ps01%gte.com@RELAY.CS.NET (Paul L. Suh) (07/13/89)
From: "Paul L. Suh" <ps01%gte.com@RELAY.CS.NET>
%In sci.military Digest Monday, 10 July, 1989 Volume 2 : Issue 41 "Nicholas
%C. Hester" <IA80024%MAINE.BITNET%CUNYVM.CUNY.EDU@CUNYVM.CUNY.EDU> writes:
%> > DU is extremely hard, and denser than tungsten (or lead); these two
%> > properties make it an excellent choice for kinetic energy armor
%> > penetrators. [ ... ] An added bonus of DU is that it is somewhat
%> > pyrophoric; that is, it is easy to ignite (say, by slamming it into a
%> > metal plate at a few thousand feet per second 8-); this gives it an added
%> > incendiary effect, which may or may not be useful against tanks. - Bill ]
%> This is interesting in that the Army is going to add DU to the armor of the
%> M1. Will this help protect the tank, or possibly create a greater incendiary
%> situation?
%In one installment of "For Your Eyes Only" in the old _Strategy_&_Tactics_, I
%recall a brief discussion on depleted uranium rounds. One interesting point
%raised (that I have not heard mentioned since) was _S&T's_ contention that upon
%encountering massive G forces (such as would occur upon striking armor at high
%speed), a DU round will emit an intensely lethal but extremely brief burst of
%radiation. They claimed this could very well be fatal to armor crews, even if
%the round did no other damage. Does this sound logical? I have the issue and
%can dig it out with some effort, if anybody wants the specifics.
%--
%NSA food: Iran sells Nicaraguan drugs to White House through CIA, SOD & NRO.
%~~~~~~~~~~~~~~~~~~~~~~~~Michael Trout (miket@brspyr1)~~~~~~~~~~~~~~~~~~~~~~~~~
%BRS Information Technologies, 1200 Rt. 7, Latham, N.Y. 12110 (518) 783-1161
%"God forbid we should ever be 20 years without...a rebellion." Thomas Jefferson
This is absolutely NOT the case. Depleted uranium rounds are only
barely radioactive. This effect _might_ occur if you used enriched
uranium, where the crushing effect of the impact (not the G forces)
would initiate a partial chain reaction. (Many tactical nukes currently
in use apply this principle: if the fissionables are squeezed to a higher
density, you can use less of them. They are the so-called
'sub-critical' tac nukes. The squeezing is done by explosive charges in
excess of those otherwise used to detonate the bomb.) However, the hull
of a tank is pretty good protection against radiation (most modern tanks
have a lead liner inside the armor) if it is not penetrated. If it _is_
penetrated, then the radiation effects are probably pointless overkill.
Not to mention that enriched uranium is expensive and in short supply;
while depleted uranium, the byproduct of the enrichment process, is
relatively abundant and cheap.
A similar sort of thing which has appeared in some science fiction works
(this does not exist currently, and probably won't for the near future)
is the collapsible round. It is a hollow shell (much like a present-day
artillery round without the HE filler) made of an element with a low
critical mass. While the shell retains its shape, it will not fission,
because although it has the necessary critical mass, that mass is spread
over a large volume. When it impacts on a target, the shell collapses,
thus triggering a nuclear explosion. These rounds were supposed to be
of ~40mm in size.
Lastly, I've heard that analysis of pictures of the inside of a T-80
shows that the Soviets have developed a DU armor insert for the front
of the turret. (The insert was removed for the pictures, but the
mounting brackets were still visible.) Can anyone confirm this?
