Thursday, March 29, 2012

Radiation and Reason - the Impact of Science on a Culture of Fear



Are you worried about radiation from the crippled Fukushima nuclear power plants? Are you confused about conflicting news reports? Do you wish you had some better information so that you can judge what's best for you and your family?


Well, the only way to do that is to educate yourself.


A good friend sends me the link to the Radiation and Reason website by professor Wade Allison. Professor Allison is Emeritus Professor of Physics at Oxford University and author of the book Radiation and Reason - the Impact of Science on a Culture of Fear




The book has been getting excellent reviews and after reading, I thought that you, dear reader, might find this quite interesting. But first, the things that initially caught my eye were some of the reviews:



Even if you disagree with where Allison takes his arguments, a large part of the book is a good accessible review of the science of radiation and its biological effects. This in itself makes it a potentially valuable read for activists interested in nuclear and environmental issues.” - Peace News, July/August 2010

"Why I'm becoming a pro-nuke nut..... I'd like to urge readers to check out two even more provocative analysts of the risks of nuclear energy..... The other scholar challenging my nuclear views is Wade Allison.... I do think that these and similar views should be included in the conversation we're having about how to solve our energy problems. These are desperate times, and we must consider all alternatives available to us—including nuclear energy, which just a few months ago I fervently opposed.” - John Horgan, Scientific American 23 August 2010



On that note, I'd like to reprint the final chapter of the book here for you to read to help you draw your own conclusions about the Fukushima nuclear accident.


