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We already know many facts of Chernobyl, but they
are rarely publicized in the media. The UN can't seem to come up with very
modest funding (~$100,000/y) to continue the excellent work of UNSCEAR. It
seems they prefer the Chernobyl myths to the facts.
It's time to rerun an old letter:
The
Editor CNS
Bulletin 9 Sandwell
Crescent Kanata,
Ontario K2K
1V2 Dear
Editor, Evolving Safety Analysis
Technology I enjoyed very much the
excellent paper by John Luxat in the August Bulletin.[1] As he pointed out, recent changes in the
electricity market are pushing the nuclear option to be more competitive, and
this is driving an evolution/revolution in safety analysis. Among the areas being examined are the
specific assumptions and their conservatisms to accommodate uncertainties in
supporting knowledge. To help me
understand these, I looked for an explanation of requirements established more
than two decades ago, and found the 1981 paper by Domaratzki et al[2]
very useful. In addition to cost
reduction, the new market requires a reduction of fear and
misunderstanding. One cause is
terminology. Even when there are no
consequences to people, we call failures in reactor systems accidents. This invites a comparison with airplane
accidents. A particularly challenging
area of analysis is a potential large-break LOCA event. Because there were no LOCAs in CANDUs by
1981, the frequency of large-pipe failures was taken to be less than one in a
1000 reactor-years, based on a 1964 survey of high pressure piping systems in
non-nuclear plants. “With 25
operating CANDU reactors, the average interval (between large LOCAs) would be at
least 40 years.” [2] It
would be appropriate to reassess this frequency, based on: our use of ASME-code
material; our practice of high-quality design, construction and operation; and
the excellent operating experience of ~450 nuclear plants during four
decades. The defined consequences of
LOCA accidents are the radiation doses which would be received by individuals at
the plant boundary and those living in the vicinity. We assume no protective action is taken
(evacuation, use of iodine tablets) resulting in an average thyroid dose and
whole-body dose for these two groups of people. And we use the LNT model to calculate
the number of fatal thyroid cancers and the number of fatal cancers (due to the
whole-body dose). At some point, we might
consider revising our assumptions to fit more realistic consequences of a
nuclear accident. The actual
consequences of the Chernobyl disaster,[3, 4] where the intensity of
the damage and lack of containment allowed a much larger release than postulated
for any western reactor accident, are as follows: ·
~40% of
reactor core and most of its radioactivity released to the
surroundings ·
population evacuated soon
after the event ·
average
whole-body dose 1.5 cGy (rad) ·
~1800
cases of operable thyroid cancer, in children, with 3
fatalities ·
no
excess leukemia or other cancers observed during the following 14
years ·
severe
psychological stress due to fear and relocation ·
severe
world reaction based on fear of contamination - social, political ·
severe
economic stress to the nation Evidence has been
accumulating for a century, and has been presented to us repeatedly by medical
doctors, especially in recent years, that the net health effect of low doses of
radiation seems to be beneficial,[5] recognizing that children are
more sensitive to significant doses.[6] We seem to be ignoring this
information. In a rational world,
we would be addressing only risks that involve the reasonable likelihood
of acute exposures greater than 10 cGy (10 rad) or continuous exposure rates
greater than the range of natural background radiation levels. So the real consequences of a severe
accident are fatalities of mostly plant workers and a very strong reaction from
the public and the media due to the fear of cancer (and genetic effects)
leading to severe economic consequences. This raises the question of how many more decades we will continue to use LNT ideology, and help perpetuate the fear that has been exploited for more than a century[7] to keep nuclear technology under a cloud of cancer. Use of a scientific model for the health effects would give nuclear energy a more positive image. Sincerely, Jerry
Cuttler
References: 1.
Luxat
JC. “Safety analysis technology:
evolution, revolution and the drive to re-establish margins.” CNS Bulletin, Vol. 21, No. 2, pp. 32-39,
Aug 2000 2.
Domaratzki Z, Campbell FR
and Atchison RJ. “The nature of
reactor accidents.” AECB paper
INFO-0053, Jan 1981 3.
“Chernobyl - ten years on:
radiological and health impact, an appraisal by the NEA Committee on Radiation
Protection and Public Health.”
Nuclear Energy Agency, Organisation for Economic Co-operation and
Development, pp. 47, Nov. 1995 4.
“The
radiological consequences of the Chernobyl accident.” UNSCEAR 2000 report to the General
Assembly, Section 1.C.18, June 6, 2000 5.
Pollycove M and Feinendegen
LE. “Epidemiology, molecular
cellular biology and occupational radiation exposure limits.” Proceedings of World Council of Nuclear
Workers (WONUC) Symposium on the Effects of Low and Very Low Doses of Ionizing
Radiation on Human Health, Versailles, France, 1999 June 17-18. 2000, Elsevier
Science, ISBN: 0-444-50513-x, pp. 305-316 6.
Tubiana
M. “Contribution of human data to
the analysis of human carcinogenesis.”
C.R. Acad Sci, Paris, Life Sciences 1999, 322, pp. 215-224
7.
Weart
SR. “Nuclear fear: a history of images.”
Harvard University Press, Cambridge, MA,1988; ISBN: 0-674-62835-7
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