– Japan Plant Gets Close Exam (Wall Street Journal, Updated May 27, 2012):
TOKYO—The operator of Japan’s damaged Fukushima Daiichi nuclear plant completed its first detailed on-the-ground inspection of one of the reactors there since the tsunami 14 months ago, in an effort to quell fears that another big earthquake could topple the building and release more radiation.
Reactor Unit 4 houses, in a pool of water at its top, what is seen as the most hazardous collection of fuel rods in the plant. Last week’s examination confirmed earlier computer analyses that showed the structure was stable, Tokyo Electric Power Co. said.
On Saturday, Goshi Hosono, the minister in charge of the Fukushima Daiichi cheanup, toured the unit and said he was satisfied with Tepco’s conclusions.
Experts say the spent-fuel pool is a concern because it holds all of Unit 4’s thousands of rods, which were being stored as maintenance was conducted on the reactor when the March 11 earthquake and tsunami hit. Those disasters sparked a series of meltdowns and explosions at the plant, including one that blew the roof off Unit 4 and damaged some of its walls.
Tepco says that the building is capable of withstanding another earthquake equivalent to the March 11 temblor. Investigators found no big cracks or metal corrosion in the structure around the pool, while a test that involves tapping on the concrete walls showed they were still strong, Tepco spokesman Junichi Matsumoto said at a news conference.
The utility did find minor buckling in an outside wall likely caused by an explosion, he said, but added that it was so slight and the wall so far from the pool that it didn’t pose a danger. To be safe, Tepco is redoing its computations with new data.
A delegation views hazardous ‘spent-fuel pool’ at the top of Unit 4 of the Fukushima Daiichi nuclear plant.
“The results of our measurements also confirmed [the building’s] strength,” Mr. Matsumoto said. Tepco already had bolstered the bottom of the pool with concrete and steel struts, and conducted this week’s tests only because of widespread concerns voiced over the structure’s safety, he added.
But activists and concerned observers—including former Japanese ambassador to Switzerland Mitsuhei Murata and U.S. Sen. Ron Wyden—continue to warn that if another big earthquake hits, Unit 4’s pool could collapse or spring a leak, exposing the thousands of fuel rods, which could then overheat and emit huge amounts of radiation.
In a worst-case scenario, some say, the radiation from those fuel rods could force workers to abandon the plant, leaving the systems that Tepco has jury-rigged to cool crippled reactor cores to fail as well.
“This is a question of global safety,” says Mr. Murata, who has for years asserted that nuclear power is dangerous.
Such concerns highlight how unclear conditions at the plant remain after a string of recent disclosures, and how deep the distrust in Japan’s nuclear industry runs—even as Japan braces for a cleanup process that is expected to take as long as 40 years.
The heavily damaged reactors No. 1, No. 2 and No. 3 remain largely too radioactive for people to approach, forcing Tepco to guess at their state by computer simulations and remote measurements.
During the past week, Tepco said its calculations suggested the accident released much more radiation than previous government studies indicated, while a government-affiliated nuclear-industry tracker said it believes the level of cooling water in Unit 1 is only a fifth of what Tepco thinks.
Earlier this year, Tepco sent a camera into the reactor of Unit 2 and found only a fraction of the water it expected.
Many nuclear experts say it is nearly impossible to gauge what would happen if there is further trouble at Unit 4, because the consequences would depend on things such as whether the fuel rods stayed intact or were stripped of their protective covering and hidden in rubble, where they would be hard to cool.
Some say Unit 4 isn’t even as big a concern as the leaky system of pipes thrown together after the accident to keep water flowing to the other three damaged reactors.
Tepco says that although it hasn’t analyzed chances of an accident destroying or cracking the pool, it has made preparations. Because the fuel rods have been cooling for more than a year, even if the water-circulation system shuts off it should take about three weeks for the heat from the rods to boil off enough water that radiation starts leaking, Tepco estimates.
If the pool springs a leak, Tepco has water-pumping trucks ready to spray more water on top of the fuel rods, said Mr. Matsumoto. As a last resort, Tepco is prepared to spray a concrete-like mixture over the rods so they are sealed, he said.
Mr. Matsumoto also said the company would consider asking for an independent evaluation of the soundness of Unit 4, to help ease public angst.
Still, even some who think there is little chance of the pool’s collapsing say the fuel rods should be transferred to a safer place as soon as possible.
“It’s a race against time,” said Hajimu Yamana, a professor of nuclear engineering at Kyoto University, who heads a government committee on decommissioning the plant. Tepco aims to start the removal process by the end of next year, and is meeting with the government this week to see if that process can be accelerated, said Mr. Hosono.
More on Fukushima Reactor 4 (SFP):
– Former Senior Reactor Operator: You Can Get A Recriticality In Fukushima No. 4 SFP – ‘There’s No Way To Shut That Down’ – ‘There You Have Another Never Ending Fountain Of Particulates And Gas’ (VIDEO)
Mitsuhei Murata, 74, a professor emeritus at Tokaigakuen University who once served as Japan’s ambassador to Switzerland:
“If the storage pool should collapse and the 1,535 fuel rods began burning in the atmosphere, an endless amount of radiation would be emitted. Of course, that would mean that Tokyo would become unlivable,” he said.
Murata continued: “Just 50 meters from the No. 4 reactor is the common pool for the No. 1 to No. 6 reactors. The common pool holds 6,375 spent nuclear fuel rods. If a fire should occur at the No. 4 reactor pool, the common pool would also not stand a chance.”
– Which Will Collapse First, The Economy Or The Spent Fuel Pool At Fukushima? (Ambassador Murata: Total Number Of Spent Fuel Rods At Fukushima Daiichi Site Excluding The Rods In The Pressure Vessel Is 11,421!!!)
Spent reactor fuel, containing roughly 85 times more long-lived radioactivity than released at Chernobyl, still sits in pools vulnerable to earthquakes.
If they are MOX fuel, containing 6% plutonium, one fuel rod has the potential to kill 2.89 billion people. If this pool collapses, as Senator Wyden is now saying too, we would face a mass extinction event from the release of radiation in those rods.
That is, if we aren’t in one already. Nuke experts like Arnie Gundersen and Helen Caldicott are prepared to evacuate their families to the southern hemisphere if that happens. It is that serious.
So now you know, if you didn’t before. We are in big trouble.
– Dr. Helen Caldicott (Co-Founder Of Physicians For Social Responsibility): What We Learned From Fukushima (Video – April 2, 2012):
Dr. Helen Caldicott: If Spent Fuel Pool No. 4 collapses I am evacuating my family from Boston.
– MUST-SEE: Fukushima Totally Out Of Control – Radioactive Fallout In the US – Reactor 4 SFP Is the Highest Risk Now: If The Cooling Water Is Lost It’ll Be Just A Few Hours At Most Before That Waste Is On Fire (RT – The Big Picture – Video)
‘Dr. Arnie Gundersen warns they need to go further than 450km.’
– Fukushima: ‘Reactor No. 4 Is Looking More And More Like The Leaning Tower Of Pisa Right Now’ – If It ‘Falls Over It’s Just Gonna Dump A Whole Reactor Core Right Out Onto The Ground’ (And Tokyo & Yokohama Will Be Lost!) (Video)
Arnie Gundersen: “… It could have cut Japan in half. But now the winds have turned, so they are heading to the south toward Tokyo and now my concern and my advice to friends that if there is a severe aftershock and the Unit 4 building collapses, leave. We are well beyond where any science has ever gone at that point and nuclear fuel lying on the ground and getting hot is not a condition that anyone has ever analyzed.”