Completion of Hamaoka plant tsunami seawall delayed

SHIZUOKA —

Chubu Electric Power Co said Tuesday that it will complete the construction of a tsunami seawall around its Hamaoka nuclear power plant in Shizuoka Prefecture by December next year, which is later than originally planned.

The power utility initially planned to build a 18-meter-high seawall but this was judged not high enough. The 1.6-kilometer-long seawall will now be 21 meters high. Chubu Electric said a coastal levee will also take longer to construct, TBS reported.

The Hamaoka plant lies just 100 meters away from the Pacific Ocean and sits in the Tokai region, southwest of Tokyo, where seismologists have long warned that a major quake is overdue because two major continental plates meet here.

Chubu Electric said it will spend about 100 billion yen on the 1.6-kilometer-long wall, as well as other measures to prevent flooding inside the plant, and programs to safeguard cooling systems that bring reactors to safe shutdown in case of severe accidents. 

Japan Today

  • 1

    TumbleDry

    Also, plan for backup power lines, generators and compatible plugs. Did I mention evacuation plans?

  • -1

    Cletus

    Yeah well, they are building this lovely wall infront of the plant l just hope they remember the sides as well. Unlikely though!!!!

    And l wonder what they are going to do to safeguard the plant from the major fault line it sites on top of.

    Seriously just shut it down and decommission it, havent you learnt anything from the recent disaster.

  • 1

    gaijinTechie

    I suppose they're decent enough to delay it's recommissioning also? Yeah, I didn't think so either.

  • 0

    nandakandamanda

    There seems to be general agreement that Hamaoka is in the worst location of all the nuclear power plants in Japan.

    Three factors contribute to this. One is that it sits right on top of a nest of major faults, although we are reassured that it can withstand any shaking imaginable. Two is the likelihood of a major tsunami there and the lack of protection apart from the sand dunes. This is being rectified at huge expense. Three is the vulnerability of Tokyo, which lies downwind of the prevailing winds...

  • 0

    wanderlust

    If you include the corrosion of parts of the reactor pressure vessel from the ingress of 5 tons of salt water, damaging the control rod mechanisms, and the damaged heat exchange tubes, after a worker dropped a heavy hatch lid on to them, and you wonder why they are even bothering to build the wall. Those costs are not included.

  • 1

    Eduardo Gonzalez

    Now you're going to kill all of us, aren't you?

    With less people paying taxes, and national economy at death's door, what you think you'll be doing with a fragile power source that powers 5 of every 7 household in the country, where long-term implications has never been understood.

  • -2

    ExportExpert

    Should have all been done when the place was originally built.

    Foresight is not a strong suit here is it.

  • 0

    nigelboy

    Cletus

    It appears that your priorities are completely messed up.

    The reason why I mentioned the coast line sea wall is because another poster mentioned about "foresight" and how the operators of TEPCO failed to see that. Then, my response was, what about the residents of the coast line? Did they not have the "foresight" to prevent a tsunami disaster? If so, it appears that they took it lightly just as TEPCO did.

    But the difference here is that residents along the coast line will result in IMMEDIATE fatality as shown throughout history, while the NPP does not as you mentioned evacuation, image, and cleanup. So by simple logic, shouldn't the former have HIGHER standards than that of the latter?

  • -5

    zichi

    There are a number of major safety concerns with this atomic plant, including the sea wall, the salt water corrosion in reactor No5 and the Tokai Earthquake. Really, this plant should be permanently shut down.

  • -1

    smithinjapan

    The question is, will they wait under the sea walls are completed and other safe-guards taken before they demand the reactors are restarted? Methinks they won't.

  • 0

    Thomas Anderson

    Wasn't this plant built right on top of a fault line? Yeah... building a sea wall is going to help. What's the matter with these people?

    When the Tokai Earthquake hits and this plant melts down, say bye bye to Japan.

  • -1

    nigelboy

    The question is, will they wait under the sea walls are completed and other safe-guards taken before they demand the reactors are restarted? Methinks they won't.

    Smith. You ought to stop with your "predictions". Hamaoka plant has not submitted her stress tests yet for there are still 20 NPP awaiting approval.

