[Marxism] Spent Nuclear Fuel Drives Growing Fear Over Plant in Japan

Louis Proyect 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 
recycled.

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 
nuclear weapons.

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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