Fukushima: Is Nuclear Safe?
The Quest for Energy
Professor Jim Al-Khalili - Horizon
Fukushima, north east Japan - the site of a partial nuclear meltdown 6
months ago.. The events still unfolding here have consequences for us all.
Energy is the life-blood of our civilization, but where it comes from and
how we get it is something that touched all our lives. Its also, I think,
one of the most important questions for science.
We all need an energy supply that's reliable, but it also has to be
safe. Around the world, many questions are now being asked about nuclear
power. Some countries are looking to abandon it, but what lessons should
we learn from Fukushima? Since the tsunami, electricity has been
rationed in Japan and the mood has turned against nuclear power.
Jim Al-Khalili
I'm a professor of nuclear physics, but I have no agenda, no axe to
grind. I'm not on the pay of the nuclear industry nor the environmental
movement. I've always believed that nuclear power is a good thing , it
provides vast amounts of cheap and reliable energy, but I want to see
how its running out in the real world. How reliable is it? How safe is
it? I want to leave the politics and economics to one side and focus
only on the science, after all I am a scientist, but I'm also a husband
and a father and I want to know what's the safest option for my family's
future.
Shortly after the Fukushima disaster, very rapidly, the perception of
nuclear power began to change and governments reacted. The Germans have
said they'll shutdown their nuclear reactors by 2022. The Swiss
announced that none of their existing nuclear plant would be replaced. A
referendum in Italy rejected plans to return to nuclear power generation
and an explosion in a nuclear reprocessing plant in France recently will
only have stoked these fears further.
For the past few years there's been talk of a nuclear renaissance,
not any more!
I want to separate fact from emotion, to see the reality for myself.
I want answers to a couple of questions. How bad was it? What was the
human impact? How lasting is the damage really likely to be?
On the edge of the Fukushima exclusion zone what is striking is the
emptiness, a lot of empty space for a country as crowded as Japan.
In May this year, an international group of scientists went inside
the Fukushima plant to investigate what went wrong. There is now a well
established story of what happened at the Fukushima Daiichi plant on
March 11th.
Scientists Investigate
First, the earthquake and tsunami wiped out the vital power supply
needed to cool the reactors once they shutdown, and they did shutdown. A
vuild up of heat and pressure caused explosions and the release of
radioactive particles into the atmosphere, including isotopes of iodine
and caesium.
The problem may not have occurred in a newer design of reactor, but
nevertheless Fukushima's 40 year old reactor did contain most of the
radioactivity.
Fukushima was an old nuclear plant, old in design, old in technology
and when you look elsewhere. at nuclear power stations of a
similar age they've mostly been retired or upgraded. Understandably,
many countries around the world are now examining the safety of their
reactors. I believe we should be careful not to make a blanket judgement
about all nuclear reactors on the basis of what happened in Japan.
The Japanese people still need to deal with the consequences and no-one
knows when the people in the evacuation centres will be able to return
to their homes. Thousands of people are still in temporary or make-shift
accommodation, but let's get things in perspective. The earthquake and
tsunami killed over 20,000 people, no-one has died as a result of
fallout from a nuclear plant. The International Atomic Energy Agency
have said that, to date, no confirmed long-term cases of health effects
on any person have been reported due to radiation exposure.
I'm in Japan, 4 months after the tsunami struck the plant. What
remains of the radiation and does it justify the exclusion zone?
Scientists from Fukushima University take soil samples, which is
where most, if not all, of the radioactive particles will have accumulated.
They are looking for two toxic elements; radioactive iodine and
radioactive caesium. But, radioactive iodine is only present for a short
time. The half-life of caesium is 30 years.
They have found high levels of radiation in the top 2 centimetres of
soil. Other studies from nearby found levels 500 times highr than
normal. These tests are out with the exclusion zone. Recently, the
Japanese government has been monitoring the radiation across 50 sites
inside the zone. They've set their safety limit at 20 millisieverts per
year ehich is the same limit for people working in the nuclear industry
in the UK.
Akiko Iwesaki
What they found is that 35 of the sites exceeded this level and the
highest reading was 500 millsieverts. To put things in perspective, you
get 20 millisieverts from 2 CT scans.
So, lets take stock
-
Governments around the world are
looking to Japan to help them make a decision
-
The exclusion zone carries an economic
cost as well as the human cost
-
The containment process, largely,
worked
-
No-one has died
One of the questions Fukushima raises is: How do we judge what level
of radiation can be considered safe? This question is relevant to one
place in particular - the site of the biggest nuclear accident in
history.
Mykola Tronko
26 Apr 1986 Chernobyl, a reactor exploded releasing 3 tons of nuclear
fuel. 28 workers who were first on the scene received extremely high
doses of radiation and died within 4 months.
But, I'm more interested in the effects of the radiation release on
the general public.
20 years after the accident, a large-scale international project, The
Chernobyl Forum, set out to understand the impact of the radiation
release.
