Yield-to-weight
Peter Fairbrother
yield-to-weight, but is this still true, especially for very large
weapons, eg 100 Mt?
If a 100 MT device was urgently need for an asteroid interception
mission, how much, or rathe how little, would it weigh?
Thanks,
-- Peter Fairbrother
loupgarous
The specs on the Tsar Bomba (which was originally designed to detonate
with a 100Mt yield, but had to have the U238 in its third stage, and
maybe the second stage tampers replaced with lead, to keep the fallout
down) would be close to what you're asking for - http://en.wikipedia.org/wiki/Tsar_Bomba
is a good starting point - I'm sure that it'll provoke discussion on
the topic, in any case.
Carey Sublette
"Peter Fairbrother" <zenad...@zen.co.uk> wrote in message
news:49b843f4$0$16173$db0f...@news.zen.co.uk...
No known device appears to have exceeded 6 kt/kg. A device concept called
"ripple" was tested in the Dominic Housatonic shot (8300 kt, 3000 kg) which
was apparently expected to yield 15 Mt, and was a test of "an inherently
clean system with maximum efficiency" that would lead eventually to a 30-40
Mt device.
The RDD document series reports that 6 months later a statement was
declassified that:
"* tests were conducted of designs which could lead to an entirely new class
of U.S. weapons which could have relatively low weights and extremely high
yields, with the fission contributions decreased to only a few percent of
the total yield.
* the yield-to-weight ratios of the new class of weapons would be more than
twice that which can now be achieved in the design of very high yield
weapons using previously developed concepts.
* a 35 Mt warhead for our Titan II -- based on these improvements, could be
stockpiled with confidence."
This is apparently a reference to the Ripple tests. Since the Titan maximum
throw weight was about 4000 kg, this implies a yield-to-weight ratio of at
least 8.75 kt/kg (including RV weight). Since the Housatonic shot came in at
about half what was expected though, it is debatable whether these
projections really panned out.
So in the high megaton range (>30 Mt) it is possible that a 9 kt/kg design
might be feasible.
But even large asteroid interceptions don't need yields this high. If
surface ablation is used to generate momentum to change the orbit, much
lower yields could divert even large asteroid/comets that are on 1 year
approach (most sizable impactors would be detected and predicted decades in
advance). You'd also likely want to use several smaller yield devices
instead of one large one for redundancy , give better control (fire one, see
what happens, refine the firing of the next, repeat), and reduce the chance
of disrupting the body into several impactors (a very bad move).
Peter Fairbrother
> "Peter Fairbrother" <zenad...@zen.co.uk> wrote in message
> news:49b843f4$0$16173$db0f...@news.zen.co.uk...
>> Ted Taylor famously said that 6 kT/kg is the maximum achievable
>> yield-to-weight, but is this still true, especially for very large
>> weapons, eg 100 Mt?
Carey, I was hoping you'd reply to that bit too :).
When did he make the 6 kT/kg pronouncement? In what context. was it
about the smaller devices he was working on - and was it before the
"ripple" concept (approx 1961)?
It is misquoted in several sources, including wikipedia, as the
"theoretical maximum possible yield-to-weight", but that's nonsense,
U/Pu fission gives 17.odd kT/kg and LiD fusion gives 64 kT/kg.
Is it correct that Ted T only actually worked on bombs until 1956 or so?
>> If a 100 MT device was urgently need for an asteroid interception mission,
>> how much, or rathe how little, would it weigh?
>
> No known device appears to have exceeded 6 kt/kg. A device concept called
> "ripple" was tested in the Dominic Housatonic shot (8300 kt, 3000 kg) which
> was apparently expected to yield 15 Mt, and was a test of "an inherently
> clean system with maximum efficiency" that would lead eventually to a 30-40
> Mt device.
>
> The RDD document series reports that 6 months later a statement was
> declassified that:
> "* tests were conducted of designs which could lead to an entirely new class
> of U.S. weapons which could have relatively low weights and extremely high
> yields, with the fission contributions decreased to only a few percent of
> the total yield.
> * the yield-to-weight ratios of the new class of weapons would be more than
> twice that which can now be achieved in the design of very high yield
> weapons using previously developed concepts.
> * a 35 Mt warhead for our Titan II -- based on these improvements, could be
> stockpiled with confidence."
>
> This is apparently a reference to the Ripple tests. Since the Titan maximum
> throw weight was about 4000 kg, this implies a yield-to-weight ratio of at
> least 8.75 kt/kg (including RV weight). Since the Housatonic shot came in at
> about half what was expected though, it is debatable whether these
> projections really panned out.
McNamara told Congress in 1963 that the 35 Mt Titan II warhead could be
built and put into service without the need for further testing. Maybe
they figured out what went wrong with Housatonic?
>
> So in the high megaton range (>30 Mt) it is possible that a 9 kt/kg design
> might be feasible.
