March 14, 2011

Nuclear Power Safety: A Smidgen of Common Sense

This just in:

r81co.jpg

Posted by Vanderleun at March 14, 2011 12:43 PM
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"It is impossible to speak in such a way that you cannot be misunderstood." -- Karl Popper N.B.: Comments are moderated and may not appear immediately. Comments that exceed the obscenity or stupidity limits will be either edited or expunged.

Actually, this accident shows how safe nuclear reactors are. The plant was designed to withstand an 8.2 Richter scale earthquake. Following an 8.9 quake - due to the logarithmic scale involved, a factor of five greater than design - the plant shutdown and emergency systems, including the emergency deisel generators (EDGs) started. Unfortunately, the tsunami exceeded design basis, and wiped out the EDGs and their 7-day fuel supply. No plant can withstand two beyond design basis accidents.

Additionally, the primary containment, designed to withstand a peak pressure of ~60 psi, is still intact following pressures of ~150 psi, 2.5 times design.

Here is two good cutaway diagrams representative of the Fulushima reactors:
http://en.wikipedia.org/wiki/File:BWR_Mark_I_Containment,_cutaway.jpg

http://commons.wikimedia.org/wiki/File:BWR_Mark_I_Containment,_diagram.png

The primary containmnet consists of the inverted light bulb (drywell) and torus (donut). The secondary containment (the rectangular structure) serves mainly to keep weather out. This is what was destroyed by the H2 explosions.

The H2 was released to the secondary containment when the primary containmnet was vented to reduce its pressure.

Based on the presence of H2 and fission prducts, I assume there is at least fuel failure: the cladding has failed. Partial fuel melting is possible.

I would place this slighty worse than Three Mile Island, because of the number of plants involved, but orders of magnitude below Chernobyl. This will be a major financial hit to the utility, but outside of the casualties at the plant, I would guess little to no casualties among the general public.

This is based on ~30-years experience in the commercial nuclear industry.

Frankly, I think the obsession about these plants is obscene when the deaths from the tsunami will be in the tens of thousands.

This is just my opinion, and you know what they say about opinions: they're like exhaust ports. Everybody has one, and everybody thinks theirs doesn't stink.

Good NRC primer on BWRs at
http://www.nrc.gov/reading-rm/basic-ref/teachers/03.pdf

Continuously updated CREDIBLE info available at:

American Nuclear Society
ansnuclearcafe.org

Nuclear Energy Institute:
http://www.nei.org/newsandevents/information-on-the-japanese-earthquake-and-reactors-in-that-region/

Don't believe anything you hear on TV.

Posted by: butch at March 14, 2011 6:26 PM

What a quote.

Posted by: cond0010 at March 15, 2011 12:05 AM
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