Why Tokai No. 2 Nuclear Power Plant Survived March 193
Kyusaku Natsume writes "In a potentially damning report, the Japanese government panel probing the Fukushima Daiichi meltdown has learned that the nuclear power plant Tokai No.2 avoided station blackout thanks to making a 6.1 m high seawall, but TEPCO failed to do the same in Fukushima. From the article: 'The tsunami that hit the Tokai plant on March 11 were 5.3 to 5.4 meters in height, exceeding the company's earlier estimate but coming in around 30 to 40 cm lower than its revised projection. After the tsunami hit, the Tokai plant lost external power just like Fukushima No. 1 did, because the sea wall was overrun, knocking out one of its three seawater pumps. But its reactors succeeded in achieving cold shutdown because the plant's emergency diesel generator was being cooled by the two seawater pumps that survived intact.'"
Huh? (Score:4, Informative)
Someone want to translate the summary? Or is this to be more evidence of lousy content and even worse editting? "as learnt" really?
Re:Huh? (Score:5, Informative)
Researchers: Your walls are too low.
Japan Atomic Power: Oh, okay, we'll fix the wall.
Tokyo Electric Power Company (TEPCO): Hmm, whatever.
Then the tsunami came. Japan Atomic Power's wall was good enough. TEPCO's wall still was not good enough.
Re:The tsunami at Fuku Dai-ichi was 15m (Score:5, Informative)
A 6m, or even a 12m sea wall would not have helped. The only thing damning about this is the summary.
From TFA
Although Tepco calculated in 2008 that tsunami higher than 10 meters could hit the nuclear plant — a height close to the actual waves seen on March 11 — it only reported its calculation to the Nuclear Industrial Safety Agency on March 7, 2011.
I don't recall the wave height to have been measured with any degree of accuracy. However, if the sea wall was 12 meters high and the tsunami actually 15 meters high, the barrier would have significantly reduced the amount of over run. If you watched the video of the wave hitting Fukashima, you saw a brief leading edge slam into and overrun the sea wall, then a mass of water that was not as high. It is certainly possible that the higher wall would have significantly limited the damage.
Re:inapt comparison (Score:5, Informative)
The Basis Design Issues of the Mk1 GE reactors ( the Hitachi and Toshiba reactors were based on that design) were known and neither of the two were correctable.
1. The evidence for the Basis Design Issue of the General Electric reactor comes from the tests of the reactor prototype by the American Society of Mechanical Engineers in Brunswick in the 1970's where it was revealed in the tests of the reactor prototypes that vented when the reactor reached 70psi internally (they tested it with air).
2. A General Electric Nuclear reactor of that design requires a constant supply of power due to the nature of the refueling gate pairs that separate the reactor head from the spent fuel containment. I understand that, due to the nature of the seals on the gates, they need to be constantly powered to prevent a loss of coolant.
These BDIs are mitigated when a reactor is operated according to the Seismic Design Criteria for Nuclear facilities, S and B class facilities (those that contain radionuclides (S) or attached to pressure vessels that contain radionuclides (B) ) should not be affected by the loss of a C class facility (a support facility like a backup generator). The actual quake measured around 140Gal at Fukushima but the plant was designed to tolerate 600Gal (S class). As evidenced the C class facilities (diesel generators) were not as they were affected by the quake, and B class facilities (the pumps) were inundated by the tsunami indicating at least two obvious cases of negligence that led to the loss of the facility.
Clear cut case of criminal negligence on TEPCOs part. Further evidence is in the amount of heat in the spent fuel in the cooling pools. There is a pool volume of 1300 tons of water, they are 12 meters deep, there is 850 tons of water above the spent fuel in each except for reactor 1 spent fuel pool which is smaller by 400 tons. There is 60 Million calories per hour heating capacity in the spent fuel rods in reactor 1 spent fuel pool, 400Mcal/h in reactor 2 spent fuel pool, 200 Mcal/h in reactor 3 and 1600 Mcal/h in reactor 4.
The failure mode for a loss of coolant event in those spent fuel pools was *exactly* in line with what would happened if plutonium in those spent fuel pools was exposed, hydrogen was produced and an explosion occurred. That is what happened. Without those spent fuel containment pools leaking there should have been several *months* to do something, ergo the reactors were operating out of spec. This analysis is based on the available data and it seems a clear cut case of criminal negligence, because the facility survived the initial catastrophes. The risk could have been mitigated years earlier but it wasn't.