Japan Earthquake: nuclear plants

etudiant

In that context, is there anything material that TEPCO is not doing that experts on this blog feel they need to do?

Surprisingly, the site is still very thinly staffed, about 500 people versus a normal complement of 4- 5000 reported in the Mainichi Daily News here:
http://mdn.mainichi.jp/mdnnews/news/...na014000c.html

If the site does indeed have only a skeleton staff, it surely indicates that no dramatic initiatives should be anticipated. So the facilities are expected to ride out the cyclone season largely as they are. There are not enough people to do much to help.

AntonL

On the last page of this Japanese document the route to transfer the highly radio active water is shown.

This route is through the turbine halls 3 and 4 and the pipes are flexible plastic pipes with metallic spiral for support.

How does plastic hold up to high radiation? will it go brittle or loose strength?

Is it wise to route highly radioactive water through what is possibly a fairly uncontaminated area, in case a leak springs. There seems to be concern regarding the couplings as they tied down and double wrapped as added precaution.

robinson

Can't verify any of this yet, but if true, quite interesting.

Japan admits daily radioactive release from Fukushima many times higher than previously announced — Nuclear commission blames calculation error

http://enenews.com/daily-radioactive...eased-everyday
http://ex-skf.blogspot.com/2011/04/f...plant-154.html

etudiant

The discussion on the scale of the emissions is somewhat moot, imo, because the reality of radiation cannot be hidden.
Japan is beginning to have summer weather, with inland winds and frequent rains. If the site continues large scale emissions, the Japanese authorities will need to further expand the evacuation zone.

dh87

I agree with this. TEPCO says that so far the released radioactivity is around 10,000,000 Curies (http://www.tepco.co.jp/en/nu/fukushi...p-gaiyou_e.pdf). As I calculated a couple pages back, this 900 mSv/hr object is a few Curies. It would be stunning if there weren't things this hot. It's not an indication that the fuel has escaped.

com.oligarchy

DH87
What difference does it make
its the same effect to living things
on this planet

rowmag

According to Yomiuri, it was not remote-controlled equipment, it was manned equipment that was used:

http://www.yomiuri.co.jp/feature/201...OYT1T00654.htm

It was discovered on the 20th, and put into the container on the 21st.

As for the source, it is thought to be related to the hydrogen explosion of Unit 3.

Jorge Stolfi

I created a rough model of Fukushima Daiichi Unit #1 using the free raytracing program POV-Ray.

http://www.ic.unicamp.br/~stolfi/EXP...vray/Main.html

Unit #1 was the only one for which I had some reliable blueprints. If I had blueprints of the other units, I could consider doing them too...

Enjoy.

NUCENG

At present workers are trying to cool and stabilize reactors and fuel pools.

They are exploring buildings with robots to gather information about damage.

They are clearing debris from the site that interferes with areas they will use to restore power and find out what systems may still be operable.

They are allowing time to reduce dose rates.

They are limiting the number of people on site to reduce the number of people getting emergency doses to a minimum.

They are testing remote control equipment and some methods like spraying a type of sealent to keep down dust and airborne doses.

They have issued a roadmap for future actions.

They have a lot of foreign "help" to consider.

If they were providing more information, forums such as this one might be able to provide a form of validation and technical review of that information.

Other than that I can't think of anything else they should be doing. You raise the question of cyclones. In Japan the word is taifun or typhoon. That is a legitimate concern. Torrential rain and winds could further damage the buildings and further disperse radioactivity to the environment. But until they have a better understanding of damage, it could be counterproductive to start bracing or repairing buidings. Getting debris cleared up will reduce potential missile damage.

Your question is a good one. What else should they be doing?

MiceAndMen

Pretty good, Jorge, although I would dispute that fig_un1_pools_and_walls.png shows the correct layout of the pools. There has been no confirmation that the smallest pool in the picture actually exists separately from the SFP in any of the reactor buildings.

