West Coast background monitoring

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Richard Hull
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West Coast background monitoring

Post by Richard Hull » Wed Mar 16, 2011 9:35 pm

While I think there is zero to worry about, our west coast folks might have an interesting project to report in the near future should any drift over actually occur from the Japanese event.

It might be prudent and instructive to start taking a single 10 minute background count each day and reduce to a CPM count. You should use a 2" pancake, if possible, and a digital scaler to get a precise count instead of using an analog meter.

I don't think this will go anywhere, but it would be interesting, nonetheless. The reading should be taken outdoors at the same place and at about the same time to be useful. Keep a log of the results and report any interesting findings.

If the reading goes up to any significant degree, it would be cool to get a large shallow aluminum pan like used under hot water heaters and fill it half way with water and put it in the back yard with a screen over it, (No bird droppings). Just let the water evaporate and once it reaches a very low level, maybe one quart or less, transfer and evaporate in a smaller container. Next take a wet napkin folded to a 3X3 patch and wipe around the edge of the pan where the water level shows. Gamma spec this and look for Cs137 or other peaks. Do the same with the one quart evaporant pan when all the water is gone. (Shades of my childhood collecting bomb fallout in Richmond from my bird bath so common to yards in the 50's)

If you guys get nuke stuff raining down, I will be super envious. Free isotopes! Such a deal.

Richard Hull
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Adam Ingle
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Re: West Coast background monitoring

Post by Adam Ingle » Thu Mar 17, 2011 8:34 pm

Good idea, Richard.

I believe the jet stream is currently passing directly over my part of the country that goes over that area of Japan. I have a RadAlert 100, no 2'' probe unfortunately, but I've also got some graphing software. I'll get everything set-up and run multiple 24 hour averages.

I'll post some graphs and if interesting happens I can also post the hard numbers.

Thanks for the idea!

Adam Ingle

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Steven Sesselmann
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Re: West Coast background monitoring

Post by Steven Sesselmann » Fri Mar 18, 2011 1:48 am

Okay so we have established that radioactivity is a problem in Japan at least..

Can anyone elaborate on what isotopes this pollution is likely to be and why?

Is it the nuclear fuel itself which becomes airborne, or is the activity resulting from neutron activation of other matter?

Steven
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Carl Willis
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Re: West Coast background monitoring

Post by Carl Willis » Fri Mar 18, 2011 4:07 am

Hi Steven,

A BBC press report from several days ago, which I linked in another thread, mentioned radioactive cesium and iodine had been identified. If that report is accurate, then it implies damage to fuel, because these radioelements are fission products formed only in the fuel.

The composition of the releases, if they are mostly fission products, would depend strongly on the source (i.e., recently-irradiated fuel in the reactor core, or older spent fuel in the storage pools) and on the method of release. At Fukushima, the most serious releases appear to be coming from spent fuel inventory in the uncovered fuel pools, brought on by thermal degradation of the fuel's cladding and evaporation of volatiles. This means that some of the longer-lived, more volatile fission products that are deposited closer to the cladding probably dominate, e.g. Cs-134 and Cs-137. Much could be learned about the accident from analysis of the radionuclides in the fallout, but data is slow to reach the public in this accident.

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Steven Sesselmann
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Re: West Coast background monitoring

Post by Steven Sesselmann » Fri Mar 18, 2011 4:25 am

Carl,

As I suspected, not much information out there....

It would be interesting to know, how and why radioactive particles become airborne.

In what form is the fuel held?
Is it lumps/rods of metal. or pellets or powder?
If the water around the spent fuel rods dry up, do they get hot enough to melt or burn?

Japanese concrete suppliers must be rubbing their hands

Steven
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Re: West Coast background monitoring

Post by John Futter » Fri Mar 18, 2011 5:40 am

Steven
the bother with this is that "U" breaks down into multiple daughters but Cs and I are a real problem as both are gasses at fairly low temperatures. So as a gas they leak into the environment. Cs is the most reactive of the alkaline metals and will grab halogens as quick as a wink so if there is saltspray present CS will displace Na to form CsCl a water soluble salt. But the double banger is that alot that comes out is CSI ceasium iodide another water soluble salt, in this case you get both nuclides together.


The fuel rods are made from U2O which is sintered into pellets that melt approx 3900
These are encased in zircalloy tubes (not sure of melting point- around 1900 i think).
Strontium and technicium are also problems, Strontium will happily replace Calcium so your bones irradiate you from the inside if you injest it and the body uses it for bone formation

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Richard Hull
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Re: West Coast background monitoring

Post by Richard Hull » Fri Mar 18, 2011 2:24 pm

As I noted in my original post, I think all this is much ado about nothing, for the U.S. at least. It is not like a bomb fallout issue where a large and almost inconceivably hot amount of fission product inventory is lofted very high into the atmosphere.

Basically, every time to see a steam cloud or H2 explosion cloud valut out of the crippled plant, fission product is moving into the atmosphere with most of it certainly coming down within a smallish area compared to the old A-bomb tests of the 40's, 50's and 60's. This is why I hold out that none of the hot stuff should be crossing the Pacific.

Still, it would be cool to know for sure. Jon Rosenstiel will also run some tests as I called yesterday and egg'd him on a bit. He always does things at a high order of fit and finish.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
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Re: West Coast background monitoring

Post by Chris Trent » Fri Mar 18, 2011 4:15 pm

I'm not expecting anything to make it to Texas, but I've got my monitoring system hooked up finally. We shall see what there is to see.

Right now the monitor is just a stock Lionel CDV 700, (calibrated to a DU check source) connected to a computer for logging. A scintillation counter is under construction, but it probably won't be ready in time.

Current readings, 9cpm; about 0.015 mR/Hr averaged over the last 12 hours.

Jon Rosenstiel
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Re: West Coast background monitoring

Post by Jon Rosenstiel » Fri Mar 18, 2011 7:07 pm

Two pronged approach here at my lab in southern California. First, I've placed my Inspector Alert (2-inch pancake tube) just outside my lab's side door and am collecting its output pulses on my MCA. The MCA is set to MCS mode (Multi-Channel Scaling mode) with a dwell time of 10-minutes and an ADC gain of 4096 channels. With these settings it will be possible to record 10-minute counts continuously for nearly 28-days. (Should be more than enough)! Present count-rate is around 43 cpm.

Secondly, I'm planning to do morning and evening wipes on our glass topped patio table. The wipes will be saved in plastic baggies and checked later for Cs-137 using a 2" x 2" NaI(Tl) detector.

A big thanks goes out to Richard and Frank for nudging me off my duff.

Jon Rosenstiel

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Steven Sesselmann
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Re: West Coast background monitoring

Post by Steven Sesselmann » Fri Mar 18, 2011 10:33 pm

John,

Thanks for enlightening me with those facts...

Just one more question that bothers me...

Why are Cs and I not normally listed in the Uranium or Thorium decay chain?

Np-U-Pa-Th-Ac-Ra-Rn-Fr-At-Po-Bi-Pb-Ti-Hg

All of these are much heavier than 137Cs and 123I ?

Steven
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