Thursday, August 4, 2011

#Fukushima I Nuke Plant: 2 Sieverts/Hr on Water Surface in the Reactor Bldg Basement??

That's what a worker at Fukushima I Nuclear Power Plant tweeted on August 4. He was expressing his concern for the radiation if the contaminated water in the basements of the reactor buildings becomes less, as TEPCO plans, because of the water treatment system.

TEPCO says that their plan to treat all the highly contaminated water at the plant is more or less intact; if not by the end of the year as planned, at least by the end of February next year.

This worker is worried that if that means lower or no water in the basement, the basement could become so radioactive; he thinks the melted fuel is in the basement. I don't know for sure which basement he is specifically referring to, but from his past tweets it could be Reactor 1 where he's been working to install the heat exchanger for the Spent Fuel Pool.

I have no way of verifying anything he says, but here are some of the things he tweeted:

Water shields radiation. If there's no water [in the basement], the highly radioactive materials will be exposed. The radiation level at the surface of the contaminated water in the basement of the reactor building is 2 sieverts/hour, and the half value layer of water is about 19 centimeters, and the water is 4 to 5 meters [400 to 500 centimeters] deep...

It could be an outrageous level of radiation... I don't think they can empty the basement... Personally I think the melted-through fuel dropped through the ICM [In Core Monitor?] pipe or RPV drain to the bottom of [or below?] the pedestal, but no way of knowing how much of the fuel is there unless you go there and look.

Well, if a worker at the plant like me worries about it, I'm sure TEPCO and the government have already thought about it and come up with the solution. But that's my concern.

I've seen a smaller number (14 centimeters) for the half value layer of water.

I don't remember that the surface radiation level of the basement water was ever released by TEPCO. If anyone is aware, please let me know with the link.

Reactor 1 is where the 4 sievert/hour steam was seen gushing through the floor of the reactor building in early June. So, if the radiation on the water surface is 2 sieverts/hour, that's an improvement, I guess.

In the so-called "hot spots" in Fukushima Prefecture and the rest of Tohoku and Kanto, we're still talking in "microsievert/hour". At Fukushima I Nuke Plant, the "hot spots" are now in "sievert/hour". Remember the good old days when anything exceeding 100 millisievert/hour was considered extremely high at the plant?

Just the "new normal" in Japan, and life goes on, apparently.

10 comments:

Anonymous said...

Possibly over 10 sv/hr in new zone:

http://www.asahi.com/english/TKY201108030268.html

Anonymous said...

"I don't remember that the surface radiation level of the basement water was ever released by TEPCO."

If you have reported on it here, I would have noted it. I have not seen any measures of the basement water, itself.

Does the worker say where the surface was measured, say compared to the 4Sievert steam hole?

Forgive my lack of knowledge, what is the half value layer?

Atomfritz said...

This worries me.

Earlier it was always suggested that the water's radioactivity would be caused by dissolved fission products.

In this case it would be sort of "shielding container", as the radioactivity contained in all this water would give a dose of 200 Sv/h from a distance of 10m, if collected into just one bucket. (Remember, the total weight of the radioactive stuff contained in all that water is only in the magnitude of around 50 pounds, if we can believe Tepco's press releases.)

However, if part of the radiation is caused by some nuclear fuel having been flushed into the basement, then this looks very different.
Unshielded, a fuel element that had 1 year to "cool off" radiates around 500 Sv/h in a distance of 1 m.

If such a "core flushing into basement" happened, then things will get really challenging.

So I find it very discomforting that there are apparently no pictures from the water and its bottom being published.
There could really be something to worry about.

netudiant said...

The water itself is so heavily charged with radioactive cesium that it is not clear that it is shielding anything.
There may be fuel loose in the basement and it surely will be a near impossibility to clean up the site, but it is not possible to entomb the site safely unless the contaminated water is removed. Eventually, the site will be filled in with sand, lead and boron, just as the Soviets did ay Chernobyl. Dismantling the site will then take place after a brief delay, no mere that 1000 years or so.

