Why Tokai No. 2 Nuclear Power Plant Survived March

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.'"

Comments

Huh?

[fluffy99]

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?

[chiasmus1]

Translation:

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:Huh?

[TheInternetGuy]

It is not that easy. Reactor no2 in Tokai mura came closer to disaster than anyone wants to admit. Two pumps may have survived, but only one generator (out of three) was working. Had it failed, the result would likely have been similar to Fukushima. That being said. It is my impression (as someone living in the vicinity) that Japan Atomic Power is running things a lot more responsibly than TEPCO. But then again the TM power plants used to be under direct control of JAEA, and JAP was created only when JAEA came under some heavy criticism after earlier incidents.

Re:Huh?

[quenda]

Translation from original Japanese:

2009:
Researchers: Somebody set up us the seawall.
Japan Atomic Power: Main wall turn on.
Tokyo Electric Power Company (TEPCO): All our time are belong to us.
2011:
Researchers: You have no chance to survive make your time.
Tokyo Electric Power Company (TEPCO): For great justice.

Re:Huh?

[Kyusaku Natsume]

Someone want to translate the summary? Or is this to be more evidence of lousy content and even worse editting? "as learnt" really?

I am the one that submitted the story, but I found my mistake until I saw the story posted. English is my third language. I'm sorry, I will buy everyone a pack of Ned Flander's eye soap.

Re:Huh?

[thegarbz]

Not to forget. Nuclear power companies, do not rely on pumps for cooling. Pumps should supply cooling reservoirs and gravity should be used to water for cooling purposes.

The capacity of cooling reservoirs should equal the required the time required to replace those pumps upon failure and maintain cooling demands, whether achieving shut-down or full load requirements.

Yes it costs more to do it that way but it is still significantly cheaper than failure of the system. Laws definitely need to be changed to make corporate executives legally and criminally liable for the decisions they make. When those decisions kill they should be charged with man slaughter and spend the appropriate extended time in prison.

And thus you have fallen into exactly the trap that got them into the position they were in.

The power was out. There was a bigarse battery bank to keep things going. But guess what, thepower was out because an earth quake and a tsunami basically screwed the nation and backup generators which could normally easily be sourced and commissioned within a day or two couldn't.

When your reservoir runs out of water you better hope there's someone more senior than you there to take the resulting beating.

The engineering solution is not to propose some contingency to counteract some ludicrous event, it's to prevent the event from happening in the first place and put the pumps in a place not so easily hammered by a wall of water.

Re:Huh?

[JasterBobaMereel]

..the real trap is: Don't run a nuclear power plant beyond it's design life, and don't continue running it when it has failed several inspections

The reason the sea wall was not higher : It cost too much

The reason the plant was not upgraded : It cost too much

The reason the plant was not replaced : It cost too much

Re:Nuclear cover-ups again

[gman003]

In a major disaster like that, the news literally cannot report on everything. There's thousands of things that, on a slow day, would be newsworthy. In this case, the media focused on the reactors that were failing, and ignored those that merely performed as designed.

The media rarely pays attention to "systems experienced abnormality, performing according to disaster plans".

Case in point: North Anna Power Station shut down automatically due to the recent East Coast earthquake. They're still actually shut down, because the government is overreacting and running additional inspections. And yet the only way I even know that is because my father works for the company that maintains their water system, and they called for information regarding that. There's been almost no mainstream media reporting on it. But the facts haven't been hidden - the top Google result for "lake anna power plant" is the official page by the plant operator, with a header about the earthquake response. The information is there, it's just not widely known to be worth reading.

Re:Nuclear cover-ups again

[LordLucless]

Newsflash: "suppress" isn't a synonym for "not delivered to your door in the morning paper"

When will they learn?

[palmer.dabbelt]

[Cut to: Ships Cockpit. The room is flooded with red light and the message "Danger" repeatedly flashes on the screens. Bender snores loudly. Enter Fry and Zoidberg.]

Fry: What's happening?

[Zoidberg turns on another screen that displays the extent of the damage to the tanker. There is a huge gash most of the way along the hull. A gauge at one side of the screen drops as the dark matter levels go down.]

Zoidberg: All 6,000 hulls have been breached!

[Fry falls to his knees.]

Fry: Oh, the fools! If only they'd built it with 6,001 hulls! When will they learn?

inapt comparison

[0WaitState]

Fukushima had multiple hardware failures, correctable design problems, and crappy management. The failure was not just due to a low seawall.

1. Reactor 1's cooling system likely failed due to the quake, not the failure of the backup diesels. This opinion is based on analysis of the remaining sensors, that indicated the reactor was having problems even while the battery-powered cooling was still running. The existing plumbing and wiring had been embrittled from 4 decades of operation in a quake zone and proximity to, well, a nuclear reactor.

