Kerncentrales Japan #25

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Op zaterdag 2 april 2011 14:21 schreef Brentmeister het volgende:
Hoe groot zijn die brandstofstaven eigenlijk?

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The table below, Table 1.4, entitled IDB Reference Characteristics of LWR Nuclear Fuel Assemblies from the 1996 Integrated Database Report provides the following reference data about PWR and BWR fuel assemblies:

Characteristics BWRa PWRb
Overall assembly length, m 4.470 4.059
Cross section, cm 13.9 x 13.9 21.4 x 21.4
Fuel rod length, m 4.064 3.851
Active fuel height, m 3.759 3.658
Fuel rod outer diameter, cm 1.252 0.950
Fuel rod array 8 x 8 17 x 17
Fuel rods per assembly 63 264
Assembly total weight, kg 319.9 657.9
Uranium/assembly, kg 183.3 461.4
UO2/assembly, kg 208.0 523.4
Zircaloy/assembly, kg 103.3c 108.4d
Hardware/assembly, kg 8.6e 26.1f
Total metal/assembly, kg 111.9 134.5
Nominal volume/assembly, m3 0.0864g 0.186g

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Alarm Over Spent Fukushima Fuel Rods Threatens “Chernobyl on Steroids”

The Daiichi complex in Fukushima, Japan … had a total of 1760 metric tons of fresh and used nuclear fuel on site last year, according to a presentation by its owners, the Tokyo Electric Power Company (Tepco). The most damaged Daiichi reactor, number 3, contains about 90 tons of fuel, and the storage pool above reactor 4, which the Nuclear Regulatory Commission’s (NRC’s) Gregory Jaczko reported yesterday had lost its cooling water, contains 135 tons of spent fuel. The amount of fuel lost in the core melt at Three Mile Island in 1979 was about 30 tons; the Chernobyl reactors had about 180 tons when the accident occurred in 1986.

And see this.
That means that Fukushima has nearly 10 times more nuclear fuel than Chernobyl.
It also means that a single spent fuel pool – at reactor 4, which has lost all of its water and thus faces a release of its radioactive material - has 75% as much nuclear fuel as at all of Chernobyl.
However, the real numbers are even worse.
Specifically, Tepco very recently transferred many more radioactive spent fuel rods into the storage pools. According to Associated Press, there were – at the time of the earthquake and tsunami – 3,400 tons of fuel in seven spent fuel pools plus 877 tons of active fuel in the cores of the reactors.
That totals 4,277 tons of nuclear fuel at Fukushima.
Which means that there is almost 24 times more nuclear fuel at Fukushima than Chernobyl.

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The travails of the Fukushima Daiichi nuclear power plant in Japan are highlighting a key question for the US: Why are America’s nuclear power plants allowed to store tons of used but still highly radioactive fuel in pools for as many as 100 years – despite the fact that those pools are far more vulnerable to terrorist attack than the reactors themselves?

In Japan, a relatively small amount of used-up fuel was sitting in Fukushima’s seven spent-fuel pools when disaster occurred. Yet after just days without a cooling system, most water in at least one pool had apparently boiled away, a fire was reported, and radiation levels soared.

By contrast, nuclear utilities in the US have over decades accumulated some 71,862 tons of spent fuel in more than 30 states – the vast majority of it sitting today in pools that are mostly full, according to a recent state-by-state tally by the Associated Press. It’s a huge quantity of highly radioactive material equal to a great many Chernobyls’ worth of radioactivity, nuclear experts say.

The reason is the lack of a national repository for spent fuel – meaning it must be stored on site – as well as the lack of a coherent nationwide policy, experts told Congress Wednesday.

“From the history of our nuclear power program, storage of spent fuel – between the reactor and the presumed repository – has been an afterthought,” said Ernest Moniz, a nuclear expert at the Massachusetts Institute of Technology, at a Senate hearing. “It has not really been part of our serious policy discussion about fuel cycle design.”

“What we need to do is to stand back and say: What is our whole integrated system?” he added. “We should really start thinking hard about that view.”

Warnings years ago
The risks posed by spent fuel held in such pools are hardly new or unknown. A 2006 study by the National Academy of Sciences (NAS) warned Congress and the Nuclear Regulatory Commission (NRC) that spent fuel pools were vulnerable to terrorist attack, with some nuclear plant designs more than others. With water gone from the pools, the spent fuel could easily catch fire and see “the release of large quantities of radioactive materials to the environment,” the study found…….
Fukushima warning: US has ‘utterly failed’ to address risk of spent fuel – CSMonitor.com

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Op zaterdag 2 april 2011 16:02 schreef THEFXR het volgende:
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Flashing Blue Light Seen Above Exploded Nuclear Reactor

Flashing Blue Light Seen Above Exploded Nuclear Reactor

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Op vrijdag 1 april 2011 10:27 schreef Bigs het volgende:
Volgens mij is het juist geen Cherenkov effect, zie http://en.wikipedia.org/wiki/Criticality_accident#Blue_glow

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Op zaterdag 2 april 2011 15:53 schreef Resonancer het volgende:

Is inmiddels 100% zeker achterhaald nu,
http://english.kyodonews.jp/news/2011/04/82782.html
Begin je de ernst van de zaak in te zien, of valt het allemaal nog steeds wel mee ?

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Experts: Scrapping Fukushima plant could take decades
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Hironobu Unesaki, a nuclear engineering professor at the Kyoto University Research Reactor Institute, said, "Looking at past examples of dismantling reactor cores in Japan, it will take a minimum of between 20 and 30 years to complete the work and return the site to (being) an empty lot."

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By Failing To Prepare, You Are Preparing To Fail ~ Benjamin Franklin

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Prime Minister Naoto Kan said Thursday the government will review its basic energy policy that includes increasing the number of nuclear reactors by 14 from the current 54 by 2030.
"Based on the examination results of the current accidents (at the Fukushima No. 1 nuclear power plant), we need new discussions about nuclear power and other energy policies," Kan said at a joint news conference with visiting French President Nicolas Sarkozy.
Kan also said that after the nuclear crisis is settled, the government will discuss whether to maintain the current system of depending on private companies, including Tokyo Electric Power Co., the operator of the Fukushima plant, for all of the nation's electricity supply.
"It is necessary to hold discussions about how electric power companies are operated, including the point of whether current private companies should be maintained," Kan said.