IEEE Spectrum - North American - March 2014 - 48

radiation-proof superhero could make sense of Japan's Fukushima Daiichi nuclear power plant in an afternoon.
Our champion would pick through the rubble to reactor 1, slosh through the pooled water inside the building,
lift the massive steel dome of the protective containment vessel, and peek into the pressure vessel that holds the
nuclear fuel. A dive to the bottom would reveal the debris of the meltdown: a hardened blob of metals with fat
strands of radioactive goop dripping through holes in the pressure vessel to the floor of the containment vessel

below. Then, with a clear understanding of the situation, the superhero could figure out how to clean up this mess.
defueled, but Lake Barrett, who served as
Unfortunately, mere mortals can't
Turbine
site director during that decommissioning
get anywhere near that pressure vesbuildings
process, says the magnitude of the challenge
sel, and Japan's top nuclear experts
was different. At Three Mile Island the buildthus have only the vaguest idea of
Reactor 6
where the melted fuel ended up in
ings were intact, and the one melted nuclear
Reactor 5
reactor 1. The operation floor at
core remained inside its pressure vessel. "At
the top level of the building is too
Fukushima you have wrecked infrastructure,
radioactive for human occupancy:
three melted cores, and you have some core
The dose rate is 54 millisieverts
on the floor, ex-vessel," Barrett says. NothReactor 1
per hour in some areas, a year's aling like Fukushima, he declares, has ever
Reactor 2
happened before.
lowable dose for a cleanup worker.
Reactor 3
Barrett, who is now a consultant for the
Yet, somehow, workers must take
Fukushima cleanup, says TEPCO is taking
apart not just the radioactive wreck
Reactor 4
the only approach that makes sense: "You
of reactor 1 but also the five other
work from the outside in," he says, dealreactors at the ruined plant.
This decommissioning project
ing with all the peripheral problems in the
is one of the biggest engineering
buildings before tackling the heart of the
challenges of our time: It will likely
matter, the melted nuclear cores. During
the site: During the 2011 accident, reactors 1, 2, and 3
take 40 years to complete and cost suffered partial meltdowns. explosions shattered reactor
the first three years of the cleanup, TEPCO
US $15 billion. The operation will in- buildings 1, 3, and 4. reactors 5 and 6 are undamaged.
has been surveying the site to create maps
of radiation levels. The next step is removvolve squadrons of advanced robots,
that water and to contain it by erecting end- ing radioactive debris and scrubbing radiothe likes of which we have never seen.
Nothing has been the same in Japan since
less storage tanks. The reactors are kept in
active materials off walls and floors. Spent
11 March 2011, when one of history's worst
check only by ceaseless vigilance.
fuel must be removed from the pools in the
tsunamis flooded Fukushima Daiichi, cripTEPCO's job isn't just to deal with the imme- reactor buildings; leaks must be plugged.
Only then will workers be able to flood the
pled its emergency power systems, and
diate threat. To placate the furious Japanese
containment structures so that the melted
triggered a series of explosions and melt- public, the company must clean up the site
globs of nuclear fuel can safely be broken
and try to remove every trace of the facility
downs that damaged four reactors. A plume
of radioactive material drifted over north- from the landscape. The ruin is a constant up, transferred to casks, and carted away.
Many of the technologies necessary for
reminder of technological and managerial
east Japan and settled on towns, forests, and
the decommissioning already exist in some
failure on the grand scale, and it requires a
fields, while plant workers scrambled to
pour water over the nuclear cores to prevent proportionally grand gesture of repentance. form, but they must be adapted to fit the
unique circumstances of Fukushima Daiichi.
further radioactive releases. Nine months TEPCO officials have admitted frankly that
later, the Tokyo Electric Power Co. (TEPCO), they don't yet know how to accomplish the "It's like in the 1960s, when we wanted to put
a man on the moon," says Barrett. "We had
the utility company that operates the plant, tasks on their 40-year road map, a detailed
rocketry, we had physics, but we had never
plan for decommissioning the plant's six
declared the situation stable.
reactors. But they know one thing: Much of put all the technologies together." Just as
Stability is a relative concept: Although
conditions at Fukushima Daiichi aren't get- the work will be done by an army of advanced with the moon shot, there is no guarantee
ting worse, the plant is an ongoing disaster robots, which Japan's biggest technology com- that this epic project can be accomplished.
scene. The damaged reactor cores continue
panies are now rushing to invent and build. But faced with the wrath of the Japanese
people, TEPCO has no choice but to try.
to glow with infernal heat, so plant employHere's some more bad news: Chernobyl
and Three Mile Island, the only other
ees must keep spraying them with water to
cool them and prevent another meltdown. commercial-scale nuclear accidents, can't To begin The firsT sTep -inspection-TEPCO
But the pressure vessels and containment teach Japan much about how to clean up
sent in robots to map the invisible hot spots
Fukushima Daiichi. The Chernobyl reac- throughout the smashed reactor buildvessels are riddled with holes, and those
leaks allow radioactive water to stream into
tor wasn't dismantled; it was entombed in
ings. The first to arrive were the U.S.-made
basements. TEPCO is struggling to capture
concrete. The Three Mile Island reactor was
PackBot and Warrior, hastily shipped over
48

mar 2014

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Table of Contents for the Digital Edition of IEEE Spectrum - North American - March 2014