Anonymous said...

As I recall from the building diagram presented with the picture of the hole in the floor w/4S/hr steam, the hole was along the wall of the building.
The water surface was probably measured from the stairwell, also along a wall of the building.

Anonymous said...

Video of 4-Sievert/Hour Steam Gushing Out in Reactor 1 at #Fukushima
http://ex-skf.blogspot.com/2011/06/video-of-4-sieverthour-steam-gushing.html

They have measured the basement water before in building 1,
"Fukushima, May 30 (Jiji Press)–Tokyo Electric Power Co. said Monday that the amounts of radioactive materials in water at a reactor building of the Fukushima No. 1 nuclear power plant were about 10,000 times the normal levels for water inside a nuclear reactor.

The water, recently found in the basement of the No. 1 reactor building of the nuclear power plant, contained 30,000 becquerels of iodine-131 per cubic centimeter, 2.5 million becquerels of cesium-134 and 2.9 million becquerels of cesium-137."

http://jen.jiji.com/jc/eng?g=eco&k=2011053000813


diagram of steam hole location,

http://4.bp.blogspot.com/-pfOtTZkRGHw/TepQqOp3shI/AAAAAAAAAdw/pgaU8bw8sFM/s1600/DRreactor1.JPG

Note that stairs to basement are in opposite corner from the steam hole, AND that radiation levels on that floor are the lowest in the stairs' corner.


Fukushima I Nuke Plant Reactor 1: Packbot Detects 4 Sieverts/Hour Radiation
http://ex-skf.blogspot.com/2011/06/fukushima-i-nuke-plant-reactor-1.html


July 8, 2011
"Reactor 1's basement water .. doesn't even go to the water treatment system."
http://ex-skf.blogspot.com/2011/07/fukushima-i-nuke-plant-reactor-3-humans.html


"From Mainichi Shinbun English, quoting Kyodo News (5/26/2011):

TOKYO (Kyodo) --The pressure vessel housing nuclear fuel at the No. 1 reactor of the Fukushima No. 1 power plant or its accessory piping is likely to have been partially damaged immediately after the March 11 earthquake, possibly allowing steam to leak out to the containment vessel encasing it, according to data made public by its operator. ..
In a report submitted to the agency, TEPCO said that if a breach around 3 centimeters in diameter occurred at the No. 1 reactor's containment vessel 18 hours after the quake and it widened to about 7 cm 50 hours after the quake, it would account for changes in pressure readings inside the containment vessel."

http://ex-skf.blogspot.com/2011/05/fukushima-i-nuke-plant-reactor-1-rpv.html

TEPCO Discloses Details of #Fukushima I Reactor 2 Entry ..
"At one spot, the steam (highly radioactive) from the Spent Fuel Pool was condensing and falling like raindrops. But TEPCO says it will be easier to work in the Reactor 2 than in the Reactor 1, because the radiation is lower. 50 millisieverts/hour sure seems infinitely lower than 1,000 or 2,000 millisieverts/hour in the Reactor 1."


Fukushima I Nuke Plant: Radioactive Materials in Reactor 1's Trench
March 30, 2011
".. detected niobium, technetium, ruthenium, silver, tellurium, iodine, cesium, and lanthanum in the water collected at the trench of unit 1."


To re-post a comment from Rob,
"Robbie001 sez:

I was starting to wonder, I had issues with some of my comment disappearing and then slowly reappearing. Separately, I've also started running up against Captcha queries during certain Google searches involving nuclear issues right when you went quiet. The blip had me thinking maybe TEPCO had finally found the "Internet Off Switch". "

comment from the same thread,

"arevamirpal::laprimavera said...
@Tim, all I want to do is this: set up so that both my computers can log onto the net using ATT's high-speed DSL service."

