Current Tritium Sources - USA?

[Encap]

I wonder how much of that actually makes it down to the ground though.

Such an interaction produces tritium atoms, probably radicals, that would need to bind with something relatively heavy to make it diffuse into the atmosphere. If it does not react it will escape the atmosphere since it is light enough to do so (like helium or molecular hydrogen).

Honestly I am not sure how much of the tritium found on the surface of the earth and the oceans actually is from cosmic ray origin. I've always understood that the very vast majority (like 99+%) of tritium in ocean water and such was produced by nuclear bomb tests.

Afaik the amount of tritium in a sample can actually be used to determine age to some dergree, at least to something being older than the massive scale nuclear tests in the 1960s or thereabouts.

The world wide planetary production of tritium from natural sources is 4 x 10 to the 6th power curies per year with a steady state inventory of about 70 x 10 to the 6th power curies. If that helps.
The natural steady-state global inventory is about 7.3 kilograms (kg).
After being produced in the atmosphere, it is readily incorporated into water and falls to earth as rain, entering the natural hydrological cycle.

Here is a whole nine yards about it including environmental concentration--is a pretty good article on it--
see: Tritium and the environment

 

[paul1598419]

The world wide planetary production of tritium from natural sources is 4 x 10 to the 6th power curies per year with a steady state inventory of about 70 x 10 to the 6th power curies. If that helps.
The natural steady-state global inventory is about 7.3 kilograms (kg).
After being produced in the atmosphere, it is readily incorporated into water and falls to earth as rain, entering the natural hydrological cycle.

Here is a whole nine yards about it including environmental concentration--is a pretty good article on it--
see: Tritium and the environment

That was a pretty interesting article. I was glad to see that what I had said about tritium in the environment from nuclear bomb tests was,in fact, true. Most of the tritium in the environment is from upper atmospheric sources as the levels from the 1960s bomb testing have been almost completely depleted. It's interesting that tritium gets from the upper atmosphere to the lower by combining with H+ and as HTO in rainfall. :thanks:

 

[Benm]

It's certainly interesting.

I still don't really understand the reaction mechanism of how tritium formed in the upper atmosphere makes its way down. Tritium radicals certainly form there, but what do they actually react with? To form tritiated water that would have to be OH radicals, but would ordinary hydrogen radicals to not as likely (or more likely due to far lower mass) to combine with those?

Or is this a proces of chances, and the vast majority of tritium produced by cosmic rays actually does never make it to the surface, but the little bit that does is detectable?

 

[paul1598419]

I don't think tritium can exist as a radical in nature. H radicals are only found, as far as i know, in mass spectrometers and other instruments like NMR for very short periods of time and evidence of their existence is only known by their spectral readings. The ion or H+ and OH- certainly do exist and the radical OH does as well. But, these radicals, by definition, do not carry a charge. What would an H radical even look like? If there are radicals of H contributing to reactions in the upper atmosphere they would be incredibly short lived. I think that most of these reactions are accomplished with ions. I have heard of H2+ radicals, but again in mass spec and the like. I suppose because of the cosmic rays and other high energy particles they could exist, but I don't know that there is any proof of it happening.

 

[Encap]

It's certainly interesting.

I still don't really understand the reaction mechanism of how tritium formed in the upper atmosphere makes its way down. Tritium radicals certainly form there, but what do they actually react with? To form tritiated water that would have to be OH radicals, but would ordinary hydrogen radicals to not as likely (or more likely due to far lower mass) to combine with those?

Or is this a proces of chances, and the vast majority of tritium produced by cosmic rays actually does never make it to the surface, but the little bit that does is detectable?

The chemical properties of tritium are essentially the same as those of ordinary Hydrogen and Hydrogen molecule H2.
Two H and one O become H20 --two T and one O becomes T20. Tritium produced in the upper atmosphere becomes incorporated with oxygen and/or H20 tritium atoms have a tendency to replace one of the stable hydrogen atoms in water to become tritiate water.
T2o is a part of the water which then falls to earth as rain.

