IEEE Spectrum - North American - March 2014 - 52

and the utility companies are scrambling to bring their facilities up to code.
At TEPCO's Kashiwazaki-Kariwa
plant, the world's largest nuclear
power station, workers are erecting a
15-meter-high wall between the buildings and the sea to guard against future
tsunamis. Each of the plant's seven
reactors has three emergency diesel
generators to power its cooling systems, but if all of those fail the plant can
lights go out during the Fukushima Daini drill.
now rely on gas turbines aboard trucks
stationed on a hill 35 meters above
sea level; these turbines can provide power to
n a mock-up control room at the Fukushima
the reactors for two days. A new water reservoir,
Daini plant, 10 kilometers down the coast
45 meters above sea level, can provide all the
from Fukushima Daiichi, workers in blue
cooling water the plant would need for one week.
tracksuits man their stations, monitoring
But even if TEPCO builds a wall up to the sky
the screens and dials that display the operand installs a miniature ocean on the hilltop,
ating parameters of a nuclear reactor. Then a
the Kashiwazaki-Kariwa plant still might not
thunderous roar booms through the room, and a
reopen: The local government hasn't yet given
shout goes up: "Earthquake!" The workers brace
its approval, and many residents are opposed
themselves and hold on to metal rails-but the
to the restart. Throughout the country, people
room is not actually shaking. It's just a safety
express considerable unease about a return to
drill. TEPCO routinely conducts these training
nuclear power. In a recent newspaper poll, nearly
sessions, varying the disaster scenarios to en60 percent of respondents said they don't agree
sure that its workers are ready for any kind of
with the government's pro-nuclear policies.
malfunction or natural catastrophe.
Back at Fukushima Daini, where workers diliThese drills are part of a campaign by Japan's
gently conduct their safety drills, TEPCO has
big utilities to convince the government and the
made some upgrades to its buildings and emerpublic that the country's nuclear reactors should
gency power systems. But Noriyuki Imaizumi,
be reopened, and that they should get back to
deputy superintendent of the power station,
the business of providing electricity. Before the
says there is no official plan to restart the plant
Fukushima Daiichi crisis, 54 reactors provided
and that the prefectural government is against
about 30 percent of the country's electric power.
it. Imaizumi says the deciding vote will ultimately
Right now, not a single reactor is in operation.
come from the people of the towns near FukuUtility companies are importing fossil fuels to
shima Daini-towns that are still evacuated due
make up the shortfall, but that work-around is
to radioactive contamination.
taking an economic toll on the companies and
"I feel we have to get the residents' approval if
their customers alike.
we are to restart," Imaizumi says. For now, FukuJapan's current administration supports
shima Daini's workers will come to work each day
reopening some nuclear plants, and in 2012
on a company bus that drives down empty roads
the government established a new oversight
and through empty towns. They'll conduct their
agency, the Nuclear Regulation Authority, to set
drills and keep vigil over the plant's four reactors,
stricter safety standards. The NRA has declared
making sure they're safe and stable-and that
that no reactor built over an active seismic fault
they can be restarted should conditions allow.
can reopen, and it has already targeted one re"The residents will return eventually," Imaizumi
actor for closure on that basis. The agency also
says, "and when they do, we have to show ourset new requirements for defenses against
selves ready to do whatever they decide." -E.S.
earthquakes, tsunamis, and power outages,

The pool was soon determined to be full of
water, but not before the chairman of the U.S.
Nuclear Regulatory Commission had caused
an international panic by declaring it dry and
dangerous. The reactor 4 pool became one
of TEPCO's urgent decommissioning priorities, not only because it's a real vulnerability
but also because it's a potent reminder of the
accident's terrifying first days.
The process of emptying that pool began
in November 2013. TEPCO workers use a
52

mar 2014

north american

newly installed cranelike machine to lower
a cask into the pool, then long mechanical
arms pack the submerged container with
fuel assemblies. The transport cask, fortified
with shielding to block the nuclear fuel's radiation, is lowered to a truck and brought to a
common pool in a more intact building. The
building 4 pool contains 1533 fuel assemblies,
and moving them all to safety is expected
to take a year. The same procedure must be
performed at the highly radioactive reactors

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1, 2, and 3 and the undamaged (and less challenging) reactors 5 and 6.
Containing the radioactive water that flows
freely through the site is the fourth step. Every
day, about 400 metric tons of groundwater
streams into the basements of Fukushima
Daiichi's broken buildings, where it mixes
with radioactive cooling water from the leaky
reactor vessels. TEPCO treats that water to
remove most of its radioactive elements, but
it can't be rendered entirely pure-and as a
result local fishermen have protested plans
to release it into the sea. To store the accumulating water, TEPCO has installed more than
1000 massive tanks, which themselves must
be monitored vigilantly for leaks.
TEPCO hopes to stop the flow of groundwater with a series of pumps and underground walls, including an "ice wall" made
of frozen soil. Still, at some point the Japanese public must grapple with a difficult
question: Can the stored water ever be released into the sea? Barrett, the former site
director of Three Mile Island, has argued
publicly that the processed water is safe, as
contamination is limited to trace amounts
of tritium, a radioactive isotope of hydrogen. Tritium is less dangerous than other
radioactive materials because it passes
quickly through the body; after it's diluted
in the Pacific, Barrett says, it would pose a
negligible threat. "But releasing that water is an emotional issue, and it would be a
public relations disaster," he says. The alternative is to follow the Three Mile Island
example and gradually dispose of the water
through evaporation, a process that would
take many years.
TEPCO must also plug the holes in the
reactor vessels that allow radioactive cooling water to flow out. Many of the leaks are
thought to be in the suppression chambers,
doughnut-shaped structures that ring the
containment vessel and typically hold water, which is used to regulate temperature
and pressure inside the pressure vessel during normal operations. Shunichi Suzuki,
TEPCO's general manager of R&D for the
Fukushima Daiichi decommissioning, explains that one of his priorities is developing technologies to find the leak points in
the suppression chambers.
"There are some ideas for a submersible robot," Suzuki says, "but it will be very difficult
for them to find the location of the leaks." He

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