Japan Earthquake | Page 2530
correct...but the neutron with a neutral charge interacts with another nuclei or atom which in turn does the ionizingby dean 10/20/2011 1:27:51 PM
@dean yes, that i meant :)by Edano 10/20/2011 1:29:05 PM- thermalized neutrons have about the same mass as a hydrogen atom and loose energy.. in a reactor a fast neutron once born from fission.. typically undergoes about 15 collisions to reach the thermal energy level ,,, in the case of U235 which has a high cross section for absorption with a thermal neutron and thus causes another fissionby dean 10/20/2011 1:30:21 PM
There is a document included with the article. Trying to translate bits to see if it tells anything.by lillymunster 10/20/2011 1:33:46 PM- @lilly.. that's why I'd like to see what kind of instrument they use for detecting and then measuring neutron field.... it would have to be some sort of instrument with a chamberby dean 10/20/2011 1:34:05 PM
- there are neutron dosimeters.by Edano 10/20/2011 1:34:41 PM
- it's pretty technical stuff when measuring neutrons and trying to segregate photons from neutrons etc...by dean 10/20/2011 1:34:56 PM
by Edano via Ptb.de 10/20/2011 1:35:24 PM- The document they attached is from the JCO criticality accident. Is that meaningful to this or no?by lillymunster 10/20/2011 1:35:33 PM
- true at Edano.. the old badges I wore were called film badges.. and the film part was for the neutronsby dean 10/20/2011 1:36:49 PM
- by Edano via Mirion 10/20/2011 1:37:39 PM
- the neutron interacted with the film material and left a track that could be detected and counted ... newer ones are used nowby dean 10/20/2011 1:37:44 PM
- The older type of neutron dosimeter is the Neutron Track Emulsion film badge. Like other film badges, it was very accurate, reliable, and a permanent record of exposure. I don't think these are being used anymore for personnel dosimetry. Once developed, it shows a number of tracks that can be counted to quantify the exposure.
The Lithium Fluoride TLD is a newer method, if you consider 1960's technology to be "new". It works much like other TLD's, and looks just like them, except for the shielding in the case.
There also is an albedo dosimeter - which means that it actually measures the radiation coming OUT of the body after being reflected. I don't know the exact combination of chips used in this TLD, but I remember that it has to be worn tight against the body to be accurate. Like most TLD's in use outside the navy, there are multiple different chips and attenuators corresponding to each.
There is also timekeeping - where you just measure the dose rate and multiply it by the time of exposure. Or, you can just figure out the ratio of neutron dose rate vs. gamma dose rate for the work area and assign a correction factor to the gamma dose to account for the neutrons.
"Primarily" is a broad term, that assumes that one method is used regularly. But, the people who work with radiation are the type of people who like to reinvent the wheel a lot - not because they are stupid, but because they think they understand the concept of roundness better than anyone else, and you can't talk them into accepting a common method when they can spend so much more time and money developing one of their own that is just about as good. So, if you can find two nuke facilities using the same dosimeter, they're certainly using them differently.by dean 10/20/2011 1:39:05 PM - @ Edano.. those are high tech compared to what I wore... and there have been lots of changes over the years..by dean 10/20/2011 1:39:41 PM
- @lilly.. for detection purposes I would say it is applicableby dean 10/20/2011 1:40:12 PM
- @ Edano, can you find how those instruments detect the neutrons.. they could be gas filled or have some material the neutrons interact with ..by dean 10/20/2011 1:45:17 PM
- by Edano 10/20/2011 1:45:21 PM
- TLD 760 Dosimeter
Fully Automated Precision Response
Thermoluminescent dosimeters (TLDs) offer the versatility to be used in all radiation environments by providing precise response to a variety of radiation types. Thermoluminescent dosimeters also offer the advantage of long wear periods due to their resistance to environmental factors such as heat and humidity. The TLD 760 badge utilizes four lithium fluoride thermoluminescent elements. This combination responds accurately to neutron, as well as, beta, gamma and X-ray radiation. The TLD 760 allows for accurate reporting of deep, lens of eye and shallow doses, and has a thin mylar window for detection and measurement of low energy beta radiation.by dean 10/20/2011 1:46:27 PM 
TLD 760
by dean 10/20/2011 1:47:32 PM- Name TLD 760 Dosimeter
Dosimeter Type 1 LiF600 and 3 LiF700 Chips
Minimum Reportable Dose 10 mrem (0.10 mSv)
Useful Dose Range 10 mrem - 1000 rads (0.10 mSv - 10 Gy)
Photon Energy Response 5 keV - 6 MeV
Beta (MAX) Energy Response 0.766 MeV - 5 MeV
Neutron Energy Response Specific Calibration Requiredby dean 10/20/2011 1:48:21 PM - NEUTRON DOSIMETRY WITH BORON-DOPED CR—39 PLASTIC PLATE www.irpa.net they use chromeby Edano 10/20/2011 1:48:31 PM
- I'm educating myself today to the latest technologies.. wow ...by dean 10/20/2011 1:49:02 PM
- again, cr39 www.osti.govby Edano 10/20/2011 1:49:56 PM
- those systems need labratory work to etch and then count... I think this link shows ways to know instantly in the field for neutrons...http://worldwidescience.org/topicpages/f/film+neutron+dosimeters.htmlby dean 10/20/2011 1:52:36 PM
- by dean 10/20/2011 1:52:41 PM
- The JCO document is mostly explaining neutrons and the ICRP guidelinesby lillymunster 10/20/2011 1:53:58 PM
- comprehensive: www.radccore.orgby Edano 10/20/2011 1:56:05 PM
Good morning everybody, I find pzling in this report fukushima-diary.com that the count at the "neutron ray" energy (LEU) was lower close to the ground than higher up. It would also be good to understand how the pre-accident level was derived and what counts they had at the energy in question.by Peter 10/20/2011 1:57:49 PM- The keys the keys: puzzling, of course.by Peter 10/20/2011 1:58:23 PM
@all JOIN THE BEYOND NUCLEAR "I HAVE A SCREAM" RALLY ON HALLOWE'EN!
