Status of Fusion Produced by Spherical Explosive Driven Implosion
SkyNet
temperatures and pressures using conventional high explosives to implode
an appropriate series of multi layer (hi/lo Z) liners to eventually shock
compress and heat an appropriate fusion fuel core?
There was a report of some low yields 10**2 to 10**7 neutrons generated
by D-T fusion fuel cores following spherical explosive driven implosion
(Qingdong-D, Jichang-Z, Zuo-LG, Hongzhi-J. "Fusion Produced by Implosion
of Spherical Explosive" Shock Compression of Condensed Matter. 1989.
Schmidt-SC, Johnson-JN, Davison-LW (eds). Elsevier Science Publishers
B.V. 1990. pp. 771-774). There are also a reasonably large number of
theroetical and modeling papers suggesting this process may be feasible.
However, I have not seen explosive driven fusion results discussed at any
great length in the literature. My concern, if this process really works,
is whether it has any implications for nuclear proliferation? What if it
occurs to someone to design explosive driven fusion targets with a U-238
tamper to hold the device together once the fusion reaction is initiated?
I know the claimed yields are not large enough (yet) to successfully make
a first pass at producing enough fast fission reactions in a U-238 tamper;
however, if the yields are only marginally increased from the currently
claimed upper limits, then it would become possible to construct a fusion
weapon without using any controlled special nuclear materials. This is a
potentially hazardous situation.
Curtis Yarvin
|What is the present status of research directed at generating D-T fusion
|temperatures and pressures using conventional high explosives to implode
|an appropriate series of multi layer (hi/lo Z) liners to eventually shock
|compress and heat an appropriate fusion fuel core?
|
|There was a report of some low yields 10**2 to 10**7 neutrons generated
|by D-T fusion fuel cores following spherical explosive driven implosion
|(Qingdong-D, Jichang-Z, Zuo-LG, Hongzhi-J. "Fusion Produced by Implosion
|of Spherical Explosive" Shock Compression of Condensed Matter. 1989.
|Schmidt-SC, Johnson-JN, Davison-LW (eds). Elsevier Science Publishers
|B.V. 1990. pp. 771-774). There are also a reasonably large number of
|theroetical and modeling papers suggesting this process may be feasible.
|
|a first pass at producing enough fast fission reactions in a U-238 tamper;
|however, if the yields are only marginally increased from the currently
|claimed upper limits, then it would become possible to construct a fusion
|weapon without using any controlled special nuclear materials. This is a
|potentially hazardous situation.
Not really; even if such a device were possible, the technology needed to
construct it (microsecond timing of high explosive detonators) is likely
greater than the expertise needed to steal or enrich uranium. Iraq has
enough U-235 for a bomb or two, but it hasn't managed to build one yet.
However, non-fission-initiated thermonuclear reactions would (correct me if
I'm wrong) have essentially no fallout, so they would be safe for
non-military duties of the Project Plowshare type: digging new Panama Canals,
and so forth. It might also be possible to produce a low-yield
thermonuclear device for tactical military use.
c
John Connor
>Not really; even if such a device were possible, the technology needed to
>construct it (microsecond timing of high explosive detonators) is likely
>greater than the expertise needed to steal or enrich uranium. Iraq has
>enough U-235 for a bomb or two, but it hasn't managed to build one yet.
This assumption is part of my problem with current "controls" on export of
critical nuclear weapons design technologies. No one really needs to deal
with the problem of simultaneously setting off multiple detonators unless
they are trying to duplicate the original design of a Fat Man (Model 1561)
style high explosive implosion driven fission bomb. Given open literature
on high explosive driven implosion techniques for use in compressed matter
studies or generation of megagauss magnetic fields, there is absolutely no
reason (except illiteracy) for using more than one detonator in generation
of a well focused set of convergent imploding spherical shock waves. Even
if one were able to reconstruct a fat man bomb, how many people have a way
to deliver a 10,800 lb iron bomb? If you could deliver one, the weapon is
so poorly designed that you could never adequately predict the yield - and
there would be an unacceptably high probably the device would fizzle. If
you could deliver something that heavy, I'd much rather replicate a device
like the Mark 41 (10,671 lbs) with 1,000 times the yield (24 MT) of a 1561.
>However, non-fission-initiated thermonuclear reactions would (correct me if
>I'm wrong) have essentially no fallout, so they would be safe for
>non-military duties of the Project Plowshare type: digging new Panama Canals,
>and so forth. It might also be possible to produce a low-yield
>thermonuclear device for tactical military use.
