Monday, June 20, 2011

"Corium Coolability Under Ex-Vessel Accident Conditions for LWRs"

The paper was written by the scientists in the Nuclear Engineering Division at the Argonne National Laboratory and published in Nuclear Engineering and Technology in June 2009.

That's exactly what has happened at Fukushima, 3 "ex-vessel" accidents.

Link to the paper, FYI:


Anonymous said...

L'amateur de thé dit
Hello arevamirpal...
Would you please give us some kind of good news from time to time?
I would appreciate this, really.
I am fed up with your news that are everiday more awful than the day before ! I require funny and happy news everiday from now !

Anonymous said...

If this wasn't so serious with so many lives being taken around the world by the contamination it would be a comedy. The corruption, lies, PR, cover ups and bungles are like a tragic comedy. Sadly, where corruption is involved, the news is normally bad.

But puting that aside, if you want humour, there is plenty of that amongst this tragedy. TEPCO hosing down their fuel pools, and "fixing" the cooling system by running the hose up the inside of the building instead of outside. Then there is the head of Japanese medicine who said that what will fix it is a positive attitude and that people with a positive attitude are unaffected by radiation!!!! The humour is in there. But we must not hide from the hard reality. This is not the time to turn away. Keep the pressure on these crooks!

Anonymous said...

" .. the head of Japanese medicine who said that what will fix it is a positive attitude and that people with a positive attitude are unaffected by radiation!!!! "

Just like the U.S. navy saying the reason they moved their ships from the east coast to the west coast of Japan was because they didn't want their equipment contaminated, not their personnel.

arevamirpal::laprimavera said...

@L'amateur de thé, I'll certainly try. Here's one: IAEA's Amano praised the Japanese government report to IAEA on Fukushima accident earlier this month, saying "It shows the maximum clarity." (Yomiuri Shinbun 6/21/2011)

In the meantime, we could go visit the news in March right after the accident, when the media and the government were saying everything was under control.

netudiant said...

That report is actually somewhat encouraging.
It suggests that the corium is getting ongoing cooling from water penetrating the cracks in the crust of oxydes around the corium. That suggests there is lower risk of a heat build up and subsequent steam explosion scattering the corium all over.
The other good news is that most of the radioactive elements produced by the ongoing corium reactions are taken up by the cooling water, rather than bubbled off. It may be a factor in the higher than expected radioactivity of the water that the filtering tests found, but it is good news for anyone who is worried about the contents of the ongoing steam emissions from the site.

Anonymous said...

Here's a quote from an article about Dounreay de-commissioning...
>Two kilometres of beach outside the Dounreay nuclear plant have been closed since 1983, and fishing banned, when it was found old fuel rod fragments were being accidentally pumped into the sea. The cause was traced and corrected but particles - including *plutonium specks, each capable of killing a person if swallowed* - are still being washed on to this bleakly beautiful stretch of sand and cliff on mainland Britain's northern edge.

A rare occasion when plutonium has escaped containment. If hot plutonium particles escaped in the number 3 explosion at Fukushima, then we may still be unaware of the damage.

Can we really imagine TepCo going after every damn particle with activity-seeking submarines and robots.

Anonymous said...

Robbie001 sez:

I just got home from dinner a little while ago so I haven’t had time to read the entire document in detail but this is what I got out of it with a quick look (always start at the conclusion). It seems there’s still lots of stuff they don’t know even after 20 years of intensive pretending that their little experiments and models are relevant to the real world.

This is the first thing that jumped out at me (At least they admit 2 tons of simulation probably doesn’t act the same as an entire operational reactor inventory).

“Although the identified cooling mechanisms certainly increase the debris cooling rate, scaling effects in many of the tests have significantly influenced test outcomes, even at extremely large experiment scale at up to 2 metric tons core melt mass. These occurrences have made it difficult to declare with certainty that a core melt can always be quenched under a wide range of conditions”.

Dr. Richard E. Webb said the same thing about scaling issues in his book “The Hazards of Nuclear Power Plants” back in the 70’s. (read it here)

I looked for projected cooling times and I couldn’t seem to find the experiment where it took 100+ days to achieve stabilization of a mud a salt encrusted core. It seems any of the extended cooling times are outside of design parameters for this study.

Researcher: “Boss it is taking over 100 days to cool down this experiment”
Boss: “You’re FIRED! Someone shred all that data…now”!

These were the longest cooling times I found skimming over the document maybe someone could point me to where I missed a longer cooling period (that isn’t a disaster).

“The later parametric variation is based on the consideration that water may be added at different times in the accident sequence, which causes the concrete content to be different due to ongoing core-concrete the cavity is flooded before the melt concrete content exceeds 10 wt %. In this range, coolability may take up to two days to achieve”

“If the containment design is such that melt depths up to 40 cm may be encountered, then stabilization may not be achieved unless the design can accommodate up to five meters of axial ablation, and only if the cavity is flooded early (i.e., concrete content ≤ 5 wt %). Under these conditions, stabilization will take in excess of one week to achieve.”

I love how they use the nucspeak word “influenced” instead of degraded in this excerpt (It also has a nice example of this is how a high paid "nucular” scientist say, “I really don’t know”)

“Although the calculations shown here are based on the experiment findings from the various test programs, these tests were all small relative to plant conditions. At plant scale, the cooling efficiency could be influenced or improved by other phenomena which could be masked at the scale of these tests.”

The “should be coolable” as a conclusion doesn’t really make me feel warm or fuzzy so I’m thinking the deeper/siliceous part is bad. This really seems like a round-a-bout way of saying, “We want to prove our critics wrong and unfortunately after extensive research over the last 20 years we couldn’t”. They should have listed all the “siliceous” reactors in service around the world.

“The primary objective of R&D efforts in the area of ex-vessel corium coolability has been to demonstrate through a combination of experiments and analysis that core melt interacting with concrete can be quenched and rendered coolable over a wide range of conditions. Unfortunately, this has been an extremely difficult objective to achieve. Results to date indicate that modestly deep (i.e., < 40 cm) core melt pools interacting with LCS concrete should be coolable. However, for deeper melts, or for melts interacting with siliceous concrete, the same conclusion cannot be drawn”

Anonymous said...


"we cannot prove that water cooling makes it impossible for corium to end up in the ground".

Anonymous said...

L'amateur de thé

Va bene, laprimavera.

Anonymous said...

@ Robbie,

".. for melts interacting with siliceous concrete, the same conclusion cannot be drawn”

I mean, is there really any other type of concrete commonly used than silica-containing concrete?

read 'silica dust' warning signs at concrete plants

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