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PostPosted: Jul 15, 2013 6:50 am 
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Had he obeyed the order, the whole of north eastern Japan would possibly have been uninhabitable for decades, if not centuries.


By that defination of risk, the whole of Japan is uninhabitable: all of it is under severe risk of tsunami, earthquake, volcanos... guess what... it's in the ring of fire.

It's funny that people consider 21 mSv/year to be uninhabitable, but will gladly live in an seismically active area. Or in a busy city, with air pollution and traffic risks.


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PostPosted: Jul 15, 2013 12:32 pm 
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Axil wrote:
It was Yoshida’s own decision to disobey HQ orders to stop using seawater to cool the reactors. Instead he continued to do so and saved the active zones from overheating and exploding. Had he obeyed the order, the whole of north eastern Japan would possibly have been uninhabitable for decades, if not centuries.


Who wrote this?


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PostPosted: Jul 15, 2013 1:48 pm 
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Certain kinds of engineering require near perfection and a zero tolerance for failure.

Bridge and dam design, passenger aircraft and spacecraft design and nuclear reactor design require absolute avoidance of catastrophic failures or the loss of public confidence due to obvious oversights and professional stupidity.


Remember how bad NASA management and engineering looked when Feynman broke an ice cooled O-ring rubber gadget at the PRESIDENTIAL COMMISSION on the Space Shuttle Challenger Accident.


NASA had trouble getting over that one.

Boing stock has gone way down with the continuing problems with the Dreamliner 787. I will stay off that one myself.

In like fashion, Fukushima makes nuclear engineering and management look bad with associated loss in public trust in nuclear related profession competence.

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PostPosted: Jul 15, 2013 4:20 pm 
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Axil wrote:
Certain kinds of engineering require near perfection and a zero tolerance for failure.
Bridge and dam design, passenger aircraft and spacecraft design and nuclear reactor design require absolute avoidance of catastrophic failures or the loss of public confidence due to obvious oversights and professional stupidity.


I don't agree with that. Dams and bridges are built with large safety factors, and minor design and construction errors should certainly be tolerable. If they aren't, that's surely itself a sign of bad design. As for nuclear power plants, they should also be designed for safety, with both active and passive safety measures. The myth perpetrated by the anti-nuclear folks is that they are a ticking time bomb just waiting to go off, but we should know better than that.

So you're the one who wrote, "Had he obeyed the order, the whole of north eastern Japan would possibly have been uninhabitable for decades, if not centuries."? What makes you think that?


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PostPosted: Jul 15, 2013 4:33 pm 
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Russ wrote:
Axil wrote:
Certain kinds of engineering require near perfection and a zero tolerance for failure.
Bridge and dam design, passenger aircraft and spacecraft design and nuclear reactor design require absolute avoidance of catastrophic failures or the loss of public confidence due to obvious oversights and professional stupidity.


I don't agree with that. Dams and bridges are built with large safety factors, and minor design and construction errors should certainly be tolerable. If they aren't, that's surely itself a sign of bad design. As for nuclear power plants, they should also be designed for safety, with both active and passive safety measures. The myth perpetrated by the anti-nuclear folks is that they are a ticking time bomb just waiting to go off, but we should know better than that.

So you're the one who wrote, "Had he obeyed the order, the whole of north eastern Japan would possibly have been uninhabitable for decades, if not centuries."? What makes you think that?



Nuclear design is the most critical design in which stupid mistakes must be avoided. People in countries all around the world are losing faith in the designers of all nuclear plants even when the designs of the reactors are not similar. This light water problem in old reactor design is affecting the reputation of all reactor designs old and new including the LFTR.


The quote came out of the article and I laid it out here as red meat to insight discussion. It seems like you want to tear into someone. true?

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PostPosted: Jul 15, 2013 5:59 pm 
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Axil wrote:
The quote came out of the article and I laid it out here as red meat to insight discussion. It seems like you want to tear into someone. true?


