Archive for March, 2011

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Information on Fukushima Nuclear Crisis [3/21 update]

March 16, 2011

A crisis has been mounting at the Fukushima-1 nuclear power plant ever since the “Sendai earthquake” and tsunami of March 11 disabled multiple cooling and backup power systems at the six-unit BWR facility.  Efforts of a skeleton operating crew are ongoing to cool the beleaguered reactors and their onsite spent fuel inventory.  Hopefully these workers, widely hailed as heroes, will avert a wider release of radioactive material.  (Tokyo Electric Power Company image, left, shows damaged reactor buildings 3 and 4 on March 15).

I am not in a position to opine on what this accident means for the future of nuclear energy, for the political fortunes of the camps aligned for or against it, or for the risk assessment methodology, regulatory framework, engineering practices, etc. that lay the foundation for safety in this business.   (For all that, stay tuned to network television, where at least one “rodeo clown” possessed of a high-school diploma and a chalkboard is on duty in front of the cameras.)  Where I think I can be helpful is in recommending  and uploading a few sources of eminently credible information.

  • First, for info on the status of the accident, the UN’s IAEA updates a staff report regularly with expert-prepared announcements free of sensationalism and technical misinterpretation.
  • Second, for general info on the power plant systems involved in this accident, I recommend reading the US Nuclear Regulatory Commission’s BWR section of their Reactor Concepts Manual.  (Page 3-16, for example, has an excellent cutaway image of the GE Mark-1 containment involved in this accident.)
  • Third, some radiological doserate information from cities across Japan, March 14 – 15, was sent to me by colleagues in Tokyo.  I’m grateful to Dr. Ryo Fujii, Cancer Intelligence Care Systems Inc., Tokyo, for this document. It is in Japanese, so I recommend Google Translate for non-Japanese-speakers.  Among the highest readings: 1.318 μGy / hr (0.1318 mrad / hr, about 20-40 times local background), was measured in Utsonomiya, Tochigi Prefecture on March 15.  At a site in Tokai, Ibaraki Prefecture (approximately 130 km SSW of the power plant), doserate spiked in the morning on 3/15 to around 5.8 μSv / hr (0.58 mrem / hr).
  • UPDATE, 4:20PM MDT March 17: Detailed dosimetric information from near the power plant, released by the Japanese Ministry of Education, Culture, Sport, Science and Technology (MEST), shows highest radiation levels (about 80 μSv / hr or 8 mrem / hr) to the WNW, 20-30 km from the station (no points within the 20-km exclusion zone are sampled).
  • UPDATE, 12:38AM MDT March 18: More dosimetric information from the Fukushima vicinity has been released.  Note increases and rates as high as 17 mrem / hr outside the expanded 30-km exclusion zone.
  • UPDATE, 10:20AM MDT March 21: New dosimetric information shows radiation levels generally falling in the Fukushima vicinity.  Additional sampling points have been added within the 30-km zone.  The Japanese government has released some contamination estimates throughout the country, showing levels of I-131 contamination as high as 93 GBq (2.7 Ci) / sq. km in Ibaraki Prefecture.  Levels of I-131 and Cs-137 in drinking water are also reported.
  • What’s in the fallout? Isotopic composition of the fallout would be a valuable key to understanding the process that is releasing contamination, and gamma spectrometry is a straightforward technique to measure this.  However, I can find NO public spectra as of March 18.  As Nature learned, the Comprehensive Test Ban Treaty Organization has had such information for a while but is not making it public.  I will opine for a moment to say that the lack of openness from CTBTO, its members, and Japan in particular regarding fallout gamma spectra is a disgraceUPDATE, 10:20AM MDT March 21: UC-Berkeley’s Nuclear Engineering Department publishes HPGe gamma spectra of fallout in their local rainwater.  Contents include I-131, Cs-134, Cs-137, Te-132, and its daughter I-132.   I-131 and Te-132 are short-lived nuclides that would have been generated by recent fission.

Finally, though my outpost here on the ‘net is probably mostly known to a niche audience with a like-minded interest in playing with radiation and collecting radioactive material, I am sobered at the thought of the human suffering brought on by the terrible circumstances unfolding in Japan—psychological terror, physical injury, shattered faith.  I wish I could do more to help.

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Nuclear Collection (Part VI)

March 13, 2011

Click any thumbnail image to view in full size. And, as always, if you have something radioactive and in need of a good home, contact me: I buy and trade all the time. Enjoy!