>
> But even large asteroid interceptions don't need yields this high. If
> surface ablation is used to generate momentum to change the orbit, much
> lower yields could divert even large asteroid/comets that are on 1 year
> approach (most sizable impactors would be detected and predicted decades in
> advance). You'd also likely want to use several smaller yield devices
> instead of one large one for redundancy , give better control (fire one, see
> what happens, refine the firing of the next, repeat), and reduce the chance
> of disrupting the body into several impactors (a very bad move).
The composition of an asteroid on an interception course is likely to be
pretty well unknown - so worst case, assume a rubble pile. The first
detonation is going to break it up anyway, so it makes sense to make the
first detonation as big as possible.
Breaking a near-extinction object up is not necessarily a bad thing, or
rather it's not necessarily worse than doing nothing.
A BOTE: at 120 days before impact breaking it into a cloud which expands
at 0.8 m/s will mean a cloud which is the diameter of the Earth when it
hits - ouch!, that's probably about as bad as it gets.
But if the cloud expands uniformly at a non-unrealistic 10 m/s then it's
going to be 100,000 km across when it arrives, and at least [1] 98.7% of
the object is going to miss entirely. And then it makes sense to look
for the bigger chunks, and zap them with smaller bombs.
[1] the figure goes from 98.7% to almost-100%
-- Peter Fairbrother
bestb...@hushmail.com
> On Mar 11, 5:07 pm, Peter Fairbrother <zenadsl6...@zen.co.uk> wrote:
>
> > Ted Taylor famously said that 6 kT/kg is the maximum achievable
> > yield-to-weight, but is this still true, especially for very large
> > weapons, eg 100 Mt?
>
> > If a 100 MT device was urgently need for an asteroid interception
> > mission, how much, or rathe how little, would it weigh?
>
> > Thanks,
>
> > -- Peter Fairbrother
>
> The specs on the Tsar Bomba (which was originally designed to detonate
> with a 100Mt yield, but had to have the U238 in its third stage, and
> maybe the second stage tampers replaced with lead, to keep the fallout
> is a good starting point - I'm sure that it'll provoke discussion on
> the topic, in any case.
The steady stream of disinformation that comes out of this newgroup is
an impediment to the advancement of science. Now you point to the fact
the Wikipedia ( a resource for the clueless) is in on the
disinformation conspiracy.
This URL:
http://www.youtube.com/watch?v=LxD44HO8dNQ
allows you to look inside the Tsar Bomba. It looks best on a 50"
plasma HDTV. The thin case is just like the M80 thermonuclear warhead.
It is thorium electrocoated sheet aluminum holraum. Granular Li6D is
contained within airtight glass canisters. A small multipoint
detonation spherical implosion fission primary is found in the nose
cone. There is no sign of a heavy U238 third stage. There is no sign
of a U238 second stage tamper.
When are you people going to grow up and tell the truth?
Any corporate entity with a valid Sigma Aldrich account and a good
supply of fissile fuel could reproduce the Tsar Bomba given this
Youtube video.
nx1...@hotmail.com
> The steady stream of disinformation that comes out of this newgroup is
> an impediment to the advancement of science. Now you point to the fact
> the Wikipedia ( a resource for the clueless) is in on the
> disinformation conspiracy.
I have no idea what you're talking in regards to misinformation in
this NG; most of the serious posters here like Carey Subblete do go
accurate and well informed information. IMO, in regards to
misinformation being posted here, I think getting confused with the
trolls (like Cyberiade and anonymous remailer) who post on this NG
(along with many others) anti-semitic spam.
>
> allows you to look inside the Tsar Bomba. It looks best on a 50"
> plasma HDTV. The thin case is just like the M80 thermonuclear warhead.
> It is thorium electrocoated sheet aluminum holraum. Granular Li6D is
> contained within airtight glass canisters. A small multipoint
> detonation spherical implosion fission primary is found in the nose
> cone. There is no sign of a heavy U238 third stage. There is no sign
> of a U238 second stage tamper.
That's a good description you gave there. Since the Tsar-Bomb (which
yielded 50MT) was 97% fusion, its fission yield was 1500KT. The
primary would've yielded ~50-100KT with the rest coming from the
secondaries sparkplugs (based on what we could see of the interior, it
had around 6-12 secondaries)and the secondaries may or may not have
had a Tu tamper. But if they did, it was a thin one. The design is
obviously a three stage design but it's very possible it didn't have a
large tertiary fitted. The secondaries are all arranged at positions
close to the holraum's wall leaving a void in the middle; this is
obviously where the tertiary would go. Now why no tertiary? Keep in
mind that as powerful as the Tsar bomb was, it was still a de-rated
test device; the full yield version was 100MT but that wasn't tested
since a) it would've pumped a huge amount of radioactive fallout into
the atmosphere, b) caused a large of damage to distant settlements
(keep in mind that it was air-dropped over Novaya Zemlya;
Semipalatinsk wasn't remote enough), and c) the Tu-95 bomber that
dropped it would never have escaped the blast/thermal effects (as it
was, by all accounts the bomber nearly didn't make it).
Carey Sublette
<nx1...@hotmail.com> wrote in message
news:03520339-1d09-4610...@b38g2000prf.googlegroups.com...
...
