Fukushima No. 1 loss of coolant due to earthquake 7

[racookpe1978]

Robotic access for photography or temperature/radiation measurement is doable, but depending on how much internal damage is to the twisting access "maze" inside the containment building, and the amount of other flooding, debris, fallen doors or administrative burden (tables, chair, bookcases falling over, filing cabients, etc) you will likely not be able to simple "drive" a robot to anywhere useful.

What's needed is access, assessment, disassembly, repair, re-assembly, and testing of connections, doors, debris field, piping and tubing.

Can't do that robotically. Pulling even an empty 2-inch 50 mm) hose through a debris-filled corridor with even only one or two twists or bends will require several hundreds pounds of force - no small robot can do that.

 

[cloa]

Zirconium is passive to chloride corrosion at every concentration. Its only second to tantulum in passivity. The real question is after suffer radiological damage is it still passive.

 

[rmw]

Does anyone know if the aux diesel generators in this plant are recips or combustion turbines. I don't NEED to know this, just curious.

rmw

 

[unclesyd]

I haven't heard of anything but there are only straight unadorned Diesels generators. According to latest news they have a new power line hooked up and are waiting on someone to push the button on the pumps. The big question is whether the pumps damaged. At the same time the US is sending so very large high pressure pumps for a backup.
The US has officially told the Japanese that we are not receiving enough information. This report also stated part of the problem was Japanese trying DIY on the event and failed miserably. Supposedly the reason that the pumps were not brought in earlier is part of the DIY syndrome.
The sowed some closeup pictures of the reactors and the damage is more than just a little or only this or that was damaged.

 

[rmw]

I've seen both recip and CT driven aux generators in Nuke plants. It would seem to me that on the engine side, a recip would be easier to recover from a flooded situation than a CT, but the generator now, well that is problematic no matter what the driver.

I was just curious.

I'll bet aux turbines are built on the turbine deck in future seaside Nuke plants, especially in earthquake prone zones.

rmw

 

[MintJulep]

In the plant I worked at - same BWR design and similar vintage to Fukoshima - the back-up generators were turned by reciprocating diesels.

Great big things. Size of a house. I don't remember the manufacturer anymore.

You might put a turbine genset on the main turbine deck, but you'd have to be crazy to put one of these up there. You'd shake things to pieces.

 

[rmw]

Oh, I think turbine deck foundations are capable of withstanding some wicked vibrations - e.g. a main turbine shucks a blade or two...

And, foundations can be designed to isolate vibrations. I just spent a week on a cruse ship and if I hadn't other wise known that there were some massive recip diesels driving the gen sets, I never would have known by feeling vibrations transmitted through the hull.

They certainly have some pretty massive other pieces of equipment on the turbine deck - again thinking of main turbine-generators and at times the turbine driven BFP's.

I think it can be done.

rmw

 

[Zogzog]

Finally some decent technical info

http://www.world-nuclear-news.org/RS_Insight_to_Fukushima_engineering_challenges_1803112.html

 

[trottiey]

Here's a 2.5 hour lecture about it:

http://mediasite.uoit.ca/mediasite/...lt.aspx?peid=158b513526014159b694242e7f922dad

 

[BJC]

"Does anyone know if the aux diesel generators in this plant are recips or combustion turbines. I don't NEED to know this, just curious."
The load pickup schedule is very fast. If I remember correctly first load was picked up in lless than 9 seconds. The cooling system is continually heated and lube oil is circulating all the time.
There would be dual seperate compressed air starters with air injected into the cylinders. Combustion turbines can't start that fast.

 

[rmw]

So.... for those Nuke plants were the aux genertors are in fact CT's, are they just screwed?

How do they get around that fast start requirement?

rmw

 

[electricpete]

There may be a CT at a nuke plant, but I'm pretty sure there will also be one or more DG's.

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(2B)+(2B)' ?

 

[rmw]

The plants I am referring to are in Ontario and had multiple CT's but I didn't pay any attention to whether or not they had any DG's. Logic would say that they must have.

rmw

 

[cloa]

http://online.itp.ucsb.edu/online/plecture/bmonreal11/rm/flashtv.html

I don't think anyone has linked this before- as well as nuclear risks there is a bit of presentation on Fukushima's present state and while fission due to plutonium pooling was stated as a possibility, that possibility is now discounted as the dangerous fuel rods seem to have collapsed (with no nuclear explosion) so a fission reaction is unlikely. The expert says that a final solution for Fukushima is going to be difficult, a salt pile is growing in the reactors, there is a lot of debris and top access is difficult with the heavy radiation so covering the top is difficult. It might need explosives to allow the rods to fall lower. Fortunately military helicopters are getting close now to water bomb, Japanese are accepting international assistance. Maybe a few more helicopter could clean it up a bit and cover the top.

 

[electricpete]

http://www.bloomberg.com/news/2011-...at-japan-s-fukushima-nuclear-plant-table.html

No. 1: Contaminated water in the turbine structure contains 10,000 times the radiation of regular cooling water, NHK said. The company has started removing contaminated water from the basement of the turbine building and will prepare more pumps to drain the water, the agency said. The unit has been damaged since a March 12 hydrogen explosion destroyed the building’s walls. The seriousness of the reactor’s threat to safety is rated level five on an international scale of 1-7.

No. 2: Contaminated water in the turbine structure contains 10 million times more radiation than normal cooling water, NHK said. The company plans to remove contaminated water as early as today, the agency said. The company plans to start using freshwater on fuel pool from March 28, the agency said. The containment chamber may have been damaged in a March 15 explosion, and a power cable was reconnected to the unit on March 19. The reactor is rated a level-five threat.

No. 3: Contaminated water in the turbine structure contains 10,000 times the normal radiation, NHK said. The company is considering ways to remove the contaminated water, the agency said. A March 14 explosion damaged the unit’s fuel cover. The reactor is rated a level-five threat

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(2B)+(2B)' ?

 

[owg]

Zogzog - thanks for the "decent technical information". Even that says "After the total failure of plant cooling systems, seawater is being pumped into the reactor cores of units 1, 2 and 3 to prevent overheating and further core damage." but does not say where the seawater goes after the reactor cores, perhaps to the sea.

HAZOP at

http://www.curryhydrocarbons.ca

 

[frankiee]

rmw.
My plant here in Ontario has 4, 15,000 KW non seismic all with separate fuel source and 2 CTs for emergency that are seismic and 5MW each

 

[electricpete]

Regarding my post 27 Mar 11 2:05 - it seemed alarming that they were reporting water activity of 10 million times normal coolant activity, which previously they were concerned about 10 thousand. This morning I hear there was probably a mistake in the reading... more info to come.

frankiee - CT's but no DG's? How fast do the CT's start up?

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(2B)+(2B)' ?

 

[trottiey]

The analysis results from the turbine building basement, in becquerels per cubic centimeter, are here:

http://www.nisa.meti.go.jp/english/files/en20110327-1-5.pdf

Some rough calculations suggest the numbers are big enough to kill you by acute radiation poisoning within days if you drink an undiluted sip.

 

[electricpete]

Very interesting chart.

It seems like we should be able to draw some conclusions from examining the isotopes. For example if one plant has higher long-lived isotopes, that favors spent fuel pool as a source while if one has higher short-lived isotopes, that favors reactor as a source. But at first glance, I didn't see any simple pattern like that.

I looked for the highest concentration of anything on the chart. Looks like Unit 2 I134 at 2.9E9y Bq/cm3 and a half-life of only 53 minutes. With such a short half-life, that can't be left over from power operation... must be a decay daughter. What decay chain gives us I134?

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(2B)+(2B)' ?