In 1976 3 GE Scientists quit in protest over flaws in reactors

[Jenn]

5 of 6 in Fukushima Daiichi power station are this type.

http://www.dailykos.com/story/2011/0...sign-w-UPDATE-

[Bearfootfarm]

None of the problems will ever be proven to be "design flaw" since all those reactors were doing perfect until an unprecedented event damaged them.

It's funny how the media can always dig up an "expert" to hype the version they want to present

[arabian knight]

True it has working just fine for the last 40 years, and it was only the tsunami that took out the generators that made things go from bad to worse.
The earthquake had nothing to do with it, other then forming the huge wave of water.

[RiverPines]

The only question I have been asking is why are these nuclear power plants built by the shore on the ocean in an area thats earthquake and tsunami ridden?
Wouldnt it have been wiser to build the plants inland?

So I just wonder why they built them in such a risky area in the first place? You cant avoid earth quakes in Japan but you can be out of tsunami reach!

Who's bright idea was seaside nuke plants?

Oh and they were built to handle a 7.5 quake on land that intersects with 3 tectonic plates? Hello, odds of bigger than 7.5 in the lifetime of a nuke plant are a little high!

I think location, location, mattered a lot. Hey let have a seaside view as the tsunami comes in to bust up the nuke plant! Yeah!

[arabian knight]

It is for one thing because of Land in Japan is in so short supply that, they have to build things where there population is sparse
Japan is a little smaller the the State of CA.
I guess people forget that they are the 3rd highest place in population in the World.
Smaller then CA is and yet Over 127 Million~!!!!!
It is basically wall to wall people. So land is hard to come by, that doesn't have people on it.

[Oggie]

Japan isn't the third-highest in population.

[arabian knight]

Oh well one source said 3rd another one said 10th. Whatever, there are a bunch of people in a small area.

[Wanda]

Originally Posted by RiverPines

The only question I have been asking is why are these nuclear power plants built by the shore on the ocean in an area thats earthquake and tsunami ridden?
Wouldnt it have been wiser to build the plants inland?

So I just wonder why they built them in such a risky area in the first place? You cant avoid earth quakes in Japan but you can be out of tsunami reach!

Who's bright idea was seaside nuke plants?

Oh and they were built to handle a 7.5 quake on land that intersects with 3 tectonic plates? Hello, odds of bigger than 7.5 in the lifetime of a nuke plant are a little high!

I think location, location, mattered a lot. Hey let have a seaside view as the tsunami comes in to bust up the nuke plant! Yeah!

Sea water is used for cooling. our plants are usually built near a lake for a water supply.

[RiverPines]

Originally Posted by Wanda

Sea water is used for cooling. our plants are usually built near a lake for a water supply.

Lake vrs tsunami ridden earth quake zone?

I know Japan is crowed. I would think though that making room away from the tsunami risk would trump the inconvenience.
Maybe its time for Japan to really look at that crowding issue, over population vrs land.

I know they had slowed their reproduction rates but then they complained not enough income to support the elderly population. Well you can have everything.
And population over kill doesn't help anyone, elderly or young.

I wonder what we will do here in the states? Some day we will look like India population wise if we dont think about it either.

[The Paw]

Originally Posted by Bearfootfarm

None of the problems will ever be proven to be "design flaw" since all those reactors were doing perfect until an unprecedented event damaged them.

It's funny how the media can always dig up an "expert" to hype the version they want to present

You are illustrating very exactly the reasoning that leads to the conclusion that nuclear power can never be safe.

You assert that the design is not flawed, because the conditions under which it failed have not occurred before. If we cannot design safety features that withstand events that have not yet occurred, we cannot ever be sure they are safe. the whole purpose of "fail-safe" is to have multiple systems capable of handling every possible contingency.

When nuclear material is at play, "they have been fine so far" is not any kind of acceptable standard.

[Explorer]

Originally Posted by RiverPines

The only question I have been asking is why are these nuclear power plants built by the shore on the ocean in an area thats earthquake and tsunami ridden?
Wouldnt it have been wiser to build the plants inland?

