Wednesday, April 27, 2011

#Fukushima I Nuke Plant: "Water Entombment" of Reactor 1 Meets Murphy, Pressure and Temperature Dropping

In other words, not as planned by TEPCO.

Asahi Shinbun (11:58AM JST 4/28/2011) reports:

 東京電力福島第一原発1号機の格納容器を水で浸す「水棺」が難航している。東電は原子炉への注水量を2.5倍にして内部の温度や圧力の変化を見る予定で 27日に作業を始めたが、まず毎時6立方メートルから10立方メートルにしたところで温度や圧力の低下が長引いた。27日中に予定していた14立方メート ルにできずにいる。

"Water entombment" of the Reactor 1 Containment Vessel at TEPCO Fukushima I Nuclear Power Plant is having some problems. On April 27, TEPCO started to increase the water injection to 2.5 times the normal amount to observe the change in temperature and pressure. However, when the water was increased from 6 cubic meter/hour to 10 cubic meter/hour, there was a prolonged decline in temperature and pressure, and the water wasn't increased to 14 cubic meters/hour as planned for later in the day.

 東電が特に気にしているのが、格納容器の圧力が低いことだ。冷たい水が増えたことで、水蒸気が水になっているとみられる。もし1気圧を下回れば外部から 空気が入り込みかねない。水素爆発を避けるために窒素を注入しているが、酸素濃度が高まると、水素と混合して爆発する危険が高まる。東電は28日、さらに 24時間、10立方メートルのまま様子を見ると発表した。

What particularly worries TEPCO is that the pressure inside the Containment Vessel is low. It is thought that the steam has turned to water in the presence of increased, cold water. If the pressure goes below 1 atmospheric pressure the air may enter from outside. Nitrogen gas is being injected inside the Containment Vessel to prevent a hydrogen explosion, but if the amount of oxygen increases [because of the air coming in from outside] the danger increases for hydrogen explosion. TEPCO has announced on April 28 that they will observe the condition for 24 more hours at the water injection rate of 10 cubic meters per hour.


The temperature within the Pressure Vessel was 132 degrees Celsius in the morning of April 27 [when they started the test]. 24 hours later it dropped to 107 degrees Celsius, and it is still dropping.

1 cubic meter of water weighs 1 tonne.

The latest plant parameter (as of 6:00AM JST 4/28/2011) shows the pressure of D/W (dry well) of the Containment Vessel for Reactor 1 at:

0.125 MPa [megapascal] abs [absolute].

1 atmospheric pressure in MPa is 0.1013 MPa.

On April 27 at the start of the test, it was 0.155MPa.


Anonymous said...

It's not that, I think. They probably just bust another seal somewhere near the bottom, from the added weight.

Now they'll keep pumping in this increased amount, to "maintain pressure". Of course, all that water will flow into the drywell and slowly fill it, so they'll be doing what they were trying to do anyway, only by accident, not by design.

Happy-go-lucky idiots.

arevamirpal::laprimavera said...

They now have a plan (oxymoronic I know) for an accidental underground storage of contaminated water. Since they now know the ground is very contaminated and contaminated water have seeped through the soil, they've come up with a brilliant idea of building the underground water storage. Over 80,000 tons of water that they have right now, and increasing.

Anonymous said...

No need to approve this one... Just wanted to say you're doing a great job here. Cheers :).

Hélios said...

Hello from France.

Can you confirm what I read on this blog ? :

I have translated your post above. If you read french, go to my blogspot :

(A bistro is a very famous place in France to drink (many bistro in every cities and villages)Humoristic name for our blog.)

I sincerely wonder what will be the future of this disaster...
For now in France, no radiation problem. Some blog's readers have radiameters and just about 0.12 or 0.16 µSvt/h are measured every day.

Do you know, in µSvt/h for US, in California for instance ? Thanks.

See you soon.


arevamirpal::laprimavera said...

@helios, the robots measured the radiation inside the reactor building, and yes, it was 1,120,000 micro-sieverts or 1,120 milli-sieverts or 1.12 sievert. I wrote about that on this post:

What's not accurate in the Bloomberg article quoted there is that it was not that "the radiation rose". It was THE FIRST TIME that TEPCO was able to measure the radiation level inside the Reactor 1 reactor building since the accident. So, the radiation could have been higher and come down to 1,120 milli-sieverts. Nobody knows. Bloomberg's Japanese writers should know that, but not sure if their English editors knows.

Anonymous said...

Robbie001 sez:

I thought they had contemplated digging and lining a temporary storage pool but nixed the idea after a few aftershocks made them rethink the issue. I don't see how they are going to insure the integrity of any improvised storage facility in any reasonable time frame. Where is the MegaFloat? On April 7 they were starting a safety refit that was supposed to take one to two weeks today is the third week with no word on the progress. The on-site waste water facility can only store 30,000 tons and they are up about 80,000 tons and counting. If the MegaFloat ever shows up it can only hold 10,000 tons. Treating this water is going to take a dedicated facility years to adequately address. The current on-site waste treatment facility was never designed to handle waste in such huge volumes or at such high contamination levels. The French are supposed to be building a proper dedicated waste water treatment facility but I haven't seen any specifications on their abilities or speed of operation.

I guess an underground storage pool would make it easy to hide the mess (out of sight out of mind). And of course there is always the chance another "who could have known" moment will happen again and make all their problems leak away. How are they going to stop aftershocks from collapsing their hastily throw together underground storage pool?

Hélios said...

Thank you, I translate for may blog.


Anonymous said...

Robbie001 Sez:

According to this article they plan to start water decontamination in June. Officials claim,

"The facility can process about 1,200 tons of contaminated water a day. According to the headquarters, the facility could clean the 87,500 tons of radioactive water currently at the Nos. 1 to 4 reactors in 73 days. "Even if all 500 tons of water being injected into the reactors every day leaked, the facility could decontaminate all the contaminated water this year," the official said."

We'll see what happens, officials also said the Fukushima disaster couldn't happen, re-criticality was improbable and evacuation wouldn't need to be expanded.

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