AT&T is one of Bush's spy companies, I recall San Francisco was one of the sites where the splitter was found routing to NSA.

http://ex-skf.blogspot.com/2011/05/fukushima-i-nuke-plant-reactor-1-rpv.html


"Cesium is quite mobile, it gets dissolved in water, goes up as fog, back down in rain etc."
http://ex-skf.blogspot.com/2011/05/tepco-discloses-details-of-fukushima-i.html

Just when I was starting to think it may be getting a little less risky for food supplies in U.S.

Anonymous said...

Video of 4-Sievert/Hour Steam Gushing Out in Reactor 1 at Fukushima
http://ex-skf.blogspot.com/2011/06/video-of-4-sieverthour-steam-gushing.html

They have measured the basement water before in building 1,
"Fukushima, May 30 (Jiji Press)–Tokyo Electric Power Co. said Monday that the amounts of radioactive materials in water at a reactor building of the Fukushima No. 1 nuclear power plant were about 10,000 times the normal levels for water inside a nuclear reactor.
The water, recently found in the basement of the No. 1 reactor building of the nuclear power plant, contained 30,000 becquerels of iodine-131 per cubic centimeter, 2.5 million becquerels of cesium-134 and 2.9 million becquerels of cesium-137."
http://jen.jiji.com/jc/eng?g=eco&k=2011053000813

diagram of steam hole location,
http://4.bp.blogspot.com/-pfOtTZkRGHw/TepQqOp3shI/AAAAAAAAAdw/pgaU8bw8sFM/s1600/DRreactor1.JPG

Note that stairs to basement are in opposite corner from the steam hole, AND that radiation levels on that floor are the lowest in the stairs' corner.

Fukushima I Nuke Plant Reactor 1: Packbot Detects 4 Sieverts/Hour Radiation
http://ex-skf.blogspot.com/2011/06/fukushima-i-nuke-plant-reactor-1.html

July 8, 2011
"Reactor 1's basement water .. doesn't even go to the water treatment system."
http://ex-skf.blogspot.com/2011/07/fukushima-i-nuke-plant-reactor-3-humans.html

"From Mainichi Shinbun English, quoting Kyodo News (5/26/2011):
TOKYO (Kyodo) --The pressure vessel housing nuclear fuel at the No. 1 reactor of the Fukushima No. 1 power plant or its accessory piping is likely to have been partially damaged immediately after the March 11 earthquake, possibly allowing steam to leak out to the containment vessel encasing it, according to data made public by its operator. ..
In a report submitted to the agency, TEPCO said that if a breach around 3 centimeters in diameter occurred at the No. 1 reactor's containment vessel 18 hours after the quake and it widened to about 7 cm 50 hours after the quake, it would account for changes in pressure readings inside the containment vessel."
http://ex-skf.blogspot.com/2011/05/fukushima-i-nuke-plant-reactor-1-rpv.html

TEPCO Discloses Details of Fukushima I Reactor 2 Entry ..
"At one spot, the steam (highly radioactive) from the Spent Fuel Pool was condensing and falling like raindrops. But TEPCO says it will be easier to work in the Reactor 2 than in the Reactor 1, because the radiation is lower. 50 millisieverts/hour sure seems infinitely lower than 1,000 or 2,000 millisieverts/hour in the Reactor 1."


Fukushima I Nuke Plant: Radioactive Materials in Reactor 1's Trench
March 30, 2011
".. detected niobium, technetium, ruthenium, silver, tellurium, iodine, cesium, and lanthanum in the water collected at the trench of unit 1."


