drdave@rocksvax.UUCP (Dave Birnbaum) (09/28/83)
Asides from the walls of the containment vessel which I agree are not a serious problem, most fusion processes involving hydrogen produce tritium (H3). With a half-life of 12.6 years and the aboility to insinuate itself into the biological chain easily (as water!) it poses a serious health hazard. Sorry to inject some physics into this fray. Dave Birnbaum
halle1@houxz.UUCP (09/30/83)
Tritium is a FUEL for the reactors, not a waste product. Any that might be produced would then be consumed.
abc@brl-bmd@sri-unix.UUCP (10/02/83)
From: Brint Cooper (CTAB) <abc@brl-bmd> "Asides from the walls of the containment vessel which I agree are not a serious problem, most fusion processes involving hydrogen produce tritium (H3). With a half-life of 12.6 years and the aboility to insinuate itself into the biological chain easily (as water!) it poses a serious health hazard." But isn't the Tritium what is needed to fuel the fusion process? And, if I read October SCI AMER correctly, too much Tritium won't be the problem, not enough Tritium will be the problem, not so? In other words, won't it be more difficult to keep the fusion process going that to generate so much Tritium that we must worry about disposing of the excess?
bill@utastro.UUCP (10/03/83)
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KING@KESTREL@sri-unix.UUCP (10/03/83)
From: Richard M. King <KING at KESTREL> Suppose a reactor contains approximately one kilogram of tritium, which is approximately 10e7 curies or 10e29 disintegrations per second. Suppose some evil force releases ALL of the tritium, which is burned and sent up to a rain cloud. Suppose that rain cloud dumps a centimeter of rain on a 10KM by 10KM area which includes a household with a rain barrel, and then suppose I drink a liter of the rain water. I think you'll have to admit that this is close to a worst case. The total amount of rain is 10e9 liters, so I drink ten millicuries. The half-life of water in the body is only a couple of weeks. A person holds a millicurie of potassium and carbon -- day in, day out, forever. The latter is more of a danger than this extremely bad scenario. This is an unlikely worst case. If the reactor designers have any sense the tritium would be stored in several separate containers. I will allow that it would all burn in an accident, because that accident might include a fire. Not all of the humidity in a given region makes it into a rain cloud - figure a 90% reduction there. Also, rain clouds are not particularly efficient at dumping their moisture; some of it evaporates before the rain falls, and some of it evaporates on the way down. I suppose that if I were "in charge" I would tell people not to drink water from their rain barrels for a few days. In the case of a municipal resivoir, 10e9 liters is a joke; 10km*10km*100m is a small municipal resivoir, and this contains 10e13 liters. Storing the stuff as LiOTr or NaOTr would reduce the probability of a leak, but I would prefer the gas form because the material would dissipate more readily. The important point is that if I have to have one of life's elements contaminated, I prefer Hydrogen. There is so much of it in the environment that dilution is effective; it doesn't concentrate anywhere in the body, and it doesn't concentrate in the food chain. (Remember that Strontium was so dangerous because it cincentrated in bone.) Also, very few life forms absorb water vapor; it has to fall, and this isn't an efficient process. Sure, it eventually ends up in the ocean but the oceal already contains far more than a kilogram of tritium (more like several tons)! No, I don't think that a fusion reactor's inventory of fuel constitutes a health hazard. Dick -------
BILLW@SRI-KL@sri-unix.UUCP (10/04/83)
On top of that, Tritium is an alpha emitter. Alpha particles have trouble getting through a piece of paper or a couple of inches of air, so the only tritium you really have to worry about is that which gets incorporated directly into cells... tritium is currently used in glow-in-the-dark watches, involving a glass envelope with phosphor and tritium inside. The alphas make the phosphor glow, but they dont get through the glass... BillW
JWJ@MIT-MC@sri-unix.UUCP (10/04/83)
From: Joseph W. Johnson <JWJ @ MIT-MC>
On top of that, Tritium is an alpha emitter.
Correction: tritium is a beta emitter, decaying into Helium-3 with a
half life of 12.33 years. the decay energy is pretty low, only 0.019 MeV.
Joe Johnsonbane@umcp-cs.UUCP (10/06/83)
Contrary to a recent posting, tritium is NOT an alpha emitter, and cannot be.
Alpha particles are helium-4 nuclei (2 protons, 2 neutrons). Tritium is
actually a mild beta (electron) emitter, converting itself into helium-3.
I own a TI glow-in-the-dark watch, and I remember looking this up once to
check the half-life of the tritium. The 12 year half life is actually a
disadvantage here; my watch is 6 years old and noticeably dimmer now.
--
Arpa: bane.umcp-cs@udel-relay
Uucp:...{allegra,seismo}!umcp-cs!banecaf@cdi.UUCP (caf) (10/08/83)
There is SOMETHING that gets through the faceplate on at least one brand of tritium illuminated watch; it made my Geiger counter go crazy. -- Chuck Forsberg WA7KGX CDI Portland OR (503)-646-1599 cdi!caf
mat@hou5d.UUCP (10/28/83)
There is SOMETHING that gets through the faceplate on at least one brand of tritium illuminated watch; it made my Geiger counter go crazy. -- Chuck Forsberg WA7KGX CDI Portland OR (503)-646-1599 cdi!caf Yup. The readiatio gets through the faceplate, but I seem to recall that if you interpose a sheet of conductive material (like the BACK of the watch) the radiation will be attenuated enourmously. Tritium, with a half life af 12 to 13 years is the FUEL in the proposed fusion reactors. (actually, it is more like an octane booster ...) The real hazard comes from the materials used to MAKE the tritium. A blanket of some lithium does niceley. And there is the neutron bambardment of the structure of the reactor. And ... The lates Technology Review hits this topic. Worth reading. Mark Terribile hou5d!mat