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Radioactive Releases at Fukushima Could Last Months - NYTimes.com
Japanese reactor operators now have little choice but to periodically release radioactive steam as part of an emergency cooling process for the fuel of the stricken reactors that may continue for a year or more even after fission has stopped. The plant's operator must constantly try to flood the reactors with seawater, then release the resulting radioactive steam into the atmosphere, several experts familiar with the design of the Daiichi facility said.

That suggests that the tens of thousands of people who have been evacuated may not be able to return to their homes for a considerable period, and that shifts in the wind could blow radioactive materials toward Japanese cities rather than out to sea.

Re-establishing normal cooling of the reactors would require restoring electric power -- which was cut in the earthquake and tsunami -- and now may require plant technicians working in areas that have become highly contaminated with radioactivity.



"People only accept change when they are faced with necessity, and only recognize necessity when a crisis is upon them." - Jean Monnet
by Melanchthon on Mon Mar 14th, 2011 at 10:28:00 AM EST
<facepalm>

So, in what may be my last act of "advising", I'll advise you to cut the jargon. -- My old PhD advisor, to me, 26/2/11
by Carrie (migeru at eurotrib dot com) on Mon Mar 14th, 2011 at 10:30:01 AM EST
[ Parent ]
Radioactive Releases at Fukushima Could Last Months - NYTimes.com
When the fuel was intact, the steam they were releasing had only modest amounts of radioactive material, in a nontroublesome form. With damaged fuel, that steam is getting dirtier.

Another potential concern is that some Japanese reactors (as well as some in France and Germany) run on a mixed fuel known as mox, or mixed oxide, that includes reclaimed plutonium. It is not clear whether the stricken reactors are among those, but if they are, the steam they release could be more toxic.

I've read somewhere that reactor n°3 is indeed using MOX.

"People only accept change when they are faced with necessity, and only recognize necessity when a crisis is upon them." - Jean Monnet

by Melanchthon on Mon Mar 14th, 2011 at 10:36:44 AM EST
[ Parent ]
If it's going to be a long term issue I expect it would be possible - not easy, but possible - to jury-rig a filter/condenser for the steam.

Longer term there would also be an issue with corrosion. I'd expect there would be a move towards restoring flushing out the sea water and replacing it with de-min coolant again.

I'd guess someone has thought of this already.

What's more of an issue is containment over the next 48 hours. If containment is lost, steam production becomes academic.

by ThatBritGuy (thatbritguy (at) googlemail.com) on Mon Mar 14th, 2011 at 10:43:16 AM EST
[ Parent ]
Melanchthon:
Re-establishing normal cooling of the reactors would require restoring electric power -- which was cut in the earthquake and tsunami -- and now may require plant technicians working in areas that have become highly contaminated with radioactivity.
At this point, the best option is to build a concrete sarcophagus around the thing. I don't think a year of increasingly polluting releases is better.

So, in what may be my last act of "advising", I'll advise you to cut the jargon. -- My old PhD advisor, to me, 26/2/11
by Carrie (migeru at eurotrib dot com) on Mon Mar 14th, 2011 at 10:47:49 AM EST
[ Parent ]
Well, releases are necessary to prevent a too high pressure buildup within the existing concrete containment vessel while cooling the core. A concrete sarcophagus would mean stopping the cooling down of the core, so it would have to be both watertight (or steamtight) and able to withstand high pressure and temperature. And it wouldn't be easy to build in a devastated area.

"People only accept change when they are faced with necessity, and only recognize necessity when a crisis is upon them." - Jean Monnet
by Melanchthon on Mon Mar 14th, 2011 at 11:11:05 AM EST
[ Parent ]
The sarcophagus would have to include a giant heat sink, and would still need active cooling. Otherwise the pressure and temperature would continue to build.

Above a couple of thousand K concrete loses its integrity. If the main assembly melted at very high temperatures it could eat its down through the core catcher and into the ground water.

That would be a major fail.

To make the idea practical you'd have to use an industrial ceramic - which might not be the easiest thing to build at short notice.

by ThatBritGuy (thatbritguy (at) googlemail.com) on Mon Mar 14th, 2011 at 11:37:12 AM EST
[ Parent ]
Cement is calcined at 1700K, I doubt concrete would survive even 1300K for very long.
by njh on Mon Mar 14th, 2011 at 08:28:22 PM EST
[ Parent ]
you'd have to use an industrial ceramic

And you would have to get that ceramic UNDER the "core catcher". The "core catcher" will only hold the core if it is dispersed far below criticality and can cool below the temperature that will degrade the concrete. Covering it all with a solution of boric acid will help greatly. I would feel better if the PR idiots at GE and TEPCO could figure out that it is pointless to refuse to talk about meltdown containment when meltdown is occurring and actually release some diagrams that would clearly confirm that they actually do have a working passive containment system.  

"It is not necessary to have hope in order to persevere."
by ARGeezer (ARGeezer a in a circle eurotrib daught com) on Mon Mar 14th, 2011 at 09:31:50 PM EST
[ Parent ]
After all, there is a reason meltdown scenarios were once referred to as "The China Syndrome", though in this case it might be "The Argentinian Syndrome". (I am presuming that corporate policy is that any publicity about meltdowns is bad publicity and that they might be too panicked to rethink the obvious problems with that assumption.)

