Japan Earthquake: nuclear plants - Daini (Plant 2)

[clancy688]

http://www.yomiuri.co.jp/dy/national/T120209007089.htm "Fukushima No. 2 plant was 'near meltdown'"

http://ex-skf.blogspot.com/2012/01/japanese-expert-says-fukushima-ii-not-i.html "Just In: Japanese Expert Says Fukushima II (not I) Nuke Plant's Containment Vessel Has Been Damaged by the Quake"

 

[tsutsuji]

There is a PCV inside / equipment inside PCV visual inspection schedule for Fukushima Daini on http://www.tepco.co.jp/nu/fukushima-np/images/handouts_120208_06-j.pdf page 27 (28/35). The visual inspection of unit 4 was performed from August to December, that of unit 1 is scheduled from December to March, and those of units 2 and 3 are not yet scheduled.

On page 15 (16/35) they say that they found nothing abnormal in units 1 and 4 during the visual inspections inside PCVs. On the same page, they say that as the temperature design value was exceeded in the suppression chambers, they need to assess the consequences (the nuclear safety commission of Japan requested it). Generally speaking, they have to check each design condition for each equipment, check if they were respected, and, if needed, assess the consequences.

On page 16 (17/35) they say they made an earthquake analysis finding that the largest strain for a reactor building was 0.11 E-3 at unit 3's 4th floor, in the south-east direction, which is smaller than the 2.0 E-3 assessment standard.

 

[zapperzero]

http://www.yomiuri.co.jp/dy/national/T120209007089.htm "Fukushima No. 2 plant was 'near meltdown'"

"we" already knew this; cold shutdown was reached something like a week in, iirc.

 

[Astronuc]

"we" already knew this; cold shutdown was reached something like a week in, iirc.

The point is that Fukushima Daini (Plant 2) was nearly in the same situation as Fukushima Daiichi (Plant 1). Had they lost power, then six units (three at FK2 and three at FK1) might have suffered catastrophic core damage rather than the three (Units 1, 2 and 3) at Fukushima Daiichi.

 

[zapperzero]

The point is that Fukushima Daini (Plant 2) was nearly in the same situation as Fukushima Daiichi (Plant 1). Had they lost power, then six units (three at FK2 and three at FK1) might have suffered catastrophic core damage rather than the three (Units 1, 2 and 3) at Fukushima Daiichi.

I think they lost off-site power too, but had working generators. Right?

 

[Astronuc]

I think they lost off-site power too, but had working generators. Right?

From the OP - Yomiuri citation:

On March 11, a 9-meter-high tsunami struck the No. 2 plant, while the No. 1 plant was hit by a 13-meter-high tsunami. The tsunami caused the No. 2 plant's seawater pumps, used to cool reactors, to fail. Of the plant's four reactors, three were in danger of meltdown.

Luckily, one external high-voltage power line still functioned, allowing plant staff in the central control room to monitor data on internal reactor temperatures and water levels.
. . . .
However, despite intense efforts by all employees, it took a long time to stabilize the reactors.

On March 11, about 2,000 employees of the No. 2 plant worked to stabilize the reactors. Some employees connected 200-meter sections of cable, each weighing more than a ton, over a distance of nine kilometers.

Masuda noted the timing of the disaster was critical in saving the plant.
. . . .

No nuclear plant should be so vulnerable! Had the earthquake/tsunami been 12 or 24 hrs later . . . .

 

[rmattila]

I think they lost off-site power too, but had working generators. Right?

The other way around. They lost 9 out of 12 generators (all at units 1 and 2), but survived due to one remaining off-site connection. The status of the EDG:s was revealed in a mid-May press conference, two months after the first inquiries were sent to NISA from foreign safety authorities. (Until May, they kept "confirming" the status of the EDGs.)