Professor Wade Allison



Chapter 11 Summary of Conclusions

Risks to health associated with ionising radiation have been
overestimated by a wide margin. This conclusion has been
reached bringing together three sources of scientific information:
firstly a century of clinical experience of radiotherapy; secondly
the current knowledge of radiobiology based on laboratory
studies; thirdly the analysis of the long-term health records of
large populations of people exposed to radiation, either as a
single (acute) dose or as a continuing (chronic) one. The result is
that new safety levels for human radiation exposures are
suggested: 100 millisievert in a single dose; 100 millisievert in
total in any month; 5,000 millisievert as a total whole-of-life
exposure. These figures are conservative, and may be debatable
within factors of two, but not ten.
There are three reasons why existing radiation safety standards
have been set at levels that are typically a thousand times more
cautious: firstly the association in the public mind of radiation
with the dangers of nuclear weapons; secondly the advice of
authorities, set up with a narrow remit to minimise public
exposure to radiation and to satisfy the public aspiration for
safety and reassurance; thirdly the lack of available firm
scientific evidence and understanding in earlier decades. During
the Cold War era there were good political reasons not to
minimise the health legacy of a nuclear war, but this association
is now engrained in the general consciousness. In their physical
destructive power nuclear weapons are especially dangerous.
But, when the initial blast with its flash of ionising radiation and
heat has gone, the residual radioactivity and fallout have a much
smaller impact on human health than was supposed in the past.
The underlying idea that a radiation dose, however small, leaves
an indelible mark on health is not supportable. The evidence that
workers exposed to radiation have 15–20% lower mortality from
cancer before age 85 suggests that low doses of radiation might
be beneficial.
New dangers are now evident. These are more global and
threatening than any local nuclear incident, and arise from
changes in the Earth's atmosphere, triggered by the continuing
use of fossil fuels. Although many initiatives are possible in
response, the only large-scale solution is a major switch to
nuclear power for electricity generation and the supply of
additional fresh water. For this to happen rapidly, cheaply and
without disruption, the public perception of ionising radiation
needs to be turned around, and substantial changes in regulations
and working practices, based on new safety levels, determined
afresh. For the future, improved biological understanding may be
able to justify relaxing safety levels still further, and legislation
and working practices should be drawn up, allowing for this
possibility. Such a relaxation of safety levels by factors of about
a thousand means that current concerns, such as waste,
decommissioning, radiation health, terrorism and costs, can be
seen in a better light.
This is a most positive conclusion. But are we able and ready to
reconsider our views, and then act fast enough to lessen the
impending change in climate?
Epilogue: Fukushima
Instability and self destruction
There is a legend in English folklore about Canute, a wise king
of England and Scandinavia (1016-1035). His flattering courtiers
told him that he was 'So great, he could command the tides of the
sea to go back'. But he knew his own limitations -- even if his
courtiers did not -- so he had his throne carried to the seashore
and sat on it as the tide came in, commanding the waves to
advance no further. When they did not, he had made his point
that, though the deeds of kings might appear great in the minds
of men, they were as nothing in the face of nature. As with the
sea, so with radiation; it is nature and science that determine the
effect of radiation and its safety, not political authority. Just
following safety regulations is no substitute for achieving some
understanding.
On 11 March 2011 a magnitude-9 earthquake struck the northeast
coast of Japan and generated a tsunami that completely
devastated a wide coastal area. The death toll was 15,247 with
8,593 missing (as at 27 May) and over 100,000 properties were
completely destroyed [62]. All eleven nuclear reactors at four
nuclear power plants in the region that were operating at the time
of the earthquake immediately shut down exactly as designed. In
the aftermath of the subsequent tsunami three nuclear reactors at
the Fukushima Daiichi plant destroyed themselves and released
radioactive material into the environment. The accident was
declared to be 'severity 7', the maximum on the nuclear accident
scale, the same as Chernobyl -- but Chernobyl was quite
different; its reactor was not shut down, there was no
containment structure to inhibit the spread of radioactivity and
the entire reactor core was exposed to the open air with a
graphite fire that burned and contributed further heat to 'boil off'
and send all volatile material high into the atmosphere.
So what happened to these reactors at Fukushima? The description 'shut down' means that the neutron flux was reduced
to zero and all nuclear fission ceased. Although there was never
any risk of a nuclear fission explosion -- a nuclear bomb -- heat
continued to be produced by radioactive decay, initially at 7% of
full reactor power and falling to 1/2% within a day. This 'decay
heat' is a feature of every fission reactor, as described in Fig. 22,
and the Fukushima reactors were provided with many ways to
disperse this heat without releasing radioactivity into the
environment. At the time of the accident the tsunami deprived
the reactors of power -- connections to the electrical utility were
severed, emergency diesel generators were flooded and back-up
batteries were exhausted after a few hours. As a result the
cooling systems failed and the reactor cores became too hot and
started to melt. In addition the pressure in the reactor
containment vessels rose beyond their design strength. To
prevent complete rupture it was necessary to reduce this pressure
by venting steam including some volatile radioactive material,
largely iodine and caesium. The released gas also included some
hydrogen which exploded (chemically) in the air, blowing the
roof off the outermost cladding of the buildings and hurling some
contaminated debris around the plant and its neighbourhood.
However, it would seem that these explosions did not involve
any further release of activity as they were external to the
primary containment vessel.
Of the dispersed radioactive elements, iodine-131 is known to be
dangerous because it causes thyroid cancer if ingested by
children who have not taken prophylactic iodine tablets. In Japan
these tablets were made available, unlike at Chernobyl (see
chapter 6). Since the activity of iodine-131 halves every eight
days following cessation of nuclear fission, there was no iodine
in the spent fuel ponds. Nevertheless the cooling of these storage
ponds and their potential radioactive discharges have been an
additional focus of attention. Radioactive caesium -- particularly
caesium-137 which has a half-life of 30 years -- was released in
significant quantities both at Fukushima and at Chernobyl.
Outside the plant at Chernobyl there were no fatalities that can
be attributed to radioactivity (other than iodine) and therefore
Instability and self destruction none attributable to caesium. 
Indeed it is a curious fact that at
Fukushima, in spite of the intense media interest in the radiation,
while the tsunami killed thousands, the radiation killed none, and
is unlikely to do so in the future. [After six weeks 30 workers
had received a radiation dose between 100 and 250 milli-sievert
[63]. At Hiroshima and Nagasaki 41 people contracted radiation induced
cancer in 50 years out of 5949 who received a dose in
this range -- that is 1 in 150 (Table 5). At Chernobyl no
emergency worker who received less than 2,000 milli-sievert
died from Acute Radiation Syndrome (Fig. 9b).]
The powerful self destruction of the reactors at Fukushima has
made arresting media headlines that have been closely followed
by predictable promises of increased safety by the authorities.
Modern reactor designs include more safety features than those
