Re: [Phys-l] Eartquaque in Japan

["Donald Polvani" <dgpolvani@verizon.net>]

My understanding of the newscasts is that the diesels failed after an hour
due to the tsunami hitting the site.  Seems likely to me that the tsunami
would have also knocked out on site generation.  To me it looks like the
present situation could have been avoided if the site was moved inland.  I
heard that the water went 6 miles inland, so, if the site was more than 6
miles inland (or some multiple of 6 miles) the diesel generators might have
done the job.

Don
Dr. Donald G. Polvani
Anne Arundel Community College
Arnold, MD

-----Original Message-----
From: phys-l-bounces@carnot.physics.buffalo.edu
[mailto:phys-l-bounces@carnot.physics.buffalo.edu] On Behalf Of Bill Nettles
Sent: Monday, March 14, 2011 12:34 PM
To: Forum for Physics Educators
Subject: Re: [Phys-l] Eartquaque in Japan

I have never understood why the electrical supply for nuclear power plants
must come from off-site grid. Yes, in general, run them on the off-site
grid, but allow the possibility to shift to local generation rather than
depending on diesel generators which get scheduled, but short term testing.
> From what I've read, the diesels operated for about an hour, then failed.
Yeah, that's not surprising when they've never been run for over an hour.

With the ability to shift to on-site generation (and I certainly don't fully
understand all the details of grid sync, etc, but it's not an impossible
shift to design), off-site grid failure still has 2 backups: diesel and
on-site.  The decay heat alone should generate enough steam to run coolant
pumps.

Am I missing something here?

Bill

> -----Original Message-----
> From: phys-l-bounces@carnot.physics.buffalo.edu [mailto:phys-l-
> bounces@carnot.physics.buffalo.edu] On Behalf Of ludwik kowalski
> Sent: Saturday, March 12, 2011 6:43 PM
> To: Forum for Physics Educators
> Subject: [Phys-l] Eartquaque in Japan
>
> Below is a message from a nuclear physicist friend in Japan
>
> Ludwik
> ==========================================
>
>
> Serious rescue efforts for isolated people in destroyed towns by
> tsunamis and quake are under way.
> Another serious concern is of the stopped nuclear power plants,
> Fukushima-I $II with 8 reactors total.
> The Fukushima-I#1, 40 years old, has got the first trouble after its
> automatic shut-down by the quake, which was caused by no electricity
> (an emergent Diesel generator did not work
> either) for driving circulation pumps of cooling water.
> Consequently, decay heat of U-fuel pins could not be cooled enough and
> temperature and steam pressure inside the reactor vessel elevated
> continuously. Finally the melt-down of reactor-core fuel started to
> happen, as detected by Cs and I activities outside as the emergency
> value of reactor vessel gas was opened to decrease the elevated steam
> pressure. It happened an explosion, by mixing hydrogen-gas (generated
> by H2O + high-temperature-metal interaction inside reactor) and oxygen
> gas at the outside of the reactor steel-container, which destroyed the
> concrete walls of the #1 plant building.
> The reactor container vessel and reactor vessel were looked not
> damaged.
> TEPCO (Tokyo Electric Power Corp.) and NISA (Nuclear and Industrial
> Safety Agency) decided to fill the inside and out-side of reactor
> vessel with sea-water adding borated acid to cool the reactor. The work
> was done. Radioactivity monitors outside showed decrease of radiation
> level to about ten times of natural BG, which was about several 100
> times just after the emergency gas-valve opening. Now the reactor is
> confined stable. Citizens inside 20 km radius were evacuated for
> safety.
> (I think, the usage of sea water, emergent use, was chosen by two
> reasons: 1) not enough pure-water was not available at the site, 2)
> NaCl contained in sea water, as well as added borated acid (B-10) has
> significant thermal-neutron absorption effect which may help avoiding a
> worst criticality accident of fallen debris of melt U-fuels into water
> pool of container vessel, if happened.)
>
> Probably the Fukushima-I#1 reactor will be closed
> (disassembled) in near future. But we still need careful watching what
> will be going on.
>
> Now it is aired that Fukushima-I#3 reactor has got a similar trouble.
> They might do similar treatment, not decided yet.
>
> Ludwik
>
> http://csam.montclair.edu/~kowalski/life/intro.html

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