> That's a good description you gave there. Since the Tsar-Bomb (which
> yielded 50MT) was 97% fusion, its fission yield was 1500KT. The
> primary would've yielded ~50-100KT with the rest coming from the
> secondaries sparkplugs (based on what we could see of the interior, it
> had around 6-12 secondaries)and the secondaries may or may not have
> had a Tu tamper. But if they did, it was a thin one.
No uranium in the fusion stage tampers -lead.
> The design is
> obviously a three stage design but it's very possible it didn't have a
> large tertiary fitted. The secondaries are all arranged at positions
> close to the holraum's wall leaving a void in the middle; this is
> obviously where the tertiary would go. Now why no tertiary?
I believe that the array of fusion stages that are seen together are the
tertiary stage. The secondary would be another smaller fusion stage.
Although one naturally envisions a "third stage" to be a single huge version
of a second, there is no reason why that need be so. And the situation of
the "Big Ivan" shot, with the device designed and built in only about 3
months from the time a political order was given to create such a bomb,
necessitated that it be built pretty much out of off-the-shelf parts.
Developing equipment and processes to manufacture a never-before-seen huge
lithium deuteride artifact seems unlikely, especially since this
pre-announced grand standing event was not a test but a political
demonstration that could not be allowed to fail.
Peter Fairbrother
> <nx1...@hotmail.com> wrote in message
>> The design is
>> obviously a three stage design but it's very possible it didn't have a
>> large tertiary fitted. The secondaries are all arranged at positions
>> close to the holraum's wall leaving a void in the middle; this is
>> obviously where the tertiary would go. Now why no tertiary?
>
> I believe that the array of fusion stages that are seen together are the
> tertiary stage. The secondary would be another smaller fusion stage.
The "array of fusion stages seen" are in the thinner tail part of the
bomb, the view through the removed panel is about 2/3 of the way back,
and looking backwards.
The bomb can be divided into four parts - the nose, the BIG main part
with the largest diameter (which could contain a large sphere), the aft
conical section (which is the one we see the inside of) and the tail
section. You can see this best at 35 seconds into the video.
The only views we get of the inside are the one of the nose, and the
view with the cylinders - which I suspect are support equipment of some
sort, maybe deuterium or tritium reservoirs or even capacitors(!), but
which are definitely not tertiaries, they are too small - which is
looking backwards into the smaller aft section.
We never see inside the main section of the bomb.
Heck, I doubt we ever see the inside of any part of the holraum - the
interior components we do see, the device inside the nose cone - perhaps
a radar fuse? and the cylinders - perhaps support equipment of some sort
- may have nothing whatsoever to do with the nuclear components at all.
<speculate>
Hmm, develop a big bomb quickly. let's see... how about we get the
biggest tested bomb available, and put it in the middle of a spherical
holraum with some already-tested fusion second/tertiaries - voila!
Interactions between the exploding capsules will likely increase the
efficiency, so yield will be a little larger than a simple calculation
would anticipate.
Show the world only the non-nuclear parts, don't spoil the mystique.
</speculate>
-- Peter Fairbrother
Peter Fairbrother
> Carey Sublette wrote:
>> I believe that the array of fusion stages that are seen together are
>> the tertiary stage. The secondary would be another smaller fusion stage.
>
> The "array of fusion stages seen" are in the thinner tail part of the
> bomb, the view through the removed panel is about 2/3 of the way back,
> and looking backwards.
http://www.youtube.com/watch?v=LxD44HO8dNQ
Looking at the cylinders again, there are only four of them (look at the
top of the back side of the ring at 49 seconds into the video - if there
was a series of cylinders all around there would be one visible there,
and there isn't. Also there would be one visible of the near side at the
bottom).
Now compare the cylinders in size with the head of the technician at 53
seconds - they can't be more than 2 l each in capacity, giving a maximum
total capacity of 8 l. That's maybe 5 kg of LiD (which is so light it
would float if it didn't react with water), and at 100% burn that's only
320 kT. They ain't the tertiaries.
At 100% burn, 57 MT would be 890 kg, or 1140 litres, or over a cubic
meter, of solid LiD. That's got to be in the main section somewhere,
there isn't room for it anywhere else, and we never see inside that part.
I'm pretty sure the cylinders aren't secondaries either. They seem to
have wires or plumbing coming out of the back of them.
>
> We never see inside the main section of the bomb.
>
>
> Heck, I doubt we ever see the inside of any part of the holraum - the
> interior components we do see, the device inside the nose cone - perhaps
> a radar fuse?
Looking again, the device inside the nose cone might be one end of a
long thin bomb of existing design, which protrudes into the main
"sphere". If that was a three-stage weapon, then Tsar Bomba might even
be a four-stage weapon.
The wires connected to the device seen in the nose-cone shots seem to be
quite thick - a speculation, do they carry the main detonator firing
currents? If so, could the cylinders in the aft section be capacitors?
Seems a long way to route the wires though, but the batteries etc might
be in the aft section.
