Nuclear plants in Japan risk meltdown

Discussion in 'Ian's Corner' started by Ian Gills, Mar 11, 2011.

  1. nukeman

    nukeman Nuclear Engineer

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    ballvalve: there are some designs out there that are based on passive cooling. One design does use the "water tower" concept by placing a large tank of water above the core inside of the containment (reactor) building. Although gravity always works, there are challenges with this too. Remember that a plant during normal operation will be at 2200 psia or so (for PWR reactors)..the GE is a BWR and typically runs around 1000 psia. You get about 0.5 psi for every foot of head, so to be able to inject under high pressures, this water tower would have to be close to 0.5 - 1 mile high (not practical). The other issue is the amount of water needed. Not only do you need enough water to fill the reactor vessel to the top of the core, but you really need enough to flood the entire reactor building to the level. If there is a break in the piping, the water that you put in just goes back out and onto the floor. If your containment is intact, you just flood the thing to the top of the core level and go into "boiling pot" mode. This might require 500,000 to 1,000,000 gallons of water or more. The other issue is that this tower and piping would need to be "safety-grade" meaning that it could withstand earthquakes, tornados, huricanes, etc. The other issue is that the containment outer shell is the last line of defense with regards to a fission product barrier (I'm talking about typical PWR reactors here). This means that you don't want penetrations through this wall to the outside.

    In the current designs that use a water tank above the core for passive cooling, they need to get the system pressure down to were the head from the tank can overcome the system pressure in order to inject. They use 4 valves that are about 14" in diameter that pop open and release to the containment. If your containment has failed, then this would be released to the environment.

    These are the reasons why active systems are typically used.

    In the design of the reactors where this event is going on (BWRs), the building that was damaged is not designed to be a real barrier. The real containment barrier is inside the building. On typical PWR (usually plants where you see a dome), the outer wall is typically 4' thick concrete, heavy rebar, plus a steel liner. Some newer designs even use a double containment ( two shells, each 4' thick, with a gap between them).

    The other aspect to this is to what levels do you design to? Typically, we will look at historical information and design for the worst + additional margin. Now say you build somewhere that has never recorded a quake bigger than 2.0. What do you design for? Do you design for a 4.0...but then maybe a 5.0 will hit? Maybe you design for 8.0 and an 8.9 hits??? Each point you go up on the scale is 10x the magnitude, so building to withstand an 8.0/9.0 in an area that has never seen over 2.0 is not very practical. Nature typically doesn't give us an upper bound for disasters. All you can do is look at the historical information and do your best to design based on that information. There is always some chance that something will happen that is worst than anything ever recorded (like this event).
  2. Redwood

    Redwood Master Plumber

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    It looks like the #3 reactor has now had an explosion.

    [video=youtube;jurlkfW4QxQ]http://www.youtube.com/watch?v=jurlkfW4QxQ[/video]

    Nukeman, Be prepared for a never ending argument that defies all logic and common sense...
    Bear in mind you are talking to an engineer....

    One whose never-ending passion for pressure relieving ballcocks and relief valves vs. expansion tanks has been opposed by every plumber on the forum...

    Good Luck with that!
  3. Cookie

    Cookie .

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    Hey hey Red, my beloved was an engineer! And, the nicest guy you would ever had met. He never let on how smart he was even though like I told him, I had a higher IQ, lol. I was smart enough to marry him.

    I got a solution for the reactor problem, build less! The world will survive loads better with less, "less is more."

    I am sure, they will rebuild another and another and another.
    Last edited: Mar 14, 2011
  4. Cookie

    Cookie .

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    I almost forgot this. I had someone tell me, that bad things happen ( storms etc) in our country, this person was from Japan by the way, because of our sins. Hmmm.
  5. jimbo

    jimbo Plumber

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    No easy answer here. An accident or natural catastrophe involving a reactor is a big thing, but rare. How many people over 100 years have developed cancer from the exhaust of fossile fuel and coal plants? What about the pending disasters at many coal sluge 'lakes' which are starting to leak?