Well, first I'd like to know whether it's true or not. I doubt it is, but I don't know for sure. If it's not true, then it's yet another classic example of ignorance about nuclear power.


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PostPosted: Jul 16, 2013 3:40 am 
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Russ wrote:

I don't agree with that. Dams and bridges are built with large safety factors, and minor design and construction errors should certainly be tolerable. If they aren't, that's surely itself a sign of bad design. As for nuclear power plants, they should also be designed for safety, with both active and passive safety measures. The myth perpetrated by the anti-nuclear folks is that they are a ticking time bomb just waiting to go off, but we should know better than that.
?


But that makes the overall design perfect - or almost so. Any good design has to cater for a failure in one area or more - either caused by imperfect subsystem design, or management (ie human error).

Generally, in most systems, to get a perfect outcome you either need a perfect design, or perfect management of the system. Fukushima had neither.

Some items are of course both. Even if Fukushima was designed without Tsunami proof diesel generators, this error should have been picked up in the decades of operation and rectified.


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PostPosted: Jul 16, 2013 9:39 am 
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Bridge and dam design, passenger aircraft and spacecraft design and nuclear reactor design require absolute avoidance of catastrophic failures or the loss of public confidence due to obvious oversights and professional stupidity.


This is impossible. It will never be safe. The planet we live on is not safe. We could all get hit by an asteroid, obliterating all of us. To survive this type of events, nuclear plants would need a mile thick concrete wall. It'd be a pretty pointless investment, since all humans are dead, no one will care about the intact nuclear powerplant.

Passenger aircraft are not safe. Many people die every year by aircraft crashes. No one has died in the last year due to radiation from nuclear powerplants anywhere in the world.

Bridges and dams are not safe. They sometimes collapse. Even recently this has been the case. Dams are inherently unsafe because you're pitting yourself against gravity with lots of unknowns in hydro-geology - the exact state of all rock layers can never be 100% ascertained - and all you've got against it is engineered layers. It's physics against engineering. It is even more the case with aircraft - hugely complicated engineering and electronics versus gravity. Gravity will always win when things get tricky.

Cars are also inherently unsafe, with incompetent idiots driving behind the wheel, the human factor squared. Unsurprisingly, traffic accidents kill 1.2 million people every year, 300 Chernobyls a year. It would be sane to spend more to make cars safer, rather than wasting this money on nuclear plant safety (no one builds Chernobyls anymore, the worst you can get is a Fukushima type, loss of all cooling, which kills no one).

Aircraft and bridges/dams are built to reasonable standards of quality control and assurance. Nuclear plants must be built to unreasonable standards of quality control, costing billions per plant, even though an historic analysis of nuclear meltdowns shows very little to no influence on quality control.

Once you realize safe is a relative term, we can further the discussion. It is relatively very unsafe to design a nuclearpowerplant to require electricity for cooling and then situate it in an area that regularly gets large tsunamis of 10-30 meters tall, with only a few meters design basis tsunami defence. It is relatively very safe to not bother about dinosaur-obliterating asteroid impacts in the design of a nuclear powerplant. Somewhere in the middle we are going to have important discussions and will have to draw arbitrary lines of what we find acceptable and what not.

It is clever to design nuclear powerplants with elimination of failure modes, where this is impossible, make the failure fail-safe or at least as benign as you can. It simplifies the discussion of remaining failure modes.


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PostPosted: Jul 16, 2013 9:51 am 
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alexterrell wrote:
Russ wrote:

I don't agree with that. Dams and bridges are built with large safety factors, and minor design and construction errors should certainly be tolerable. If they aren't, that's surely itself a sign of bad design. As for nuclear power plants, they should also be designed for safety, with both active and passive safety measures. The myth perpetrated by the anti-nuclear folks is that they are a ticking time bomb just waiting to go off, but we should know better than that.
?


