[TML] RTT FGMP

[Jerry W Barrington]

On 7/14/08 12:08 AM, "Grimmund" <grimmund at gmail.com> wrote:

> On Sun, Jul 13, 2008 at 9:57 PM, Jerry W Barrington
> <jerry.barrington at gmail.com> wrote:
> 
>> I'm not familiar with "collapsing nuclear rounds".
> 
> IIRC, this came out in Striker.
> 
> High Guard introduced nuclear screens.
> 
> Striker takes that a step further.  If you've got a nuclear damper
> field, you can store short half-life isotopes safely, by using the
> damper field to stop them from decaying.  If you can do that, you can
> make a nuclear weapon with short-half-life isotopes that have *very*
> small critical masses.
> 
> If you use the sudden stop at the target to unite the two sub-critical
> masses into a critical mass, you can make a nuclear device, without a
> large explosive charge, that is small enough to be fired from an
> cannon.
> 
> (Alternately, you can just use a critical mass and a very small damper
> built into the casing of the round.  Impact destroys the damper, and
> the chain reaction proceeds.  This is less safe for the owning forces,
> because if the damper *ever* fails, the round detonates.  Not
> something I'd want to be carrying around, no matter how good the
> dampers are.)
> 
> Either way, Boom.

In-between alternative: during missile/shell flight, have a simple mechanism
push the 2 pieces together gently.  :)

> The postulated devices produced fission explosions, but since they
> were exotic, short-life isotopes, they produced "very small"
> fractional kiloton nuclear explosions.

Assumes a useful source of short-life isotopes, with a damper on hand to
"freeze" them.

But I'm not sure the half-life is really relevant to critical mass.  After
all, a uranium bomb detonates in a fraction of a second, *way* less than
U-235's 703,800,000 years.  Neutron capture cross-section is far more
important than the rate of spontaneous decay.

Besides we already have nuclear weapons down to 10 tons (not mega- or
kilo-tons)!

In any case, nuclear dampers are one of the hand-waves I don't buy into...

> Contact-detonating nuclear rounds, fired from conventional CPR guns.
> 
> Perfect for taking out *really* heavy armor.
> 
> I'll see if I can dig through Striker and confirm this.
> 
>>> Once the plasma cools and stops fusing, so does the radioactivity.
> 
>> Not entirely.  Other atoms that absorb the neutrons may thus
>> become unstable isotopes.
> 
> Are we talking about the FGMP becoming radioactive, or the environment?

Both, to the extent that the fusion generates neutrons and/or radioactive
isotopes.

> My point was that the ball of flaming, fusing plasma doesn't scatter
> radioactive material all over the neighborhood the way a fission
> weapon does.
> 
> A fission weapon starts with radioactive isotopes of uranium (or
> plutonium, if you *really* don't like the target) and the non-consumed
> radioactives, as well as the radioactive fission products, end up
> scattered  all over the target area.
> 
> A ball of plasma from a fusion gun may *emit* some radiation as part
> of the fusion process, but does not contain any radioactive isotopes,
> and doesn't produce them as a direct by-product.

Depends on the specific fusion reaction you use.  Many *do* produce them.

> I agree that you
> *may* manage to create a few atoms of radioactive isotopes, but those
> are a lucky incidental byproduct of the neutrons emitted by the fusion
> reaction hitting atoms in the environment, not an intentional result
> of the functioning of the weapon, as it is in fission devices.

I think this is the big difference between nukes and plasma/fusion guns.
Nukes produce and/or scatter *tons* of radioactive stuff, over many km.
Even a "dirty" gun is only putting out *grams*, in a very small region.

> The weapons themselves should be adequately shielded.  Everything else
> in the Imperium, from starships down to air/rafts, seems to run on
> fusion reactors, without radiation from the reactor being a concern.

More hand-wavium, but let's not go to far into that.  :)