To re-post a comment from Rob,
"Robbie001 sez:
I was starting to wonder, I had issues with some of my comment disappearing and then slowly reappearing. Separately, I've also started running up against Captcha queries during certain Google searches involving nuclear issues right when you went quiet. The blip had me thinking maybe TEPCO had finally found the "Internet Off Switch". "

comment from the same thread,

"arevamirpal::laprimavera said...
@Tim, all I want to do is this: set up so that both my computers can log onto the net using ATT's high-speed DSL service."
AT&T is one of Bush's spy companies, I recall San Francisco was one of the sites where the splitter was found routing to NSA.
http://ex-skf.blogspot.com/2011/05/fukushima-i-nuke-plant-reactor-1-rpv.html

"Cesium is quite mobile, it gets dissolved in water, goes up as fog, back down in rain etc."
http://ex-skf.blogspot.com/2011/05/tepco-discloses-details-of-fukushima-i.html

Just when I was starting to think it may be getting a little less risky for food supplies in U.S.

Anonymous said...

".. the half value layer of [clean] water is about 19 centimeters, and the water is .. [400 to 500 centimeters] deep .."

oops

"The water itself is so heavily charged with radioactive cesium that it is not clear that it is shielding anything."

Fukushima I Nuke Plant: Radioactive Materials in Reactor 1's Trench
March 30, 2011
".. detected niobium, technetium, ruthenium, silver, tellurium, iodine, cesium, and lanthanum in the water collected at the trench of unit 1."
Still detecting all of the above? They won't say.

July 8, 2011
"Reactor 1's basement water .. doesn't even go to the water treatment system."
http://ex-skf.blogspot.com/2011/07/fukushima-i-nuke-plant-reactor-3-humans.html

Video of 4-Sievert/Hour Steam Gushing Out in Reactor 1 at Fukushima
http://ex-skf.blogspot.com/2011/06/video-of-4-sieverthour-steam-gushing.html
That's a steady steaming from a considerable heat source if under 4-5 meters of water.

They have measured the basement water before in building 1,
"Fukushima, May 30 (Jiji Press)–Tokyo Electric Power Co. said Monday that the amounts of radioactive materials in water at a reactor building of the Fukushima No. 1 nuclear power plant were about 10,000 times the normal levels for water inside a nuclear reactor.
The water, recently found in the basement of the No. 1 reactor building of the nuclear power plant, contained 30,000 becquerels of iodine-131 per cubic centimeter, 2.5 million becquerels of cesium-134 and 2.9 million becquerels of cesium-137."
http://jen.jiji.com/jc/eng?g=eco&k=2011053000813

diagram of steam hole location,
http://4.bp.blogspot.com/-pfOtTZkRGHw/TepQqOp3shI/AAAAAAAAAdw/pgaU8bw8sFM/s1600/DRreactor1.JPG

Note that stairs to basement are in opposite corner from the steam hole, AND that radiation levels on that floor are the lowest in the stairs' corner.

Meltdown isotopes in trench water on March 30.
How many tons of water pushed thru this building since March?
Don't/won't disclose or measure steam components.
Thirsty requirements for not shielding something.

It's like some kind of Frankenstein project where the mad doctor fiddles with the control knobs to your resolution device? F*#k that.

Anonymous said...

TOKYO, July 26 (Reuters) - Japan's Fukushima Daiichi nuclear plant ranked as one of the most dangerous in the world for radiation exposure years before it was destroyed by the meltdowns and explosions that followed the March 11 earthquake. For five years to 2008, the Fukushima plant was rated the most hazardous nuclear facility in Japan for worker exposure to radiation and one of the five worst nuclear plants in the world on that basis. The next rankings, compiled as a three-year average, are due this year.

http://www.reuters.com/article/2011/07/26/idUSL3E7IE3Z920110726

Anonymous said...

Robbie001 sez:

@ Anon 12:53

"what is the half value layer?"

Half value layer defines the radiation attenuation factor of various materials. It denotes the amount of material needed to reduce the incident radiation intensity by a factor of two. This factor varies depends on the energy level emitted by the material in question. Netudiant is right I don't think half value layer is applicable in this case because the water is so thoroughly contaminated it is more of a source point (emitter) than a shield.

Post a Comment