On 04/02/17 12:55, AnthonyL wrote:
On Sat, 4 Feb 2017 10:54:04 +0000, Nightjar wrote:

On 03-Feb-17 8:15 PM, AnthonyL wrote:
I'm a bit out of my depth in an argument I'm having with someone on
the viability of nuclear energy production.

They are arguing that the green argument is false because of the cheap
uranium processing that keeps greenhouse gasses in the southern
hemisphere

I don't know how the southern hemisphere features in this, the world's
largest uranium processing plant is in Canada, but the basic argument is
that processing uranium into nuclear fuel requires a lot of energy, most
of which currently comes from fossil fuel plants. However, a life cycle
analysis of the greenhouse gas emissions for various forms of
electricity generation shows that for nuclear power is only slightly
above that for hydroelectric and wind power and less than that for
biomass an solar PV:

http://www.world-nuclear.org/uploade..._lifecycle.pdf

and the massive energy requirement to build a power station
in the first place.

It is not so much the energy required to build a nuclear power station
as the energy consumed in other aspects of generation; mining and
producing the fuel, running the plant, storing the waste and
decommissioning. These can be 6-8 times as much as the energy needed to
build the plant.

The appropriate measure to compare this aspect of different power
generation methods is energy return on investment. The major study on
this is a 2013 paper by D Weissbach et al entitled 'Energy intensities,
EROIs (energy returned on invested), and energy payback times of
electricity generating power plants'. It is not available online without
payment, but it gives the following figures for EROIs (the higher the
better):

Nuclear with centrifuge enrichment of fuel 75
Hydroelectric 50
Brown coal opencast 31
Coal deep mine 29
Natural gas 28
Wind 16
Solar thermal parabolic 9.6
Solar PV polycrystalline Si 3.8
Solar PV amorphous Si 2.1

These take into account all relevant aspects of each form of generation
from cradle to grave, including capacity factors.

However, while this is considered to be the major study and is broadly
in agreement with many others, you can find different values if you
search for them. Proponents of renewable energy generally quote the
figures from a 2002 study by Gagnon et al, which is widely divergent
from most other studies. This gives the following EROIs:

Hydroelectric 205
Wind 80

Gagnon does not give figures for nuclear, but you can find studies that
put its EROI as low as 1.


Some good pointers here and others (Harry excepted of course). I'll
follow some of the references up. My adversary misled me by saying
that uranium was obtained from 3rd world southern hemisphere countries
(implying on the cheap), omitting Canada, Kazakhstan.

Idle question ~ how would today's radioactive waste radiation levels
in 2000 years compare to today's radiation levels in Cornwall?
Approx.

depends in how thin you spread it.

Dumbed in the ocean no one would notice


--
The biggest threat to humanity comes from socialism, which has utterly
diverted our attention away from what really matters to our existential
survival, to indulging in navel gazing and faux moral investigations
into what the world ought to be, whilst we fail utterly to deal with
what it actually is.