[Marxism] Spent Nuclear Fuel Drives Growing Fear Over Plant in Japan
lnp3 at panix.com
Sat May 26 16:18:19 MDT 2012
NY Times May 26, 2012
Spent Nuclear Fuel Drives Growing Fear Over Plant in Japan
By HIROKO TABUCHI and MATTHEW WALD
TOKYO — What passes for normal at the Fukushima Daiichi plant today
would have caused shudders among even the most sanguine of experts
before an earthquake and tsunami set off the world’s second most serious
nuclear crisis after Chernobyl.
Fourteen months after the accident, a pool brimming with used fuel rods
and filled with vast quantities of radioactive cesium still sits on the
top floor of a heavily damaged reactor building, covered only with plastic.
The public’s fears about the pool have grown in recent months as some
scientists have warned that it has the most potential for setting off a
new catastrophe, now that the three nuclear reactors that suffered
meltdowns are in a more stable state, and as frequent quakes continue to
rattle the region.
The worries picked up new traction in recent days after the operator of
the plant, Tokyo Electric Power Company, or Tepco, said it had found a
slight bulge in one of the walls of the reactor building, stoking fears
over the building’s safety.
To try to quell such worries, the government sent the environment and
nuclear minister to the plant on Saturday, where he climbed a makeshift
staircase in protective garb to look at the structure supporting the
pool, which he said appeared sound. The minister, Goshi Hosono, added
that although the government accepted Tepco’s assurances that
reinforcement work had shored up the building, it had ordered the
company to conduct further studies because of the bulge.
Some outside experts have also worked to allay fears, saying that the
fuel in the pool is now so old that it cannot generate enough heat to
start the kind of accident that would allow radioactive material to escape.
But many Japanese have scoffed at those assurances and point out that
even if the building is able to withstand further quakes, which they
question, the jury-rigged cooling system for the pool has already
malfunctioned several times, including a 24-hour failure in April. Had
the failures continued, they would have left the rods at risk of
dangerous overheating. Government critics are especially concerned,
since Tepco has said the soonest it could begin emptying the pool is
late 2013, dashing hopes for earlier action.
“The No. 4 reactor is visibly damaged and in a fragile state, down to
the floor that holds the spent fuel pool,” said Hiroaki Koide, an
assistant professor at Kyoto University’s Research Reactor Institute and
one of the experts raising concerns. “Any radioactive release could be
huge and go directly into the environment.”
Senator Ron Wyden, Democrat of Oregon, expressed similar concerns during
a trip to Japan last month.
The fears over the pool at Reactor No. 4, amplified over the Web, are
helping to undermine assurances by Tepco and the Japanese government
that the Fukushima plant has been brought to a stable condition and are
highlighting how complicated the cleanup of the site, expected to take
decades, will be. The concerns are also raising questions about whether
Japan’s all-out effort to convince its citizens that nuclear power is
safe kept the authorities from exploring other — and some say safer —
options for storing used fuel rods.
“It was taboo to raise questions about the spent fuel that was piling
up,” said Hideo Kimura, who worked as a nuclear fuel engineer at the
Fukushima Daiichi plant in the 1990s. “But it was clear that here was
nowhere for the spent fuel to go.”
The worst-case situations for Reactor No. 4 would be for the pool to run
dry if there is another problem with the cooling system and the rods
catch fire, releasing enormous amounts of radioactive material, or that
fission restart if the metal panels that separate the rods are knocked
over in a quake. That would be especially bad because the pools, unlike
reactors, lacks containment vessels to hold in radioactive material.
(Even the roof that used to exist would be no match if the rods caught
fire, for instance.)
There is considerable disagreement among scientists over whether such
catastrophes are possible. But some argue that whether the chances are
small or large, changes should be made quickly because of the magnitude
of the potential calamity.
Senator Wyden, whose state could lie in the path of any new radioactive
plumes and who has studied nuclear waste issues, is among those pushing
for faster action. After his recent visit to the ravaged plant, Senator
Wyden said the pool at No. 4 poses “an extraordinary and continuing
risk” and the retrieval of spent fuel “should be a priority given the
possibility of further earthquakes.”
Attention has focused on No. 4’s spent fuel pool because of the large
number of assemblies filled with rods that are stored at the reactor
building. Three other reactor buildings at the site are also badly
damaged, but their spent fuel pools held fewer used assemblies.
According to Tepco, the pool at the No. 4 reactor, which was not
operating at the time of the accident, holds 1,331 spent fuel
assemblies, which each contain dozens of rods. Several thousand rods
were removed from the core just three months before so the vessel could
be inspected. Those rods, which were not fully used up, could more
easily support chain reactions than the fully-spent fuel.
Mr. Koide and others warn that Tepco must move more quickly to transfer
the fuel rods to a safer location. But such transfers have been greatly
complicated by the nuclear accident. Ordinarily the rods are lifted by
giant cranes, but at Fukushima those cranes collapsed during the series
of disasters that started with the earthquake and included explosions
that destroyed portions of several reactor buildings.
Tepco has said it will build a separate structure next to Reactor No. 4
to support a new crane. But under the plan, released last month, the
fuel removal will begin in late 2013.
The presence of so many spent fuel rods at Fukushima Daiichi highlights
a quandary facing the global nuclear industry: how to safely store — and
eventually recycle or dispose of — spent nuclear fuel, which stays
radioactive for tens of thousands of years.
In the 1960s and 1970s, recycling for reuse in plants had seemed the
most promising option to countries with civilian nuclear power programs.
And as Japan expanded its collection of nuclear reactors, local
communities were told not to worry about the spent fuel, which would be
The idea of recycling fell out of favor in some countries, including the
United States, which dropped the idea because it is a potential path to
Japan stuck to its nuclear fuel cycle goal, however, despite leaks and
delays at a vast reprocessing plant in the north forcing utilities to
store a growing stockpile of spent fuel.
“Japan did not want to admit that the nuclear fuel cycle might be a
failed policy, and did not think seriously about a safer, more permanent
way to store spent fuel,” said Tadahiro Katsuta, an associate professor
of nuclear science at Tokyo’s Meiji University.
The capacity problem was particularly pronounced at Fukushima Daiichi,
which is among Japan’s oldest plans and where the oldest fuel assemblies
have been stored in pools since 1973.
Eventually, the plant had to build an extra fuel rod pool, despite
suspicions among residents that increasing capacity at the plant would
mean the rods would be stored at the site far longer than promised.
(They were right.)
Tepco also wanted to transfer some of the rods to sealed casks, which
have become a popular storage option worldwide in recent years, but the
community was convinced that it was another stalling tactic.
In the end, the company was able to load a limited number of casks at
the plant. Unlike the fuel pool at Reactor No. 4 that has caused so much
worry, they survived the disaster unscathed.
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