    There is no free lunch. And Darwn always wins.
  6. ballvalve

    ballvalve General Engineering Contractor

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    Seems the japanese agree with pressure relief valves - to vent Hydrogen that blows up on bad days. But plumbers and their design knowledge, and ability to think beyond grandpa's ideas [just a bit over roofers on the scale of clear thought] Would have used a few expansion tanks for the reactors core. And they would have put them out front on the ocean side.

    If it wasn't for the engineers you'd be out threading iron pipe day in and day out. And if it was not for plumbers unions, we would have had PEX 30 years ago.

    Placing backup power on the beach, is what defies logic. If the highest predicted wave was 25 feet, then a few more sticks of iron would raise that genset to 50'.

    Pretty elementary, Watson. And today, one of the plants ran out of fuel for the gensets. I guess there is a shortage on diesel tanks to place around power plants.

    There are some engineers with dirty hands, JB weld and a few excavators that were raised with common sense, who think outside the box. But most of the plumbers, roofers and painters I have used had, at best, just dirty hands.

    You are correct in that at least 80% of engineers can't tie their shoes, and have never driven a screw, drilled a hole or set a big valve....
  7. Ian Gills

    Ian Gills Senior Robin Hood Guy

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    Stop this talk of Darwin all the time!

    Just because he wins does not mean he is right.

    The problem with evolution is that it is too short-term.

    In other words a species that will thrive later can be completely wiped out by a simple short-term event, like a radiation leak or global warming.

    American values seem to be based on natural selection. And in this sense are also too short-sighted.

    Some of those you discredit and choose not to help today, may be the ones you need tomorrow.
  8. ballvalve

    ballvalve General Engineering Contractor

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    Nukeman, my wine cellar has a domed 6 to 12" thick high strength concrete roof, with at least as much steel as the average Nuke dome. Now if I can afford that, and the existing plants are at 4", we have a pack of dopes building them.

    The passive nuclear plant designs exist, and will continue to be improved upon:

    http://en.wikipedia.org/wiki/ESBWR

    The operator can sleep for 3 days and it won't blow.

    GRAVITY! a CONSTANT.... PUMPS - a problem. Valves - problematic, but redundancy helps.

    That is just one of them, and an example what an engineering team with some common sense and an angry public can inspire.

    Natural selection is as constant as gravity, and will always prevail over social 'programs'. Just turn off the power in Japan -entirely- for a month and assume the red cross and the supply chain is otherwise engaged. That would make a fine horror film.

    Under such conditions, those you helped yesterday, may be roasting you on a spit tomorrow.
    Last edited: Mar 14, 2011
  9. Redwood

    Redwood Master Plumber

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    Yea...
    30 years ago the engineers gave us Polybutylene with Acetal fittings...
    Can you blame us for being a tad bit reluctant to jump up and down with joy eagerly accepting the next generation of plastic miracle pipe?
    When the plumbers were left holding such a large liability on a defective product...

    Especially when the lawsuits started up with Kitec http://www.plumbingdefect.com/index.html, Zurn, Rehau, and DuraPex....
    And many of those same companies that made the polybutylene are doing the same thing over again...
    The plumbers are going out of business and the manufacturer says "There isn't anything wrong with our product but we are going to stop selling it."

    Ummm Ballvalve....
    I'm seeing some sloppy engineering here...
    Attention to detail is very important in engineering especially when life safety is involved.
    Nukeman said 4' thick.... the difference between 4' and 4" is 44" which is a fairly large error when you are designing a nuke reactor containment dome...

    Please whatever your area of engineering excellence is please go there and stick with it....

    This Jack of All... Master of None... is getting a little scary....
    You are clearly out of your league both in Plumbing and Nuke Design...

    Clearly you aren't saying that you as an engineer would be using JB Weld on a Plumbing or, Nuke Build....
    That is not thinking outside the box or, with common sense! That is just plain Hackery!

    I'm beginning to think that I have met an engineer that hacks his way along using JB Weld to cover his mistakes, Ties his shoes with a granny knot, puts in screws and forgets to tighten them, drills crooked holes, & we can only hope hasn't set a big valve where life safety might be an issue....
    Last edited: Mar 14, 2011
  10. nukeman

    nukeman Nuclear Engineer

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    BV: I think we have a problem with units here. A typical containment is 4' (FEET) thick. It looks something like this:

    [​IMG]

    On the plants that are having problems, the building that was destroyed is nothing but a roof for the building for the most part. The actual containment is intact, which is pretty impressive given what it has endured.

