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heat transfer is meant to be much larger with water, but steam still has some levels of cooling effect apparently, according to one of the earlier discussions on the exposure of fuel rods

Any idiot can face a crisis - it's day to day living that wears you out.
by ceebs (ceebs (at) eurotrib (dot) com) on Wed Apr 6th, 2011 at 10:48:03 AM EST
[ Parent ]
Boiling water reactor - Wikipedia, the free encyclopedia
Water exiting the fuel channels at the top guide is about 12 to 15% saturated steam (by mass), typical core flow may be 45,000,000 kg/h (100,000,000 lb/h) with 6,500,000 kg/h (14,500,000 lb/h) steam flow. However, core-average void fraction is a significantly higher fraction (~40%).

Economics is politics by other means
by Migeru (migeru at eurotrib dot com) on Wed Apr 6th, 2011 at 10:50:19 AM EST
[ Parent ]
Get out your old steam tables book...  :-)
by asdf on Wed Apr 6th, 2011 at 05:23:09 PM EST
[ Parent ]
of the zirconium to burn.  

Not to be off topic, why aren't they feeding boron into the reactors?  Except for one story about a request for boron from South Korea, I am not aware of a word about it since.  

Given that we know for real that reactor no. 1 has gone critical several times since the accident (radioactive chlorine, the blue glow, heat spikes, and neutron episodes) they could actually be creating more heat than they are dissipating, as well as making the site more radioactive.  

The Fates are kind.

by Gaianne on Wed Apr 6th, 2011 at 03:09:45 PM EST
[ Parent ]
By the way, how did you end up looking into a hot fuel pool?

The last time I saw fuel rods

in a pool--which I admit was some years ago--the blue glow of Cherenkov radiation (that's the radiation due to beta particles traveling faster than the speed of light in water) extended out at least one half meter from the rods.  

(It was  very beautiful, by the way.)  

The safe distance will obviously be very sensitive to your personal level of machismo.  

It occurred to me later that standing near the edge of that pool was not the brightest thing I have ever done in my life.

Economics is politics by other means
by Migeru (migeru at eurotrib dot com) on Wed Apr 6th, 2011 at 03:28:05 PM EST
[ Parent ]
Had a friend in low-energy physics.  

(Low-energy means nuclear.)  

They had a research reactor for producing neutrons and such, studying energy levels in excited states in atomic nuclei, both stable and unstable.  

If I understood correctly, this was background to test models targeted at the Island of Stability--heavier elements that might exist or that might be created, beyond the existing elements and beyond the gap of impossible elements.  

They were pretty hands-on:  Technicians ran the reactor, but they set up their own equipment (lead bricks, detectors, computer cables)--which meant they were in and out of the reactor building more or less daily.  

The Fates are kind.

by Gaianne on Wed Apr 6th, 2011 at 08:58:18 PM EST
[ Parent ]
NY Times: U.S. Sees Array of New Threats at Japan's Nuclear Plant (April 5, 2011)
The steps recommended by the nuclear commission include injecting nitrogen, an inert gas, into the containment structures in an attempt to purge them of hydrogen and oxygen, which could combine to produce explosions. On Wednesday, the Tokyo Electric Power Company, which owns the plant, said it was preparing to take such a step and to inject nitrogen into one of the reactor containment vessels.

The document also recommends that engineers continue adding boron to cooling water to help prevent the cores from restarting the nuclear reaction, a process known as criticality.

Even so, the engineers who prepared the document do not believe that a resumption of criticality is an immediate likelihood, Neil Wilmshurst, vice president of the nuclear sector at the Electric Power Research Institute, said when contacted about the document. "I have seen no data to suggest that there is criticality ongoing," said Mr. Wilmshurst, who was involved in the assessment.

It is implied that they're doing it already.

Economics is politics by other means
by Migeru (migeru at eurotrib dot com) on Wed Apr 6th, 2011 at 04:22:45 PM EST
[ Parent ]
We saw that earlier. From the latest TEPCO status report:

TEPCO : Press Release | Plant Status of Fukushima Daiichi Nuclear Power Station (as of 8:00 pm, April 6)

-We have been injecting seawater into the reactor, but from 10:10 am on
 March 26th, we started injecting freshwater (with boric acid).

This is for No. 2. The NISA status reports, however, for example the latest, mention "borated water" (sic!) for No. 1 (from 12 March) and No. 3 (from 13 March).

*Lunatic*, n.
One whose delusions are out of fashion.

by DoDo on Wed Apr 6th, 2011 at 05:08:25 PM EST
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