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Excerpt: "'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.'"

Reporters and Tepco workers at Reactor No. 4 at Fukushima Daiichi. (photo: Tomohiro Ohsumi/Bloomberg News)
Reporters and Tepco workers at Reactor No. 4 at Fukushima Daiichi. (photo: Tomohiro Ohsumi/Bloomberg News)



Spent Nuclear Fuel Drives Growing Fear Over Plant in Japan

By Hiroko Tabuchi, Matthew L. Wald, The New York Times

28 May 12

 

hat 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 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 scoff at those assurances and point out that even if the building is strong enough, 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 outages 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 are helping to undermine assurances by Tepco and the Japanese government that the Fukushima plant has been stabilized, 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 there 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 for fission to restart if the metal panels that separate the rods are knocked over in a quake. That would be especially bad because the pool, unlike reactors, lacks containment vessels to hold in radioactive materials. (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, he 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 that reactor building. Three other reactor buildings at the site are also badly damaged, but their pools hold 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.

While Mr. Koide and others warn that Tepco must move more quickly to transfer the fuel rods to a safer location, 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 need to build a separate structure next to Reactor No. 4 to support a new crane.

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 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, leading utilities to store a growing stockpile of spent fuel.

As early as the 1980s, researchers, including those at the United States Nuclear Regulatory Commission, started warning of the risks of storing growing amounts of nuclear fuel in pools. The United States has since concluded that densely packed pools are safe enough, but Tepco says that it never even specifically studied the risks posed by the pools.

"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 plants and where the oldest fuel assemblies have been stored in pools since 1973.

Eventually, the plant built 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, but the community was convinced that it was a stalling tactic, and the company loaded only a limited number of casks there.

The casks, as it turns out, were the better choice. They survived the disaster unscathed.

 

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+10 # Granny Weatherwax 2012-05-28 10:18
Second most serious?
Come on!
 
 
+10 # Granny Weatherwax 2012-05-28 10:24
Late 2013? In an earthquake-pron e area?

I believe it is now the UN responsibility to pool world's talent and treasure to solve that problem as soon as possible, as it will does affect only Japan.

We see much faster reaction and "humanitarian intervention" when the considered country can be coerced into "sharing" its resources.
Let's see what we the human race can muster when our health is at stake.
I am not holding my breath.
Maybe I should.

What world are we going to leave to our children?
 
 
+5 # Vardoz 2012-05-28 10:36
If reactor 4 goes every living thing on Earth will be polluted with radiation for generations. This is the most dangerous and insane way to heat water. Using this lethal substance puts us and our great grand children at risk. Dr. Micho Kaku, a nuclear physics expert who teaches at the City College of New York made a documentary years ago and showed how radioactive it still is at the above ground testing sites in our south west. Also the NRC here are not maintaing old reactors. We are all stitting on a time bomb and the NRC are not the ones who should be making the decisions. Perhaps they could shore up the building with cement? I am very worried about this. If this building collapses it will release 85 times more radiation than Gernobyl which is still melting down by the way.
 
 
+3 # jwb110 2012-05-28 11:02
Tepco has lied about the situation from the beginning and the Japanese Gov't has done the same and put its own people in jeopardy by not evacuating the area and all to "save face". I am sure Tepco and the Gov't are holding out for an international cleanup that would save them bearing the cost.
This cloud is running almost directly up against the state of Alaska. Where is Sarah Palin now?
 
 
+2 # Douglas Jack 2012-05-28 13:47
With 3 of 6 Fukushima's nuclear reactor cores so radioactive that humans & robots can't get close we have 3 uncontrolled atomic reactions, with melted fuel flowing out of rod zirconium sheathing. Robot electronics can't operate in this level of radioactivity for any time periods necessary to intervene.

15 kilograms of refined uranium fuel pooling into a small softball size cluster, has capacity to reach criticality & explode, setting off even more uncontrolled reactions in the nearby other 5 reactors spent fuel storages & cores. #4 Fukushima site is where most of the spent fuel are stored some at 100 feet high in a hydrogen explosion damaged building. Given present worldwide consequences of uncontrolled radioactive releases from Fukushima 1, 2 & 3 reactor buildings & potential for greater catastrophe, it's important that all the world's nations offer expertise, experts & resources to help Japan bring these reactions under control, shore-up / reinforce & provide emergency containment capture tanks at #4 site.

With massive radio-active releases swirling in atmosphere, ground-water & oceans, it's important that human plant a trillion trees to absorb & store radio-active isotopes & other complex synthetic chemical toxins of nuclear's failed imperial/indust rial experiment. Trees self-create the greatest bio-mass available. Humans should turn to massive tree nut, fruit & greens food, materials & ecological services productivity. www.indigenecommunity.info
 
 
+3 # doleary 2012-05-28 14:06
If you want stronger oversight from the NRC, please call you U.S. senator and encourage opposition to the re-appointment of Kristine Svinicki, and encourage the confirmation of Allison Macfarlane.
 
 
+2 # PABLO DIABLO 2012-05-28 23:05
Don't worry, we'll just hide under our desks and cover our heads.
 
 
+3 # gzuckier 2012-05-28 23:14
Well, the NRC and industry figures assure us it couldn't happen here. I guess in Japan, their nuclear industry kept telling them that it could happen there. How silly of them.

Seriously, as long as the industry insists on reactor designs which require active coolant pumping to keep them stable, they cannot be "foolproof". And given that there are reactor designs which do have passive stability built into the design, the various molten salt cooling designs for example, as long as nuclear advocates keep pushing the water cooled varieties, any claims of being as safe as possible, or of safety being the number one design concern, can be dismissed out of hand, without even having to think about the other issues, like the environmental effects of uranium mining.
 
 
-1 # Mamazon 2012-06-01 10:07
We are on the verge on annihilation and TEPCO and the NRC would rather continue lying than ask for help. We have to dry cask every spent fuel rod in the world at the cost of a million bucks a cask (according to Arnie Gundersen). Since governments won't do it -- which rich billionaire would rather kick in money for planetary survival? ZERO they's rather stick with the plan to flood the media with billions of dollars for Citizen's United anti-Obama propaganda... It seems we have lost our survival instincts in exchange for remote controls!
 

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