A nuclear power setback
Clive Cookson, Financial Times
Published 8:17 AM, 14 Mar 2011 Last update 10:14 AM, 14 Mar 2011
How serious is the partial meltdown at Japan’s Fukushima plant?
It is certainly alarming and sure to have grave
implications for the nuclear industry and energy sector as a whole – but
far from being another Chernobyl, where a runaway nuclear reaction blew
the top off a rudimentary containment system.
The three operational reactors at the Fukushima
Daiichi power station shut down automatically as planned when their
motion sensors felt tremors from the magnitude 8.9 quake on Friday. But
multiple cooling systems, required to remove heat from the core, failed.
The tsunami soon knocked out the backup diesel generators that were
pumping cooling water around the core. Batteries kept the circulation
going for another few hours until they ran flat.
At that point the uranium fuel elements began to
overheat, evaporating the water from the system and generating some
explosive hydrogen. To relieve pressure, the plant’s operators vented
gas from the reactor. This gas seems to have been responsible for the
spectacular explosion that demolished part of the Number One building on
Saturday. There has also been a pressure build-up and venting of the
two other reactors, with the risk of another explosion. The latest step
has been to pour sea water into the reactors, to reduce the overheating
and exposure to the air.
The Japanese authorities have not communicated
clearly – and may not know themselves – what is happening inside the
core of the reactors. The fuel rods seem to have melted to some extent,
adding to the risk of an explosion inside the reactor’s steel and
concrete containment vessel. But western experts say there is almost no
chance of the main vessel failing in an explosion and releasing
radioactive contamination on anything like the scale of Chernobyl.
Some radioactivity has already been released with probably more to come. What health risk does it pose?
Despite some reports in the media of “radiation
poisoning” near Fukushima, no one has suffered the acute – and often
fatal – effects that the Chernobyl explosion inflicted on Soviet
firefighters and reactor staff in 1986.
To reduce the risks of radiation exposure to the
population, the authorities have imposed a 20km exclusion zone around
Fukushima and will make potassium iodide tablets available to people
living closest to the plant. The tablets saturate the thyroid gland –
the body’s hormonal manager – with iodide, limiting the amount of
radioactive iodine it takes up through exposure to emissions from a
damaged reactor. Thyroid cancer is the most important long-term health
risk from a nuclear accident. It is clear that contamination from
Chernobyl caused thousands of extra thyroid cancers across Europe,
though estimates of the final toll vary widely.
Fortunately the winds over northern Japan have been
blowing – and according to weather forecasts will continue to blow –
from the south-west or west, which will move all radioactive releases
out to sea, away from Japan and the Asian continent.
Since the death toll from even the worst
conceivable disaster at Fukushima is likely to be less than those from
the quake and tsunami, why is everyone so caught up by the nuclear
drama?
From the dawn of the nuclear industry in the 1950s,
people have regarded atomic power with fascination and dread. The atomic
bombs dropped on the Japanese cities of Hiroshima and Nagasaki showed
both the immediate destructive power of untamed nuclear fission and the
slow, lingering effects of radiation poisoning.
The Japanese people have long had an ambivalent
response to nuclear energy, though in a resource-poor country they have
tolerated its growth – to the extent that it now accounts for about a
third of electric generating capacity.
The global environmental movement began to vilify the
nuclear industry in the 1960s – partly in response to the industry’s
secretive attitudes and its origins in the “military-industrial
complex”. Since then, anti-nuclear campaigners have picked up on any
failings by the industry and any evidence of harm from radiation.
Can Fukushima and the Japanese nuclear industry recover from this?
The three stricken Fukushima reactors have in effect
been written off by their owner, Tokyo Electric Power Company. Once a
nuclear core has been flooded with sea water to prevent a catastrophic
meltdown, it is almost impossible to restore to operation without
prohibitive expenditure.
All three boiling water reactors date from the 1970s –
Number One reactor was due to celebrate its 40th birthday next week –
and would probably only have run for another decade or so anyway, if
nothing had gone wrong.