Does the continued promotion of nuclear power by the Obama administration – even after Fukushima – make you want to scream? If so, you are not alone. Join like-minded activists at the Beyond Nuclear I Have A Scream rally on Hallowe’en at 12 noon, Monday, October 31 outside DOE headquarters (see flyer for details).
On October 31, an aptly chosen date, the US Energy Department’s Blue Ribbon Commission on America’s Nuclear Future will finally close its supposedly open doors to any further public comment on its mandate to “solve” this country’s radioactive waste problem. Using millions of our taxpayer dollars, and after junkets to France and Finland, the commission has come up with nothing new at all! To wit: it recommends that a new search should be made for a geologic repository; reactor waste should be transported to centralized interim storage sites; and that research, development, and demonstration dollars from taxpayers should continue to be wasted on reprocessing.
Wear a costume, bring a sign and let your voices - and screams - be heard!
www.beyondnuclear.orgby smoss 10/20/2011 1:58:50 PM- good one @ Edanoby dean 10/20/2011 2:01:01 PM
- @Peter.. hi.. it is puzzlingby dean 10/20/2011 2:02:27 PM
- If we can come up with a list of questions I can post it to their site and see if we get any answers.by lillymunster 10/20/2011 2:03:38 PM
- as far as i can see there seem to be numerous techniques of neutron dosimetry.by Edano 10/20/2011 2:07:01 PM
- indeed @ Edanoby dean 10/20/2011 2:08:01 PM
- aha: The Hiroshima neutron dosimetry enigma: Missing puzzle piece No. 6 mystery.........by Edano 10/20/2011 2:09:22 PM
- gaddhafi captured ???by Edano 10/20/2011 2:12:26 PM
- @Edano.. the news I've seen varies from captured,, to captured and injured leading to his death.. to deadby dean 10/20/2011 2:13:58 PM
- all awaiting confirmation of courseby dean 10/20/2011 2:14:37 PM
- this explains why they did not surrender.by Edano 10/20/2011 2:14:41 PM
- dead.. they showed a photo in tv.by Edano 10/20/2011 2:16:02 PM
- Gadhafi reportedly shot on the run
Fighters attacked the house where Moammar Gadhafi was hiding and shot him when he tried to flee, a spokesman for Libya's new government says.by dean 10/20/2011 2:17:13 PM - that's from CNNby dean 10/20/2011 2:17:31 PM
english.kyodonews.jp
Fukushima assembly adopts petition for decommissioning local reactors
FUKUSHIMA, Japan, Oct. 20, Kyodo
The Fukushima prefectural assembly adopted on Thursday a petition calling for decommissioning all 10 reactors at the prefecture's two nuclear power plants in the aftermath of the nuclear disaster at one of them following the March earthquake and tsunami.
The request over Tokyo Electric Power Co.'s crisis-hit Fukushima Daiichi plant, where four of six reactor units were damaged, and nearby Fukushima Daini plant with four reactors goes further than statements by the utility and the central government, which have yet to unveil their plan on the future of the plants' six undamaged reactors.
Fukushima Gov. Yuhei Sato said the assembly's move ''really has weight'' and reiterated his view that it is impossible for the Daiichi and Daini plants to resume operations. english.kyodonews.jpby Edano via English.kyodonews.jp 10/20/2011 2:18:43 PM- reuters confirms death.by Edano 10/20/2011 2:18:54 PM
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