But that makes the overall design perfect - or almost so. Any good design has to cater for a failure in one area or more - either caused by imperfect subsystem design, or management (ie human error).

Generally, in most systems, to get a perfect outcome you either need a perfect design, or perfect management of the system. Fukushima had neither.

Some items are of course both. Even if Fukushima was designed without Tsunami proof diesel generators, this error should have been picked up in the decades of operation and rectified.


Large safety factors are not attractive because
1. They cost a lot and make inefficient use of natural resources
2. They are an "admittance of ignorance". Better to investigate better than to increase safety factors. The Fukushima tsunami design basis was based upon a flawed model which showed 10 meters is enough. A large safety factor of 2, meaning a tsunami protection of 20 meters, would have prevented the Fukushima accident. However, a better investigation showed quite large tsunami's can hit the Fukushima coast area, with over 30 meters runup height having a quite reasonable chance of happening. But the probability of a 60 meter runup height is far from zero; an investigation would probably have concluded that powerplant siting on a hill away from the coast is a much better idea than to have a reasonable safety factor. Another example of this is in investigating the strength and state of geologic layers near dams. You can make a dam with 10x safety factor, but if the ground it's on is weak, and you're using a high safety factor of the dam itself as an excuse not to investigate further, then you have false safety.


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PostPosted: Jul 16, 2013 12:04 pm 
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Cyril R wrote:
Quote:
Bridge and dam design, passenger aircraft and spacecraft design and nuclear reactor design require absolute avoidance of catastrophic failures or the loss of public confidence due to obvious oversights and professional stupidity.


This is impossible. It will never be safe. The planet we live on is not safe. We could all get hit by an asteroid, obliterating all of us. To survive this type of events, nuclear plants would need a mile thick concrete wall. It'd be a pretty pointless investment, since all humans are dead, no one will care about the intact nuclear powerplant.

Passenger aircraft are not safe. Many people die every year by aircraft crashes. No one has died in the last year due to radiation from nuclear powerplants anywhere in the world.

Bridges and dams are not safe. They sometimes collapse. Even recently this has been the case. Dams are inherently unsafe because you're pitting yourself against gravity with lots of unknowns in hydro-geology - the exact state of all rock layers can never be 100% ascertained - and all you've got against it is engineered layers. It's physics against engineering. It is even more the case with aircraft - hugely complicated engineering and electronics versus gravity. Gravity will always win when things get tricky.

Cars are also inherently unsafe, with incompetent idiots driving behind the wheel, the human factor squared. Unsurprisingly, traffic accidents kill 1.2 million people every year, 300 Chernobyls a year. It would be sane to spend more to make cars safer, rather than wasting this money on nuclear plant safety (no one builds Chernobyls anymore, the worst you can get is a Fukushima type, loss of all cooling, which kills no one).

Aircraft and bridges/dams are built to reasonable standards of quality control and assurance. Nuclear plants must be built to unreasonable standards of quality control, costing billions per plant, even though an historic analysis of nuclear meltdowns shows very little to no influence on quality control.

Once you realize safe is a relative term, we can further the discussion. It is relatively very unsafe to design a nuclearpowerplant to require electricity for cooling and then situate it in an area that regularly gets large tsunamis of 10-30 meters tall, with only a few meters design basis tsunami defence. It is relatively very safe to not bother about dinosaur-obliterating asteroid impacts in the design of a nuclear powerplant. Somewhere in the middle we are going to have important discussions and will have to draw arbitrary lines of what we find acceptable and what not.

It is clever to design nuclear powerplants with elimination of failure modes, where this is impossible, make the failure fail-safe or at least as benign as you can. It simplifies the discussion of remaining failure modes.



Quote:
Once you realize safe is a relative term, we can further the discussion.


Perfect safety must be an absolute thing for nuclear power.

