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Nuclear events taking place in Japan.

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Ash Small

Fri Mar 25 2011, 01:18PM

Registered Member #3414 Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245

Proud Mary wrote ...

.It's difficult to make much out of uncontextualised figures like the "10,000." For example, the Radiation Weighting Factor for alphas and fission fragments is usually - but not always - given as 20, so here, as an illustration only, 500 Gy x WF(Î±) = 10,000 Sv.

Yes, but the fact that the water in the cooling system is '10,000 times more radioactive than normal' must indicate a meltdown, surely? (and the black smoke seems to back this up)

Steve Conner

Fri Mar 25 2011, 01:20PM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

Weighting factors or not, you don't have to be Sir John Cockroft to figure out that nuclear fuel has got out of the fuel rods and into the cooling water, which has got out of the reactor and/or fuel pond and is sloshing around the site. This is backed up by the earlier hydrogen explosions which implied that the fuel rods' metal casings were melting and burning. The hydrogen is generated by metal burning under water or in the presence of steam. Given that enough hydrogen was generated to destroy a reinforced concrete building, that says to me a lot of fuel has melted. I don't know what the nuclear engineering definition of a "meltdown" is.

It is a heavy situation and we can only be grateful that the core wasn't vaporised and ejected wholesale into the air. And maybe be a little shamed by the courage of the "Atomic Samurai", some of whom are actually middle managers, so I take back my earlier snark about middle management. The might of nature and the uselessness of bureaucracy have given us a f*** up of colossal proportions, and these people are putting their lives on the line to limit the damage, not sitting on a forum analysing why it should never have happened in the first place.

Ash Small

Fri Mar 25 2011, 01:56PM

Registered Member #3414 Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245

Steve McConner wrote ...

. ...........not sitting on a forum analysing why it should never have happened in the first place.

I think it's more a question of trying to work out what is actually happening, given the lack of information coming from the official sources.

Steve Conner

Fri Mar 25 2011, 07:19PM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

Well that's what I think has happened. At least one thing has melted down, whether a reactor or a spent fuel pond isn't clear, but either way pieces of radioactive fuel are floating around the site.

Proud Mary

Fri Mar 25 2011, 07:37PM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

Ash, this piece from today's Daily Telegraph identifies "iodine, caesium and cobalt 10,000 times the normal level."

Japanese officials said further investigations were needed to determine how the three men replacing a cable at the No. 3 reactor were sloshing about in water containing iodine, caesium and cobalt 10,000 times the normal level.

"At present, our monitoring data suggest the (No. 3) reactor retains certain containment functions, but there is a good chance that the reactor has been damaged," said Hidehiko Nishiyama, a spokesman for Japan's nuclear agency.

Proud Mary

Fri Mar 25 2011, 09:22PM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

Exclusion zone around stricken Japanese nuclear plant widened over fears reactor core may be cracked

By Mail Foreign Service
Last updated at 6:28 PM on 25th March 2011

Radiation fears and panic levels were rising rapidly in equal measures again after officials admitted that the nuclear reactor core at Fukushima may be cracked, raising the prospect of more poison being released into the atmosphere.

The threat of widespread contamination is so great that the exclusion zone around the stricken plant has been widened to 19 miles.

It is feared the containment shield around the nuclear fuel rods might have been weakened, resulting in dangerous contamination leaking out.

Read more:

Martin King

Sat Mar 26 2011, 12:28AM

Registered Member #3040 Joined: Tue Jul 27 2010, 03:15PM
Location: South of London. UK
Posts: 237

Hm seems to me to be a classic case of drip feed information to try and avoid mass panic even though they know full well how bad the situation has become.

Ash Small

Sat Mar 26 2011, 02:20AM

Registered Member #3414 Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245

Radiation levels now 12,500 times legal limit. Levels of radioactive iodine in the sea now 150 times normal.

EDIT: 200 millisieverts per hour at one point.

EDIT: Tokyo nuclear firm protected, but not shareholders

EDIT: 07.30 GMT Iodine 131 levels in the sea over 1,250 times legal limit, according to BBC and Reuters.

EDIT: Experts unsure on source of radiation leak

Similar levels of radiation now found at reactor 1:

Steve Conner

Sat Mar 26 2011, 08:58AM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

Martin King wrote ...

Hm seems to me to be a classic case of drip feed information to try and avoid mass panic even though they know full well how bad the situation has become.

Well, I'd say when a nuclear plant explodes, catches fire, three different colours of smoke are coming from a hole in the wreckage about where the spent fuel pool is, and everyone is wading around in radioactive water, the situation has become really bad. Tepco are obviously not saying a word more than they have to, and we may not know the truth for a long time. It was almost 10 years before the nuclear community would admit that Three Mile Island had melted down. They wouldn't believe the results of a sonar survey that showed a gaping void where the core should have been, and commissioned a second, much costlier one with video.

There is a good technical discussion on world-nuclear.org under Fukushima Accident 2011.

Martin King

Sat Mar 26 2011, 10:23PM

Registered Member #3040 Joined: Tue Jul 27 2010, 03:15PM
Location: South of London. UK
Posts: 237

Another article that tries to put things into poerspective

of course there is the caveat that the author of that article is also selling a book

personally I'm still on the fence as I don't know enough about the subject, but I'm tending towards the view that whilst this is of course bad maybe it's been blown up a bit out of all proportion. Suddern distasters such as this make the news, long term damage from oil use doesn't, a bit like air crashes make the news but the thousands of deaths caused by other forms of transport don't.

Martin.

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