  • 2

    basroil

    CletusAug. 01, 2012 - 08:05AM JST

    Yeah well, they are building this lovely wall infront of the plant l just hope they remember the sides as well. Unlikely though!!!!

    You mean the 50m+ hills? Not sure why they should excavate the hills to put a much smaller wall there.

  • 2

    basroil

    Thomas AndersonAug. 01, 2012 - 01:03PM JST

    When the Tokai Earthquake hits and this plant melts down, say bye bye to Japan.

    If the quake is strong enough to take down an ABWR reactor, say goodby to Japan for far more serious issues, like Tokyo being leveled along with the 35 million who live there. I doubt anyone will care about 100-1000 cases of cancer when a thousand times that died in a day.

    • Moderator

      All readers please stay on topic.

  • 2

    basroil

    zichiAug. 01, 2012 - 12:55PM JST

    Really, this plant should be permanently shut down.

    And just how does that help anything? They still need the sea-wall.

  • -2

    Cletus

    basroil

    You mean the 50m+ hills? Not sure why they should excavate the hills to put a much smaller wall there.

    Well lets see Basroil the ocean frontage on the NPP is over 2.1 km (they are building a 1.6 km wall. At each end of the NPP property are rivers (dont know to many rivers that can climb 50+m hills). And the river frontage at the east end of the plant is flat land not hilly. The hills you refer to are behind (landward) side of the plant.

  • -2

    Cletus

    basroi

    "Really, this plant should be permanently shut down." And just how does that help anything? They still need the sea-wall.

    LOL really how does shutting a reactor built on a earthquake fault line in a tsunami prone area that is 30+years overdue for a massive earthquake and you ask how will shutting it down help.

  • 1

    Thomas Anderson

    basroil

    If the quake is strong enough to take down an ABWR reactor, say goodby to Japan for far more serious issues

    You really love to overrate the strength of nuclear plants, don't you... The Hamaoka plants can only withstand 600-800 Gal. The Tohoku earthquake has experienced 2933 Gal.

  • -3

    zichi

    Hamaoka is built directly over the subduction zone near the junction of two tectonic plates.

  • 2

    basroil

    Thomas AndersonAug. 01, 2012 - 01:31PM JST

    You really love to overrate the strength of nuclear plants, don't you... The Hamaoka plants can only withstand 600-800 Gal. The Tohoku earthquake has experienced 2933 Gal.

    You really love to ignore nuances in engineering speech. Built to withstand and "can only withstand" are two very different things. In order to be able to be built to withstand something, you build it 2-10x stronger than it needs to be. On top of that, the plant specifications are based on internal vibration, and since the plant is built floating, internal vibration is much lower than external one. Not to mention that the issue is vibration related and not acceleration related, and the frequency response of the building could further dampen a large earthquake while increase the strength of a small one. It is far more likely the sea wall fails in the earthquake than the plant failing in an earthquake.

    And Tohoku quake was a completely different type and strength of quake than what is possible in the hamaoka area. It would be more like the Kobe quake or 1923 quake, and you would see only 1g peak. The main issue is that the area is very susceptible to tsunami damage due to the almost non-existence of a shore to strip the wave of energy.

  • 1

    nandakandamanda

    You bring up an interesting point, basroil. Everyone likes to think of the seawall as only having to withstand a tsunami, but as you correctly state, the wall may first have to withstand an earthquake, (unless the quake epicenter/centre is way out at sea).

  • 1

    Thomas Anderson

    basroil

    You really love to ignore nuances in engineering speech. Built to withstand and "can only withstand" are two very different things. In order to be able to be built to withstand something, you build it 2-10x stronger than it needs to be.

    You've gotta be kidding me... so you're saying that the Hamaoka plants can "really" withstand 1200-8000 Gal? Bahaha... sorry but that is just impossible. I don't know what major building can withstand that much shaking. Many seismologic experts and engineers agree that the supposed ability for the Hamaoka plants to withstand over 1000 Gal (with additional retrofitting) is "nonsense".