The Russians fired a 12.5 Mt bomb a week before Tsar Bomba. Pause for
thought. Does anyone know what percentage fission that one was? (shot
123 iirc). Hmm, put one of those and three (or six/seven) final stages
in a big holraum, with perhaps the primary end sticking out ...
1.5 MT of the Tsar yield was from fission - that's more than just a
primary. Secondary? Spark plugs?
Am I getting closer? Thoughts?
and the cylinders - perhaps support equipment of some sort
> - may have nothing whatsoever to do with the nuclear components at all.
>
>
>
> <speculate>
>
> Hmm, develop a big bomb quickly. let's see... how about we get the
> biggest tested bomb available, and put it in the middle of a spherical
> holraum with some already-tested fusion second/tertiaries - voila!
>
> Interactions between the exploding capsules will likely increase the
> efficiency, so yield will be a little larger than a simple calculation
> would anticipate.
>
> Show the world only the non-nuclear parts, don't spoil the mystique.
>
> </speculate>
>
> -- Peter Fairbrother
-- Peter Fairbrother
Carey Sublette
> Carey Sublette wrote:
>> <nx1...@hotmail.com> wrote in message
>
>>> The design is
>>> obviously a three stage design but it's very possible it didn't have a
>>> large tertiary fitted. The secondaries are all arranged at positions
>>> close to the holraum's wall leaving a void in the middle; this is
>>> obviously where the tertiary would go. Now why no tertiary?
>>
>> I believe that the array of fusion stages that are seen together are the
>> tertiary stage. The secondary would be another smaller fusion stage.
>
> The "array of fusion stages seen" are in the thinner tail part of the
> bomb, the view through the removed panel is about 2/3 of the way back, and
> looking backwards.
>
> The bomb can be divided into four parts - the nose, the BIG main part with
> the largest diameter (which could contain a large sphere), the aft conical
> section (which is the one we see the inside of) and the tail section. You
> can see this best at 35 seconds into the video.
>
> The only views we get of the inside are the one of the nose, and the view
> with the cylinders - which I suspect are support equipment of some sort,
> maybe deuterium or tritium reservoirs or even capacitors(!), but which are
> definitely not tertiaries, they are too small - which is looking backwards
> into the smaller aft section.
Oh, right. It has been years since I looked at the pictures. I was
mis-remembering.
The main assembly in the middle we never see.
>
>
> We never see inside the main section of the bomb.
>
>
> Heck, I doubt we ever see the inside of any part of the holraum - the
> interior components we do see, the device inside the nose cone - perhaps a
> radar fuse? and the cylinders - perhaps support equipment of some sort -
> may have nothing whatsoever to do with the nuclear components at all.
On this, I still think we see the primary in the nose. It is a sizeable
package.
>
>
>
> <speculate>
>
> Hmm, develop a big bomb quickly. let's see... how about we get the biggest
> tested bomb available, and put it in the middle of a spherical holraum
> with some already-tested fusion second/tertiaries - voila!
The biggest tested bomb was only 2.9 Mt, though they did test a 12.5 Mt
device one week before the 50 Mt test.
If the 12.5 Mt was dirty then its clean yield would have been only 6.25 Mt
or so. So, 4-8 of these as tertiary stages and a smaller device (2.8 Mt?) as
a secondary.
> Interactions between the exploding capsules will likely increase the
> efficiency, so yield will be a little larger than a simple calculation
> would anticipate.
They would likely have avoided any complex behaviors they possibly could
have - it was a case of KISS, it had to be predictable and reliable with
only a few weeks available for the main design effort.
Peter Fairbrother
> "Peter Fairbrother" <zenad...@zen.co.uk> wrote in message
> news:49ba4218$0$16161$db0f...@news.zen.co.uk...
>> Carey Sublette wrote:
>> Heck, I doubt we ever see the inside of any part of the holraum - the
>> interior components we do see, the device inside the nose cone - perhaps a
>> radar fuse? and the cylinders - perhaps support equipment of some sort -
>> may have nothing whatsoever to do with the nuclear components at all.
>
> On this, I still think we see the primary in the nose. It is a sizeable
> package.
See my later email - it may be primary end of an existing design long
thin bomb?
>> <speculate>
>>
>> Hmm, develop a big bomb quickly. let's see... how about we get the biggest
>> tested bomb available, and put it in the middle of a spherical holraum
>> with some already-tested fusion second/tertiaries - voila!
>
> The biggest tested bomb was only 2.9 Mt, though they did test a 12.5 Mt
> device one week before the 50 Mt test.
>
> If the 12.5 Mt was dirty then its clean yield would have been only 6.25 Mt
> or so. So, 4-8 of these as tertiary stages and a smaller device (2.8 Mt?) as
> a secondary.
Why not a 12.5/6.25 MT secondary?
But a dirty 2.8 MT secondary does fit well with the 1.5 MT fusion yield.
>> Interactions between the exploding capsules will likely increase the
>> efficiency, so yield will be a little larger than a simple calculation
>> would anticipate.
>
> They would likely have avoided any complex behaviors they possibly could
> have - it was a case of KISS, it had to be predictable and reliable with
> only a few weeks available for the main design effort.
