Kerncentrales Japan #12

quote:

Op dinsdag 15 maart 2011 23:35 schreef mschol het volgende:
staan de 6 sarcofagen al klaar?

quote:

Op dinsdag 15 maart 2011 23:32 schreef capricia het volgende:
P&W beetje saai: Hoe krijg je je huis vergoed als je niet verzekerd ben voor Tsunami in Japan?
Terwijl ik alleen maar denk: Men...als dit mis gaat heb je geen huis meer nodig.

quote:

Op dinsdag 15 maart 2011 23:19 schreef Fireblast het volgende:
Quote van de OP:

[..]

Ik mis alleen waarom? Wat is er erg aan een meltdown?

quote:

The warnings were stark and issued repeatedly as far back as 1972: If the cooling systems ever failed at a Mark 1 nuclear reactor, the primary containment vessel surrounding the reactor would probably burst as the fuel rods inside overheated. Dangerous radiation would spew into the environment.

Now, with one Mark 1 containment vessel damaged at the embattled Fukushima Daiichi nuclear plant and other vessels there under severe strain, the weaknesses of the design — developed in the 1960s by General Electric — could be contributing to the unfolding catastrophe.
[..]
In some reactors, known as pressurized water reactors, the system is sealed inside a thick, steel-and-cement tomb. Most nuclear reactors around the world are of this type.

But the type of containment vessel and pressure suppression system used in the failing reactors at Japan’s Fukushima Daiichi plant — and in 23 American reactors at 16 plants — is physically less robust, and it has long been thought to be more susceptible to failure in an emergency than competing designs.

G.E. began making the Mark 1 boiling water reactors in the 1960s, marketing them as cheaper and easier to build — in part because they used a comparatively smaller and less expensive containment structure.

American regulators began identifying weaknesses very early on.

In 1972, Stephen H. Hanauer, then a safety official with the Atomic Energy Commission, recommended in a memo that the sort of “pressure-suppression” system used in G.E.’s Mark 1 plants presented unacceptable safety risks and that it should be discontinued. Among his concerns were that the smaller containment design was more susceptible to explosion and rupture from a buildup in hydrogen — a situation that may have unfolded at the Fukushima Daiichi plant.

“What are the safety advantages of pressure suppression, apart from the cost saving?” Mr. Hanauer asked in the 1972 memo. (The regulatory functions of the Atomic Energy Commission were later transferred to the Nuclear Regulatory Commission.)

A written response came later that same year from Joseph Hendrie, who would later become chairman of the N.R.C. He called the idea of a ban on such systems “attractive” because alternative containment systems have the “notable advantage of brute simplicity in dealing with a primary blowdown.”

But he added that the technology had been so widely accepted by the industry and regulatory officials that “reversal of this hallowed policy, particularly at this time, could well be the end of nuclear power.”

Questions about the G.E. reactor design escalated in the mid-1980s, when Harold Denton, an official with the N.R.C., asserted that Mark 1 reactors had a 90 percent probability of bursting should the fuel rods overheat and melt in an accident. A follow-up report from a study group convened by the commission concluded that “Mark 1 failure within the first few hours following core melt would appear rather likely.”

quote:

Op dinsdag 15 maart 2011 23:25 schreef eleusis het volgende:
Vroeg of laat zou de situatie toch moeten stabiliseren?

quote:

Op dinsdag 15 maart 2011 23:38 schreef Elvi het volgende:
Oh... En nu?