Well, this is a very sad misconception. The key concept is the design of any
thermonuclear weapon is to wrap the Li6-D core in an active U-238 tamper. The
fast fissions induced by the fission trigger device and by the neutrons which
are liberated by the D-T fusion reactions in the U-238 tamper are essential in
initially triggering the fusion reactions and in retarding device disassembly
until most of the D-T fuel is consumed. The fast fission reaction products in
the U-238 tamper are as dirty as any products generated in other U-235/Pu-239
based devices. Unfortunately, substantially more fission reactions occur in a
thermonuclear device than in a fission only device. One possible exception is
the enhanced radiation device (neutron bomb) which may achieve it's effects by
reducing the thickness of the U-238 tamper -- thereby capturing fewer neutrons
in the tamper (consequently liberating more neutrons from the device surface),
substantially reducing the explosive yield, and increasing the amount of waste
tritium released [characteristics were desribed in old Ted Taylor Sci American
article]. The bottom line is that fusion weapons still generate large amounts
of extremely dirty U-238 fission products. The Peacefull Nuclear Explosions
(PNE) program tried to make the use of such devices acceptable by capturing as
much of the dirtiest fission products in underground cavities formed when the
device was detonated -- but I wouldn't want such unhealthy fission products in
the ground anywhere near a previously inhabitable region.
JC
Curtis Yarvin
>In article <85...@brunix.UUCP> c...@cs.brown.edu (Curtis Yarvin) writes:
>>However, non-fission-initiated thermonuclear reactions would (correct me if
>>I'm wrong) have essentially no fallout, so they would be safe for
>>non-military duties of the Project Plowshare type: digging new Panama Canals,
>>and so forth. It might also be possible to produce a low-yield
>>thermonuclear device for tactical military use.
>
>thermonuclear weapon is to wrap the Li6-D core in an active U-238 tamper.
You missed the original posting; sure, this is how A-bombs are built today,
but someone was saying that, given advances in conventional explosive
technology, it may be possible to build a thermonuclear device _without_ the
fissioning tamper.
He gave references, too. Could someone dig them up and confirm or deny his
conclusions?
c
CHUCK PARSONS 617-253-4157
clean explosion. Tritium BTW is one of the most dangerous radioactive
elements. When you want to design an experiment with this the safety people
go bonkers.
That is not to say it couldn't be a lot cleaner than a fission device.
But there is still going to be many curies of radiactive stuff
created and released. A key point would be to absorb the neutrons
cleanly.
Regards, ch...@mitlns.mit.edu (lns is Lab for Nuclear Science)
Barry Merriman
617-253-4157) writes:
> Tritium BTW is one of the most dangerous radioactive
> elements. When you want to design an experiment with this the safety people
> go bonkers.
>
I thought T was one of the least dangerous elements. Its true the saftey
people go bonkers, but I'm guessing that is because its easy to leak
T (its a tiny molecule, like to contaminate water, reactive)---not
because its so dangerous when leaked. I've heard you can drink
a glass of tritiated water with little ill effect, since the
T passes out of the body before being absorbed into permanent
tissues (not that I recommend it). And the decay mode for T is
not particulalry damaging to biological organisms. I'n not
saying its harmles, just that its much less dangerous than strontium,
plutonium, etc.
--
Barry Merriman
UCLA Dept. of Math
UCLA Inst. for Fusion and Plasma Research
ba...@math.ucla.edu (Internet; NeXTMail is welcome)
John G. DeArmond
>|however, if the yields are only marginally increased from the currently
>|claimed upper limits, then it would become possible to construct a fusion
>|weapon without using any controlled special nuclear materials. This is a
>|potentially hazardous situation.
>Not really; even if such a device were possible, the technology needed to
>construct it (microsecond timing of high explosive detonators) is likely
>greater than the expertise needed to steal or enrich uranium. Iraq has
>enough U-235 for a bomb or two, but it hasn't managed to build one yet.
Not really. While I agree that the hazard ranks down around that of a
meteor impacting earth, the technology involved in weapons initiators is
fairly common knowledge even if some people who have that knowledge don't
realize it.
Example. My wife works for Dornier Medical Systems. Dornier invented
the kidney stone Lithotripter. This device, for those who have never
heard of it, uses high energy spark discharges to generate shock waves
that are focused in situ on kidney stones and fracture them. A couple of
days ago I got a technical tour of the American facility. As the engineer
showed me the diagrams of the shock wave generator, I had to blink once or
twice to remind myself that I was not looking at an initiator. Information
on the actual detonators, the only missing piece in this puzzle,
is available in public literature as is the rest of the implosion design.
>However, non-fission-initiated thermonuclear reactions would (correct me if
>I'm wrong) have essentially no fallout, so they would be safe for
>non-military duties of the Project Plowshare type: digging new Panama Canals,
>and so forth.
No. A significant portion of the fallout from a weapon consists
of neutron-activated isotopes from materials in the vicinity of
the explosion. While the bomb would be cleaner than a fission
detonated device, it would still generate a lot of fallout.