Yes - but that interaction would have happened after the main event, so
to speak! The final stage capsules would have done their bit, but so
many close together would give a bit more burnup?
Also, if I was one of the designers, I'd make damn sure it was more than
50 MT - a 49 MT shot would have been embarrassing, and they might have
ended up on the railroads!
-- Peter Fairbrother
loupgarous
Which is where an Orion-type vehicle would come in handy.
Let's assume that the propulsion units in a properly engineered Orion
are dial-a-yield, with the yield remotely adjustable (through
encrypted radio or wired connections in the magazine where the
propulsion units are stored).
This would give the Orion vehicle an opportunity to adze off any
surviving "chunks" of the asteroid after the BIG device had been
delivered from the payload section of the Orion craft. Or you could
design a "double-ended" Orion for space use, unmanned to tolerate high
gees in both directions, and which could decelerate without having to
fire attitude control rockets to re-orient the vehicle. Either or
both ends could be used to fire charges at the asteroid/comet/cloud of
cosmic crap until the pieces were either vectored away from Earth
intercept or small enough to burn up in our atmosphere on entry.
Peter Fairbrother
> "Peter Fairbrother" <zenad...@zen.co.uk> wrote in message
>> Heck, I doubt we ever see the inside of any part of the holraum - the
>> interior components we do see, the device inside the nose cone - perhaps a
>> radar fuse? and the cylinders - perhaps support equipment of some sort -
>> may have nothing whatsoever to do with the nuclear components at all.
>
> On this, I still think we see the primary in the nose. It is a sizeable
> package.
Looking more, I tend to agree. The main section could be a slightly
egg-shaped holraum. The bit at the front may then be the primary, with a
just-visible cylindrical holraum section going to the secondary, which
would lie just inside the narrow part of the egg-shaped holraum.
The tertiary capsules could then be spread out at the wide end of the
holraum, giving some needed space between the secondary and the tertiaries.
The 4 cylinders in the aft section might be tritium reservoirs, one for
each of four 12.5 MT tertiaries?
-- Peter Fairbrother
Peter Fairbrother
careysub
The target is more likely going to be a long period comet, any
substantial asteroid threat will likely be observed decades in
advance.
But be that as it may, the first (or any other) detonation does not
have to break it up at all.
large impactor threats are gravitationally bound together with escape
velocities on the order of 10 m/sec. Any impulse applied to the body
that is much smaller than that (see below) will not break it up,
though it may stir it around a bit.
The thermal radiation ablation idea has the merits that:
* It derives a large impulse from a relatively small energy input
(due to the mass of ablated material).
* The ablation force is applied to a large area, and by varying the
detonation stand-off the intensity can be varied at will.
* The ablation phenomenon is controlled by a thin surface layer that
can be studied remotely.
Using this against a rubble pile is not necessarily a bad thing - the
loose nature of the debris would tend to quickly damp out the ablation
shock (sort of like kicking a nerf ball).
>
> Breaking a near-extinction object up is not necessarily a bad thing, or
> rather it's not necessarily worse than doing nothing.
>
> A BOTE: at 120 days before impact breaking it into a cloud which expands
> at 0.8 m/s will mean a cloud which is the diameter of the Earth when it
> hits - ouch!, that's probably about as bad as it gets.
>
> But if the cloud expands uniformly at a non-unrealistic 10 m/s then it's
> going to be 100,000 km across when it arrives, and at least [1] 98.7% of
> the object is going to miss entirely. And then it makes sense to look
> for the bigger chunks, and zap them with smaller bombs.
>
> [1] the figure goes from 98.7% to almost-100%
OTOH - it is a lot better to have a 100% chance of nothing hitting at
all. This can be accomplished by diverting the entire body intact.
Consider this: a worst case impactor would be headed dead center for
the Earth, but a course change of only 6500 km will make it miss the
Earth completely (though scary close). In the 120 day scenario, you
have 10 million seconds for a course change to cause it move off the
impact trajectory. This amounts to a lateral course change of only
0.65 m/sec. A more glancing strike is even easier to deflect. This
velocity deflection could be applied by 10 small bombs as well as one
big one.
Very good trajectory info will be needed, but two separate long
baseline optical interferometers (say one on Earth and one on the
Moon, each with a 3000 km baseline) should be able to do this without
trouble.
careysub
> >news:49ba4218$0$16161$db0f...@news.zen.co.uk...
> >> Carey Sublette wrote:
> >> Heck, I doubt we ever see the inside of any part of the holraum - the
> >> interior components we do see, the device inside the nose cone - perhaps a
> >> radar fuse? and the cylinders - perhaps support equipment of some sort -
> >> may have nothing whatsoever to do with the nuclear components at all.
>
> > On this, I still think we see the primary in the nose. It is a sizeable
> > package.
>
> See my later email - it may be primary end of an existing design long
> thin bomb?
>
> >> <speculate>
>
> >> Hmm, develop a big bomb quickly. let's see... how about we get the biggest
> >> tested bomb available, and put it in the middle of a spherical holraum
> >> with some already-tested fusion second/tertiaries - voila!
