Japan's Nuclear Crisis:
Fukushima's Legacy Of Fear
Japan Nuclear Crisis
EMF Computer Protection
Magnetic Field Detector
Geoff Brumfiel & Ichiko
Fuyuno
07 March 2012
Yoichi Tao is busily shovelling dirt in Iitate, a small
village about 40 kilometres from the ruined Fukushima
Daiichi nuclear plant.
It is certainly different from his day job. Tao has a
background in high-energy physics, and teaches students
about information-security systems at Kogakuin University in
Tokyo. But on this sunny February morning, he and a dozen
volunteers have joined local farmers in removing the top few
centimetres of radioactive soil from rice fields. “When the
soil is frozen, we can remove it easily, like a board,” Tao
says. In a corner of the field, they dump the soil in a hole
lined with absorbent sheets. “When spring comes, the ice
melts but the [radioactive] caesium will be absorbed, so we
can protect it from leaking out,” he explains.
The volunteers, mostly researchers, informally call
themselves Fukushima Saisei-no Kai (roughly translated as
the
Fukushima revitalization association), and come armed
with car-mounted sodium iodide scintillators and Geiger
counters linked to the Global Positioning System. Only in
one of the world's most technically advanced societies could
an ad hoc group have the means to cope with radioactive
decontamination.
But there is a dark side to Tao's efforts: he is there
because he and many others have lost faith in their
government. “Since 11 March, people haven't trusted
scientists who receive funding from the government,” Tao
says. “They trust people who act without government funding
and who work together with them.”
One year after Japan's nuclear crisis began, researchers
contacted by Nature say that a strong, evidence-based
understanding of the accident, and the risks the reactors
continue to pose, is within reach. The findings could inform
decisions on public health, environmental clean-up and
economic recovery (see 'The fallout'). But outside
observers, and even some critics in Japan, are increasingly
worried that the loss of public trust, together with
politicians' desperation to regain it, could undermine
rational decision-making about clean-up and resettlement. At
stake are the futures of more than 100,000 residents who
have been displaced from the area around the plant, and
billions of dollars in economic activity across the region.
Meltdown
The crisis began on 11 March 2011, when a magnitude-9.0
earthquake on the Pacific floor sent a massive wall of water
rolling towards the Japanese coastline (see page 141). The
three operating reactors at Fukushima Daiichi automatically
shut down in the moments after the quake, but 41 minutes
later the tsunami burst through the plant's defences and
inundated the reactor buildings. Water flooded emergency
generators, leaving the plant without power for cooling
systems, while radioactive decay continued to heat the
cores. In the control room, workers struggled to run crucial
instruments, using torches and car batteries scavenged from
nearby vehicles. Over the following days, the last line of
emergency systems failed and the three reactors melted down.
The process released hydrogen gas, which eventually
triggered explosions in the reactor buildings. Volatile
radioactive chemicals, notably iodine-131 and caesium-137,
began to stream into the air and sea.
When unit 4 of the Chernobyl nuclear power plant exploded in
1986, the Soviet government imposed a strict information
blackout. The situation could hardly have been more
different at Fukushima: within the first 24 hours, the
government began reporting radiation readings. In the
following days and weeks, the deluge of information became
swollen with data from university researchers, the military,
international monitors, representatives of the US government
and concerned citizens such as Tao.
“We've almost got too much,” says Malcolm Crick, secretary
of the United Nations Scientific Committee on the Effects of
Atomic Radiation (UNSCEAR) in Vienna. At the UN's request,
the committee has spent the past six months trying to unpick
which data came from where, and how they were calibrated.
The committee will deliver its preliminary findings in May,
and Crick says they should be able to say a great deal about
how much radioactivity was released, where it went, and how
much workers and the general public received.
Dose levels
It is already evident that rapid evacuation and careful
screening protected Fukushima's citizens from harm, says
Wolfgang Weiss, a physicist at Germany's Federal Office for
Radiation Protection in Munich and chair of UNSCEAR. Early
and informal analyses by his colleagues suggest that no
members of the public received a dangerous dose of
radiation.