In nature, tritium is produced as a result of the interaction of high energy cosmic radiation with gases in the upper atmosphere expresed as:
14N + 1n ---> 3H + 12C or 14N(n,3H)12C
and
2H + 2H (deuterium + deuterium)---> 3H + 1H (one tritium and one hydrogen)

The major reaction involved is that of thermal neutrons with nitrogen to become Tritium and Carbon.

IN 1946 Willard Libby, a professor of chemistry at the Unversity of Chicago and the youngest full professor at U of C,
showed that when cosmic rays strike the upper atmospheric nitrogen, tritium and Carbon 12 are formed.
Libby developed the method of separating U-235 from U-238 by gasoeus diffusion, invented Carbon14 dating. and was awarded the Nobel Prize in Chemistry in 1960 among many other things at different times in his life. He died in 1980.
See: Willard Libby - Anthropology - iResearchNet

Have a look at Libby's Nobel Prize lecture on invention/development of Carbon14 dating--the pictures of the equipment he put togather alone are worth a look--very much reminds me of LPF member Laserbulider and his lasers made with technology available from that era.
See: https://www.nobelprize.org/nobel_prizes/chemistry/laureates/1960/libby-lecture.pdf

Pretty humble guy as well--from his Nobel banquet speech:
"You honor me greatly and beyond my ability as an individual but in so doing you honor my colleagues also who made possible the results you have cited. Most achievements in science are to a certain degree group efforts. True, the initial ideas are in general those of an individual, but the establishment of the reality and truth is in general the work of more than one person." ~ Willard F. Libby 1960

 

[paul1598419]

Encap, see my posts #21 and #29 as you have pretty much quoted me from them. Of course I know the chemical reactions of tritium and hydrogen are identical. I'd like to see a Lewis structure for a H radical.

 

[Encap]

Encap, see my posts #21 and #29 as you have pretty much quoted me from them. Of course I know the chemical reactions of tritium and hydrogen are identical. I'd like to see a Lewis structure for a H radical.

Didn't see them before 21 and 29---yes correct right about T production
Was replying to Benm's thought and rattled on. I included your reply to him because it was there--have deleted it.

Are you meaning as in hydrogen atom transfer which is any chemical reaction in which a hydrogen free radical is abstracted?
If so there are 8 Pages of diagrams here: http://www.scripps.edu/baran/images/grpmtgpdf/Lo_Apr_14.pdf

Since we were talking about H2O as "water" and T2O tritiated water, it is simply false to say that water is H2O unless we are speaking very, very loosely. An individual molecule of H2O doesn’t have any of the observable properties we associate with water so chemists use the ‘mixture of ions’ model to describe water’s macroscopic behavior.The idea that water, as in a glass of or raindrop of, simply is H2O is one of those false reductions that people can't seem to get out of their heads.

 

[paul1598419]

I know that water is not the same as a single H2O molecule and doesn't share the properties, such as polarity and surface tension that water has. The OH-, H+ and H3O+ species are just ways to describe the actual properties we observe. I don't believe that T2O actually exists in anyway except very small quantities in nature and it is actually HTO, the species that does exist in large quantities in nature relative to T2O. T2O is a molecule that is made in reactors for the most part. To expect that two protons in a water molecule are bombarded by high energy neutrons to create T2O is highly unlikely.

 

[Benm]

There is no reason T2O could not exist just like D2O does, apart from it being very radioactive and difficult to handle due to that.

You can buy D2O with 99+ percent deuterium in it (so most of it is actually D2O and only a small fraction is DHO) from most laboratory supply stores. It is fairly expensive, but just comes in a bottle or vial and looks like ordinary water. There is no reason to assume T2O would be any different, apart from the price and a hunk of plexiglass around it to shield the radiation.