>
> > The biggest tested bomb was only 2.9 Mt, though they did test a 12.5 Mt
> > device one week before the 50 Mt test.
>
> > If the 12.5 Mt was dirty then its clean yield would have been only 6.25 Mt
> > or so. So, 4-8 of these as tertiary stages and a smaller device (2.8 Mt?) as
> > a secondary.
>
> Why not a 12.5/6.25 MT secondary?
The secondary would need to implode faster (and thus be smaller in
diameter) and 6.25 Mt is far more powerful than needed to implode the
tertiaries. If one supposes a 50:1 or 100:1 yield ratio to be
reasonable then 1-2 Mt should be fine (say a clean version of the 2.9
Mt that would give 1.45 Mt).
BTW - the 12.5 Mt test 7 days before the 50 Mt test would give added
confidence as a "pre-test" if the secondary really was bundled in Big
Ivan. Alternatively, a failure would have given a last minute heads up
to retool the device and shoot it a bit later.
>
> But a dirty 2.8 MT secondary does fit well with the 1.5 MT fusion yield.
>
> >> Interactions between the exploding capsules will likely increase the
> >> efficiency, so yield will be a little larger than a simple calculation
> >> would anticipate.
>
> > They would likely have avoided any complex behaviors they possibly could
> > have - it was a case of KISS, it had to be predictable and reliable with
> > only a few weeks available for the main design effort.
>
> Yes - but that interaction would have happened after the main event, so
> to speak! The final stage capsules would have done their bit, but so
> many close together would give a bit more burnup?
Their behavior should be quite modular.
Once the fusion stages get well underway in imploding they are
essentially unaffected by the outside world, and the designers would
want to make sure they don't interact.
Any effective disturbance of the implosion-and-burn process would
likely be detrimental not enhancing.
>
> Also, if I was one of the designers, I'd make damn sure it was more than
> 50 MT - a 49 MT shot would have been embarrassing, and they might have
> ended up on the railroads!
Even in an instrumented test shot yields are hard to measure more
accurately than a few percent. If it were 45 Mt then they could claim
50 and it would be hard to dispute. As it is, I think the U.S.
estimate of 58 Mt is high, even though the U.S.S.R. publicly adopted
this as its 'official' yield. Since the end of the Soviet Union
weaponeers have generally claimed the design yield of 50 Mt.
>
> -- Peter Fairbrother
Peter Fairbrother
cs:
>>> The biggest tested bomb was only 2.9 Mt, though they did test a 12.5 Mt
>>> device one week before the 50 Mt test.
>>> If the 12.5 Mt was dirty then its clean yield would have been only 6.25 Mt
>>> or so. So, 4-8 of these as tertiary stages and a smaller device (2.8 Mt?) as
>>> a secondary.
>> Why not a 12.5/6.25 MT secondary?
>
> The secondary would need to implode faster
why?
(and thus be smaller in
> diameter) and 6.25 Mt is far more powerful than needed to implode the
> tertiaries. If one supposes a 50:1 or 100:1 yield ratio to be
> reasonable then 1-2 Mt should be fine (say a clean version of the 2.9
> Mt that would give 1.45 Mt).
>
> BTW - the 12.5 Mt test 7 days before the 50 Mt test would give added
> confidence as a "pre-test" if the secondary really was bundled in Big
> Ivan. Alternatively, a failure would have given a last minute heads up
> to retool the device and shoot it a bit later.
Indeed. That lead me to assume that the test was of a component of the
"big one" - and that it would be clean, as the big one was going to be -
after all, the big one was the one that HAD to work.
That means a likely four final "clean" stages, and the 4 cylinders
almost have to be one per stage - the only thing I can think of is
tritium reservoirs.
>> Yes - but that interaction would have happened after the main event, so
>> to speak! The final stage capsules would have done their bit, but so
>> many close together would give a bit more burnup?
>
> Their behavior should be quite modular.
>
> Once the fusion stages get well underway in imploding they are
> essentially unaffected by the outside world, and the designers would
> want to make sure they don't interact.
Sure, I don't mean that. What I'm talking about is in the tail-off,
after 90% of the reaction has happened, and the device has expanded to
maybe twice it's original size.
The figure for a normal bomb assumes it's expanding into maybe the air,
at essentially zero density and pressure - but these will be expanding
at last partly into the high-pressure and high-temperature after-effects
of their neighbours - a different thing entirely, they will stay hotter
and at higher pressure for longer, and perhaps this would be enough to
make the reactions go a bit further.
>
> Any effective disturbance of the implosion-and-burn process would
> likely be detrimental not enhancing.
This is *after* the implode-and-burn, and most of the expand bit.
-- Peter Fairbrother
nx1...@hotmail.com
>
> Also, if I was one of the designers, I'd make damn sure it was more than
> 50 MT - a 49 MT shot would have been embarrassing, and they might have
> ended up on the railroads!
