I was assuming that concrete meant concrete, as in building debris, given that the building had exploded back in March... but I have a desperately literal mind.
Meanwhile some information on tritium:
NISA asked TEPCO for tritium measurements in the subdrains and in the inner harbor, and TEPCO recently provided that information.
What is tritium, and why does NISA care about it?:
Idaho State University has a great set of information on radioactive substances. It is worth remembering that the Idaho National Laboratory is the US Department of Energy's lead nuclear research and development laboratory. Here's information from them on tritium.
http://www.physics.isu.edu/radinf/tritium.htm
Tritium/tritiated water occurs in all the water on earth, as tritium is produced in the upper atmosphere and falls to earth with the rain. It is formed from the following reactions:
[SUP]14[/SUP]N + 1n ---> [SUP]3[/SUP]H + [SUP]12[/SUP]C
or [SUP]2[/SUP]H + [SUP]2[/SUP]H ---> [SUP]3[/SUP]H + [SUP]1[/SUP]H
Cosmic rays interacting with either nitrogen as in the first reaction, or with deuterium, as in the second reaction lead to tritium production. The total amount of tritium on earth from natural sources is about 70 x 10[SUP]6 [/SUP]curies.
A number of commonly used products contain tritium. Tritium was substituted as a less hazardous material for producing reliable light without the need of electricity or batteries than radium. Consequently, tritium is used in EXIT signs (as in theaters), rifle sights, and as paint for watch dials and hands.
A typical rifle sight has 0.012 curies of tritium. A typical watch with luminescent hands has 0.200 curies of tritium. Exit signs have several curies of tritium. In the case of rifle sights and exit signs, the tritium is in gaseous form and is contained in a glass tubes.
Tritium is a radioactive substance.
The radioactive decay product of tritium is a low energy beta particle that cannot penetrate the outer dead layer of human skin. Therefore, the main hazard associated with tritium is internal exposure from inhalation or ingestion. In addition, due to the relatively long half life and short biological half life, an intake of tritium must be in large amounts to pose a significant health risk. Although, in keeping with the philosophy of ALARA, internal exposure should be kept as low as practical.
The curie (Ci)is a unit of radioactivity. It is the amount of a radioactive substance that has 3.7 x 1010 decays per second.
The tritium used in rifle sights and exits signs is human-made, and is generated by bombarding hydrogen with neutrons in a nuclear reactor or an accelerator (MLM-3719, 1991).
Tritium is used in some self-illuminating exit signs to light the exit in the event of an electrical outage or a fire. Signs often have several curies of tritium in them. If the exit signs were severely damaged, HT gas might escape into the local area, but it should be dispersed by ventilation or wind quickly. The damaged sign would be expected to have relatively high levels of tritium on it, and should not be handled without gloves.
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To help evaluate the potential risks from tritium exposure, consider the following made-up scenarios:
1) all of the activity of a rifle sight is ingested;
The rifle sights contain 12 mCi of tritium. If all of its activity were ingested, the CEDE would be 768 mrem or roughly two years of dose from natural background.
..
Another scenario
5) as a worker, you are told that you have 30,000 pCi/L of tritium in your urine for the whole year;
30,000 pCi/ liter would give a dose of 2 mrem per year.
6) as a worker, you are told that you were exposed with a single uptake of 8 mCi of tritium;
An uptake of 8 mCi would result in a dose of 500 mrem, or about one and a half years of natural background radiation dose
Is Tritium harmful?http://www.trijicon.com/na_en/support/faq_general.php
(a rifle sight company)
According to documentation by health physicists in statements on file at the U.S. Nuclear Regulatory Commission (NRC), it would take the simultaneous rupture of 10,000 of these small glass capsules in a small room 10 foot by 10 foot to potentially constitute a radiation health hazard. For this reason, customers need not be concerned about the potential risk of the night sight system. Furthermore, our front sight is 0.018 curies and the two rear sight dots are 0.018 curies each. A complete sighting system is 0.054 curies. This is less than many tritium watches, which have up to 0.200 curies or roughly four times as much radioactivity. In addition, the weapon is not as close to the body, and in less constant use than a watch.
I became curious about how much tritium exactly was used to produce theater exit signs, so I posted the question on Rod Adams' nuclear blog. Rod was kind enought to answer:
June 23, 2011 | 4:40 AM
http://www.nrc.gov/reading-rm/doc-collections/fact-sheets/fs-tritium.html
After reading this, I wondered how hazardous the tritium spill at Vermont Yankee nuclear plant was, and also wondered how many exit signs it would be.
Rod Adams
June 23, 2011 | 5:40 AM
@D.P.
First of all, your comment inspired me to check my units and math one more time. It turns out that I was off by a significant amount – the total amount of tritium released by the Vermont Yankee leak was 0.35 curies, but a curie of tritium has a mass of 0.1 milligrams, not 0.1 grams. Therefore, the amount of tritium should have been 0.035 milligrams, not 0.035 grams. I am going to correct the post as soon as I finish this comment.