Then of course if a U-238 tamp is used, we're back to where we
were before regarding fallout.
John
--
John De Armond, WD4OQC | "Purveyors of speed to the Trade" (tm)
Rapid Deployment System, Inc. | Home of the Nidgets (tm)
Marietta, Ga | "It's not a bald spot, its a solar panel for a
j...@dixie.com | a sex machine."
Michael Robinson
|>This device, for those who have never
|>heard of it, uses high energy spark discharges to generate shock waves
|>that are focused in situ on kidney stones and fracture them. A couple of
|>days ago I got a technical tour of the American facility. As the engineer
|>showed me the diagrams of the shock wave generator, I had to blink once or
|>twice to remind myself that I was not looking at an initiator.
So, is this why you need krytrons? I've never been able to figure that out.
--
------------------------------------------------------------------------------
Michael Robinson USENET: ucbvax!cogsci!robinson
ARPA: robi...@cogsci.berkeley.edu
John Connor
>So, is this why you need krytrons? I've never been able to figure that out.
No. The kind of people trying to get krytrons appear to be interested in
duplicating the the original Fat Man (Model 1561; 10,800 lb; 23 Kt yield)
high explosive driven implosion based fission bomb detonated over Nagasaki
on July 16, 1945. This was a highly unreliable device with unpredictable
yield in large part because of the difficulty of simultaneously detonating
the large number of detonators spread over the surface of the device. In
my opinion, such amateur nuclear weapons designers would do well to study
the open literature on high explosive implosion devices which can be set
off using a single detonator; thereby bypassing any potential problems in
simultensously triggering multiple detonators. Krytrons would be used to
make such simultaneous detonation more likely.
John G. DeArmond
>clean explosion. Tritium BTW is one of the most dangerous radioactive
>elements. When you want to design an experiment with this the safety people
>go bonkers.
Dead wrong. Not even close. Tritium presents about the least radiation
hazard of all isotopes, probably only surpasses in lack of hazard by
C-14. H-3's lone beta lacks the energy to penetrate a solution or solid.
That's why it's used in almost all luminous applications. There are
curies of H-3 in luminous exit signs as used on airliners and some motels.
My mil-spec analog dial watch contains glass tritium gas and phosphor on
each hand and for each number. According to the specification it contains
about 500 mCi. Another indication of how wrong you are is to examine
the table of exempt quantities of radioactive materials. H-3 is at the top
of the list.
Large physical quantities (huge radiological quantities) are controlled
because H-3 is a weapon component but that has NOTHING to do with it's
radiological properties. The quantities you and I can obtain are more than
enough for almost any conceivable experiment.
Henry Spencer
>>elements. When you want to design an experiment with this the safety people
>>go bonkers.
>
>Dead wrong. Not even close. Tritium presents about the least radiation
>hazard of all isotopes, probably only surpasses in lack of hazard by
>C-14. H-3's lone beta lacks the energy to penetrate a solution or solid.
If it's inside you, that is entirely irrelevant. Tritium is classed as
very dangerous not because its radiation is penetrating, but because the
stuff is so readily transformed into water and taken into the body.
>That's why it's used in almost all luminous applications. There are
>curies of H-3 in luminous exit signs as used on airliners and some motels.
There is a very large difference between walking past an encapsulated exit
sign and *working* with raw tritium or tritium compounds. Again, the hazard
is absorption, not radiation.
--
Programming graphics in X is like | Henry Spencer @ U of Toronto Zoology
finding sqrt(pi) using Roman numerals. | he...@zoo.toronto.edu utzoo!henry
CHUCK PARSONS 617-253-4157
>ch...@pierre.mit.edu (CHUCK PARSONS 617-253-4157) writes:
>
>>clean explosion. Tritium BTW is one of the most dangerous radioactive
>>elements. When you want to design an experiment with this the safety people
>>go bonkers.
>
>Dead wrong. Not even close. Tritium presents about the least radiation
>hazard of all isotopes, probably only surpasses in lack of hazard by
>C-14. H-3's lone beta lacks the energy to penetrate a solution or solid.
>That's why it's used in almost all luminous applications. There are
>curies of H-3 in luminous exit signs as used on airliners and some motels.
Bzzt, your statement has some validity, but is a vast over statement.
Most of the world measures quantities by weight not curies. 1 gram of
tritium, small by the standards _of_ _this_ _group_ has about 10,000 curies
of activity. The beta emitted by tritium is only 18KeV very low
yes, _but_
1. Tritium is a gas, few other sources are. Hence you can breath it.
2. Tritium is explosive when mixed with room air, few other
radioactive sources are, in the state they come in. (True, however
people in this group might want to grind them up and put them stars)
3. The by product of Tritium burning is water, extremely easily
absorbed by the body.