2. Design flaw and hardware failure: locating the backup diesel generators in a basement under the reactors, such that they were guaranteed to flood if water entered the area.

3. Design flaw: locating the spent fuel pools directly above the reactors in the same buildings, such that if the reactor had a little problem (hydrogen explosion, or moderated prompt criticality), said fuel would get blown sky-high, which it did in the reactor 3 explosion.

4. Design flaw: no externally located terminals for "connect portable generators HERE", and no rationalization of Japan's two different electrical standards (it's a fucking nuclear power plant that will blow up if not cooled, so support both standards, guys).

5. Management failure: All reactors should have been flooded with seawater immediately after the quake, as soon as the situation on the ground at the site became clear. This might have averted the hydrogen explosion by keeping the reactors cool enough to not oxidize the zirconium fuel-rod cladding. Local personnel correctly identified the situation, remote management denied permission to flood the reactors with seawater (because that basically ends the reactor's productive life). Eventually a local guy did so anyways.

Re:inapt comparison

[MrKaos]

Fukushima had multiple hardware failures, correctable design problems, and crappy management. The failure was not just due to a low seawall.

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.

Bairly survived

[TheInternetGuy]

It may have survived, but it did so hanging on by a hair. The article only mentions the pumps, but in fact two of the three diesel generators were also out of order. Which means this could easily have turned real bad really fast.
Quoting Wikipedia. http://en.wikipedia.org/wiki/TC5%8Dkai_Nuclear_Power_Plant#Incidents

Following the 2011 Tohoku earthquake and tsunami the number 2 reactor was one of eleven nuclear reactors nationwide to be shut down automatically.[4] It was reported on 14 March that a cooling system pump for the number 2 reactor had stopped working.[5] Japan Atomic Power Company stated that there was a second operational pump and cooling was working, but that two of three diesel generators used to power the cooling system were out of order.[6]

Also it remains to see if the reactor will survive politically. The Mayor of Tokai Mura has called on the government to decommission the number 2 reactor which is over 30 years old. There is a population of over one million people living within a 30km radius of the plant. And they have lost their confidence in the governments ability to safely run the plant. The well known Tokai Mura critically accidents a number of years ago probably didn't do much to boost their confidence either.

Re:The tsunami at Fuku Dai-ichi was 15m

[ColdWetDog]

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:Nuclear cover-ups again

[gman003]

OK then. Let me try again:

The REAL reason they haven't reported on it? Microsoft, in conjunction with Sony, working on behalf of the MPAA/RIAA, using Republican tax breaks, funded a top-secret re-education camp run by the Westboro Baptist Church to brainwash the entire country of Japan into becoming their mind-controlled cannon fodder for their war against truth, justice, and open-source software. Jack Thompson is rumored to be involved.

We should all immediately panic. Once we finish panicking, we should immediately go out and shoot every lawyer, politician or corporate executive you can find. The revolution begins now.

obligatory xkcd

Re:Fail safe versus fail deadly

[mug funky]

i don't know about "so many disasters", so much as "1 major disaster, 1 medium disaster caused by a much bigger catastrophe and 1 small gas leak and messed up but contained core".

it's not good, but it's not bad either. you write like the world is a pulsating green wasteland without so much as cockroaches surviving.

i agree that greed will fuck up anything. it's up to the engineers to design these things as greed-proof as possible. that's just another safety feature. to that end, i'd rather a new gen reactor designed with a modern nuclear engineer's cynicism than one built in the era of "Peaceful Atoms" and almost sickening faith and optimism.

The real reason: Luck

[tp1024]

There is one simple way that would have prevented the tsunami from taking out all emergency generators.

To comply with international standards and have at least four emergency generators per reactor placed around the reactors with adequate spacing between each of them to prevent common cause failure. For purely geometric reasons (to keep the distance between each other) at least one per reactor would have to have been behind the reactor buildings on higher ground. Which exactly how spacing alone mitigates common cause failure.

It would also have been helpful had TEPCO installed Passive Autocatalytic Recombiners in their reactor buildings to catalytically "burn" the hydrogen before it can reach combustible or explosive concentrations. (Those do their job by hanging on the wall. No power required.) Or if they had hardened and filtered containment vents.

Both of those measures were implemented in Sweden, Germany and France some time after the analysis of the Three Mile Island accident, which quite accurately predicted how Fukushima Daiichi turned out, which was deemed unacceptable. Hence the additional safety features. I'm not saying that those are the only countries that implemented such measures, but with those I'm sure. And I stopped making assumptions about those things seven months and two weeks ago.