    Anyway, "can only withstand" are my own words. Chubu Electric Power themselves have said that the maximum amount that the Hamaoka plants can withstand is 800 Gal:

    http://www.chuden.co.jp/english/initiatives/eini_nuclearpower/enuc_earthquakemeasures/countermeasures/chapter3_txt/index.html

    The Hamaoka Nuclear Power Station assumes maximum bedrock tremor strength of 800 Gals in consideration of the anticipated three simultaneous earthquakes.

  • 0

    Thomas Anderson

    basroil

    And Tohoku quake was a completely different type and strength of quake than what is possible in the hamaoka area.

    You're right, they're completely different. Since the Hamaoka plants are sitting right on the top the fault line, the shaking will be much, much more intense than the Tohoku earthquake.

  • -2

    smithinjapan

    Nigelboy: "Smith. You ought to stop with your "predictions". Hamaoka plant has not submitted her stress tests yet for there and 20 NPPs still waiting approval"

    Just going on past government politics and collusion with the energy companies. You do recall Edano said no NPPS will be restarted before the new group is formed. I didn't say I predicted them to demand restart by tomorrow, but I'm pretty sure it'll be before they've finished the wall.

  • 2

    basroil

    Thomas AndersonAug. 01, 2012 - 04:39PM JST

    Brush up on engineering and get back to us.

  • 0

    Terry Tibbs

    Cletus It appears that your priorities are completely messed up. The reason why I mentioned the coast line sea wall is because another poster mentioned about "foresight" and how the operators of TEPCO failed to see that. Then, my response was, what about the residents of the coast line? Did they not have the "foresight" to prevent a tsunami disaster? If so, it appears that they took it lightly just as TEPCO did. But the difference here is that residents along the coast line will result in IMMEDIATE fatality as shown throughout history, while the NPP does not as you mentioned evacuation, image, and cleanup. So by simple logic, shouldn't the former have HIGHER standards than that of the latter?

    >

    I think what Cletus is saying might not be so much referring to immediate fatalities (which will happen regardless) I think he is referring to the release of more strontium 90 and cesium into the atmosphere close to Tokyo, a city with over 13 million inhabitants (not including Yokohama and surrounds).

    I think Japan can and should have some nuclear plants, but this Hamaoka plant and the Oi plant in Fukui sit on top of fault lines and should be decommissioned immediately.

    There should be no evacuation, image and clean up regarding a the NNP in Hamaoka because it shouldn't even exist in the first place.

  • 1

    basroil

    Thomas AndersonAug. 01, 2012 - 04:39PM JST

    Anyway, "can only withstand" are my own words. Chubu Electric Power themselves have said that the maximum amount that the Hamaoka plants can withstand is 800 Gal: The Hamaoka Nuclear Power Station assumes maximum bedrock tremor strength of 800 Gals in consideration of the anticipated three simultaneous earthquakes.

    First, maximum here refers to design specification, not actual maximum the plant can take without core damage. Additionally, earthquake power increases exponentially with magnitude increase, so an 8.0 quake is actually 32 times greater power than an M7.0 quake. Shaking intensity is closely correlated with quake strength, so you can't just use simple multiplication. Wave heights are also similarly affected.

    From this though, lets put their design specification into perspective (http://www.chuden.co.jp/english/resource/initiatives/countermeasures013.pdf):

    For many years, Chubu Electric Power's Hamaoka Nuclear Power Station has anticipated three simultaneous earthquakes. Its anticipated magnitude is as great as 8.7.

    8.7 would make it several times stronger than the biggest recorded quake in the area, though several times smaller than the tohoku quake. The maximum wave height was only expected to be 10m for an M8.7 triple quake, but they decided to build a 18m (soon to be 21m) and 20m embankments in addition to individual parts protection.

  • 1

    basroil

    Terry TibbsAug. 01, 2012 - 07:59PM JST

    I think he is referring to the release of more strontium 90

    Even if the wall were to fail and cause the plant to fail, you have nothing to worry about from Sr-90. Neutron flux in reactors is not optimal for Sr90 formation, and thus considered an atomic bomb issue not reactor meltdown one.