"It is not necessary to have hope in order to persevere."
by ARGeezer (ARGeezer a in a circle eurotrib daught com) on Mon Mar 14th, 2011 at 09:35:49 PM EST
[ Parent ]
Then they should devise a way to run the steam through a water bath in the release cycle so as to wash out particulates - if such a scheme is feasible at scale. It will be the particulates which will produce the most cancers.

"It is not necessary to have hope in order to persevere."
by ARGeezer (ARGeezer a in a circle eurotrib daught com) on Mon Mar 14th, 2011 at 11:13:19 AM EST
[ Parent ]
I can't see why they hadn't built filter towers, towers filled with crushed rock that is supposed to catch 99,9 % of all radioactivity if you have to vent vapout to reduce the pressure in the containment. All nuclear power plants should be required to have them.

Peak oil is not an energy crisis. It is a liquid fuel crisis.
by Starvid on Tue Mar 15th, 2011 at 01:24:28 PM EST
[ Parent ]
On the backup problems, a new version:

Radioactive Releases at Fukushima Could Last Months - NYTimes.com

Christopher D. Wilson, a reactor operator and later a manager at Exelon's Oyster Creek plant, near Toms River, N.J...

...The problem, he said, was that the hookup is done through electric switching equipment that is in a basement room flooded by the tsunami, he said. "Even though you have generators on site, you have to get the water out of the basement," he said.



*Lunatic*, n.
One whose delusions are out of fashion.
by DoDo on Mon Mar 14th, 2011 at 11:58:58 AM EST
[ Parent ]
They built the emergency generators of a seaside plant in a floodable basement!?

So, in what may be my last act of "advising", I'll advise you to cut the jargon. -- My old PhD advisor, to me, 26/2/11
by Carrie (migeru at eurotrib dot com) on Mon Mar 14th, 2011 at 12:41:28 PM EST
[ Parent ]
and the guy with a bucket to bail it out no doubt just happens to be on holiday this week

Any idiot can face a crisis - it's day to day living that wears you out.
by ceebs (ceebs (at) eurotrib (dot) com) on Mon Mar 14th, 2011 at 12:45:55 PM EST
[ Parent ]
Nb41 has a comment just up about the sheer number of buckets of water needed to cool this thing.

So, in what may be my last act of "advising", I'll advise you to cut the jargon. -- My old PhD advisor, to me, 26/2/11
by Carrie (migeru at eurotrib dot com) on Mon Mar 14th, 2011 at 12:53:29 PM EST
[ Parent ]
Who could have known?

"It is not necessary to have hope in order to persevere."
by ARGeezer (ARGeezer a in a circle eurotrib daught com) on Mon Mar 14th, 2011 at 09:37:11 PM EST
[ Parent ]
I once inspected an malfunctioning emergency diesel generator on an oil rig in the Persian Gulf off Abu Dhabi. The generator was located in the open, exposed to the seawater spray, including the electrical and electrics racks. Well, these were supposed to be waterproof, but they weren't (and neither condensation proof)... I had to recommend to build a shed around it to protect it...  

"People only accept change when they are faced with necessity, and only recognize necessity when a crisis is upon them." - Jean Monnet
by Melanchthon on Mon Mar 14th, 2011 at 01:03:43 PM EST
[ Parent ]
I've got a year's supply of idiotic-to-dangerous design horror stories.  


She believed in nothing; only her skepticism kept her from being an atheist. -- Jean-Paul Sartre
by ATinNM on Mon Mar 14th, 2011 at 01:03:53 PM EST
[ Parent ]
probably go with my year supply of idiotic user and management stories

Any idiot can face a crisis - it's day to day living that wears you out.
by ceebs (ceebs (at) eurotrib (dot) com) on Mon Mar 14th, 2011 at 01:06:55 PM EST
[ Parent ]
That's exactly what I was referring to in this comment:

Melanchthon:

They [the generators] must be located in safe places and well protected, and that includes the diesel fuel storage tanks and supply lines, the air intake system, the electric and/or compressed air starting devices, the batteries, the engine cooling system as well as the electric and electronic devices that are supposed to automatically start them and connect them to the pumps whenever there is a power shortage and to pilot them. So if they were flooded, there was no chance they could run for long.


"People only accept change when they are faced with necessity, and only recognize necessity when a crisis is upon them." - Jean Monnet
by Melanchthon on Mon Mar 14th, 2011 at 12:51:48 PM EST
[ Parent ]
Radioactive Releases at Fukushima Could Last Months - NYTimes.com

To pump in the water, the Japanese have apparently tried used firefighting equipment -- hardly the usual procedure. But forcing the seawater inside the containment vessel has been difficult because the pressure in the vessel has become so great.

One American official likened the process to "trying to pour water into an inflated balloon," and said that on Sunday it was "not clear how much water they are getting in, or whether they are covering the cores."

The problem was compounded because gauges in the reactor seemed to have been damaged in the earthquake or tsunami, making it impossible to know just how much water is in the core.

And workers at the pumping operation are presumed to be exposed to radiation; several workers, according to Japanese reports, have been treated for radiation poisoning. It is not clear how severe their exposure was.



*Lunatic*, n.
One whose delusions are out of fashion.
by DoDo on Mon Mar 14th, 2011 at 12:03:02 PM EST
[ Parent ]

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