I've arranged to meet Professor Mykola Tronko who's in charge of The
Institute of Endocrinology & Metabolism in The Ukraine. Initially,
many doctors expected Chernobyl to cause different types of cancer in
hundreds of thousands of people, but what acrually happened was very
different. Prof. Tronko "Starting from 1990 we saw an increase in
thyroid cancer incidents among children"
Despite this wave of cases of thyroid cancer, there were no confirmed
increases in any other type of cancer in the general population
The thyroid glands were removed, studied and stored. They found that
radioactive iodine had been taken up by the throid and there it had
caused tumours. It affected children more because the rate of cell
division is faster in the thyroid when young. This might have been
prevented, iodine tablets contain the stable form of iodine which your
body takes up in preference to the radioactive form, so cancers don't
start. But, unlike Fukushima, in Chernobyl these tablets weren't
immediately made available.
Once the findings of scientists from across the other contaminated
area of Belarus and Russia were added in, they found a total of 15
deaths among 6,000 cases of thyroid cancer within a population of some
6 million. At a human level the deaths are, of course, significant, but
they're lower than anyone expected.
The Chernobyl victims still live in fear and anxiety. Its a large
scale problem as Dr Marina Gresko knows first-hand.. She specialises in
counselling Chernobyl evacuees although she's also one herself. At the
time of the accedents she was a nine year old attending school. She
tells us "As a rule the most widespread problems are depressive
moods, anxiety symptoms and worry for the future, for their health and
that of their children and grandchildren, Some have serious alcohol
problems."
The UN backed Chernobyl Forum report has stated that the mental
health impact of Chernobyl is the largest public health problem
unleashed by the accident. Its indisputably tied up with economics and
politics. But, its a debate that needs to be informed by an assessment
of the scientific risks.
So, what does this mean for the people of Fukushima who've had their
lives turned upside down by the tsunami and nuclear evacuation. It seems
the greatest threat to their health is now may be the fear of radiation
to their health and the stress of evacuation.
But, of course, the events in Japan have a much wider importance. We
all face choices over the coming years about how we get our energy. Its
a question that's made all the more urgent by the issue of climate
change. If we carry on burning fossil fuel at the rate we're doing then
we risk changing our planet's climate, the effect of which could be
devastating and, to my mind, that can never be a purely scientific
problem.
The influence of politics and economics on nuclear power is, of
course, nothing new and from the first moment scientists started to
understand the power bound up inside the atom it was inevitable that
politicians would be drawn into this irresistible bounty of energy.
The creation of the atomic bomb was one of the most monumental
projects of the 20th century. It brought terrible destruction but it
also demonstrated the power of nuclear physics and shortened America's
war in the Pacific.
After the second world war, physicists were lionised as heroes and
there was this tremendous faith in science to provide solutions and
answers to all the world's problems. As for nuclear technology, the
belief was it had brought an end to the war and now it would provide us
with electrical power.
But, in the new atomic age, there were deep connections between the
civilian programmes for nuclear power and the earlier military projects
to build the bomb. The bomb programme and the later civilian programmes
used the same reactor physic based on uranium, but it didn't have to be
that way.
Alvin Weinberg
Scientists experimented with other ways of producing nuclear power,
and one of these involved, possibly the most overlooked element in the
periodic table, thorium. Some scientists have made great claims for its
potential, including its efficiency, cleanliness and abundance. But,
others saw it as a difficult element to work with. Its harder to trigger
and maintain a nuclear reaction. Crucially, thorium reactors don't
produce plutonium in a form that can be readily used in weapons.
One extraordinary man was keen to push thorium. His name was Alvin
Weinberg. As head of a government lab, Weinberg pushed forward his
suggestion for what he thought was a potentially safer way to produce
nuclear power. This was a moment when politicians were faced with a
choice. They could continue with the thorium reactors and explore safer
options or they could stick with uranium based reactors they knew and
had invested in. They chose uranium.
Now things have changed, the cold war is over and there's renewed
interest in finding safer ways to approach nuclear power. People are
exploring new idea and some are returning to thos that were shelved in
the 1970s and revisitimg the work of scientists such as Weinberg. What
Weinberg had planned was a radically different kind of reactor. Not only
did he propose using thorium he also wanted to use it in liquid form.
Its too early to judge if thorium will live up to its potential.
There are already glimmers of what might be achieved if we
experiment, I think one of the most exciting prospects is how we deal
with nuclear waste.. Long-term waste remains radioactive for tens of
thousands of years. At the moment the only accepted thing to do is bury
it underground.
In Grenoble in south east France they are working on how to turn
long-term waste into something that can be disposed of more efficiently.
Dr Ulli Koester is in charge of researching this process. Its called
transmutation.
Further Reading:
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Nuclear Power: A
Very Short Introduction - Maxwell Irvine |
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Atomic Awakening:
A New Look At The Histor - James Mahaffey |