  • 0

    FightingViking

    @Zichi

    Really, this plant should be permanently shut down.

    My own thoughts exactly... They keep trying to force us to believe we need nuclear power in a country that couldn't be less suited to it... Instead of spending this money on a great big wall, spend it on shutting it down, permanently.

  • 1

    basroil

    nandakandamandaAug. 01, 2012 - 03:42PM JST

    You bring up an interesting point, basroil. Everyone likes to think of the seawall as only having to withstand a tsunami, but as you correctly state, the wall may first have to withstand an earthquake, (unless the quake epicenter/centre is way out at sea).

    http://www.chuden.co.jp/english/resource/initiatives/countermeasures013.pdf

    The walls were designed under the assumption of 1000gal, so it would need to be quite a powerful quake. It is possible though, and even if the wall holds, the primary embankment could easily fail and leave the plant vulnerable to aftershocks.

    Even if the wall does fail, we can assume it won't be catastrophic failure since they aren't interlocked the same way as a dam. The plant itself is also being retrofitted with tsunami protections, and secondary power is being moved to higher grounds and the backup generators are not in the basement as was the case of fukushima.

  • -2

    zichi

    The epicenter of the Tohoku earthquake was some distance away from the Fukushima atomic plant but the epicenter of the Tokai Earthquake could be very close to the Hamaoka atomic plant and could generate a tsunami 34 meters high. Some experts call this atomic plant the most dangerous in the country. There's strong local opposition.

  • -4

    zichi

    The atomic plant has five reactors but three of them may not operate again, leaving just two which can generate a little more than 2 GW.

  • 0

    Thomas Anderson

    basroil

    Brush up on engineering and get back to us.

    Ok? Please stop with the ad hominems if you can't even counter my points.

    First, maximum here refers to design specification, not actual maximum the plant can take without core damage.

    You're right, it's only an assumption that it can supposedly withstand 800 Gal. We may never know when the earthquake actually hits. But I'm pretty sure what they mean that if the shaking is over 800 Gal, then the plant is pretty much guaranteed to collapse, unless miraculously it still happens to be standing. But of course you'd think that nuclear plants are just invincible and never collapse, ever.

    Plant #1 and #2 are designed to withstand up to 450 Gal, while the Emergency core cooling systems in Plant #3 and #4 are designed to withstand up to 450 Gal.

    8.7 would make it several times stronger than the biggest recorded quake in the area, though several times smaller than the tohoku quake.

    The Great Hanshin earthquake's magnitude was 6.8, yet the maximum record was over 800 Gal.

    http://www.fhwa.dot.gov/publications/publicroads/96fall/p96au17.cfm

    At solid ground near the JMA Kobe station in particular, the extremely strong ground motion reached its maximum acceleration of 818 gal in the north-south component.

    You may remember from the photos of the post-quake damages that the highways in Kansai have collapsed, even though they were supposed to be designed to withstand earthquakes.

  • 2

    basroil

    zichiAug. 01, 2012 - 08:36PM JST

    Earthquake could be very close to the Hamaoka atomic plant and could generate a tsunami 34 meters high. Some experts call this atomic plant the most dangerous in the country.

    Never seen anything stating 34m tsunami at sea level, most I've seen was 20m runup (why they are making it 21m even though the wave itself is only expected in 8-10m wave for M9.0). No expert in the field of nuclear engineering has ever called it the most dangerous plant, nor have seismology experts they ever stated it was related to tsunami risk that the wall addresses.

  • 0

    Thomas Anderson

    Really, even for pro-nuclear, supporting Hamaoka, "the most dangerous plant in Japan", must be crazy. You WOULDN'T want a nuclear plant to collapse, right? This plant is just begging to be collapsed when the earthquake hits.