In one of my earlier posts I mentioned that the Tsar bomb was a clean,
derated version of the design tested. The production was supposed to
have a yield of ~100MT and it would've used uranium tampers in the
fusion stages (almost certainly natural uranium, Oralloy would've
dramatically increased the cost of the weapon). Assuming the full
yield design used the same amount of Li6D, its' fusion fraction
would've been 48.5% making it a very high-yield standard TN bomb.
However as a result of the test, from what i've read the few Tsar
bombs that were produced, were of the clean, derated design. The Tu-95
that dropped the Tsar bomb, by all accounts, was barely outside the
lethal blast radius (I haven't about what, if any damage it may've
suffered from the thermal pulse). As to the design's internal
components, i'd say that both the primary (that large ~18" sphere) and
its' secondary(s) were off the shelf and tested designs. The tertiary
may or may not've been an existing design. I imagine it was a fairly
simple design; one of the bomb's designers said in an interview that
it was a relatively conservative design, the only thing of note was
just its' design yield.
As for its' fusing, it's very clear from the images that it was
barostatically fused. Those two long prongs projecting from its' nose
were very obviously the barostatic probes.
nx1...@hotmail.com
> That means a likely four final "clean" stages, and the 4 cylinders
> almost have to be one per stage - the only thing I can think of is
> tritium reservoirs.
That doesn't make sense; aside from the fact the Tritium is horribly
expense to manufacture in a breeder reactor (the same excess neutron
flux can be used to make on a weight-for-weight basis, 70 times as
much Plutonium). Tritium gas only makes sense as a boost gas for a
hollow boosted primary. The most convenient fusion "Fuel" is Li6D,
where the Li6 gets fissioned into Tritium and Helium-4 by the
sparkplug's neutron flux; in other words, the Tritium is manufactured
in-situ as the secondary is exploding.
Peter Fairbrother
>> That means a likely four final "clean" stages, and the 4 cylinders
>> almost have to be one per stage - the only thing I can think of is
>> tritium reservoirs.
>
> That doesn't make sense; aside from the fact the Tritium is horribly
> expense to manufacture in a breeder reactor (the same excess neutron
> flux can be used to make on a weight-for-weight basis, 70 times as
> much Plutonium). Tritium gas only makes sense as a boost gas for a
> hollow boosted primary.
A fusion stage typically needs some method of ignition - either a
fission sparkplug, or a D-T fusion igniter at the center of the stage.
A few grams of tritium is enough - on compression this burns with some
D, which ignites more D-D burning, producing neutrons, which then split
the Li producing more tritium, and whooomph!
The most convenient fusion "Fuel" is Li6D,
> where the Li6 gets fissioned into Tritium and Helium-4 by the
> sparkplug's neutron flux; in other words, the Tritium is manufactured
> in-situ as the secondary is exploding.
In a sparkplug-ignited Li6D stage most of the neutron population comes
from D-D fusion, not the sparkplug - the sparkplug neutrons get very
rapidly swamped in number by these D-D neutrons.
Overall about 6% of the D burns in D-D reactions, then these neutrons
fission the Li producing T etc, which burns rapidly with the remaining D.
-- Peter Fairbrother
nx1...@hotmail.com
> nx1...@hotmail.com wrote:
> >> That means a likely four final "clean" stages, and the 4 cylinders
> >> almost have to be one per stage - the only thing I can think of is
> >> tritium reservoirs.
>
> > That doesn't make sense; aside from the fact the Tritium is horribly
> > expense to manufacture in a breeder reactor (the same excess neutron
> > flux can be used to make on a weight-for-weight basis, 70 times as
> > much Plutonium). Tritium gas only makes sense as a boost gas for a
> > hollow boosted primary.
>
> A fusion stage typically needs some method of ignition - either a
> fission sparkplug, or a D-T fusion igniter at the center of the stage.
>
> A few grams of tritium is enough - on compression this burns with some
> D, which ignites more D-D burning, producing neutrons, which then split
> the Li producing more tritium, and whooomph!
>
I know that and I do believe it's referred to as "Hot-spot" ignition.
However the what is publicly known, the Tsar bomb was a conservative
design; so in this case this quite likely meant an Orally spark-plug
was used. Keep in mind that of the 1500KT of fission yield, roughly
50-100KT of it came from the primary; the rest could easily have come
from the spark-plugs.
> The most convenient fusion "Fuel" is Li6D,
>
> > where the Li6 gets fissioned into Tritium and Helium-4 by the
> > sparkplug's neutron flux; in other words, the Tritium is manufactured
> > in-situ as the secondary is exploding.
>
> In a sparkplug-ignited Li6D stage most of the neutron population comes
> from D-D fusion, not the sparkplug - the sparkplug neutrons get very
> rapidly swamped in number by these D-D neutrons.
Well, to be more precise the x-ray and neutron flux do deposit a lot
of heat in the Li6D mix; yes the D-D reaction is significant early on.
However, once the spark-plug's neutrons start to seriously fission the
Li-6 (that reaction alone is very exothermic), forming Tritium. The
fusion reactions go into over-drive as a result of the D-T fusion
reaction.
>
> Overall about 6% of the D burns in D-D reactions, then these neutrons
> fission the Li producing T etc, which burns rapidly with the remaining D.
