On Wed, 16 Mar 2011 22:26:32 -0400, "Ed Huntress"
wrote:


"Rich Grise" wrote in message
...
Ecnerwal wrote:

Might be time to move some spent fuel from "re-racked" (overstuffed)
pools into dry cask storage at a lot of other plants.

We should be reprocessing it into new fuel and high-value isotopes used
in research and medicine, but the NIMBYs seem to be all obsessed with
the "Oh, my God! The TERRORISTS will make BOMBS!" mentality.

Can't they see that that ship has sailed decades ago?

Why don't we ask the US Navy what they're doing with the spent fuel from
the reactors on all those warships and submarines?

They turn it into HLW (liquid waste; mostly unfissioned uranium and
plutonium) and make that into replacement warhead pits or into mox-type fuel
to go back into the reactors. The balance of it is stored in liquid form, in
stainless tanks, on various DOD sites. The plan is to "solidify" this waste
(presumably in glass or ceramic) for deposit in the national waste facility,
should one be found that isn't on top of a geological fault -- like Yucca
Mountain.
Why trash a valuable resource and concentrated source of
energy?

HLW is hot stuff. 99% of it in the US comes from defense reactors, and we
have quite a load of it. Our naval reactors are the primary users of
plutonium-loaded fuel for power generation.

One of the huge advantages of a molten salt thorium reactor
is that it can use much of the current nuclear waste and
plutonium as fuel, and much of the thorium cycle waste can
be [re] processed on site with a little planning and
investment.
http://en.wikipedia.org/wiki/Thorium_fuel_cycle
http://en.wikipedia.org/wiki/Breeder_reactor
http://energyfromthorium.com/essay3rs/
{see section on how a fuel rod with 98% of its fissile
material can be "spent."}
snip
Thorium and the fluoride reactor present an entirely
different approach to fuel management that makes repeated
recycling not only easy but economically advantageous. That
is because nuclear fuel in the liquid fluoride form rather
than in the solid oxide form has distinct advantages. It is
already in a chemically stable form as a fluoride. There is
no reagent to treat the fuel that will be favored over its
current state. Thus it is protected from chemical attack,
combustion, burning, or corrosion. But more importantly, as
a fluid is it in a form where chemical processes can be
employed directly to remove fission products or to add new
fuel to compensate for burnup. Additionally, the ionic
nature of liquid-fluoride salt renders the fuel essentially
impervious to radiation damage. Despite the passage of large
amounts of gamma radiation, neutron radiation, alpha
radiation, etc. the fuel remains chemically unaltered and
with a complete retention of its physical properties.

Gaseous fission products, including the important fission
product poison xenon-135, are effortlessly easy to remove
from liquid-fluoride salt. They simply come out of solution
in the pump bowl during the pumping of the fluid through the
loop. This has the additional benefit of keeping pressures
low and allowing the reactor to change power states rapidly
without concern for the effect of xenon on power changes.
snip

==It is well to remember that a typical "spent" fuel rod
has in reality used up only about 2% of the fissile material
[energy] it contains, thus simply storing or discarding this
material is throwing away 98% of the energy and the
investment in mining/refining the uranium.==


For heaven's sakes, let's put the reactors on oceangoing barges - didn't
we learn how to build undersea cables about a century or so ago?

Hard to do if you are inland. Another suggestion is to site
these far underground or deep inside a mountain high enough
up to be above any possible flood or tsunami.

Can you say, "tsunami"? d8-)

AFAIK one of the safer places to be in a tsunami is in deep
water as the "tidal wave" is barely noticeable as it sweeps
by. Its when these reach shallow water that the wave rears
up. Thus if the power barges were say 10 miles off shore in
reasonably deep water no problem and no problem with cooling
water either. Another product could be desalted sea water
to help keep the reactor power output level, [simply run a
pipe line beside the power cables] and the brine that is
generated should also have some commercial value.


-- Unka George (George McDuffee)
...............................
The past is a foreign country;
they do things differently there.
L. P. Hartley (1895-1972), British author.
The Go-Between, Prologue (1953).