Sunday, September 9, 2012

#Fukushima I Nuke Plant: Pipe Shavings Causing the Decrease in Water Flow, TEPCO Thinks

Incurious TEPCO's conclusion for now is that the white pieces floating in the buffer tank and caught by the strainer are the shavings of plastic pipes and they are the cause of the decreased water flow into the reactors.

From Yomiuri Shinbun (9/6/2012):


Decrease in the amount of water injected [into the reactor] caused by shavings from the pipes?


TEPCO announced on September 6 that it was likely that the shavings from the polyethylene pipes were clogging up the valves and pipes and causing the amounts of water injected into the reactors at Fukushima I Nuclear Power Plant to fall below the necessary amounts for cooling.


TEPCO had hinted at the possibility of metal rust clogging the pipes. However, the company thought it important that the problem started to happen after August 30, when the 2.7-kilometer pipes that transport the treated water to the cooling tanks were switched from polyvinyl chloride pipes [probably Kanaflex] to polyethylene pipes (15 centimeter in diameter). The shavings are considered to have been generated when the pipes were being cut. White substances that looks like the shavings have been found inside the [buffer] tank and on the filter of the cooling equipment.

If it is true, I don't know what to say, other than that TEPCO is fast running out of money and quality subcontractors. This is decidedly not the "nuclear plant" spec.


Anonymous said...

TEPCO has been busy shoring up mostly NR#3 & then NR#4 & NR#1 from the recent EQ the last week.

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Anonymous said...

Such a relief that it is only plastic pipe shavings. I was worried it was newspaper shreds they used to seal up the cracks.

BTW, how much nuclear poisons are being dumped into the Pacific Ocean every hour from 3 melted down nuclear reactors via lost liquid cooling?

Anonymous said...

Off topic: atrocious program on TV Asahi by Takeshi on energy policy on air right now.

Anonymous said...

Excellent news those top Tepco engineers have figured out that plastic shavings from cutting pipes reduce flow.

We were all really waiting on the edge of our seat to hear what the excuse.. err.... scientific analysis was this time.

I'm sure once they figure out how to fix the plastic shavings in the pipes, all will be well and the nuke plant will be running smoothly again.

Good job Tepco!!! Ice cream for everyone.

Anonymous said...

It depends on the path of course, but 2,7 km does not mean a lot of cuting : mainly glue the factory-cut pipes one to another. So much shaving would be abnormal.

Atomfritz said...

Still unsure what to think about.

Pipe shavings are normal when setting up a PE piping network. But this normally poses no problems because you can flush the new piping after construction. Normal household water supply street piping often gets flushed for several hours after construction to make sure it's really clean.
I somehow have difficulties to believe flushing has been forgotten.
But what do I know if the standards of water tubing for cooling three "cold shutdown" reactors via a 2.7 kilometer PE pipe is less stringent than for potable water supply. ( I doubt there already exists a standard for PE tubing for nuclear reactor cooling, lol)

But - what is the brownish slimey goo that settled in the (probably lower) half of the strainer? [*]
Rust by itself isn't slimy.
[* look at the photo enlarged: ]

And, see also this photo:

The strainer shown there is new, it's NOT the original situation found when disconnecting the tube at the strainer.
Tepco didn't tell us whether the stuff seen in the previous photo was all which was found in the strainer.

As I have difficulties to believe that the few little stuff visible in the strainer photo can have such a "clogging efficiency" to produce such massive clogging that results in to such continuous substantial water flow variations [**] I ask myself what the real clogging situation was.

[** water flow measurements published today by Tepco: ]

Did they find the strainer full of shavings and brown goo, dropped the gunk into a bucket, cleaned the strainer a bit under water and then photograph it, to make the situation appear less ugly?

Did they even spill some of the goo, cleaned/hosed it away quickly, put a new strainer into the socket and took a photo? (Hints could be the spreading of water drops around the scene and the gooish-colored dirt in the lower left wall/floor corner)

Anyway, I am not yet sure there is nothing foul.
Stil thinking about and yet no conclusions.

Greyhawk said...

I cannot understand the stubbornness of the people in TEPCO. Their negligence has created a threat to people all over the planet. Their efforts to fix this problem are being done as cheaply as possible. They keep telling everyone that there is no danger in the huge amounts of radiation released from their four smashed reactors. They are refusing any help from anyone on the planet. They are trying to convince us that there is something wrong with us if we do not trust them. What is wrong with the people in TEPCO?

Greyhawk said...

Let me get this straight. TEPCO has built this water recirculation system out of plastic and now say they are surprised that highly radioactive, hot, corrosive water is dissolving the plastic. They are in denial that the heat and radiation are dissolving the plastic. Then they act offended when anyone questions their wisdom. I don't know what they are smoking or drinking but I don't want any of it.

Anonymous said...

Greyhawk, it's not so much TEPCO but the government. Particularly when it comes to help from outside. Very early on in the accident in March last year, they asked for help from the US military, which was squashed by the Japanese government under Naoto Kan. How dare you ask foreigners for help? Our SDF can do just as well.

Atomfritz said...

What did Tepco actually say?
"We'll adust the water flow."
But, what did they mean?
Did they mean "We increased pressure strongly, some goo apparently was flushed from the strainer to the reactor. But, every time the pressure resistance increased after flushing. Now our pumps were at their limits, and we finally had to look what's obstructing the water flow.

This really because of that little bit of dirt what we have been shown at the photo?

Atomfritz said...

@ Greyhawk

Don't worry, the PE probably won't dissolve from these few kilo- or megasieverts absorbed. IMHO it's a better alternative to PVC (Kanaflex allegedly used) as it's substantially less biofilm-prone. However, compared to metals it's still extremely biofilm-friendly.
(There are many studies about that question available in the web, especially in the medical trade)

Anonymous said...

Agreed. Same happened with Kobe earthquake.

Anonymous said...

Why Tepco is so vague?

Atomfritz said...

I am still thinking about this thing.
Tepco is indeed as vague as possible, hoping people will accept the explanation of this little bit of shavings.

But, what happened actually?
I still think it's possible that this happened:
-The water flow decreased more and more.
-Tepco flushed the line by turning the pumps to maximum power.
-The brownish slimey soft goo simply got pressed and flushed through the strainer.
-After the strainer was flushed the flow resistance sharply decreased, water flow thus got back to normal level what is expected with obstacles removed.
-Tepco then regulated pumps down to the normal circulation power.

I still believe it's not unrealistic that the true problem could be an increasing biofilm developing, releasing more and more goo in it's maturing and expansion process.
Just consider the sheer size of the tank farm and the nearly optimal conditions to develop biological growth over the summer time.

Experience shows, according to the literature available in the Web, that biofouling must be addressed as soon as possible in early stages to avoid it becoming a major, even grave problem.
However, this requires some sort of vigilance instead of incuriosity like we constantly see at Tepco.

So I am still worried and not calmed at all by Tepco's "explanations".

Anonymous said...

I hope EX-SKF can restore the chart on the right sidebar that showed water levels at the reactors.
Because of the dire situation going on now it would be useful.
Many horrible things have happened (caught on the live cam) in the past 2 days.

I have some screenshots on my blog

TechDud said...

@Anonymous September 10, 2012 7:36 AM
Quote: "It depends on the path of course, but 2,7 km does not mean a lot of cuting : mainly glue the factory-cut pipes one to another."

Polyethylene does not "glue" as adhesives are notorious for not adhering to polyethylene. The only durable joinery i've seen with PE is through welding.
It would also be helpful to characterize the type/density of PE used.
The shaving shapes & particle size(s) will assist in determining the cause(s) of degradation.

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