In the short to medium term, Japan cannot afford to
decommission the remainder of its nuclear power stations, if it wants to
keep its lights on and the wheels of industry turning. There is no way
to replace so much generating capacity.
In the long run, the nuclear industry’s prospects for
building new plants will depend on winning the trust of a public that
was deeply sceptical about its operations even before events at
Fukushima. A series of mishaps over the past two decades have convinced
many Japanese that operators and regulators are prone to cover up
accidents and incompetence.
And what will the effect be on the global nuclear industry?
Fukushima has already cast a big shadow over the
“nuclear renaissance” to which the industry is looking forward, as the
world begins to warm to a carbon-free source of electricity that would
reduce its dependence on politically unreliable sources of oil and gas.
Germany showed the first sign of this on Saturday,
when protesters came out in force to urge the government to drop plans
to extend the life of its atomic reactors. The demonstration had been
planned for some time but crowds of about 50,000 turned up after news of
the Japanese disaster.
In the UK, where plans are well advanced to build up
to 11 new reactors over the next 15 years, the government asked its
chief nuclear inspector, Mike Weightman, to prepare a report on the
implications of the situation in Japan and any lessons that can be
learnt from the disaster.
John Sauven of Greenpeace UK, which opposes nuclear
power, says the issue with nuclear is “somehow akin to a Faustian pact:
yes, you are getting a large amount of power but there is also an
element of catastrophic risk associated with it”.
The events of recent days “will certainly have an
impact on the nuclear renaissance in developing countries, especially in
places where earthquakes are frequent”, says Olli Heinonen, who was
until last year deputy head of the International Atomic Energy Agency.
How will the industry respond to these new doubts?
Supporters of nuclear power say the industry’s safety
culture changed fundamentally after Chernobyl, claiming that it is now
far more safety conscious than the oil and gas sectors.
Furthermore “third generation” reactor designs, two
of which are under consideration by the UK safety regulator, come
equipped with superior safety mechanisms.
The AP1000 from Westinghouse features passive safety
systems. In the event of an accident, for example a break in a coolant
pipe, the plant can shut down without any operator action or the need
for electric power or pumps. Instead of relying on active components
such as diesel generators – which failed in Japan on Friday – the AP1000
relies on the natural forces of gravity, convection and compressed
gases to prevent overheating.
But in many countries new nuclear programmes have
been delayed more by concerns about economics than safely. In the US,
for example, proposals for 16 new plants have been filed with
regulators, but only two have started any construction work. “The
nuclear renaissance was on the rocks in any case,” says Peter Bradford, a
former US nuclear regulator.
Presumably such a setback for nuclear will increase the demand for other energy sources?
The earthquake and tsunami have shut down 9,700
megawatts of nuclear capacity, temporarily or permanently. Japan is
already the world’s third-largest oil importer – and the largest
importer of liquefied natural gas – and additional purchases on world
markets to make up for the nuclear shortfall are likely to push global
fuel prices higher in the short term.
Yet it remains to be seen whether this short-term
boost to Japanese fuel consumption is tempered by widespread factory
closures and a reduction in economic activity because of earthquake and
tsunami damage.
Looking further ahead, any worldwide setback for
nuclear energy may encourage governments and the private sector to
increase investment in other non-carbon energy sources.
The industry has sought, with some success, to
persuade people to view it in the same way as renewable sources such as
solar, wind and wave – as a clean way of generating electricity that
does not contribute to global warming. If nuclear loses its green
credentials and the fight against climate change remains an important
political issue, then governments may feel compelled to spend more on
developing renewable energy sources.
The problem is that the two main contenders, solar
and wind, are intermittent and their increasing use is already a
challenge for electricity grid managers. But the disaster is likely to
increase long-term demand for natural gas, which emits less carbon
dioxide than coal and is becoming more readily available thanks to new
production techniques.