4. Once it is inside you 18KeV is plenty to cause damage.
Combine these factors and you come out with a _uniquely_ dangerous
source. Compare it to say a cobalt 60 source. You can't have
a gas leak with a cobalt 60 source! At Brookhaven National Lab
an experiment needed a few liters of tritium for a gas target. They
had to jump through hoops. The Brookhaven Saftey office was concerned
about radiation exposure not building a bomb. A few litters of T2
is about a gram.
It is simple to figure out the activity of Tritium. The 1/2life is
12.3 years. Atomic number is 3. 1curie=3.7E10 decays per second. Lets just
take the _average_ activity over 12.3 years.
6.023E23/3 gives 2E23 atoms per gram
1/2*2E23=1E23 the number that decay in 12.3 years
1E23/12.3/365.25/24/60/60 = _average_ of 2.6E14decays/second
2.6E14/3.7E10 = 7,000 curies per gram.
Now how does that compare with 1gram of natural uranium? Ok,Ok how does
that compare with 1gram of U235? How about 1gram of Radium?
1Gram of plutonium? True if you are a medical physicist these are not what
you consider common sources, but what sources were most of the readers of
this group likely to think about?
>My mil-spec analog dial watch contains glass tritium gas and phosphor on
>each hand and for each number. According to the specification it contains
>about 500 mCi.
Or about 70 _micro_ grams
>Another indication of how wrong you are is to examine
>the table of exempt quantities of radioactive materials. H-3 is at the top
>of the list.
Listed by weight or activity?
>
>Large physical quantities (huge radiological quantities) are controlled
>because H-3 is a weapon component but that has NOTHING to do with it's
>radiological properties. The quantities you and I can obtain are more than
>enough for almost any conceivable experiment.
>
1 gram is not a large physical quantity by my standards. It is not
nearly enough to build a bomb. Try and get a permit for a 10,000 curie
source. Come on, the post was about building a bomb! you are going to
need _pounds_ of tritium!
John Moore
]of neutron-activated isotopes from materials in the vicinity of
]the explosion. While the bomb would be cleaner than a fission
]detonated device, it would still generate a lot of fallout.
Which gets back to a question I had a while back: how much neutron activation
radiation hazard is induced by the explosion of a "neutron bomb?" It is
just a thermonuclear device with enhanced neutron yield, with a large
neutron flux hitting the ground (since that's where it's target is). Shouldn't
this cause the area to become radioactive by neutron activation?
Another question: in a moist climate, how far do the neutrons travel
through the air before they become thermalized... and what difference
does this make?
--
John Moore NJ7E, 7525 Clearwater Pkwy, Scottsdale, AZ 85253 (602-951-9326)
ncar!noao!asuvax!anasaz!john jo...@anasaz.UUCP anasaz!jo...@asuvax.eas.asu.edu
"It would be thought a hard government that should tax its people one tenth
part..." B. Franklin - Standard Disclaimer Applies -
- - Support ALL of the bill of rights, INCLUDING the 2nd amendment! - -
CHUCK PARSONS 617-253-4157
> 2. Tritium is explosive when mixed with room air, few other
> radioactive sources are, in the state they come in. (True, however
> people in this group might want to grind them up and put them stars)
>1Gram of plutonium? True if you are a medical physicist these are not what
>you consider common sources, but what sources were most of the readers of
>this group likely to think about?
Just wanted to let people know that I replied to this on rec.pryotechnics
I didn't notice that folloups were directed to this group. Hence
'this group' refers to rec.pyrotechnics rather sci.physics.fusion
Regards, Ch...@mitlns.mit.edu
John Logajan
>>Tritium BTW is one of the most dangerous radioactive
>>elements.
>hazard of all isotopes, probably only surpasses in lack of hazard by
>C-14. H-3's lone beta lacks the energy to penetrate a solution or solid.
Caulk it up to the hysteria of the times. In previous years we were
informed that plutonium was the most poisonous element known to man. It
is actually only mildly poisonous. Then there were the non-radioactive
deadly poisons scares, such as dioxin -- now the original dioxin danger
reports are being retracted, oops sorry for the scare, folks.
Then there were PCB's. PCB's were killing us! Well, no, PCB's were merely
accumulating because of their relative inertness. In fact, the only
significant toxicity associated with PCB's were those subjected to
extreme heat, such as fire, in which they were transformed from PCB's
to something else.
Don't forget DDT. DDT like the PCB's could exist in the environment for
a few weeks before it decomposed. Therefore it tended to accumulate.
It wasn't that it was doing any harm, it was that it existed to be measured
and therefore shot waves of hysteria through the usual hysteria crowd.