--Paul
ps01@gte-labs.comjohn@gatech.edu (John DeArmond) (08/29/89)
From: stiatl!john@gatech.edu (John DeArmond) [An old article got released from some site, with misinformation that was corrected when it first came out. I'm posting John DeArmond's reply so no one is misled, but I'm not going to allow any more posts on this. If you're interested in the original discussion, ask military-request@att.att.com for the appropriate digests. --CDR] In article <8230@cbnews.ATT.COM> ps01%gte.com@RELAY.CS.NET (Paul L. Suh) writes: >%In one installment of "For Your Eyes Only" in the old _Strategy_&_Tactics_, I >%recall a brief discussion on depleted uranium rounds. One interesting point >raised (that I have not heard mentioned since) was _S&T's_ contention that upon >encountering massive G forces (such as would occur upon striking armor at high >%speed), a DU round will emit an intensely lethal but extremely brief burst of >%radiation. I hate to inject some physics into this discussion but this thread has gone way past the ridiculous. All of the above is patently false. The forces exerted on matter, even when traveling at the velocity of cannon rounds are trivial compared to the nuclear forces that hold atoms together. It is simply impossible to "jar a few neutrons" out by hitting Uraninum. Some particulars. Yes, there is a class of atomic weapon known as the implosion bomb. Which has nothing to do with this discussion. An implosion bomb uses specially shaped explosives to drive a sphere (or other shape) of fissionable into a smaller, denser, and critical mass. Even when the explosion creates a massively supercritical mass, massive fission does not commence for a period of time ranging from a few to very many milliseconds depending on how neutronically quiet the area is. Uranium and plutonium both undergo spontaneous fission so a neutron will eventually become available. In any event, this time frame is an eternity compared to the impact time of a bullet. Atomic weapons do not rely in spontaneous fission. They contain devices that supply bursts of precisely timed neutrons to the supercritical mass. The effects of depleted U projectiles are strictly limited to the physical and chemical properties of the metal. It is the heavist naturally occuring metal so it delivers the greatest knetic energy for a given bullet size. And since it is pyrophoric, it will be on fire and probably molten when it penetrates the target. Both are very destructive but have NOTHING to do with the nuclear properties of the metal. John -- John De Armond, WD4OQC | Manual? ... What manual ?!? Sales Technologies, Inc. Atlanta, GA | This is Unix, My son, You ...!gatech!stiatl!john **I am the NRA** | just GOTTA Know!!!
MT666_VINARC@kcgl1.eng.ohio-state.edu (04/11/90)
From: MT666_VINARC@kcgl1.eng.ohio-state.edu Based on the discussion so far, I assume that so-called "depleted uranium" is actually U-238, the stable isotope of Uranium. (Please correct me if I am wrong). U-238 is mostly useles as fuel in atomic reactors, since it is difficult to impossible to get sustained chain reactions with it. However, it can be placed in a "breeder" reactor to form Plutonium 239, which is a lot more usefull (so we need more breeder reactors to prevent any shortages of fissionable material). Anyway, U-238 forms about 99.7% of all Uranium present on Earth (maybe it's a little less, but it's the predominant isotope). It has a half-life of 4.5 x 10^9 years......that means that after 4.5 x 10^9 years, one-half of it will have decayed into by-products. So I would say it's pretty stable, and does not have a high amount of radioactivity associated with it. (consider that some elements have half-lives measured in x10^-7 seconds!) So while DP shells are radioactive, I wouldn't think it is something a thin lead coating wouldn't stop....maybe they are lead-coated, since that shouldn't degrade performance appreciably, and it would increase the safety effect. My reference for this is "Nuclear Fission Reactors", by I.R. Cameron, and Prof. R. Bailey (I'm taking a course in Nuclear Engineering this quarter). Michael J. Vinarcik The Ohio State University Metallurgical Engineering Standard disclaimers apply!
djm@castle.ed.ac.uk (D Murphy) (04/14/90)
From: D Murphy <djm@castle.ed.ac.uk> In article <15438@cbnews.ATT.COM> MT666_VINARC@kcgl1.eng.ohio-state.edu writes: > >So while DP shells are radioactive, I wouldn't think it is something a thin >lead coating wouldn't stop....maybe they are lead-coated, since that shouldn't >degrade performance appreciably, and it would increase the safety effect. > Erm, not a good idea, I'm afraid. OK, coating a DU shell in lead film would stop alpha emissions from the metal, but any beta emissions would cause the lead to emit X-rays on the outside of the shell. These in addition to the gamma radiation that will normally be present anyway (and which thin lead won't do anything about) might present a a significant hazard, especially to crew who won't be able to keep themselves distant from the radiation source (the best method of hazard avoidance). The lead emits X-rays when bombarded by beta radiation, since the particles are fast free electrons. This is pretty much the principle on which clinical and scientific X-ray sources work, by electron bambardment of a heavy metal target. >Michael J. Vinarcik Murff...
phil@pepsi.AMD.COM (Phil Ngai) (04/14/90)
From: phil@pepsi.AMD.COM (Phil Ngai) In article <15438@cbnews.ATT.COM> MT666_VINARC@kcgl1.eng.ohio-state.edu writes: |So while DP shells are radioactive, I wouldn't think it is something a thin |lead coating wouldn't stop....maybe they are lead-coated, since that shouldn't I took a tour of a Navy ship equipped with a Phalanx system and the sailors commented on how they used protective gear when handling the rounds. I had the impression it was related to the chemical properties of uranium, which is after all, a heavy metal and probably at least as bad for you as lead. -- Phil Ngai, phil@amd.com {uunet,decwrl,ucbvax}!amdcad!phil The War on Drugs is the modern day Inquisition.