So I just wonder why they built them in such a risky area in the first place? You cant avoid earth quakes in Japan but you can be out of tsunami reach!

Who's bright idea was seaside nuke plants?

Oh and they were built to handle a 7.5 quake on land that intersects with 3 tectonic plates? Hello, odds of bigger than 7.5 in the lifetime of a nuke plant are a little high!

I think location, location, mattered a lot. Hey let have a seaside view as the tsunami comes in to bust up the nuke plant! Yeah!

Cost. By building on the coast they could unload the very heavy plant equipment directly from the ship or barge it was shipped upon

Water, sea or lake, has little to do with it. One of the worlds largest nuke plants is located in the desert 50 miles outside Phoenix.

[poppy]

Originally Posted by The Paw

You are illustrating very exactly the reasoning that leads to the conclusion that nuclear power can never be safe.

You assert that the design is not flawed, because the conditions under which it failed have not occurred before. If we cannot design safety features that withstand events that have not yet occurred, we cannot ever be sure they are safe. the whole purpose of "fail-safe" is to have multiple systems capable of handling every possible contingency.

When nuclear material is at play, "they have been fine so far" is not any kind of acceptable standard.

Risk assessments are made for everything. Your car is not safe either if an earthquake collapses the bridge under you but is that reason enough to stop making cars or bridges?

[Darren]

Originally Posted by The Paw

When nuclear material is at play, "they have been fine so far" is not any kind of acceptable standard.

You are absolutely correct. Since TMI things happen very differently in the nuclear power industry. If there's an issue about anything, it is immediately sent to every plant. Each plant at that point has to address the equipment, procedure, design, whatever the alert detailed. The Nuclear Regulatory Agency (NRC) tracks those very intently. If changes are required, plants have very little leeway. In some instances plants might have to shut down. In less critical situations, a planned outage must be specified for correction of the issue.

It's hard to communicate the environment at a nuclear power plant. Years ago many nukes were shutdown for various reasons by the NRC. The NRC doesn't care how much money a utility loses by shuting down, they just want the changes made. No one messes with the NRC. The resident inspectors have all the authority they need to ensure compliance. They can look at anything and everything with absolutely no conditions to allow delay.

[Bearfootfarm]

You assert that the design is not flawed,

No, that is not what I said:

None of the problems will ever be proven to be "design flaw"

No other reactors of that design have failed.

ANY design will fail if you lose ALL cooling

[The Paw]

Originally Posted by poppy

Risk assessments are made for everything. Your car is not safe either if an earthquake collapses the bridge under you but is that reason enough to stop making cars or bridges?

This is really a superficial analysis. If a bridge falls on my car, I am totally screwed, but my remains won't be giving people cancer for the next 30 years.

The risk assessment has to factor in the negative consquences of the worst case scenario, including the depth and breadth of the impact.

I have read that the NRC stopped approving these kinds of reactors for construction in the 1980's or so. That would suggest it is a sub-optimal design, or at least not state of the art as of that time.

Any reactors of this sort left in the US, and those in Japan, would have been allowed to continue operating because someone determined the risk inherent in the design was not large enough to warrant the cost in immediate decommissioning. This is Ford Pinto thinking, logical enough from an economic standpoint, completely unacceptable from a human health perspective.

Now that the chickens are coming home to roost on this design, there is going to have to be some somber reflection on where those trade off points are.

[Darren]

Paw, all of the nuclear power plants whether old or newer rely on the same emergency sources of power should power from the grid be lost. They all have at least two (one for backup) and sometimes more diesel generators to provide emergency power. That means any power plant in the US, new or old, is going to have the same situation the Japanese are facing if all power from the diesel generators and offsite fails. At that point they can operate for a short time from batteries.

The diesel genrators are housed in hardened bunkers to resist hurricanes and tornadoes. We really need to understand how the tsunami affected the diesel generators in Japan. The generators continued running for two hours after the tsunami. The tsunami didn't immediately stop the generators. Some later effect did apparently. That is what we need to understand.