If bird egg shells were thin and DDT was found in the eggs, then it must
be the DDT that caused the thinning -- never mind that the incidence of
thin egg shells did not go up from historical times before DDT -- never
mind that controlled scientific studies on various birds found that massive
dosages of DDT had no thinning effect.
In Sri Lanka, before the advent of DDT usage, there were over 2 million
cases of malaria a year. The usage of DDT brought that number down to
less tha 100 a year. THen DDT was banned. In two years the number of
malaria cases was back up to 2 million a year. Thank god for the
environmentalist hysterics!
You can read about all these amazing "gifts" bestowed upon us by the
hysteria mongers by getting a copy of Dixie Lee Ray's 1989 book,
"Trashing the Planet."
--
- John Logajan @ Network Systems; 7600 Boone Ave; Brooklyn Park, MN 55428
- log...@ns.network.com, 612-424-4888, Fax 612-424-2853
Mike Van Pelt
>Tritium BTW is one of the most dangerous radioactive elements. When you
>want to design an experiment with this the safety people go bonkers.
This conflicts with what I've been told by friends in the Health
Physics field. It is also not consistent with the known activity of
tritium, the kind of emission (weak beta), and the biological
persistence of hydrogen. (There's no concentration mechanism; water
comes, water goes, with a very high turnover.)
--
Mike Van Pelt Paradimethylaminobenzaldehyde,
Headland Technology Go soak your head in a good strong insecticide,
m...@hsv3.lsil.com Slosh it around and impregnate your brain
...ames!vsi1!hsv3!mvp With dichlordiphenyltrichloroethane.
John Scott McCauley Jr.
ch...@pierre.mit.edu's calculation about the dose from T20.
Tritium has a very short Biological half live around 12 days. This means
that if you ingest 1 g of Tritium in 12 days you will then have only 0.5 g in
your body, the rest winding up in sweat, water vapor, and urine. So if
you've been exposed to Tritium, the treatment is to load you up with
Beer or other chemicals to encourage hydrogen exchange. It's no fun --
you would probably be placed in a 120 degree F steam bath with 100 percent
humidity round the clock to make you sweat as well. I can imagine that
under such care the Biological half life could be cut in half.
Strontium-90 can be mistaken by the body as Calcium. Hence it has a
long Biological half-life and is probably far more dangerous than Tritium.
However, there are tritiated Amino acids that might wind up in someone's
DNA and have a hard time coming out.
As far as Tritium needed for weapons, I think the global Tritium inventory
is about 100 kg for 20,000 or so H bombs (including SU). So 5g or so is
a typical amount. Note that most of the Tritium in a modern three stage
weapon is produced by bombarding Lithium-6 with neutrons. However, Tritium
in gas form may also be used in the core of the first fission stage to
help liven things up.
There are variable-yield mostly-fission (?) weapons that may use
Tritium to control the yield -- if there is no Tritium inside the core
you might get 10 kT. Flip the switch, heat up the Uranium (or Titanium)
getter to boil off some Tritium into the central core, and your weapon
in a matter of seconds becomes a 100kT device. Check your favorite
bomb book for details.
Now, here is my confusion about chuck's article:
In article <13SEP9...@pierre.mit.edu> ch...@pierre.mit.edu writes:
(analysis of daily dose from a glass of T20)
>
> So your drink will give you 30,000 Rads per day
>
>
>50% mortality rate is 250 to 300 Rads. I think you are pretty
>much dead meat.
>
>
>The quality factor for beta radiation is 1 so 30,000 Rads is
>3 million rems. Unless they lowered it the total allowable
>yearly occupational dose is 5rems. So even a milligram (1/220,000) is
>a problem at 13 rems per day.
These aren't the units I use: I guess 1 Rad = 100 rad:
Dose (in rem) = QF x Dose (in rad).
and
1 rad = 100 erg/gm (== 0.01 joule/kg)
Anyway I also get ~3 Mrem/day. I also remember that the LD50/30
(dosage that kills 50% of the people exposed to such a dose in 30 days)
is around 300 rem or 300 rad from gammas.
Scott
P.S. Did you know Tritium is used in Oil Exploration?
John Scott McCauley Jr.
>critical nuclear weapons design technologies. No one really needs to deal
>with the problem of simultaneously setting off multiple detonators unless
>they are trying to duplicate the original design of a Fat Man (Model 1561)
>style high explosive implosion driven fission bomb.
But precision explosive coordination technology is probably used
many places in a modern weapon! Here are some examples:
1. Preventing Predetonation of the Fusion Stage
One of the key concerns in bomb design is 'predetonation', the risk that
a bomb component explodes before it is supposed to. A modern three-stage
weapon is quite complex. It wouldn't suprise me at all if the fusion
stage is protected from the first fission stage (by a Uranium gamma mirror?)
during the early stage of the explosion to prevent it from going off too soon.
