Re: Re: Re: starship-design: Pellet track

[kuo@bit.csc.lsu.edu (Isaac Kuo)]

KellySt@aol.com wrote:
>In a message dated 8/27/97 10:37:05 AM, kuo@bit.csc.lsu.edu wrote:
>>KellySt@aol.com wrote:
>>>In a message dated 8/23/97 12:37:20 AM, kuo@bit.csc.lsu.edu (Isaac Kuo)
>>>wrote:

>>>>Actually, a fusion plant only has to compete with fission plants to
>>>>acheive great profit potential.  The initial and running costs for
>>>>motive fission plants are so great that they're now restricted to
>>>>aircraft carriers and nuclear submarines.  The running costs for any
>>>>practical fusion plant would be much less than fission or conventional,
>>>>so that just leaves initial cost--including R&D.

>>>Actually the weight of the power plants reduces them to fairly large craft.

>>Huh?  Nuclear power plants have been operated on _aircraft_
>>(research into a nuclear powered bomber included actual flights
>>of a conventionally propelled bomber with a nuclear power plant
>>operated on board).  They are light and small enough to potentially
>>be used on smaller ships, but they are expensive.

>Not a power plant with the power to drive an aircraft or ship.  The nuclear
>airplane research program caried A power plant, but not one that could power
>it, much less one that was SHEILDED.  Surface area rules are nasty to small
>nukes.

The one which they carried did operate, and was deemed sufficient to
perform research on safety issues as well as generally demonstrating
the technology.  More powerful small nuclear power plants have since
been developed (for instance, research into particle bed reactors
have led to 300/1 thrust/weight ratio solid core rocket engines).

>About the only small nuclear ship was the Savana.  She ran well, but the
>reactors weight cut into her cargo capacity, and long shorman refused to
>unload her.  Some ports refused her entry.

Probably the most important small nuclear powered vessel is the USN's
NR1, the world's smallest nuclear submarine.  Even though it's only
44.4m long and 336 tons submerged, it is a fully operational nuclear
powered submarine with a nominal endurance of 210 man-days.  This thing
is actually used by civilian researchers (with USN crew running the
boat) for things like searching for the wreckage of Brittanica and
mapping coral reefs.  I think it was used to search for TWA 800
wreckage, but I don't recall specifically.

Seeing as civilians are allowed to use her regularly, I'd say she's
a safe, seaworthy vessel that isn't spraying its crew members with
deathly radiation.

>>> Legal restrictions complicated their use so the navy does use them on all
>>>large ships.

>>Mostly, however, they are expensive.  Otherwise, the USN would find
>>a way to go all nuclear.  Thanks to the late Admiral Rickover, at
>>least our submarine fleet is all nuclear.

>Life cycle wise nukes aren't as expensive then conventional plants.  Not that
>thats much of an argument for DOD contracts.

Really?  I doubt that.  If nukes were less expensive, we would
already see at least some civilian nuclear cargo ships--even if
the cost savings were long term.  The DoD may not be financially
shrewd, but international corporations tend to be.  As a point
of fact, there have indeed been many civilian proposals for
nuclear cargo vessels, nuclear ocean liners, and even nuclear
oil tanker submarine (to, among other things, shuttle underneath
the Arctic).  However, none of these proposals have gotten anywhere.
Large ocean going ships are very fuel efficient, for the payload mass.

>Subs need the air free nature, and Carriers need to stay clear of ports (and
>would burn non-nuke fuel at a tremendous rate).

Huh?  Carriers _do_ burn non-nuke fuel at a tremendous rate--the
majority of carriers in service today are non-nuclear.  How do they
stay clear of ports in wartime?  The same way as the rest of her
fleet, by refueling at sea from tankers.

However, nuclear carriers have an edge in that they have a lot more
space for aviation fuel and munitions, more free deck space, and
landing on them is a bit easier.  Such a pity they're so expensive.
-- 
    _____     Isaac Kuo kuo@bit.csc.lsu.edu http://www.csc.lsu.edu/~kuo
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