But what i was hinting at is the production in the upper atmosphere. nitrogen-14 could be struck by a neutron, resulting in 12-carbon and 3-hydrogen just fine.

Question is: where does the charge go, and what do the bonds do?

Nitrogen is normally present as N2. So what happens if one of those two nitrogen atoms gets hit by a neutron and splits into carbon and tritium? In theory it could all just recombine into a molecule of tritiumcyanide. But would it not be more realstic that the neutron impact breaks up the molecule into radicals, that then each find -something- to react with?

Chemistry that high in orbit with low pressures and radiation bombardment can be very different from what we normally observe in the lab on the ground. The ozone layer is a good example of that: ground level O2 does not convert into O3 unless you do something pretty extreme lik running a spark gap. Up there it does due to UV radiation that has enough energy to break O2 bonds and each oxygen radiacal produced has enough energy to attack an ordinary O2 molecule to produce O3 in the end.

I'm not sure how hydrogen or tritium would fare under those conditions, but there has to be some mechanism that bonds it into heavier molecules if is ever to return to the ground. I suppose there is, but i'm curious -what- that mechanism is exactly.

 

[paul1598419]

I think you misunderstood my point entirely. I know you can get T2O in supplies from chemical houses such as Aldrich. I don't think you will find it in large, relative quantities in nature. The species that are bombarded by a high energy neutron are H+ and maybe radical H. Whatever the mechanism, the fact is that it does recombine with OH- or radical OH to produce HTO. You said it yourself that in the upper atmosphere there are high energy bombardments going on. It has been shown that the amount of tritiated water in nature is in the form of HTO. It would be unusual to see a high amount of T2O in the environment.

 

[Down with Umbrella]

Thread subscribed, I was just looking the other day for tritium sources as the subject was brought up on the watch thread.
-I'm curious how quality varies from distributor. Hmm.
Good info guys.

 

[Benm]

@paul

Oh, like that!

Protons (and deutrions and tritions) exchange between water molecules happens quickly even at room temperature and normal pressure. If you mixed 1 ml of D2O with 100 ml of H2O, the next day virtually all of the deutrium would be in DHO molecules. Same for tritium.

In the upper atmosphere radicals have a bit of a free pick though, tritium radicals could also bond with ammonia for example, and not come down as (half)tritiated water molecules. I was kinda curious about what percentage of tritium generated up there actually makes it back to the ground/ocean/etc.

 

[paul1598419]

I never said that protons, deutrions or tritons will spontaneously react with water at normal temperature and pressure. To say what I have tried to get across is anything like that is ridiculous. It wouldn't surprise me to find that tritium bonds with N to form something like ammonia, but I haven't given that any attention or thought. Have you tried to research anything on this subject, or are you just going by what you learned in school? I have looked at at least three different articles on the subject of tritium in the environment and all three have basically stated the same thing. Most of the tritium in the environment are from natural sources as opposed to nuclear bomb testing and most of the tritiated water is in the form of HTO in nature.

 

[Benm]

I haven't learned anything about it in highschool, but a bit more at university studying for chemistry, and some more during a radiological safety course to actually work with radiolabeled compounds.

Those focus mainly on handling procedures and biological effects from exposure, and don't really go into details of formation of elements.

The material did mention the origin of tritium briefly, stating that most of what is now collected on earth is from bomb tests. One thing i'm not sure about is when these texts were originally written. They could be as old as from the 70s, about 4 to 5 tritium half-lives ago.

It could very well be that at the time of writing most tritium came from bomb tests, but that most of that has now decayed and returned to 'natural' levels caused by cosmic rays.

Given no (large) nuclear bomb tests have been done in decades and probably will not be for quite some time, logic dictates that tritium will go back to it's natural, pre-WW2, levels in time, and at that point will be mostly of cosmic ray origin.

Maybe north korea will eventually make a new blip on the man-made tritium record, though i doubt it will register considering the size of the tests done around 1960 with multiple megaton yields.