When the fission stage reaches optimum power, a precision chemical
explosive perhaps moves the gamma mirror so the fusion stage gets
maximum irradiation at the best time.
2. Preventing Predetonation of the Core From Noise Neutrons
The predetonation of the critical mass by 'noise' neutrons was apparantly
a big concern to the Manhattan project. The chain reaction can start
any time the bomb is in a critical configuration. However, to get a
good yield, the chain reaction must start when the core is optimally
compressed. So my guess is that the critical mass is shielded from
the Neutron initiator (a Po-Be source?) until the bomb is as supercritical
as it is going to get. Then the shielding is removed really quickly
(very likely with a precision explosive) and the supercritical mass is
flooded with neutrons.
[Stray neutrons can also be caused by the Alphas (from U or Pu decay)
reacting with trace light atoms in the core. (Be + alpha -> n + whatever).
For this reason, the U or Pu must be *very* pure to get a good yield).]
3. Timed Blast Doors in Weapons Effects Tests
I've also heard stories of weapons-effect tests in which a satelite
is placed in an underground, high vacuum tunnel several hundred yards
away from a bomb. Between the bomb and the satelite lies a huge blast
door. The door can be closed very quickly by a precision chemical explosion.
The bomb is detonated. Hard radiation travels to the satelite. The
door explosive is then detonated just in time for the blast wave from
the bomb to be deflected. Hence, the satelite survives for later
analysis.
I think the government has good reason for keeping controls on precision
explosive coordination technology.
Scott
John Logajan
>plutonium.
You might want to compare this to drinking a glass of gasoline or a glass
of anti-freeze.
At about any dosage level you can think of, I'm pretty sure I can think of
some industrial or household chemical that is as deadly.
CHUCK PARSONS 617-253-4157
>A couple more comments about Tritium, then some confusion I have about
>
post. I'd like to thank Scott for pointing out my unit error. However as
Scott notes, despite writing "rad" where I meant "gray" the calculations
and results are correct because I did use 1J/kg(==1gray) and 1REM=100*QF*#grays
>Tritium has a very short Biological half live around 12 days. This means
>that if you ingest 1 g of Tritium in 12 days you will then have only 0.5 g in
>your body, the rest winding up in sweat, water vapor, and urine. So if
I didn't know an exact figure, though of course it must vary a lot. I
figured it would be a couple of weeks from my mass/(liquid intake)
ratio. That is why I only used one day for the calculation.
>
>Strontium-90 can be mistaken by the body as Calcium. Hence it has a
>long Biological half-life and is probably far more dangerous than Tritium.
>However, there are tritiated Amino acids that might wind up in someone's
>DNA and have a hard time coming out.
Definetely true, and this helps make tritium safer. Tritium gas and
Tritium oxide are particularly dangerous because they are easily leaked
(especially gas) and easily absorbed (T20). People as we know do stupid
things, a friend of mine at BNL drinks out of a beaker. Of course its one
he reserves _only_ for his coffee, but the chances that someone else might
pick it up and use it for something else without realizing that are scarey.
Hence something that looks tastes and feels like ordinary distilled
water is particularly dangerous. Tritium Oxide _evaporates_!!! I
don't think Strontium 90 does. Tritium is dangerous because it is a lot easier
in the lab to screw up and get it inside you or the cleaning people.
>
>As far as Tritium needed for weapons, I think the global Tritium inventory
>is about 100 kg for 20,000 or so H bombs (including SU). So 5g or so is
I didn't know the actual figures are these correct? Can any one
explain the need for 5grams of tritium? I suppose its because its
easy to get a neutron out, so it helps prime the Li6.
>a typical amount. Note that most of the Tritium in a modern three stage
>weapon is produced by bombarding Lithium-6 with neutrons. However, Tritium
Yes but the origional posting was talking about a _non_ coventional
bomb specicfically not requiring an atomic bomb to initiate it. Thus
you don't have the neutrons for the Li6 without a lot of Tritium.
>
>There are variable-yield mostly-fission (?) weapons that may use
>Tritium to control the yield -- if there is no Tritium inside the core
>you might get 10 kT. Flip the switch, heat up the Uranium (or Titanium)
>getter to boil off some Tritium into the central core, and your weapon
>in a matter of seconds becomes a 100kT device. Check your favorite
>bomb book for details.
Too scary for me. I can just see the artillery guys deciding whether
they want the hole to include Queens or just Manhatten.