I was going to do a large-scale plant layout in 3D until I saw someone beat me to it.
http://www.turbosquid.com/3d-models/...kushima/594020
I downloaded some of the jpegs from that page and saw many inaccuracies. The overall work is good, but not precise enough for my liking. The guy even duplicated the paint scheme on the side of the buildings! For that price, I would expect near perfection, and even if everything was perfect I don't think I would pay $299 for the model

rowmag

Don't know if these have been mentioned:

"The government is considering building an underground barrier near the Fukushima No. 1 nuclear power plant to prevent radioactive material from spreading far from the plant via soil and groundwater, a senior government official said."

Reactor 1 already half-entombed with water:
"At a press conference held Friday, TEPCO said it believed pressure suppression pools at the bottom of the No. 1 reactor's containment vessel were full of water, and that the top section of the containment vessel was about half full. Under normal circumstances, the pressure suppression pools are about 50 percent full with water."

http://www.yomiuri.co.jp/dy/national/20110423dy01.htm

TCups

10,000,000 Curies?! Really? The equivalent radioactivity of ten thousand kilograms of radium?! Ten metric tonnes?!

What sort of things accumulate in precipitators? Co 60? Can someone tell us more about "radwaste buildings" please? Does contamination from the radwaste building fit with these early measurements? (see attached)

http://i306.photobucket.com/albums/n...s/4000d390.png

Borek

As I explained earlier, feel free to discuss other matters in different threads, you can start them either in Nuclear Engineering or Politics & World Affairs subforums.

It is not about censorship, it is about keeping some order in the discussion. Putting everything into one thread means mess.

dh87

Well, yes. TEPCO says 3.7e+17 Bq, and there's 3.7e+10 Bq/Ci. Radium 226, on which the unit is based, has a 1600-year half-life, resulting in that large mass that you quote (since becquerels and curies are both units of decays per unit time). If you calculate for I-131, you'll get a much smaller mass.

The number that TEPCO announced doesn't appear to include the radioactivity that's in the 70,000,000 liters of water sloshing around the reactors, nor the 100,000 Curies (4,700 TBq) that has already been released into the Pacific Ocean.

tyroman

From Cainnech's post #4653:
http://www.physicsforums.com/showpos...postcount=4653

"TEPCO suspects that the water leaked from the RPV is leaking through the cracks in the wall that separates the Reactor 3 turbine building and the Reactor 4 turbine building."

Could the features I have noted in the photos below possibly be evidence of the size of the "cracks" between the two turbine buildings? Does anyone know where these central control rooms are located?

From:
http://cryptome.org/eyeball/daiichi-...hi-photos3.htm
See: pic41.jpg [EDIT: sixth photo from top]
Caption of above:
"In this photo released by Tokyo Electric Power Co., the central control room of Unit 3 is pictured after lights went on while that of Unit 4, left side, is still dark at the Fukushima Dai-ichi nuclear power plant in Okumamachi, northern Japan Tuesday, March 22, 2011. (Tokyo Electric Power Co. via Kyodo News)"

If my annotations on pict41[zoom].JPG are correct, there has been a significant dislocation caused by the quake.

.

Attached Thumbnails

   

PietKuip

I do not know what fragments of demineralizers might look like, but I would be surprised if it could be described as pieces of concrete.

This is not something that would be lying about. If it is a normal part of the plant, it would be shielded by a lot of concrete, steel, or lead.

It might also be something that radioactive cesium or iodine vapors had sublimated on, or that a radioactive liquid had evaporated from, after the earthquake before the explosion.

So there are several possibilties. Maybe they did find out what it was - they moved it a day after it had been found.

|Fred

If I understood the couple of paper I read, right (UNSCEAR). Sources, Effects, and Risks Of Ionizing Radiation, BEIR, ircrp, EPA 402-R-93-084, and envhper00536-0363.
Basicaly we have a measured risk factor from one shoot ionization >0.1 Sv <1Sv between 0.11 et 0.06 % for adults. When it comes to over time rather that one shoot either we arbitrary reset the counter every year or we apply a damping factor and the risk factor is dropped to 0.05 to 0.02. (doing so we diverge already from the LNT)

But this is still for >0.1 Sv <1Sv dose , as for extra the 1mSv/year we don't know as we rather have data suggesting it wont make a difference.