Lithograph by Leo Vartanian commemorating the CP-1 nuclear reactor.  In what has to be the winningest art idea ever,  moderator graphite from the historic reactor was actually ground up to make the ink in which the portraits of physicists Leo Szilard, Arthur Compton, Enrico Fermi, and Eugene Wigner were rendered.  Prints were distributed by Argonne National Laboratory to honor long and illustrious careers.  The ink is not detectably radioactive.  See my other mementos of CP-1 here. Size is 17″ by 22″(framed).

Though it is in many ways a modern and progressive nation, Japan steadfastly clings to certain curious anachronisms.  From the land of whaling and sailor-suit school uniforms come these examples of radioactive “quack cures”, modern instances of a fad phenomenon that, half a century ago, had largely been driven into extinction in the US and Europe.  Both items pictured—the Wellrich Co. Ltd. “Health Card” (top) and the “Mainasu ION” plaque (bottom)—contain natural thorium as verified by gamma spectrometry.    The “Health Card” claims to offer benefits that include denaturing nicotine in cigarettes.  The health benefits of the negative ion disk aren’t mentioned on it, but surely have no basis in sound science.  It is equipped with an adhesive surface on the back for mounting.  Dozens of varieties of negative ion quack products are peddled by Asian eBay sellers, and I have no idea how many of these items might be radioactive.  The Wellrich card and the ion disk measure 1400 CPM and 550 CPM respectively on a Ludlum 44-9 pancake Geiger tube.  (Donated to my collection by Bill Kolb.)

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More radioactive vacuum tubes. All the specimens in this batch were kindly donated anonymously, and all are receiver protection tubes for military radar sets.  In this application, gas breakdown, aided by deliberately-included radioactivity, dissipates any high-power RF energy that finds its way into the receiver waveguide.  From left to right in the top photo: Varian MA37002X with Co-60 (originally “0.7 microcuries max.”), date code 1995; Omni-Wave MPT-24 with (originally) 25.0 microcuries of Kr-85, date code 1984; Omni-Wave MPT-47-B with (originally) 25.0 microcuries Kr-85, date code 1976.  The gamma spectra of the two Kr-85 tubes clearly shows the residual 514-keV gamma activity of the 10.8-year fission product and even permits a coarse estimate of the quantity remaining (about 3 microcuries in the MPT-24, 0.2 microcuries in the MPT-47-B).  More radioactive tubes are described here and here.

Large receiver protection tube with tritium. The application is the same as the tubes mentioned above, but this one is a monster, measuring almost 16 inches in length.  The part number is MA3948L-12, the manufacturer is Varian, and the contents are mostly argon and a small amount of radioactive tritium (H-3), 10 mCi.  The second photo shows an electrodeless RF discharge established in the tube.
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Contaminated Geiger counter strap from Chernobyl trip. Last summer’s trip to Pripyat resulted in detectable radioactive contamination of my shoes (see description) as well as this shoulder strap.  Gamma spectrometry easily identifies Cs-137, one of the handful of long-lived fission products, in a hot spot on the strap.  The activity in the spot is small, only about one nanocurie (~35 Bq).  Some possible contribution from the synthetic transuranic americium-241 is also noted.

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More radioactive goodies from Bayo Canyon

March 2, 2011

I’ve written about this place twice before, and a bumper crop of radioactive souvenirs from a February visit compels my new assessment that Bayo Canyon, New Mexico is simply unmissable for any hardcore nuclear tourist.  Of course, there’s the historical dimension:  the radiolanthanum experiments that commenced here in 1944 provided crucial insight into the implosion weapon design validated in 1945 by the Trinity test (and embodied later by “Fat Man” and virtually all successive bombs).  But what makes Bayo so special is that the history here is tangible, collectable, and detectable provided you come with a Geiger counter.

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The next four photos at left show pieces of blast debris that were scattered across the surface near the escarpment under Point Weather (where I am standing, 2nd photo above), along with readings in counts per minute on a Ludlum 44-9 pancake GM tube.  While the great majority of findings are not detectably hot, there is so much debris available that the prospects for major finds here are good.  This is my second piece of radioactive cable, and the other two pieces appear to be aluminum metal.  For comparison, local background is about 60 CPM.

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There is sufficient gamma radiation to identify uranium in one of these samples by scintillation spectrometry and to estimate its present activity.  The piece of cable was my choice for this test, owing to easy source-detector geometry and negligible self-absorption.  The last image is the 2000-second NaI:Tl gamma energy spectrum.  The peaks are consistent with the prominent decay radiation of U-235 at 185.72 keV (emitted in 57.2% of decays).  Assuming a geometric efficiency of ~50% and an intrinsic photopeak efficiency of ~75%, the piece of cable contains about 8 mg of uranium if the uranium has its natural isotopic ratio, or about 20 mg if it is depleted. (Both DU and natural U were used in the Bayo experiments.)

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