Has Fukushima's Reactor No. 1 Gone Critical?

[flamingdem]

http://ecocentric.blogs.time.com/2011/03/30/has-fukushimas-reactor-no-1-gone-critical/

On March 23, Dr. Ferenc Dalnoki-Veress, a Research Scientist at the Monterey Institute of International Studies saw a report by Kyodo news agency that caught his eye. It reported that Tokyo Electric Power Company (TEPCO) had observed a neutron beam about 1.5 km away from the plant. Bursts of neutrons in large quantities can only come from fission so Dalnoki-Veress, a physicist, was faced with an alarming possibility: had portions of one of Fukushima's reactors gone critical?

To nuclear workers, there are few events more fearful than a criticality accident. In such a scenario, the fissile material in a reactor core--be it enriched uranium or plutonium--undergoes a spontaneous chain reaction, releasing a flash of aurora-blue light and a surge of neutron radiation; the gamma rays, neutrons and radioactive fission products emitted during criticality are highly dangerous to humans. Criticality occurs so rapidly--within a few fractions of a second--and so unpredictably that it can suddenly kill workers without warning. There have been 60 criticality incidents worldwide since 1945. The most recent occurred in Japan in 1999, at an experimental reactor in Tokai, when a beam of neutrons killed two workers, hospitalized dozens of emergency workers and nearby residents, and forced hundreds of thousands to remain indoors for 24 hours.

Dalnoki-Veress did not see any further reference to a neutron release. But two days after the Kyodo agency report, on March 25, TEPCO made public measurements of different isotopes contributing to the extremely high measured radioactivity in the seawater used to cool reactor No 1. Again, a piece of the data jumped out at Dalnoki-Veress: the high prevalence of the chlorine-38 (CL-38) isotope. CL-38 has a half-life of 37 minutes, so would decay so rapidly as to be of little long-term safety concern. But it's very presence troubled Dalnoki-Veress. Chlorine-37 (CL-37) is part of natural chlorine that is present in seawater in the form of ordinary table salt. In order to form CL-38, however, neutrons must interact with CL-37. Dalnoki-Verress did some calculations and came to the conclusion that the only possible way this neutron interaction could have occurred was the presence of transient criticalities in pockets of melted fuel in the reactor core.
(see more at link, including criticism of his theory)

Yesterday, he published those calculation in a paper for the blog ArmsControlWonk:
http://armscontrolwonk.com/

Read more: http://ecocentric.blogs.time.com/2011/03/30/has-fukushimas-reactor-no-1-gone-critical/#ixzz1I4dmdqdb

[flamingdem]

1. Link to comments and .pdf by Ferenc Dalnoki-Veress on armscontrolwonk.com

http://lewis.armscontrolwonk.com/archive/3822/localized-criticalities-at-fukushima

See download for .PDF analysis

Localized Criticalities at Fukushima?

By Jeffrey | 29 March 2011 | 21 Comments

My colleague at MIIS, Ferenc Dalnoki-Veress has written a paper, What Was The Cause Of The High Cl-38 Radioactivity In The
Fukushima Daiichi Reactor #1. Ferenc concludes that we cannot exclude the possibility that little pockets of melted fuel have gone critical, even if for a short period of time. The possibilty of localized criticalities could severely hamper on-site operations.

[MineralMan]

2. That's certainly possible.

Here's a long post that tries to tie the whole disaster together:

http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=439x773838

[WheelWalker]

3. Thanks. I've linked this to several friends.

Blessings.

[MineralMan]

4. You're more than welcome.

[jp7]

5. Japan Weighs Entombing Nuclear Plant on Chain Reaction Risk

http://www.bloomberg.com/news/2011-03-30/record-high-levels-of-radiation-found-in-sea-near-crippled-nuclear-reactor.html

[FBaggins]

6. "Bursts of neutrons in large quantities can only come from fission"

And when they see such a "burst"... you be sure to let us know. Ok?

I swear... it's hilarious watching people who seem to think that you can have a busted reactor restart a fission chain reaction, but have the only evidence of same be some leaking radioactive water and a handful of neutrons detected a mile away.

Criticality occurs so rapidly--within a few fractions of a second

And yet you feel a need to ask if it's been going on for DAYS???

[ReturnoftheDjedi]

7. how do you explain the chlorine38, Frodo??

there shouldn't be any, yet there is.

[FBaggins]

9. A bad reading obviously.

On the other hand, how do explain the lack of everything else that comes with active fission?

[ReturnoftheDjedi]

11. so that's two bad readings that otherwise would have indicated fission, right?

[FBaggins]

13. Yep

And hundreds that indicate a LACK of fission.

[ReturnoftheDjedi]

14. I've thought for days that you were actually blind, but you're not. You just have your eyes closed.

on purpose.

[FBaggins]

15. Oh come now... this must be clear even to you.

There are several OBVIOUS signs of ongoing active fission that couldn't possibly be missed if that's what is occuring.

Why have we not seen them? How on earth could reactor temperatures and pressures be so low if there's a multi-thousand-degree mass of corium inside them? Where are all of the OTHER fission products that MUST be there if this is occuring? Where's the massive unstoppable steam explosion? Why are people in the basement dealing with highly radioactive water and not kill-you-in-seconds doses from exposed core material?

You really think that the only thing they would notice is a small amount of a given isotope?

[ReturnoftheDjedi]

16. you discount actual readings for supposition

you don't have any evidence of your claim.

you can't just ignore what you don't like.

[FBaggins]

17. Actually.. that's what you are doing.

You just don't want to see it.

There are "actual readings" of the temperature and pressure in the reactors. In some cases, the temperature is reported multiple times in multiple locations (bottom of the RPV, feedwater inlet, etc). There are "actual readings" showing a lack of all the other isotopes that would be present in the case of active fission.

Those readings clearly indicate that there is no active fission chain reaction going on in those reactors.

You can't pretend that this "isn't evidence".

OTOH, it's very easy to assume that a field test of individual isotopes could make a mistake.

[girl gone mad]

8. The lengths you'll go to..

just so you don't have to cop to being wrong.

:eyes:

[FBaggins]

10. How ironic coming from you. n/t

:rofl:

[girl gone mad]

12. Guess we can add "the meaning of irony"..

to the lists of things you don't know.