, people brought in literally of the streets, trained to perform one action (often, something as simple as "walk down that hall, take that bit of pipe, put it in the hamper and walk out again").

These are expendable, in the sense that they can be sent on missions where they get their allowable limit (250 mSv is where it stands today, may be upped to 500) in one go, if needed. They are employed through sub-sub-contractors, so the paper trail is tenuous at least. As we found out earlier in the crisis, they are also not provided with dosimeters. What the crew chief says is what gets done.

You then have junior management and specialists, mostly plant operators and maintenance personnel drafted into the role for their knowledge of specific systems or areas of operation. They are employed by sub-contractors, generally, but can also be company men. They head the work crews, set up equipment that is brought in, operate the robots and provide dosimetry on-site. They get into trouble occasionally, but it's generally from accident or inattention.

Then, you have senior management, salary men with a sprinkling of outside experts, also on site, who do the complex stuff - thinking, making plans, coordinating logistics and collating reports.

They rarely get exposed, but it happens, because sometimes information needs to be collected, a decision needs to be made and an action taken at the exact spot in space-time where something bad is happening.

So, some of these guys, usually fit old codgers who've seen it all and aren't afraid of death, invisible or otherwise, are kept on-hand for emergencies.

The system is good, it works. It keeps people reasonably safe, given the circumstances. The occasional error gets buried in a yellow barrel with the other rad-waste, sure, but then, it's an emergency. Omelette, eggs, all that.

It can fail only if through error or mischance dose rates on-site increase again. Then complex work becomes impossible and the options narrow to "bury it and hope for the best".

Oops said...

With not all workers even wearing dosimeters, I think the company can almost claim what it wants to in terms of radiation exposure? When the company makes claims to what the workers were actually exposed to, I would like to know if those are the company's fuzzy estimates, or if the radiation has actually been measured. I read an article not very long ago about internal radiation measurements not even being measured. I suspect that they don't want to know....

Nearly two months after the start of the crisis at the Fukushima No. 1 nuclear power plant, only 10 percent of workers there had been tested for internal radiation exposure caused by inhalation or ingestion of radioactive substances, due to a shortage of testing equipment available for them.

....The man, an employee of a company that works with TEPCO, installed power cables near a reactor building at the plant for a month beginning at the end of March.

The test is conducted by a device called a "whole-body counter."

While a normal internal radiation level would range from several hundred cpm to 1,000 cpm, he was told his level was 30,000 cpm.

Anonymous said...

Regarding my previous post regarding the PhysicsForum; My comment was directed at the Anonymous poster who said "These are the questions I would like answered, and I have not seen ONE thing mentioned about it." I mistakenly directed it toward 4:17, but it should have been Anon@5:00. Apologies for the mistake.

Anonymous said...

must see. NHK ETV special

whomeco said...

Youtube may be better

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