Recent reports indicate the Japanese are close to restoring power to the plants.

[The Paw]

Originally Posted by Darren

Paw, all of the nuclear power plants whether old or newer rely on the same emergency sources of power should power from the grid be lost. They all have at least two (one for backup) and sometimes more diesel generators to provide emergency power. That means any power plant in the US, new or old, is going to have the same situation the Japanese are facing if all power from the diesel generators and offsite fails. At that point they can operate for a short time from batteries.

The diesel genrators are housed in hardened bunkers to resist hurricanes and tornadoes. We really need to understand how the tsunami affected the diesel generators in Japan. The generators continued running for two hours after the tsunami. The tsunami didn't immediately stop the generators. Some later effect did apparently. That is what we need to understand.

Recent reports indicate the Japanese are close to restoring power to the plants.

Darren you point about the generators is well taken, but not the whole story I would argue.

1. As i understand it, the tsunami swamped the gens, I don't know if they physically damaged them or just filled them with water. It sounds like the bunkers would protect against physical shock, but how do you place a generator by the seaside in the nation that coined the word "tsunami", and not waterproof it?

2. According to the link in the OP, some reactors are engineered to handle loss of coolant better than others...

This design, a General Electric Mark I, has been criticized by nuclear experts and even Nuclear Regulatory Commission staff for decades as being susceptible to explosion and containment failure.

I know coolant loss is a bad and unlikely scenario, but it sounds like the design flaw has been known for some time.

3. I hope you are correct about power being restored, and I hope that enables the quick restoration of proper pumping and cooling. But given how govts tend to manage information in crises like this, I will believe it when it happens.

My point isn't that there should be no nuclear power ever, although I would personally prefer that there wasn't. My point is that if there is to be nuclear power, then there are some hard questions to answer:

(a) where is the real trade-off between risk management and cost of upgrades or decommissioning?

(b) are "the Ring of Fire" or major fault lines appropriate reactor sites?

(c) what is the "safe" useful life of these reactors? 40 years is sounding too long to me.

[NRS Farm]

Originally Posted by RiverPines

The only question I have been asking is why are these nuclear power plants built by the shore on the ocean in an area thats earthquake and tsunami ridden?
Wouldnt it have been wiser to build the plants inland?

So I just wonder why they built them in such a risky area in the first place? You cant avoid earth quakes in Japan but you can be out of tsunami reach!

Who's bright idea was seaside nuke plants?

Oh and they were built to handle a 7.5 quake on land that intersects with 3 tectonic plates? Hello, odds of bigger than 7.5 in the lifetime of a nuke plant are a little high!

I think location, location, mattered a lot. Hey let have a seaside view as the tsunami comes in to bust up the nuke plant! Yeah!

Google topography of Japan. The inside portions of Japan are mountainous.

[CJ]

Wait a sec... who cares what a scientist thinks? Design flaws are handled by engineers, not scientists!!!

[Darren]

Strictly speaking we're not talking about a LOCA (loss of coolant accident). A LOCA ocurrs when something like a main steam line ruptures. At the temperatures and pressures in power plants a ruptured pipe can whip around like limp spaghetti. The stress analysis of piping is a specialty in itself. To prevent pipe whipping, massive pipe whip restraints are part of the overall plant design to ensure that a broken pipe will not whip back and forth and damage something else.

A LOCA is a massive immediate loss of coolant and nuclear power plants are designed to safely shutdown if that happens. That is not what happened at the Japanese plants. Over time the heat from the fuel rods boiled the water off. FWIW, coal fired power plants run higher pressures than nuclear power plants.

As for the forty year license period, if you maintained your autombile like they have to maintain a nuclear power plant it would still look like you had just driven it off the showroom floor and it would still perform like new even with 600,000 miles on it assuming you drove 15,000 miles per year over a forty year period. And you would have the test reports, documentation, and every thing else to prove that the work was done according to NRC requirements.

If NASA's requirements were as severe as those overseen by the NRC, the two space shuttle disasters would have never happened.