Sunday, April 27, 2014

#Fukushima Reactor 3 MSIV Room Investigation: No Leak from Feed Pipes, Says TEPCO


Now to the real, very serious problem at Fukushima I Nuclear Power Plant and potentially far beyond.

Remember the highly contaminated water found leaking from the MSIV (Main Steam Isolation Valve) room in Reactor 3 in January this year?

The water contained high levels of radioactive cesium (1.7 million Bq/L of cesium-137) and all-beta (24 million Bq/L) that even TEPCO admitted it was not the water being injected into the reactor (treated water) and implicitly admitted that it was the water coming out of the reactor.

Without much fanfare or publicity, TEPCO did the preliminary investigation of the Reactor 3 MSIV room to identify the location of the leak on April 23 and inserted the report on the result in the Roadmap updated and announced on April 24, 2014. There has been hardly any press coverage since.

After reading and re-reading TEPCO's investigation report, I think I have adequately figured out what they are trying to say (and not say).

TEPCO's explicit conclusion: The leak is not from the two Feed Pipes, not from the two spare (reserve) penetrations.

TEPCO's implicit conclusion: The leak is from somewhere else, below the grating.

What's there, below the grating? TEPCO lists two potential leak locations that they will look into in May:

  • Main Steam Pipe; or

  • Main Steam Drain Pipe


And what TEPCO doesn't explicitly list?
  • Main Steam Isolation Valve (MSIV) itself.


To recap, MSIV is, according to Fukushima I NPP worker "Sunny":

MSIV (Main Steam Isolation Valve) is a huge valve attached to the main steam pipe that connects the reactor building and the turbine building. When this valve closes, it means there is some extraordinary incident happening in the reactor core. Conversely, one might say that it would be a problem if this valve did not close in such an incident.

When the reactor scrammed on March 11, 2011, the MSIV should have promptly, securely closed, without breakage, without leak. It is not supposed to fail. Implications for nuclear reactors around the world would be grave, if it did.

From TEPCO's Reactor 3 MSIV room investigation and the preliminary result of the April 23, 2014 investigation from TEPCO's Roadmap latest version (4/24/2014; PDF pages 268 to 281, English labels are by me):

Page 274:


TEPCO inserted a pan-tilt camera, an endoscope, and a dosimeter from Main Steam (MS) Process Monitors that go through the floor of the Air Conditioning Machine Room located right above the MSIV room in Reactor 3.

The diagram on the left shows the types of penetrations between the MSIV room and Primary Containment Vessel (PCV):

Above the grating (investigated on April 23),

  • Two spare (reserve) penetrations, marked "X-46, 47"

  • Two feed pipes, marked "A" and "B"


Below the grating (to be investigated in May),

  • Four Main Steam Pipes, marked "A", "B", "C", "D"

  • One Main Steam Drain Pipe, marked "X-8"


Page 275: Summary of findings

Preparation (April 21, 22): Drilled three holes for MS Process Monitors
Result of investigation (April 23):

Sound of running water: heard from the Air Conditioning Machine Room through MS Process Monitors

Survey by the pan-tilt camera:

  • There was no leak from the feed pipes.
  • There was no leak above the grating.
  • There was water on the floor below the grating.

Page 276: Feed Pipe A - no leak found


Page 278: No leak from spare penetration holes X-46 and X-47


Page 279: View through the grating - water seen flowing on the floor


Although there is no apparent leak above the grating, the pipes seen in the photos show stains and discoloration. Something did seem to have happened:

From TEPCO's photos and videos library, 4/14/2014:



Compared to the Reactor 3 MSIV Room, the Reactor 2 MSIV Room looks to be in pristine condition, both below and above the grating.

From TEPCO's photos and videos library, 4/16/2013:


I also remember anonymous workers at the plant saying they saw the first floor of the reactor building filled with steam, and that it could only be from the Main Steam Pipes. I think it was in the first or second week of the accident, but I don't remember which reactor building. It could have been Reactor 1.

10 comments:

Anonymous said...

Is this another piece of Tepco kabuki theatre?

Even if they identify the source of the leaks in R3, the radiation levels are way too high for workers to repair the leaks - way too high for robots to repair the leaks. It's just busy work.

Meanwhile......Tepco....WHERE ARE THE CORIUMS?

Anonymous said...

Don't you get it? If MSIV in Fuku-I broke for whatever reason, all the boiling water reactors operating in the world would have to stop, for serious safety concern. Location of corium at Fuku-I is not a trouble for the rest of us.

Anonymous said...

Anon @ 3:12

Yes I get it only too well.

Let's see...

Reactors built in region of intense geological activity to specifications unable to withstand predicted earthquake levels.

Sea walls built to less than predicted tsunami levels.

Culture of incompetence, lies and greed within operator and oversight bodies.

Cavalier disregard for the well being of citizens when disaster strikes resulting in large numbers of people evacuating into greater harms way.

...and you are worried about the integrity of one critical component?

You should rather be worried about the integrity of the whole endeavour.

You are focussing on the detail to avoid seeing the big picture.

Anonymous said...

Anon at 12:01AM, devil is in the detail, not in the generalized big statements you seem to be fond of.

Anonymous said...

Thank you, ex-SKF, for plowing thru these Tepco documents.

12:12, good point on the safety of all other reactors in the world.

And, of course, if these Daiichi reactors were able to scram after THE QUAKE, They Would Have. They didn't
The Tsunami served to obscure those facts.

That is a prime example why the nuclear industry is untrustable. They are scamming the world's intelligence.

Anonymous said...

Is there some links to support the statement that the reactors didn't scram after the quake. Seems like a big claim to make, given there was about 45 minutes in between the quake and tsunami. I've never heard anyone claim the reactors were still in operation mode after the quake.

Anonymous said...

Mustn't make too good a point, 3 PM, as you've highlighted that that factotum should be crystal-clear by now: who verified they'd scrammed?

5 & 6 did, supposedly.

Offsite power was lost. How long did the backup generators run for?

Anonymous said...

Not from feed water pipes (I thought we knew that already)... well, then where is the water coming from? Did I miss something?
*mscharisma*

Anonymous said...

TEPCO has now published that they found a leak at unit 3 main steam line D, outside the containment, about 4 meters from the containment wall.

http://www.tepco.co.jp/en/press/corp-com/release/2014/1236458_5892.html

This indicates that water level in the reactor is at the level of the main steam line. And this indicates that the lower head of the reactor pressure vessel is not broken - otherwise the water would flow out through the bottom, not through the steam line. And this indicates that the corium is still inside the reactor at unit 3.

riin nov said...

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