X-Message-Number: 20699
Date: Tue, 24 Dec 2002 01:30:38 +0100 (MET)
From: Magnus Redin <>
Subject: Nuclear

Hi!

This post do not advance the state of the art for cryogenic
suspention but might be mildly intresting from a technology discussion
standpoint. 


Yvan Bozzonetti writes:
> Fuel making: mostly U235 enrichement by gas diffusion process

That is an obsolete process. Gas centrifuge plants use about 5% of the
energy needed for gas diffusion. Laser separation is even more energy
efficient but as far I know it is not yet used commercially.

> Reactor building: Special seel and massive concrete structures are
> energy hungry.

Yes but the volumes are not extraordinary. Its not like a big hydro
power dam or a steelworks smelting ore into iron and steel.

The largest Swedish BWR:s used 190 000 m3 of concrete and 18 700 tons
of reinforcement steel in the building.  The reactor tank with lid is
760 ton. Round off the figuers to 200 000 m3 and 30 000 tons of steel.
Steel seems to cost less then 30 000 kWh/ton. (Based on badly done web
surfing. ) 30 000 x 30 000 is about 10^9 kWh. The reactor used in the
example gives about 1200 MW, say it is 1000 MW. 10^9 kWh / 1000000 kW
gives 1000 hour, six weeks. I did not find any energy figures for
concrete production but I can have a fudge factor of 10 for the steel
and double that for the concrete and misc stuff and still have a
strong argument.

> Peperwork: When you pay someone to do a job, a part of that income
> goes to energy expanse.

Can be minimized with standardisation and series production. And it is
a borderline silly argument, the next one would be that plentiful
electricity enables manny other things that uses fossil fuels.

> The most costly: dismantling the reactor at the end of its useful
> life, not a simple job with hightly radio-active parts, and keeping
> them under control for centuries. This account for something as 90
> percent of the energy cost.

The overwhelming bulk of the building has not been activated from the
radioactivity. Real activation requires neutron radiation and that is
only present near the reactor vessel and contaminations get deposited
on surfaces. Most of the metals and reiforcing steel can be recycled
recovering a lot of the energy used for production. And most of the
concrete can be crushed and reused as ballast in new concrete for
road building etc.

Oskarshamn 1 had its reactor vessel manually inspected and serviced by
people working in overpreassure dust proof coveralls after about 25
years of service. They washed the reactor vessel with weak acids to
etch away the top layer and had a telescoping radiation screen
inserterd covering the inside of the walls. Dismantling can not be
that hard when it is possible to have peaople working inside a reactor
vessel used for half its life lenght.

Building a hole in bedrock does not cost massive ammounts of energy
and having it laying there, covered with concrete or so cost 0
kWh/year. 

> I think I have put here all my arguments, I don't see what to say
> more on that subject, so I'll stop to write here on nuclear energy
> for some time. I could say the same for religions. My ideas are
> known, not everyone may agree. We could endlessly exchange arguments
> without changing the mind of anyone. So I stop that exchange too. If
> someone feels otherwise, we can continue by private mail...

I do not write to make you pro-nuclear about the current mature
technology but to help the other people reading the list from
needlessly getting to be anti-nuclear.


Best regards,
---
Titta g rna p  http://www.lysator.liu.se/~redin och kommentera min
politiska sida.
Magnus Redin, Klockareg rden 6, 586 44 LINK PING, SWEDEN
Phone: Sweden (0)70 5160046

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