    I'm fully aware of passive plant (Didn't I already say that?). I have even worked on some of them. What you have to understand is that even passive plants do require some active systems to get the job done. For instance, if you want to inject water using gravity, you 1st need to drop the system pressure. This means opening some large valves and dumping to containment. When you do, steam/coolant/contamination goes out with it. If your containment had failed, this gets released to the public. So to get the water into the system, you may have to have a significant release to the public. In addition, if multiple valves fail to open, the pressure won't drop fast enough to get the water in there before the core melts. Like anything, there are advantages and disadvantages to any design.
  11. Terry

    Terry Administrator Staff Member

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    Mark,
    It does get a little silly sometimes the bickering. This is truly a tragedy and it is far, far from being over.
    Arguing over which nation can help the most? This is a time when whoever can help, should help. More power to them. As far as fixing blame for something of this magnitude, it's easy to see after the fact, that things went badly. But is there really anyone of us that would have guessed that a wave would do that much damage?
    Until St Helen's blew in the state of Washington, experts said that type of destruction would take millions of years. And after the mountain blew, textbooks were changed to read; It happens in seconds.

    My Japanese sister in-law used to live in Hilo, on the big Island of Hawaii. They had Tsunami's there too.



    The West Coast of the United States is well aware that we too can suffer the same fate. And we have nuclear plants pretty close to our coast line. Like anything that happens, and remember, this is the worst occurance in our recorded history. Sure it may have happened before, but I don't think anyone really believed it until now.
    Now we in Seattle, now we know.

    Last edited: Jul 19, 2014
  12. Ian Gills

    Ian Gills Senior Robin Hood Guy

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    There's been a third reactor blast. These are all old GE reactors.

    We still have lots of those on the East Coast. But then we don't get quakes here often.

    This is all pointing to a California quake soon. These fractures are all related, or so I fear.

    One thing I don't get is if powering the cooling pumps was the problem then why wasn't a line run to link up to one of the American carriers off the coast? The last time I looked, these plants were located on the coast, so distance shouldn't have been a problem.
    Last edited: Mar 14, 2011
  13. Redwood

    Redwood Master Plumber

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    Wow!
    That's horrible!

    Here are before and after the tsunami arial photos of the plant.
    As you can see a lot of the equipment surrounding the plant was wiped out.

    Before...
    [​IMG]


    After...
    [​IMG]

    It's no wonder they had problems keeping things going....

    Ian I don't think it matters what kind of reactor was installed or how old they are...

    It's that same as what would happen with any car if you drained the radiator and went on a long drive....

    Something is gonna get hot and nothing good will come from it....
    Last edited: Mar 14, 2011
  14. ballvalve

    ballvalve General Engineering Contractor

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    Terry, you must be referring to my reply to Ians and redwoods play about darwin and natural selection. Its not about Japanese, its about the thin veneer of civilization we live under and what would happen ANYWHERE on earth when the power goes out and the MRE's stop arriving.

    Japanese in our family too, and very fond memories of my ex-Japanese fiancee. We were well taught by our parents to know and tolerate all races, but to seperate out the morons on an individual basis. Dad watched all his buddies die by the hands of the japanese, but never had a harsh word for the people as a whole.

    4" of containment or 400" do not matter when you put the back-up generators on a beach instead of those big flat, unused roofs. And forgot to store enough fuel anyway.

    It's all about design, and the willingness to spend enough money for higher levels of redundancy. Considering our devotion and awe of japanese cars, I find it highly ironic that a country that has engineers that can make the Prius cannot notice that for the cost of a few, their generators could have been protected.

    The Russians had an excuse for Chernobyl [and I have been there] ; A society beaten down into a bottle of vodka by a monstrous socialist system creating "5 year plans"

    If you didnt meet the "plan" your life went into the toilet. So every shortcut possible was taken to meet absurd goals. A quick way for a reactor to get built is to not bother with a containment structure. Then, because jobs were often dispensed not by performance and merit, but rather by a communist party buddy system, incompetents often ran them. Recipe for disaster.

    The Japanese don't have those excuses and could have done a better job.