According to Meredith Angwin at Yes Vermont Yankee, a tritium exit sign will typically contain about 30 curies of tritium.
http://liveshots.blogs.foxnews.com/...try-faces-concern-nationwide/?test=latestnews
We’re talking about picocuries of tritium that we’re seeing. The highest about 2.8 million picocuries, that’s a trillionth of a curie.” explained Smith. “To put it in perspective, if you see exit signs in buildings that are illuminated- they typically have 15 curies of tritium. So we’re talking about a very small amount but, nonetheless, this is important for us to find the source of the leak and to stop it.”
So Rod did some calculations and found:
100,000 gallons (roughly 370,000 liters) at slightly less than one million picocuries per liter contains approximately 0.35 curies. (370,000 x 970,000 picocuries x 1 curie/10^12 picocuries = 0.35 curies)
If you want to extract tritium from that source of water to produce exit signs, you would need to have 30/.35 or 86 times as much water. Let me say that one more time – you would need 8.6 MILLION gallons of water containing nearly 50 times the drinking water standard in order to produce enough tritium for a single exit sign.
See why I truly believe that the reports about tritium leaks need some perspective?
http://www.epa.gov/rpdweb00/radionuclides/tritium.html#where
Here's what the EPA has to say:
How does tritium get into the environment?
Tritium occurs naturally in the environment in very low concentrations. Most tritium in the environment is in the form of tritiated water, which easily disburses in the atmosphere, water bodies, soil, and rock.
In the mid-1950s and early 1960s, tritium was widely dispersed during the above-ground testing of nuclear weapons. The quantity of tritium in the atmosphere from weapons testing peaked in 1963 and has been decreasing ever since.
Today, sources of tritium include commercial nuclear reactors and research reactors, and government weapons production plants. Tritium may be released as steam from these facilities or may leak into the underlying soil and ground water. However, such releases are usually small and are required not to exceed federal environmental limits.
A recently documented source of tritium in the environment is tritium exit signs that have been illegally disposed of in municipal landfills. Water, which seeps through the landfill, is contaminated with tritium from broken signs and can pass into water ways, carrying the tritium with it.
So if you're worried about tritium, you should be sure that building wreckers dispose of the EXIT signs correctly.
How does tritium change in the environment?
Tritium readily forms water when exposed to oxygen. As it undergoes radioactive decay, tritium emits a very low energy beta particle and transforms to stable, nonradioactive helium. Tritium has a half-life of 12.3 years.
Current treatment of landfill leachates do not remove tritium.
And perhaps the most important thing:
What does tritium do once it gets into the body?
Tritium is almost always found as water, or "tritiated" water. Once tritium enters the body, it disperses quickly and is uniformly distributed throughout the body. Tritium is excreted through the urine within a month or so after ingestion. Organically bound tritium (tritium that is incorporated in organic compounds) can remain in the body for a longer period.
Tritium atoms can exchange with any hydrogen atoms. If the hydrogen atom is part of an organic molecule, the tritium becomes 'organically bound' and is transported with the molecule rather than moving freely like water.
Health Effects of Tritium
As with all ionizing radiation, exposure to tritium increases the risk of developing cancer. However, because it emits very low energy radiation and leaves the body relatively quickly, for a given amount of activity ingested, tritium is one of the least dangerous radionuclides. Since tritium is almost always found as water, it goes directly into soft tissues and organs. The associated dose to these tissues are generally uniform and dependent on the tissues' water content.
Everyone is exposed to tiny amounts of tritium, much of it produced naturally. If you live near, or work at, a nuclear research facility, a commercial reactor, or a government weapons facility, you should be aware that your tritium exposure may be elevated. Also, be careful not to break open an exit sign, or other device that may contain tritium as an illuminating agent.
So when Vermont decided to close Vermont Yankee nuclear because of a tritium leak, they were worried about a problem that was less than one improperly disposed of theater exit sign, and was diluted in 100,000 gallons of water.
http://www.gazettenet.com/2011/06/21/vt-reactor-continues-tritium-cleanup
The Vermont Senate was so troubled by tritium leaks - as high as 2.5 million picocuries per liter at the reactor, or 125 times the EPA drinking-water standard - that it voted to block relicensing. The Senate vote also followed admissions by the plant that it misled Vermont regulators and lawmakers about whether the plant had the kind of underground piping that carries radioactive material.
So how does this compare to what TEPCO found?
In seawater, they found 180 becquerels per liter.
Ci=2.7×10[SUP]-11[/SUP])×Bq. Bq=37000000000×Ci. Definitions and calculation
pico is 10[SUP]-12[/SUP], from piccolo, Italian for very small indeed.
That would be 486x10[SUP]-11 [/SUP]Curies or 4,860 picocuries per liter, or 4.86 nanocuries or
0.00486microcuries or 0.00000486 millecuries. A complete sighting system for guns would them be 54 millecuries. In other words, you would need a huge amount of this water to make a single set of gunsights.
Now lets look at the water in the subdrain of Unit 2 (no tritium was found in the Unit 5 subdrain).
TEPCO reported that 3,700 becquerels per liter were found in the Unit 2 subdrain. That would be 99,900 picocuries or 99 nanocuries or 0.099 microcuries or 0.000099 millecuries, and you would still need a huge amount of that water to make a single set of gunsights, let alone a theater EXIT sign.