>
>Now, here is my confusion about chuck's article:
>
>In article <13SEP9...@pierre.mit.edu> ch...@pierre.mit.edu writes:
>(analysis of daily dose from a glass of T20)
>>
>> So your drink will give you 30,000 Rads per day
****
should be GRAYS, my mistake.
>>
>>
>>50% mortality rate is 250 to 300 Rads. I think you are pretty
****This is correct
>>much dead meat.
>>
>>
>>The quality factor for beta radiation is 1 so 30,000 Rads is
**** Should be Grays
>>3 million rems. Unless they lowered it the total allowable
>>yearly occupational dose is 5rems. So even a milligram (1/220,000) is
>>a problem at 13 rems per day.
>
>These aren't the units I use: I guess 1 Rad = 100 rad:
>
> Dose (in rem) = QF x Dose (in rad).
>
> and
>
> 1 rad = 100 erg/gm (== 0.01 joule/kg)
Sincere apologies, you are absolutely correct I try to use SI units
but only made half the transition. I was using Grays, wrote rads
1Gray==1J/kg=100Rad.
Rest is the same. I prefer Grays myself since 1J/Kg is easy to remember.
Of course then you have to remember the 100 when converting to rems.
>
>Anyway I also get ~3 Mrem/day. I also remember that the LD50/30
>(dosage that kills 50% of the people exposed to such a dose in 30 days)
>is around 300 rem or 300 rad from gammas.
>
> Scott
Here we differ slightly, my source (Particle Properties Data Booklet
April 1990) says LD50/30 is 250-300 rems from _ionizing_ radiation measured
internally on the bodies centerline. Of course thats the whole idea of rems it
should be the same, and most of the ionization from the gammas will be
from the electrons released.
>
>P.S. Did you know Tritium is used in Oil Exploration?
Yes, Schlumberger Co. made a fortune on it. You use it with an tiny
accelerator (only about foot long) to make a neutron source.
Regards, ch...@mitlns.mit.edu
Mark North
>Which gets back to a question I had a while back: how much neutron activation
>radiation hazard is induced by the explosion of a "neutron bomb?" It is
>just a thermonuclear device with enhanced neutron yield, with a large
>neutron flux hitting the ground (since that's where it's target is). Shouldn't
>this cause the area to become radioactive by neutron activation?
There is a rule of thumb for neutron activation -- Only those isotopes with
a half life on the order of the activation time will become significantly
activated. In the case of the neutron bomb I would expect a *very* highly
activated area for a *very* short time. Comments welcome.
>Another question: in a moist climate, how far do the neutrons travel
>through the air before they become thermalized... and what difference
>does this make?
The amount of moisture around makes a significant difference in how far
the neutrons can propagate. In very dry air neutrons can thermalize in
a few tens of meters. In moist air a factor of 10 reduction would not be
unreasonable to expect.
Remember this, however, neutron propagation follows an exponential decrease.
Not a range cutoff like charged particles. Hence, with a very large source
significant activation could occur quite a distance from the initial
source. Again comments welcome.
Mark
Mark North
>In article <11SEP9...@pierre.mit.edu> ch...@pierre.mit.edu writes:
>>Tritium BTW is one of the most dangerous radioactive elements. When you
>>want to design an experiment with this the safety people go bonkers.
>This conflicts with what I've been told by friends in the Health
>Physics field. It is also not consistent with the known activity of
>tritium, the kind of emission (weak beta), and the biological
>persistence of hydrogen. (There's no concentration mechanism; water
>comes, water goes, with a very high turnover.)
This is correct. But not the whole story. Actually, Tritium is one of the
least and most dangerous of radioactive materials depending upon
circumstance. The betas are very weak and non-penetrating. As long as the
tritium is outside the body there is no problem. Even ingesting into the
digestive tract is not particularly bad but inhalation is a definite
problem. Overall, though, I think the major concern of tritium is
one of chronic exposure (inside the body.)
I would be very cautious of the Health Physics folks. On the one hand they
can be quite reactionary and on the other quite ignorant. Let me give you
examples.
In our last radiation lecture given by the HP folks a question on our 'test'
was 'How many kinds of radiation are there?' I answered 'two.' Thinking
charged and uncharged. The answer was four -- alpha, beta, gamma and neutron.
When I asked the 'instructor' about the difference about charged and
uncharged interaction with matter and the differences in cautionary
methods he didn't have a clue. This was the ignorance example.
In the reactionary case: I was working with a heavy duty PuBe source one day
and made sure it was less than 2mr/hr everywhere where non-radiation workers
had access to. (This is the level non-radiation workers are allowed to
sustain without damage -- according to regulations based on years of
data and analysis). Being conscientious, I left the survey meter in the hall
outside the lab. It read .5 mr/hr at all times. Apparently the sight of it
caused some concerned calls, etc. I was told never to do that again. As a
consequence I cannot know what dose those poor bastards are getting because
I'm not allowed to measure it where it matters to them. To be fair to the
HP folk I'm not entirely sure that wasn't a political decision by upper
management but they had to have concurred, it seems to me.
