On 7/27/2010 1:00 PM, chaniarts wrote:
Robatoy wrote:
On Jul 27, 11:20 am, wrote:
I keep trying to reconcile the what we know about nuclear powered
satellites and the size of the behemoths we seem bent on building on
the ground. Even the small units that power subs and aircraft
carriers. Why do these power plants always have to be so big and
unwieldy? I don't want to go as far as suggesting 'Neighbourhood Black
Power Boxes' but....(I understand there would be security issues but
that is not why the big nukes are as big as they are.)

nuke plants are large because of the generation size, and containment
(accidents).

subs don't have 'large' plants because they skip a lot of the safety and
containment bits. if they get a meltdown, it just goes out the bottom of the
hull.

There has never been a meltdown on a US warship including several which
were lost at sea with reactors in operation. Avoiding a meltdown is a
matter of dropping the rods and providing sufficient cooling to deal
with the transient, which is difficult with land-based power plants but
not with power plants that have a whole ocean to use as a heat sink.

In any case, the power output of the largest naval reactor in the US
inventory is somewhere around 100 megawatts, 1/10 the output of a
typical base-load electric generating plant, and the ones used in
submarines are much lower capacity.

And this all leaves aside the different compromises that are made in
military vs civilian installations.