Re: OT: Nuclear Waste (Was Re-Marketing Ada)

[Ludovic Brenta <ludovic.brenta@insalien.org>]

dmytrylavrov@fsmail.net (Dmytry Lavrov) writes:

<long rant/>

According to COGEMA, the French agency for nuclear fuel and waste, a
nuclear plant uses fuel that consists, for 100 kg of fuel, of:

93 kg non-radioactive Uranium 238
 7 kg radioactive Uranium 235

After 4 years, part of the fuel load is replaced in each reactor.  For
100 kg of fuel, the outcome is this:

93 kg non-radioactive Uranium 238
 1 kg radioactive Uranium 235
 1 kg radioactive Plutonium 239
 3 kg other wastes

2 kg are missing: they've been turned into energy (e=mc2).

The only question is: what do we do with the 1 kg of plutonium and 3
kg of other wastes?  First, the various wastes are sorted according to
their half-life.  The half-life is the time it takes for half of the
material to degrade (through nuclear fission) into other products.
The longer the half-life, the bigger the problem.  Wastes with a short
half-life (milliseconds, seconds, even a few days or months) are not a
big problem and can be treated on-site.  Now plutonium is a different
matter, because its half-life is 26 thousand years.

- it is possible to reuse the plutonium, mixed with uranium, in some
  existing power plants to produce energy.  Thus, we do not produce
  ever more plutonium but "burn" it as we go.  At the very least, this
  reduces the net amount of plutonium produced.  For example, France
  burns plutonium in 900 MW reactors, but not in 1300 MW reactors.

- it is possible to store it and wait for 26 thousand years until half
  the plutonium has turned into other (possibly radioactive) elements.

- it is possible to use it in nuclear weapons.  This is akin to
  storage, until (God forbid) such time as the weapons are used.

My opinion is this: we should not trust our children for 26 thousand
years (by which time only half the problem will be solved anyway).  We
cannot even trust ourselves for a couple of decades without going to
war or doing something stupid.  We must treat this plutonium and turn
it into something harmless.  It is not an urgent problem for now, but
will become one around 2040 when most of the existing reactors reach
their end of life (the existing reactors with their infrastructure are
absolutely required for treatment of nuclear waste; nobody would
accept building a treatment plant where nothing "nuclear" exists yet).

-- 
Ludovic Brenta.