    BV wrote;

    Last edited: Mar 15, 2011
  15. ballvalve

    ballvalve General Engineering Contractor

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    So Ian, I notice your opinion of the American aircraft carriers has adjusted upwards a bit since that statement.

    .

    If anyone knows japanese culture, they are an intensely proud and "do for ourself" nation. Often to the point of very bad decisions. In an airplane crash some years a go, the Americans found the site, and were landing men there when the Japanese rescue forces forbid them to help.

    The japanese did not get there until the next morning, and 30 or 40 people perished in that night. I have a feeling that some of that pride will be found to have contributed to the meltdown.
    Last edited: Mar 15, 2011
  16. Ian Gills

    Ian Gills Senior Robin Hood Guy

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    Not really. I think they will come into play once the search and rescue stage has ended. They will be an intgeral part of feeding and watering the population affected, now the infrastructure has been destroyed. But they were never needed in the early stages of this catastrophe. They look good to the American media and a public eager to see what America is "doing". But are of little use in pulling survivors from the rubble. The British have just sent a second search and rescue team, which is great.

    But my hunch is that the US military could have done more regarding the nuclear issue and were either: a) too scared to assist due to fears over radiation and the health of US servicemen; or, b) the Japanese did not want their help. We will find out the truth in the years to come.

    But keep this in mind. Of anything, or anyone, a US carrier is probably best equipped to deal with the problems these nuclear plants experienced. They are designed to work in radioactive environments (think Cold War), they are equipped to do this and they have lots of power on tap. Why was more not done to get power to those pumps? Somebody is not telling us the whole facts.

    Those carriers certainly starting running away like scared rabbits when the radiation levels went up a *little*, so you'll know where to look first. Makes you wonder how they could have survived the Cold War, were it to have turned hot. Any navyman will tell you the safest place to be in times of radiation is on a boat or sub. I think someone got the jitters.

    Let's see if the Americans are brave enough to do some water drops from the air on the plants now things seem to have progressed too far. Their decision will be telling.

    I certainly have admiration for those few Japanese workers left at the plants trying their best to keep things stable. They are heros.
    Last edited: Mar 15, 2011
  17. ballvalve

    ballvalve General Engineering Contractor

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    Carriers are not floating radiation shields. And the Military likely knows what the japanese are afraid to say, that its melting now. Prudent move.

    The japanese have many of their own large ships, and they can run an extension cord to shore on their own if they so wish.

    I can't find any reason for the American navy to commit Hari-Kari over a non American civillian crisis. Food, fuel, shelter yes. But I see no evidence that the Japanese have requested their help - except today, finally they accepted a team of US nuclear SWAT guys in.

    Read the Chernobyl book. The air drops only managed to kill the pilots. Ask Nukeman what he thinks of dropping water from a helicopter on a melting containiment vessel.
    Last edited: Mar 15, 2011
  18. Cookie

    Cookie .

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    The "real" heros are the people who speak out against building more nuclear power plants.
  19. Ian Gills

    Ian Gills Senior Robin Hood Guy

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    Yes they are. It doesn't get much better than being in a ship at this time.

    Everything is shielded; stuff is lead lined; they have clean-up apparatus and the suits.

    The only place you can't go is the deck. These were built to survive a nuclear attack from Russia for heaven's sake, or at least long enough to retaliate!

    Every navy man on that boat will have done nuclear training, the first part of which is probably shutting the doors.

    When this crisis unfolded there was no radiation. Just a couple of aircraft carrier powerplants sitting off the coast doing nothing. Well played everyone.
    Last edited: Mar 15, 2011
  20. ballvalve

    ballvalve General Engineering Contractor

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    Funny how we are all happily willing to drive on a 2 lane highway full of drunks and sharp curves with half bald tires in the snow, but fear a nuclear power plant.

    More people will die TODAY in auto accidents worldwide than have been killed by nuclear power plant accidents since their inception.

    Safe designs exist, but the public does not read blueprints, so its back to enviromental disaster fuels.

    We will be laughed at one day at how we squandered oil by burning it in our primitive 8% to 15% efficient engines. To go get a big Mac.

    .

    Surely you jest about running a power line from an aircraft carrier? Even redwood can explain that away to you.
    Last edited: Mar 15, 2011

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