  • 0

    kwbrow2

    It is plausible to assume a strong earthquake would damage the seawall and leave the power plant at risk. 100 billion yen is a lot of money to spend on something that might not work. And more likely will never be needed. The more logical and much safer choice is to invest in alternative power. Anyone read about Germany setting a world record for generating the most solar power in a day. 22GW of power. That is more than 20 nuclear power plants running at full capacity. Article can be found at the following link. http://www.rt.com/news/solar-energy-record-break-332/ It is time to go green. Geothermal power is also another great choice for Japan. It seems clear that a large percentage of Japanese people are against nuclear power. The demos in Tokyo keep getting bigger. Listen to your people PM Noda.

  • 1

    basroil

    homas AndersonAug. 01, 2012 - 08:47PM JST

    Plant #1 and #2 are designed to withstand up to 450 Gal, while the Emergency core cooling systems in Plant #3 and #4 are designed to withstand up to 450 Gal.

    I think you are now stating safe shutdown (non-SCRAM) levels in place of design levels?

    Regardless, your post has nothing to do with the wall being made that is the topic of this thread.

  • -3

    Cletus

    Basroil,

    8.7 would make it several times stronger than the biggest recorded quake in the area,

    That's strange as the previous 8 recorded in this area have been 7.9 to 8.5 with only one being 7.9 and the other 7 in the range of 8.3 to 8.5

    The maximum wave height was only expected to be 10m for an M8.7 triple quake, but they decided to build a 18m (soon to be 21m) and 20m embankments in addition to individual parts protection.

    Again strange as most of the predictions l found mention a forecast height of 34 meters.

    Again with the downplaying hey

  • -1

    zichi

    basroil

    No expert in the field of nuclear engineering has ever called it the most dangerous plant,

    Would they be the same nuclear experts who told us the Fukushima atomic plant, and every other atomic plant was safe?

  • -1

    zichi

    Professor Katsuhiko Ishibashi, a former member of a government panel on nuclear reactor safety, claimed in 2004 that Hamaoka was 'considered to be the most dangerous nuclear power plant in Japan'

  • -1

    nigelboy

    Just going on past government politics and collusion with the energy companies. You do recall Edano said no NPPS will be restarted before the new group is formed. I didn't say I predicted them to demand restart by tomorrow, but I'm pretty sure it'll be before they've finished the wall.

    Smith.

    What I recall was Edano stating his own personal view that restart of NPP **other than **Oi's #3 #4 should be based on decision from the new agency.

    http://www.47news.jp/CN/201204/CN2012042201001294.html

  • -2

    zichi

    If two mega-thrust earthquakes occurred at the same time, at shallow depths off the Hamaoka coast, the sea wall would be putty.

  • 2

    basroil

    zichiAug. 02, 2012 - 01:20AM JST

    If two mega-thrust earthquakes occurred at the same time, at shallow depths off the Hamaoka coast, the sea wall would be putty.

    Interesting, as the only mega-thrust capable fault is the one they rate for M9 wave height at only 10m due to the distance. The three near the plant are estimated to max out around M8.7, and none are considered to be capable of a megathurst level quake. For the quakes in the immediate region, there is little chance of problems. http://www.chuden.co.jp/english/corporate/ecorreleases/erelpressreleases/__icsFiles/afieldfile/2012/03/19/0229.pdf shows why this is true, showing that the slip planes for the faults are perpendicular to the plant, and unlikely to send large amounts of water to the plant. In the case of tohoku, the slip planes were parallel with the coast and thus caused very large waves.

  • 1

    oikawa

    Anyone with a brain can see the "experts" prediction are worthless when it comes to earthquakes and tsunamis. Based on a quick reading of history and a dose of common sense you can make a much better estimation.

  • -1

    basroil

    oikawaAug. 02, 2012 - 07:57AM JST

    Anyone with a brain can see the "experts" prediction are worthless when it comes to earthquakes and tsunamis. Based on a quick reading of history

    Just how do you expect to do that when earthquake magnitude measurements only began about a hundred years ago, and the region experiences serious quakes every 100-150 year? You need experts for that, since the only way to figure out when and how strong a quake was is to analyze the faults and model the quake intensity. For tsunami, you need to first locate an earthquake in the region that could potentially cause one, then find traces of the tsunami. Then you figure out the maximum height from models of how the area would have looked like at the time of the tsunami. That is not something you can do in your head.

