Re: Being eyeballed

In message <499188a5$6$fuzhry+tra$mr2ice@xxxxxxxxxxxxxxxx>, Shmuel Metz
<spamtrap@xxxxxxxxxxxxxxxxxxxxxxxxxx> writes
In <P25kfTEu5CjJFwFq@xxxxxxxxxxxxxxxxxx>, on 02/06/2009
at 12:34 PM, Robert Sneddon <fred@xxxxxxxxxxxxxxxxxx> said:

We don't need most radio-isotopes that much,

The ones that are active enough would be usable for powering a suitably
designed generator.

You're thinking about radio-thermal isotope generators? The main use
for them is on spacecraft, especially the long-duration deep-space
missions. The isotopes used for such purposes are limited by the decay
chains, the radiation environment produced and above all weight and
compactness. The sweet spot is Pu-238 for various reasons, but there's
not a lot of it about. Existing stocks in the US have been depleted by
assorted spacecraft missions plus a few black-book spook satellites and
submarine detector systems that need to be very compact and not have big
visible solar panels or other noticeable power feeds. The research
reactors used to produce Pu-238 have mostly shut down or been repurposed
and they would require being re-engineered again to restart production
of RTG fuel.

You're thinking that alpha and beta particles are electromagnetic in
nature?

No way, Jos‚. I'm thinking that light is EM in nature.

The particles do radiate, but they are not radiation.

Of course they are; in the case of Beta, they're even ionizing.

Get something moving fast enough, you can make it ionizing. See how
Manny explained the yield of X-rays from Adam's rock impacts when the
Terrans claimed the Loonies were chucking nukes. Still doesn't make them
radiation, just big dumb rocks.

Unless the US plans to build lots and lots of new nuclear warheads or
starts handing out their excess supplies of Pu-239 to anyone who asks
for it, proliferation is not really a problem.

You trust our guards that much?

It's not that difficult to make it hard to steal. Mix it in with a lot
of other stuff and the thieves would either have to steal thousands of
tonnes of material to get a few kilos of weapons-grade, or they'd have
to refine it on-site which is kind of difficult and somewhat hard to
disguise. Of course, there's always Langford's "The Leaky Establishment"
where the problem wasn't acquiring the stuff but trying to put it
back...


Other countries reprocess fuel, remove the small amounts of Pu
produced and store it safely. There are reactor operating regimes
that can burn the Pu produced now but at the moment uranium is
so cheap and plentiful

Enriched Uranium isn't.

Enriching uranium costs money and takes time, energy and equipment to
do safely. A tonne of yellowcake ore will yield about 15kg of uranium
metal with a "natural" enrichment level of about 0.6% U-235. Reactor
fuel rods run about 3-4% so fuel-grade enrichment requires a
concentration ratio of about 6:1, not that hard (or expensive) to do.
AIR the nominal cost of a kilo of fuel-rod grade uranium metal is about
500 dollars US.

nobody's bothering to invest in the new reactor designs required.

There's a large fleet of existing reactors out there, some of which are
coming to end-of-life it is true. Their replacements are likely to be
developments of existing designs, including the new-generation (pun not
intended) PWR units from General Electric. They are optimised to burn
"regular" enriched uranium fuel rods, as are the existing fleet
worldwide. A mixed-oxide reactor (MOX) burning a Pu/U cocktail is a leap
in the dark and it will cost more to put on-grid than another boring old
PWR off the production line. Adding small amounts of Pu-239 to the
refuelling process also increases the chances of some of it escaping
into the wild.


Thus externalizing their costs. *Any* mining operation causes
environmental damage, including coal and Uranium, and in a well run
society that damage would be counted as part of the cost.

It takes a couple of thousand tonnes of yellowcake ore to fuel a 1GW
reactor complex (typically two 600MW reactors) for a year. An equivalent
coal station burns tens of millions of tonnes of coal in the same period
(we will pass lightly over what the Germans are doing, which is to burn
dirt aka lignite in new-build coal stations to replace their nuclear
fleet in the name of Green ecology)). The environmental damage for nuke
power is much less, and provably so -- it is not a requirement for coal
power stations to monitor and restrict the amount of radioactive
materials they release into the atmosphere.

It's possible to fuel and operate power reactors to minimise the amount
of weapons-capable Pu-239 produced.

I don't want to minimize it; I want to use it as fuel.

We can do that in the future, when the supplies of cheap uranium do
actually start to diminish and the fuel price goes up. This will be a
couple of centuries from now though, and by that time fusion power will
be only 25 years away so we might never actually need to use it at all.
--
To reply, my gmail address is nojay1 Robert Sneddon
.

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