Before any radophobes start jumping down my neck hole please research the
dose one gets on a cross country airplane trip. Or by living in Denver.
Mark
CHUCK PARSONS 617-253-4157
>In article <11SEP9...@pierre.mit.edu> ch...@pierre.mit.edu (CHUCK PARSONS
>617-253-4157) writes:
>
>> Tritium BTW is one of the most dangerous radioactive
>> elements. When you want to design an experiment with this the safety people
>> go bonkers.
>>
>
>I thought T was one of the least dangerous elements. Its true the saftey
>people go bonkers, but I'm guessing that is because its easy to leak
>T (its a tiny molecule, like to contaminate water, reactive)---not
>because its so dangerous when leaked. I've heard you can drink
>a glass of tritiated water with little ill effect, since the
>T passes out of the body before being absorbed into permanent
>tissues (not that I recommend it). And the decay mode for T is
>not particulalry damaging to biological organisms. I'n not
>saying its harmles, just that its much less dangerous than strontium,
>plutonium, etc.
>
I've done the following calculation I think it is correct to factors
of two. I didn't worry about small factors.
1gram trituim is aprox 10,000 curies
(see previous post average over 12 years is 7,000...)
1 glass of tritium oxide (a little heavier than normal water)
weighs 220 grams to pick a convient number.
==> This is 60 grams of tritium or 600,000 curies
Tritium decays releasing a beta with endpoint energy of
about 18,000 ev. I don't remeber the phase space enough
to calculate the average energy. I will use 10,000 ev. I
wouldn't be surprised if this is wrong by a factor of 2.
6E5 curies * 3.7 Decays/sec/curie * 1E4eV/decay * 3600sec/hr *24hr/day
== 1.9E25 eV/day
Now:
1eV=1.6e-19 joules.
1.9E25eV/day*1.6E-19joules/ev = 3,000,000 joules per day
1 Gray or Rad = 1J/kG lets take 100kG/person (football players)
So your drink will give you 30,000 Rads per day
50% mortality rate is 250 to 300 Rads. I think you are pretty
much dead meat.
The quality factor for beta radiation is 1 so 30,000 Rads is
3 million rems. Unless they lowered it the total allowable
yearly occupational dose is 5rems. So even a milligram (1/220,000) is
a problem at 13 rems per day.
Even ingesting 1 gram (not 220) of the water is going to kill you.
Since it is going to take a week or two for your body to over all
the fluid in it.
Tritium is a radiological hazard, it may not be more dangerous than
plutonium. It depends, on the form. If the plutonium is plated on
a metal substrate and over plated with nickel it is probably safer
than a ballon full of tritium. If the tritium is part of solid
compound that can't be easily decomposed then it is certainly safer
than a bowl of plutonium dust. Tritium gas or tritium oxide is
certaintly not safe in even small (milligram) quantities.
Regards, Ch...@mitlns.mit.edu
Arnie Frisch
>In article <35...@usc.edu> con...@neuro.usc.edu (John Connor) writes:
>
>But precision explosive coordination technology is probably used
>many places in a modern weapon! Here are some examples:
>
>1. Preventing Predetonation of the Fusion Stage
>
>One of the key concerns in bomb design is 'predetonation', the risk that
>a bomb component explodes before it is supposed to. A modern three-stage
>weapon is quite complex. It wouldn't suprise me at all if the fusion
>stage is protected from the first fission stage (by a Uranium gamma mirror?)
>during the early stage of the explosion to prevent it from going off too soon.
>When the fission stage reaches optimum power, a precision chemical
>explosive perhaps moves the gamma mirror so the fusion stage gets
>maximum irradiation at the best time.
Precision chemical explosives detonate at the rate of 30,000 feet per
second.
Given dimensions on the order of a foot, it's going to take 30 usec, to
get that Uranium mirror out of the way.
It's my impression that things happen much faster than that.
I'll just repeat these comments respecting the remainder of the posting.
Incidentally, the latest novel by Clancy - The Sum of All Fears - has a
fairly accurate description of how one of these things really works.
Arnold Frisch
Tektronix Laboratories
LT Scott A. Norton, USN
have to be careful with your detector. Its shielded by water, so
you have to wait for a spill to dry. You can't protect your detector
with a piece of paper, and you have to put the detector close to the
source, so you easilly contaminate the detector.
Scott Norton nor...@nosc.mil
KLAURENS
tritium crystals in the sights for night shooting. They glow rather
nicely, and I've never seen any health warnings. In fact I've heard
nothing but praise about them.
Doc