  • 0

    oikawa

    Basroil

    I'm not saying the past earthquake and tsunami information provided by experts is not important, I just think their predictive abilities are quite poor. This should be no a surprise, as predictive ability and scientific knowledge are completely different skills. I was just amazed at how shocked may scientists seemed to be at the size and location of 3/11 for a start, when a quick google and a dose of common sense when seeing the size of earthquakes and tsunamis in the last century alone should nullify any surprise at all at the extent of 3/11.

  • 0

    basroil

    oikawaAug. 02, 2012 - 04:49PM JST

    I was just amazed at how shocked may scientists seemed to be at the size and location of 3/11 for a start, when a quick google and a dose of common sense when seeing the size of earthquakes and tsunamis in the last century alone should nullify any surprise at all at the extent of 3/11.

    http://earthquake.usgs.gov/earthquakes/eqarchives/poster/2011/20110311.php shows you that there are just three known quakes before, and all of them are ESTIMATED in size BY EXPERTS. The quake capable of happening in the area was expected to be M8.1 to M8.3 and was actually ten times (ten to twenty times actually) more powerful. What geologists did not know is that there was a previously unknown type of fault there, and the slippage was much longer than they had anticipated. The direction of the wave was also different in both prior quakes, as the 869 quake is thought to have produced around 9m (incomplete study), and the 1933 quake was 10.2m. The 2011 quake was 50% higher than anything recorded, so that's a pretty big difference that you generally don't see.

    For Hamaoka, they decided to re-evaluate the risks to levels that could happen one in ten thousand years or rarer, like a triple interlocked quake or an M9 quake. There is certainly a possibility that their models are incorrect or lacking data, but that would certainly be another shock because no recorded evidence states anything that big has ever happened, let alone something bigger. To be able to predict something is impossible. But to be able to state a scientifically derived statistical chance that something may happen (or likely not to happen) within a certain period of time is not that hard if you know the thing you are studying well enough.

  • 1

    oikawa

    Again, all I'm saying is I don't trust the scientists predictions. I look at figures from the article you quoted like,

    The Japan Trench subduction zone has hosted nine events of magnitude 7 or greater since 1973.

    The M 7.6 subduction earthquake of 1896 created tsunami waves as high 38 m and a reported death toll of 22,000.

    The M 8.6 earthquake of March 2, 1933 produced tsunami waves as high as 29 m

    which, added to the fact these are all related to only the last century, which is a mere millisecond in the history of the world, and I think the logical conclusion is that a 9.0 earthquake producing a massive tsunami in 2011 simply cannot be said to be unexpected, and from what I see it is illogical of scientists to say otherwise, especially when the very same scientists often readily admit on the other hand how little they really know about earthquakes. It just doesn't add up. "I admit I don't really know much about subject X but please trust my prediction on it (which I revise every few months...)"

  • 0

    basroil

    oikawaAug. 02, 2012 - 09:15PM JST

    These scientists are not always correct, but the almost always err on the side of caution/apocalyptic views. It is very rare when they significantly underestimate something by orders of magnitude, probably last being when they discovered tritium fusion in a deuterium weapon (also previously not documented). The difference between M8.3 and M9 is not within reasonable calculations, especially when the only previously recorded levels were 8.7 or lower.

    As stated earlier, hamaoka region is entirely different than the sanriku region, as the near faults are perpendicular to the plant rather than parallel with it (wave propagates mostly in the parallel path). And using information learned, they are planning for M8.7 local quake, which is nearly statistically irrelevant due to the small probability. Even with the most apocalyptic scenarios, the highest wave height is expected to be under 21m (and under standard IAEA submitted scenarios it is much less), hence they are re-doing the entire project to stop even the highest wave.

    If the region were to have a quake as large over the expected quake in tohoku, you would be talking about a 9.5+ quake, which would be the largest quake ever recorded, and due to it's probable location, it would flatten everything in shizuoka, as well as possibly exceed the reactor core design factor by 2-4 times (and make the wall useless anyway). I really don't think that protecting nuclear plants would matter when you get hit by a quake that large that close to major population centers.

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