Would you please explain this "6% figure" please; also, do please if
you can, provide a URL to the website/article, where you obtained this
information.
Peter Fairbrother
> On Mar 14, 10:45 pm, Peter Fairbrother <zenadsl6...@zen.co.uk> wrote:
>> nx1...@hotmail.com wrote:
>>>> That means a likely four final "clean" stages, and the 4 cylinders
>>>> almost have to be one per stage - the only thing I can think of is
>>>> tritium reservoirs.
>>> That doesn't make sense; aside from the fact the Tritium is horribly
>>> expense to manufacture in a breeder reactor (the same excess neutron
>>> flux can be used to make on a weight-for-weight basis, 70 times as
>>> much Plutonium). Tritium gas only makes sense as a boost gas for a
>>> hollow boosted primary.
>> A fusion stage typically needs some method of ignition - either a
>> fission sparkplug, or a D-T fusion igniter at the center of the stage.
>>
>> A few grams of tritium is enough - on compression this burns with some
>> D, which ignites more D-D burning, producing neutrons, which then split
>> the Li producing more tritium, and whooomph!
>>
>
> I know that and I do believe it's referred to as "Hot-spot" ignition.
> However the what is publicly known, the Tsar bomb was a conservative
> design; so in this case this quite likely meant an Orally spark-plug
> was used. Keep in mind that of the 1500KT of fission yield, roughly
> 50-100KT of it came from the primary; the rest could easily have come
> from the spark-plugs.
Could be. I'm not saying I'm definitely right about the "cylinders"
being tritium reservoirs, but it is possible - however they are most
definitely not secondaries or tertiaries.
Heck, for real belt-and-braces security, they might have T-boosted the
sparkplugs!
>
>> The most convenient fusion "Fuel" is Li6D,
>>
>>> where the Li6 gets fissioned into Tritium and Helium-4 by the
>>> sparkplug's neutron flux; in other words, the Tritium is manufactured
>>> in-situ as the secondary is exploding.
>> In a sparkplug-ignited Li6D stage most of the neutron population comes
>> from D-D fusion, not the sparkplug - the sparkplug neutrons get very
>> rapidly swamped in number by these D-D neutrons.
>
> Well, to be more precise the x-ray and neutron flux do deposit a lot
> of heat in the Li6D mix; yes the D-D reaction is significant early on.
> However, once the spark-plug's neutrons start to seriously fission the
> Li-6 (that reaction alone is very exothermic), forming Tritium. The
> fusion reactions go into over-drive as a result of the D-T fusion
> reaction.
>
>> Overall about 6% of the D burns in D-D reactions, then these neutrons
>> fission the Li producing T etc, which burns rapidly with the remaining D.
>
> Would you please explain this "6% figure" please; also, do please if
> you can, provide a URL to the website/article, where you obtained this
> information.
S'easy enough to estimate.
Suppose there are 1 million atoms of D and 1 million atoms of Li (yes
that's about a sextillion times out, but never mind :).
The sparkplug provides about 300 neutrons [1] and some heat, and then
40,000 [2] atoms of D react in D-D reactions to provide about 20,000
neutrons.
The Li-D reaction sequence is now reacting twice as fast as the D-D
reaction (the rates are equal at about 10,000 neutrons, or 1% neutron
concentration, or 2% D-D burnup). About 4% of the D gets burned as D-D
during this buildup stage.
The neutron concentration now slowly increases for a while, Li-6 is
eating neutrons and producing T, while D-T reactions are eating the T
and producing neutrons, these two balance out. The increase comes from
further D-D reactions.
There are a few other things going on, like n,2n interactions and
neutrons escaping, but the net effects of these on the neutron
population is small until disassembly begins to affect it.
Note that the concentration of T never gets very high - as soon as it it
is produced it reacts with D, the D-T reaction rate is about 100 times
the D-D reaction rate.
While the main Li + n -> T + He, T + D -> He + n reactions are going on,
about 2 % more of the D reacts as D-D, ie another 20,000 atoms of D
react in D-D reactions.
That's 6% of the D reacting in D-D reactions overall. Probably not
exact, but it's likely to be not too far out.
[1] calculated from the 97% fusion yield
[2] Note that in order to calculate this the only figure you need to
know is ratio of reaction rate constants for D-Li and D-D (which is
about 100:1 under these conditions).
For the D-Li reaction to go faster than D-D, the neutron concentration
has to be above 1% of the D concentration, so a 1.5% neutron
concentration is about the minimum for the first stage, when neutron
numbers are building up. 2% is more likely, which equates to 4% of the D.
-- Peter Fairbrother
loupgarous
You know what? Most of the steady stream of disinformation in this
newsgroup is your own postings.
I DO read the articles I post links to - and if you can list the
specific "disinformation" in that particular link with proof as to
where and how it is wrong, I'd appreciate it. Otherwise, shut the
fuck up.
Your framing every post in terms of your own theories of how
thermonuclear devices might best be made is entertaining on the first
reading... it gets old after the twentieth iteration.