That finding is supported by
a sweeping public-health study begun last summer at
Fukushima Medical University. With a ¥78.2-billion
(US$958-million) budget, the survey is designed to monitor
the health of some 2 million people from the region for 30
years. According to the latest estimates, released on 20
February, 99.3% of 9,747 people living in towns or villages
close to the plant received less than 10 millisieverts (mSv)
in accumulated effective dose in the first four months after
the accident. The highest recorded dose was 23 mSv, well
below the acute 100-mSv exposure levels linked to a slight
increase in cancer risk.
Yet suspicion is hampering
the ambitious health survey, which hopes to nail down the
long-term impact of Fukushima on ordinary citizens. Despite
efforts to promote the study among evacuees, participation
stands at just 21%. “Most of the people I've met here refuse
to fill in the questionnaires. They don't see credibility in
what the government does, and they say, 'this is just a
survey of guinea pigs',” says Shizuko Otake of the
non-profit organization Shalom, which supports refugees in
neighbouring Minamisoma and Iitate.
The roots of mistrust can be
traced to the confusing days immediately after the
explosions, when authorities made a series of inconsistent
statements, issuing radiation readings that often turned out
to be incorrect. As radioisotopes spread from the plant, the
government was repeatedly forced to raise its recommended
safety limits for radiation exposure to citizens and workers
— otherwise, it would have been legally required to evacuate
the site immediately. As a result, some Japanese people
believe that the government is corrupt; others think it is
incompetent. The prevailing feeling is that “what the
government says always changes”, Otake says.
Abel González, a
radiation-protection expert with Argentina's nuclear
regulatory authority in Buenos Aires, says that the
government was forced to raise the safe limits because it
started with an international standard that made no
provision for accident scenarios or for emergency workers
likely to receive higher doses. Without clear guidelines,
the Japanese government simply had to increase the safe
limits to enable people to keep working to bring the nuclear
plant under control, he says. The downside is that “when you
relax the regime in the middle of an accident, you lose
credibility immediately”.
In an effort to win back the
trust of its citizens, the government is planning one of the
most extensive and costly clean-up operations ever — an
effort some experts view as unrealistic. Last autumn, it
announced plans to bring radiation doses from the accident
to below 1 mSv per year in as much of the evacuation zone as
possible. But the goal is based on an international standard
for doses received during the normal operation of a nuclear
plant, not following an accident.
It is also seen by veterans
of nuclear accidents as highly ambitious, especially given
the mountainous and heavily wooded terrain around Fukushima.
“The best thing to do, according to Chernobyl, is to really
turn the first metre of soil upside down,” says Weiss. “But
if you do that, you would kill the whole ecosystem.”
The Japanese authorities
acknowledge the problem, and have started trialling a
variety of clean-up methods in Fukushima. The most prominent
pilot project began last November under the Japan Atomic
Energy Agency (JAEA), with an estimated budget of ¥10.9
billion. The JAEA contracted the project to joint ventures
led by three major construction companies — Taisei, Obayashi
and Kajima — which are testing various technologies to clean
up radioactive materials in 11 cities, towns and villages
whose citizens mostly remain evacuated.
“I am impressed how
companies have come up with novel ideas to remove
decontaminated caesium based on existing technologies,” says
Shinichi Nakayama, deputy director of the JAEA's Fukushima
Environmental Safety Center. For example, scouring caesium
from roads with a high-pressure water jet was thought to be
insufficient because contaminated water would simply spread
out across the pavement. But engineers have modified the
system to recover the contaminated water, purifying and
recycling it, he says.
Many communities are taking
matters into their own hands. With the help of independent
researchers like Tao, they are removing contaminated soil
and conducting other clean-up operations. But without a
central disposal location, Weiss says, these clean-up
operations are just creating a different waste problem.
“People are not allowed to transport the waste, so they put
everything in holes on their property.”