I hope that designers of nuclear power plants are not taking your philosophy and message to heart. Or even better, don’t give this design philosophy a chance to be realized in the market place as have been expressed by most people in japan. There is a good deal of lip service and propaganda paid to perfect safety by mission critical nuclear engineering, but it all comes down to economics. Many people would not drive the cars or aircraft that you would build or let the reactors you would build be located in their close vicinity. I think this thinking is based in flawed and lazy human nature. There is always a perfect solution to be had if enough work and inspiration is applied to the problem. The defeatist attitude kills a project before it is even started.

Cost is always subjected to averaging but safety is not. Safety is all or nothing for the people affected. Yes, the electric costs for the people beyond the radiation downwind plume would be exceedingly cheap and very safe, by the cost to the people next to your nuke would be exceedingly high in terms of both blood and treasure.

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PostPosted: Jul 16, 2013 2:34 pm 
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Actually billions of people do in fact drive cars whose safety is partially dictated by the market economics of "good enough". As a result millions of people die. This is acceptable as evidenced by all the people who buy cars.
Millions of people every year also show that the dangers of air travel are acceptable when weighed against the convenience offered.
Perfectly safe will never apply to any human endeavours.
Nuclear power has an exemplary safety record and is leaps and bounds better than fossil fuels that are currently killing our planet.


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PostPosted: Jul 16, 2013 3:38 pm 
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nuclear1 wrote:
Actually billions of people do in fact drive cars whose safety is partially dictated by the market economics of "good enough". As a result millions of people die. This is acceptable as evidenced by all the people who buy cars.
Millions of people every year also show that the dangers of air travel are acceptable when weighed against the convenience offered.
Perfectly safe will never apply to any human endeavours.
Nuclear power has an exemplary safety record and is leaps and bounds better than fossil fuels that are currently killing our planet.



True, people can chose to buy cars based on the safety level they wish to endure.

I would not buy a used Pinto because I can afford more.

And given a choice, many people will not fly on the Boeing 787 Dreamliner.

Loss of reputation has a steep price... sometimes deserved or not.

Many governments are choosing to abide by the wishes of their electorates and use non-nuclear power sources because of a loss in reputation of nuclear safety.

The US will be out of the nuclear business in a few years in favor of gas fired generation. Sad but true.

Lassa fare engineering practices have a price. I am just learning and reporting from what I am observing.

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PostPosted: Jul 16, 2013 4:42 pm 
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Axil wrote:
nuclear1 wrote:
Actually billions of people do in fact drive cars whose safety is partially dictated by the market economics of "good enough". As a result millions of people die. This is acceptable as evidenced by all the people who buy cars.
Millions of people every year also show that the dangers of air travel are acceptable when weighed against the convenience offered.
Perfectly safe will never apply to any human endeavours.
Nuclear power has an exemplary safety record and is leaps and bounds better than fossil fuels that are currently killing our planet.



True, people can chose to buy cars based on the safety level they wish to endure.

I would not buy a used Pinto because I can afford more.

And given a choice, many people will not fly on the Boeing 787 Dreamliner.

Loss of reputation has a steep price... sometimes deserved or not.

Many governments are choosing to abide by the wishes of their electorates and use non-nuclear power sources because of a loss in reputation of nuclear safety.

The US will be out of the nuclear business in a few years in favor of gas fired generation. Sad but true.

Lassa fare engineering practices have a price. I am just learning and reporting from what I am observing.


Axil, This is the very attitude we must challenge OR people will die because of the poor choice. Take the natural gas replacement of nuclear power as an example. Natural gas has so many fatal accidents each year that they don't make national news and the story doesn't last. Yet people (apparently including you) think it is appropriate to continually ratchet up the cost of nuclear to increase safety until we don't build them anymore. We just lost San Onofre out of concerns about radiation leaks - yet there weren't any to the environment - nor was there a significant risk that there would be. So, in the name of safety we abandon the safest form of power generation and replace it with a form with a fatality rate many times higher.

