Message-Id: <v01540b01b053bc10f5bf@[12.64.1.254]>
To: pinhole@exploratorium.edu
From: kstreet@worldnet.att.net (Karen Street)
Subject: Re: half life and nuclear reactors
Date: Sun, 28 Sep 1997 15:51:25 +0000
Ellen,
This may be more of an answer than you were looking for!
I recommend very highly to anyone looking at energy issues
Aubrecht, Gordon Energy Prentice Hall 1995 Written for the layman by a
physicist, this is an excellent introduction to energy. There is an
explanation of some basic physics followed by a very thorough, very
understandable discussion of issues in energy policy today. Written as a
textbook, it includes questions after each chapter, plus an extensive set
of references. This is the best book I've seen on the subject of energy.
First a lecture, then I'll address your two questions below.
The discussion of the safety of nuclear energy is usually couched in terms
of how safe is nuclear energy compared to nothing. A more productive
question is "Which energy (for this application) is best for us and the
planet?" Renewables and conservation are often presented as an alternative
to nuclear energy (but not coal for some reason, though coal is considered
thousands of times more dangerous both immediately--particulates and ozone
from coal kill tens of thousands of Americans each year and coal damages
the environment and agriculture--and in the future--the predictions of
global climate change are unpleasant).
Hydroelectric is considered by many in energy to be more dangerous than
nuclear, see Aubrecht's book for example. The World Bank has stopped
funding hydroelectric plants.
Solar energy (photovoltaics) as an energy source in the city, is not
promoted within the solar industry--all the glowing reports I could find
about our hope for its future were in US News and World Reports type
publications.
Wind energy seems to get good marks, but its use is limited by locality and
even then, it can provide a maximum of 30% of the energy used, because of
its intermittent quality. And it has problems as well.
Renewable seems to be synonymous with apple pie and motherhood. We need to
look at renewables in the same objective way we look at all energy sources.
We speak glowingly about conservation. We as individuals and a nation need
to invest our time and efforts in figuring out how we're going to live with
less energy; it will require more than greater fuel efficiency for cars and
double glazed windows. Anyone using the word conservation should be
required to define it: double glazed windows or a radical change in our
lifestyle? Meanwhile, on the way to conservation, what energy sources are
best for us and the planet?
1. Wastes in fuel rods (from Bodansky, David Nuclear Energy: Principles,
Practices and Prospects American Institute of Physics 1996 see p. 129 for
the full table (your university library may have a copy)
Half-lives are given in years
Sr 90, 28.8
Y 90, <<1
Tc 99, 211k
Cs 137, 30.1
Ba 137, <<1
Np 237, 2.14M
Pu 239, 24.1k
Pu 240, 24.1k
Pu 241, 14.35
Am 241, 432
Bodansky discusses issues in nuclear waste disposal in chapter 10. After as
little as 300 years, the waste becomes less radioactive than the original
ore. The 10,000 and 1,000,000 year timelines for radioactive decay are
produced by the EPA with their belief in the best available technology (for
nuclear energy--they are too lax on all fossil fuels according to most
people in the industry).
Or to put it in context, is it worth one person driving to protest nuclear
waste? Automobile drivers voluntarily participate in a system in which
45,000 will die this year from accidents, and another very large number
will have their lives ruined. Another 30,000 will die yearly from
pollution. And an unknown but very large number will die worldwide over the
next 100 years, 500 years, millennia from global climate change.
2. Chernobyl is usually brought up in the US to protest US nuclear
policies, though, as far as I know, Lake Aral is rarely brought up to
protest US water policies. Chernobyl used a design that would never, since
day 1, have been successful in the West. Unfortunately, the chances are
quite reasonable that we will have another Chernobyl soon, as the Soviets
are selling their energy to Westerners for valuable currency and then
failing to invest in maintenance or paychecks for the employees.
Again from Bodansky, pp 223 + The radioactive release was mainly volatile
nuclides, including iodine and cesium. Much less strontium, etc. escaped.
The first detection was by the monitors in Scandinavian nuclear power
stations, 2 days later. The major isotopes, and their half-lives:
Kr 85, 10.8 years
Xe 133, 5.25 days
I 131, 8.02 days
Cs 137, 30.2 years
Sr 90, 28.8 years
(not from Bodansky) It is unknown how many people will eventually die from
Chernobyl. All cases of thyroid cancer can be attributed to Chernobyl, as
well as Soviet failure to provide its children powdered milk. Soviet
inability to find housing in other communities for some of the more
affected people will also increase the harm done. (back to Bodansky) The
groups that studied Chernobyl afterwards found a radioactivity level half
that the Soviets announced, except that there was no way to reconstruct the
original level of the iodine. It is expected that many will die from cancer
due to the increased radioactivity, but there will not actually be a way to
detect this, as the increase is relatively small compared to normal cancer
levels.
The issues are very complicated, much more complicated than we generally
have been willing to pay attention to. Good luck with all your efforts!
Karen Street