The government's ambitious
goals for decontamination could harm evacuees by inciting
needless fears, says Oleg Nasvit, a radioecologist at the
National Institute for Strategic Studies in Kiev, Ukraine,
who has studied the impact of the Chernobyl nuclear
accident. In 1986, the Soviet authorities demanded
“obligatory evacuation” of residents living in regions where
the additional radiation exposure from the accident was
greater than 5 mSv per year, he says. Evacuees struggled to
cope with their dislocation, and many were stigmatized
because they had come from a contaminated region. “Frankly,
this brought to people more harm than good,” he says.
Setting low radiation-dose
limits is already damaging the economy around Fukushima.
Later this year, the health ministry is planning to lower
the safe level for caesium in vegetables, grain and other
foods from 500 becquerels per kilogram (Bqkg−1) to 100 Bqkg−1
(see 'The limits'). Tomoko Nakanishi, a researcher
specializing in plant radiophysiology at the University of
Tokyo, says that food with radioactivity lower than 500 Bqkg−1
is not harmful to human health, and that areas not heavily
affected by Fukushima's radioisotopes may already exceed the
proposed lower limits because of older nuclear fallout. Some
mushrooms from Chiba prefecture, more than 200 kilometres
south of Fukushima, exceed 100 Bqkg−1, for example, but the
relative amounts of radioisotopes are characteristic of
residual contamination from nuclear weapons tests in the
1950s and 1960s or the Chernobyl accident, not Fukushima.
Fukushima prefecture is among the largest rice producers in
Japan, but last year the agriculture ministry considered
completely prohibiting cultivation where crops contained
more than 100 Bqkg−1 of caesium. Nakanishi and her
colleagues at the University of Tokyo were concerned that
the excessively stringent safety measures could hinder not
only the recovery of the region's agriculture, but also the
collection of scientific data. “Continuous cultivation is
very important to predict what will happen in the future. We
don't know if rice paddies that produced high-level caesium
will do the same this year,” she says. Backed by strong
demand from farmers, the ministry recently decided to allow
cultivation in most areas of Fukushima as long as cities,
villages and towns can prevent the distribution of rice
containing more than 100 Bqkg−1 of caesium. But the ministry
will allow only experimental cultivation in areas that
produced rice containing more than 500 Bqkg−1 last year.
In April, the environment
ministry will begin the nation's full-scale decontamination
programme, the core part of a ¥990-billion recovery roadmap.
The ministry says that it wants science to underpin its
programme. “We would like to make detailed plans based on
feedbacks from government-led pilot projects as well as
other scientific data,” says Kuniaki Makiya, an official in
charge of the decontamination roadmap. Already, the ministry
has decided to prioritize areas of mid-level contamination
above those with very high or very low levels, a move that
Nasvit says makes the plan more credible because the areas
that will benefit the most from decontamination will be
dealt with first.
At the moment, there is no
clear plan for allowing displaced residents to go home.
Although the government's goal is to ensure that people
should not receive a dose in excess of 1 mSv per year if
they return, it is not a firm rule. Indeed, locals can
already go home to villages outside the 20-kilometre
restricted zone around the plant if they choose, but many
public facilities, such as schools, have not yet reopened.
Nasvit believes that citizens should move back, even to
zones where they might receive up to 20 mSv per year.
González agrees, noting that in some parts of the world,
natural annual levels of radiation are in the range of
10–100 mSv.
But Tatsuhiko Kodama,
director of the Radioisotope Center of the University of
Tokyo, thinks the safety margin is not so clear cut. “There
are various interpretations about what to do in the area of
1–20 mSv per year,” he says. He agrees, though, that
ultimately the public must choose the course of action. “The
most important thing is to respect what the residents think.
We have to proceed with plans based on their decisions.
Fred Mettler, a radiologist serving on the UNSCEAR
panel, agrees. Rather than setting a strict number or limit,
he says, the discussion should be more open ended. “We tell
the people what's there, we tell people what the
consequences are, and they decide whether to accept the
risk.”
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