I’m looking for a factual answer to a fictional quote:
In Spider Man 2 Doc Ock says there is 25 pounds of tritium in the world.
Is this true? I know tritium is an isotope of Hydrogen and is therefore present in sea water, what percentage of sea water has a tritium component?
Surely given the billions of tons of water in the oceans of the world even if tritium is only a tiny proportion of the water then it would come to more than 25 pounds.
BTW is tritum gaseous or solid in its natural state?
Tritium is normally produced in specially configured nuclear reactors. It is a gas at standard temperature and pressure. It is commonly used to boost the yield of fission devices used in nuclear weapons, where it is injected into the fission core before implosion.
While it may be present in the atmosphere and oceans in trace amounts, it would not be practical to extract it from those sources.
So where do we get the tritium for watches and pistol night sights from? The reactor thingees?
I believe they buy it from the Department of Energy, who produced it in reactors. I used to have a DoE price list for all sorts of weird radioactive isotopes.
The DoE’s tritium production facilities were shutdown in 1988 due to environmental and safety concerns. Tritium is recovered from dismantled nuclear weapons. Due to its relatively short half-life, existing stockpiles are shrinking rapidly. New tritium production will be accomplished by installing special fuel rods in existing nuclear reactors.
See http://www.nrc.gov/reading-rm/doc-collections/fact-sheets/tritium.html
Tritium is a radioactive isotope of hydrogen - a proton and two neutrons. It decays over time (presumably by beta-decay - one of the neutrons spits out an electron to leave a proton, giving you two protons and a neutron - helium 3). There isn’t any in seawater - if there ever was any, it would have all decayed away by now.
Chemically, tritium is identical to hydrogen. As an element it would be a gas like hydrogen, burn it and you’d get tritium oxide, “extra-heavy water”. (My terminology! As opposed to deuterium oxide, “heavy water”, or protium oxide, normal or “light” water.) Presumably drinking it would be a radiological hazard. It would probably also be slightly toxic in the same manner as heavy water - the slightly greater mass of tritium and deuterium makes them mess up diffusion and osmosis rates and screw with cellular interactions.
Tritium is made by exposing lithium to neutrons, e.g. by strapping lithium to the outside of a fission reactor. It boosts fission bomb yields, meaning you can use a smaller quantity of plutonium/uranium for the same bang. Since plutonium/fissile uranium are expensive, tritium boosting has become standard. A lot of fission bombs would probably still be viable as weapons if you eliminated the tritium - they’d just have a smaller yield. However, where the fission bombs are used as triggers for H-bombs you have to maintain the tritium level or the H-bomb stage might not fire.
Thanks everyone for enlightening me about tritium. However, no one has yet mentioned the rate at which we can produce it and therefore the quantities in existence at any given time.
BTW what is the half life of tritium?
I typed [“half-life” tritium] into Google and the first hit on the Google page says:
That wasn’t so hard, was it?
Sorry, too lazy to google, as I was already logged on here it seemd the easiest and best way to get an answer.
This link is an article on deuterium/tritium fusion. it states that there are approximately 18.5 kg “on hand.” I can’t say whether this means worldwide, in the US, or available ay Los Alamos, but at 2.2 lb/Kg, this means that there is at least 40 lbs of tritium, somewhere, so Doc Oc is full of shit, but what else would you expect from an evil scientist?
That sounds wrong for a couple of reasons:
firstly it seems unlikely that it would decay away entirely - just keep on halving - perhaps to the point where it is exceptionally rare, but not absent, surely.
Secondly, and perhaps more importantly, aren’t there ongoing natural processes that produce tritium?
IIRC, it wasn’t tritium that Doc Oc needed, but some fictitious material that sounded similar.
Tritium has a half life of 12.3 years (give or take a month). So over 120 years you’d have 0.1% of the original left over.
As for natural formation, cosmic rays interact with nitrogen and hydrogen in the upper atmosphere to produce tritium. It then tends to form a type of heavy water (HT0 and occasionally TTO). That rains down, but let’s face it, in such minute amounts that I can’t even find a % abundance number any where. Anyone got some?
I’ll take the second one first, since it’s relevant to answering the first one.
Elements are typically radioactive because they are a) too heavy, or b) have unfavourable ratios of protons to neutrons in their nuclei. Too many neutrons and they can convert a neutron to a proton by its spitting out an electron. That is beta decay. Too heavy and they can spit out an alpha particle, that is two neutrons and two protons bound together. An alpha particle is a helium nucleus, so alpha decay constantly generates helium.
Now, when a radioactive element decays either by alpha or beta, the number of protons changes so it becomes a new, lighter element. That element may be either stable or unstable. If unstable, it will undergo decay again until some stable element is formed. That constitutes a decay chain. Typically, your naturally radioactive elements are HEAVY, and they produce lighter isotopes as they decay. Those decay chains tend to stop at lead rather than proceeding onto lighter elements.
As far as I know, there are no natural elements that have tritium in their decay chain so there are no natural processes that produce tritium. (If I’m wrong, it’ll be far from the first time!) The “unnatural” elements on the other hand are typically produced by fission, where the heavy fissile atoms split apart to produce lighter atoms (fission fragments) and neutrons. The fission fragments may have tritium in their decay chains (not sure). “Unnatural” elements are also produced by neutron absorbtion by natural elements, so tritium can be produced if e.g. lithium is struck by neutrons. There may be other reactions.
Now, there have been natural subterranean fission reactions in the past, when highly concentrated uranium ore got together with ground water and formed a natural reactor. So technically you could get natural tritium, but it isn’t happening right now. We can safely say that the quantity of natural tritium that has ever existed on Earth was small.
As to your first point, you’re right about half-lives but you can’t split your last tritium atom in half. The half life of tritium is a tad over 12 years, let’s not quibble and say 13. In 1300 years, that’s 100 halvings. Which on average is enough to reduce 6.3 tonnes of tritium down to ONE ATOM, which will itself decay. So with a small enough half life and a long enough time, you can indeed lose the lot.
See! Cosmic rays! I forgot the cosmic rays!
Yeah, I came across this information whilst reaching my Staff Report on heavy water. Duterium occurs naturally at the rate of about one atom per 6700 atoms of hydrogen, while tritium occurs naturally at the rate of about 1 per 10[sup]17[/sup] hydrogen atoms.
Teach me to post before having my coffee. That should be “researching”, not “reaching”. Sheesh.
Of course if I looked a little harder…
from this pdf Environmental Agency (UK).
Anything that uses a unit based on 10[sup]-19[/sup] is damn small. 
Any research I do tends to involve a fair bit of reaching anyway.
Ok the USGS says there are 326 million cubic miles of water on earth. The 3100 cubic miles in the atmosphere can be neglected.
1 cubic mile is 4x10[sup]12[/sup] liters. So we have 1304x10[sup]18[/sup] liters of water on earth. That gives us 143.4x10[sup]3[/sup] moles of tritium.
At 3 g/mole for tritium there is about 433 kg just waiting for you out there. Best of luck!
Tritium’s a gas. But didn’t Doc Oc have a “chunk” of it. WTF