‘Inadvertent Criticality’

September 21, 2013

radioaktivitaet-fukushima-ia-14586-20130711-71Under the news layers, another slice of possible horror from the never-ending terror-tale of the Fukushima nuclear plant — this time the possible extraction of 1300 spent fuel rods from Unit 4: Conditions in the unit 4 pool, 100 feet from the ground, are perilous, and if any two of the rods touch it could cause a nuclear reaction that would be uncontrollable.
Worse-case scenario is a major world-wide-effecting fuck-up — a spew factor 15,000 times more-severe than Hiroshima.

All this maybe in less than two months.

(Illustration found here).

According to the dangerously-incompetent Tokyo Electric Power Co — or known by its insipid moniker, Tepco — they will begin an attempt at the end of October to remove the 400 tons of way-mega-malignant shit from the badly-perched pool, and if any of the past actions of Tepco are any indication, we can expect some major malfunction.
Details of the operation comes via a lengthy Reuters piece last August, and the ingredients of this undertaking is head-shaking, creepy-scary — a few drama points:

“They are going to have difficulty in removing a significant number of the rods,” said Arnie Gundersen, a veteran U.S. nuclear engineer and director of Fairewinds Energy Education, who used to build fuel assemblies.
The operation, beginning this November at the plant’s Reactor No. 4, is fraught with danger, including the possibility of a large release of radiation if a fuel assembly breaks, gets stuck or gets too close to an adjacent bundle, said Gundersen and other nuclear experts.
That could lead to a worse disaster than the March 2011 nuclear crisis at the Fukushima plant, the world’s most serious since Chernobyl in 1986.
No one knows how bad it can get, but independent consultants Mycle Schneider and Antony Froggatt said recently in their World Nuclear Industry Status Report 2013: “Full release from the Unit-4 spent fuel pool, without any containment or control, could cause by far the most serious radiological disaster to date.”

Each fuel rod assembly weighs about 300 kilograms (660 pounds) and is 4.5 meters (15 feet) long. There are 1,331 of the spent fuel assemblies and a further 202 unused assemblies are also stored in the pool, Nagai said.
Almost 550 assemblies had been removed from the reactor core just before the quake and tsunami set off the crisis.
These are the most dangerous because they have only been cooling in the pool for two and a half years.

Spent fuel rods also contain plutonium, one of the most toxic substances in the universe, that gets formed during the later stages of a reactor core’s operation.
“There is a risk of an inadvertent criticality if the bundles are distorted and get too close to each other,” Gundersen said.
He was referring to an atomic chain reaction that left unchecked could result in a large release of radiation and heat that the fuel pool cooling system isn’t designed to absorb.
“The problem with a fuel pool criticality is that you can’t stop it. There are no control rods to control it,” Gundersen said.
“The spent fuel pool cooling system is designed only to remove decay heat, not heat from an ongoing nuclear reaction.”

And the kicker:

Removing the rods from the pool is a delicate task normally assisted by computers, according to Toshio Kimura, a former Tepco technician, who worked at Fukushima Daiichi for 11 years.
“Previously it was a computer-controlled process that memorized the exact locations of the rods down to the millimeter and now they don’t have that.
“It has to be done manually so there is a high risk that they will drop and break one of the fuel rods,” Kimura said.

One of the most-insane scenarios ever.
And more than fairly serious — so serious, in fact, there’s a petition to the UN and President Obama to mobilize the global scientific and engineering community to safely transfer those spent fuel rods.
Harvey Wasserman at Global Research: The one thing certain about this crisis is that Tepco does not have the scientific, engineering or financial resources to handle it. Nor does the Japanese government. The situation demands a coordinated worldwide effort of the best scientists and engineers our species can muster.

Or we’ll unwittingly reach the point at which a nuclear reaction is self-sustaining, and a kind of first — a species self-destruction.

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