at Fukushima and spending many millions of dollars on
protecting a reactor against self destruction has always been a
major element of its design and construction. But the record
shows that human lives are far less at risk in nuclear than in
conventional accidents -- at Windscale (0), Three Mile Island (0),
Chernobyl (50) or Fukushima (0) than at Piper Alpha (167),
Bhopal (3,800) or the Deepwater Horizon oil spill (11). The
distinction would seem to be the simple legacy of fear associated
with nuclear radiation. Distance is no barrier to alarm and fear;
press reports of traces of activity from Fukushima detected as far
away as Scotland, often failed to note the miniscule level found.
Such reports sometimes have serious consequences; following
Chernobyl, statistics for births in Greece published in the
medical literature showed evidence for nearly 2,000 extra
induced abortions attributed to the perceived threat [64]. Instead
of spending large sums on appeasing fears by isolating people
from radiation yet further in the name of safety, resources should
be spent on real public education about nuclear radiation and its
benefits for mankind.
Within days of the accident at Fukushima the media had
exhausted their ability to described the size of the radiation
threat, so spread panic rather than information. As a result many
people fled Tokyo by plane and train. The cause was the fear that
nuclear radiation engenders, rather than any knowledge of the
radiation effect itself. Over-cautious radiation safety limits,
enshrined in regulation in Japan as elsewhere, caused apparently
incomprehensible information to be given by the authorities. For
example, the Tokyo Electric Power Company (TEPCO), the
electric utility company responsible for Fukushima, said that in
the week of the 4 April it had released 10,400 tons of slightly
contaminated water into the sea and that, although this contained
100 times the legal limit for iodine-131, this level would be safe,
and that eating fish and seaweed caught near the plant every day
for a year would add some 0.6 mSv to the dose above natural
background [63]. These statements are probably true but their
apparent mutual contradiction is a source for understandable
alarm. This contradiction would not have occurred if the legal
limits had been set to match a level As High As Relatively Safe
(AHARS) instead of As Low As Reasonably Achievable
(ALARA), a difference of a factor of 1000 or so.
However the story is not yet over and the task of containing the
fuel and keeping it cool continues. Water, so essential to the
cooling task, has become contaminated and must be filtered.
Even with the use of robots the management of these tasks is
daunting. Although the current position [4 June 2011] may not
improve for some months yet, it is worth noting that at
Chernobyl the fuel was open to the sky at high temperature so
that the fate of the cooling water became irrelevant.
Much attention has been given to pointing a finger at who is to
blame for the accident at Fukushima. For many TEPCO is seen
as the villain. But I argue that this is unreasonable; those who
live in Japan accept a very unstable geological environment. In
the tsunami other buildings and plant were swept away
completely, but the Fukushima Daiichi plant survived. It seems
that the nuclear plant was able to withstand an earthquake well
beyond its design and with a few changes it would have
withstood the tsunami too, for instance, a better site, a higher sea
wall and protected diesel generators. Indeed the other reactors in
Japan did so with little or no damage. With hindsight it is easy to
find measures that could have been taken, but why should
nuclear safety be treated as exceptional? Nobody died from
failure of nuclear safety but they died in tens of thousands from
failure of general protection against the effect of a tsunami, about
which there is far less comment [66]. This blame game arises
from a preference to pin responsibility on someone rather than to
sit down and think carefully about what happened -- and whether
a nuclear radiation incident is worse than a tsunami. In more
stable parts of the world these natural forces represent no hazard
to a nuclear plant in any event. However, irrational fear and a
loss of trust in fellow human beings and the organisations for
which they are responsible show the presence of instabilities in
society, just as earthquakes show geologically unstable regions.
International reactions to Fukushima have indicated that many
countries suffer from such instability, whether through
inadequate public education, uninformed political leadership or a
lack of readiness among individuals to learn about the science
that affects their lives. In every community a few members of
society should find out and others should trust them. Mutual trust
is essential for human survival and there is no reason to treat
nuclear radiation safety as a special case.
Explanation or appeasement
A lack of public information and over-cautious radiation
regulations, mis-interpreted as danger levels, caused widespread
despair and misery at Chernobyl where the enforced evacuation
at short notice of the local agricultural population to distant and
unfamiliar accommodation was responsible for serious social
damage; the consequences of this dislocation have been
emphasised in recent reports [12]. The nuclear accident
highlighted the fractures inherent in Soviet society and when
Gorbachev reflected on the disaster it was the socio-economic
earthquake of the end of the Soviet era that he saw. Abroad, the
over-cautious regulations based on appeasing public opinion
caused serious economic damage, as admitted, for instance, in
the press by the authorities in Sweden in 2002 [28].
At Fukushima too there has been damage to families,
communities and the economy caused by the evacuation on top
of the destruction and death from the tsunami. The exposure
level (20 milli-sievert per year) used to define the evacuation
zone is too low and large numbers of people have been evacuated
who should not have been displaced. The criterion for such
invasive socio-economic surgery should be set relatively high,
perhaps up to 100 milli-sievert per month, which is still some
200 times smaller than the monthly dose rate received by the
healthy tissue of patients on a course of cancer therapy.
Evidently concerns for human health based on ALARA are out of
balance with concerns for human health applied in clinical
medicine. At Fukushima, as at Chernobyl, the principal threat to
health has come from fear, uncertainty and enforced evacuation,
not from radiation. In Japan official caution about radiation has
damaged many lives and generated extra socio-economic cost,
misery, recrimination and loss of trust in authorities.
We need better public explanation and realistic safety standards.
Currently these are set on the advice of the International
Committee for Radiological Protection (ICRP) “based on (i) the
current understanding of the science of radiation exposures and
effects and (ii) value judgements. These value judgements take
into account societal expectations, ethics, and experience” [65].
In the past ICRP has followed opinion rather than leading it, a
mistaken approach given the state of popular understanding of
radiation derived from the primitive picture left by last century's
political propaganda. After Chernobyl the chairman of ICRP
admitted that the approach of extra caution had failed (see final
pages of chapter 6). The ICRP has been urged to revise its
approach by academic national reviews [21,22] and others [41].
Accordingly, it should now show some leadership; safety levels
should be revised in the light of modern radiobiology and
supported with programmes of public re-education -- some in the
community are quite bright and welcome reasoned explanation.
The new levels should be as high as is relatively safe (AHARS)
rather than as low as reasonably achievable (ALARA). For their
sakes we need to educate young people for the dangers of the
21st century, not shackle them with the misunderstandings of the
20th. In a world of other dangers -- earthquakes, global warming,
economic collapse, shortages of jobs, power, food and water --
the expensive pursuit of the lowest possible radiation levels is in
the best interest of no one.

Thanks to Timo Budow

No comments:

Post a Comment

Related Posts Plugin for WordPress, Blogger...