Why should nuclear have a standard of "absolute safety" when other forms of energy generation have a standard of good enough? If safety is your top priority (another debate) then shouldn't the standard be to replace the most dangerous form of generation with the safest?


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PostPosted: Jul 16, 2013 4:59 pm 
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Lars wrote:
Axil wrote:
nuclear1 wrote:
Actually billions of people do in fact drive cars whose safety is partially dictated by the market economics of "good enough". As a result millions of people die. This is acceptable as evidenced by all the people who buy cars.
Millions of people every year also show that the dangers of air travel are acceptable when weighed against the convenience offered.
Perfectly safe will never apply to any human endeavours.
Nuclear power has an exemplary safety record and is leaps and bounds better than fossil fuels that are currently killing our planet.



True, people can chose to buy cars based on the safety level they wish to endure.

I would not buy a used Pinto because I can afford more.

And given a choice, many people will not fly on the Boeing 787 Dreamliner.

Loss of reputation has a steep price... sometimes deserved or not.

Many governments are choosing to abide by the wishes of their electorates and use non-nuclear power sources because of a loss in reputation of nuclear safety.

The US will be out of the nuclear business in a few years in favor of gas fired generation. Sad but true.

Lassa fare engineering practices have a price. I am just learning and reporting from what I am observing.


Axil, This is the very attitude we must challenge OR people will die because of the poor choice. Take the natural gas replacement of nuclear power as an example. Natural gas has so many fatal accidents each year that they don't make national news and the story doesn't last. Yet people (apparently including you) think it is appropriate to continually ratchet up the cost of nuclear to increase safety until we don't build them anymore. We just lost San Onofre out of concerns about radiation leaks - yet there weren't any to the environment - nor was there a significant risk that there would be. So, in the name of safety we abandon the safest form of power generation and replace it with a form with a fatality rate many times higher.

Why should nuclear have a standard of "absolute safety" when other forms of energy generation have a standard of good enough? If safety is your top priority (another debate) then shouldn't the standard be to replace the most dangerous form of generation with the safest?



The engineering decision to produce nuclear waste of slightly used fuel was an economic decision to reduce the cost of the light water reactor. This fuel was store on site in Fukushima where its containment system failed.

If the decision to use the LFTR system was made way back in the beginning, the waste problem would have been covered by the nature of a better reactor design.

We are all here because the current light water design is bad and need to be replaced with a more perfect LFTR design.

Please don’t defend the present design of nuclear reactors around the world as perfectible.

I can list pages of reasons why the LFTR is a better design and inherently safer. Please do not defend a design mistake as a defense of nuclear power in general. Nuclear power must be done correctly from the very beginning and not made safe using huge retrofit costs.

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PostPosted: Jul 16, 2013 5:25 pm 
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Axil wrote:
The engineering decision to produce nuclear waste of slightly used fuel was an economic decision to reduce the cost of the light water reactor. This fuel was store on site in Fukushima where its containment system failed.

If the decision to use the LFTR system was made way back in the beginning, the waste problem would have been covered by the nature of a better reactor design.

We are all here because the current light water design is bad and need to be replaced with a more perfect LFTR design.

Please don’t defend the present design of nuclear reactors around the world as perfectible.

I can list pages of reasons why the LFTR is a better design and inherently safer. Please do not defend a design mistake as a defense of nuclear power in general. Nuclear power must be done correctly from the very beginning and not made safe using huge retrofit costs.


I don't defend the decisions made at Fukushima. As with other nuclear accidents it took a series of poor decisions to overcome the defense in depth of the reactors. HOWEVER, it is pure folly to use stupid decisions that cost a power station as the reason to eliminate nuclear power from a variety of countries. Out of public fear (that a tsunami might overwhelm the reactors in inland Germany???) Germany has shutdown several nuclear reactors and plans to shutdown the rest and replace them with deadly coal.

Absolutely we can do better. However, nuclear is setup against an impossible standard of perfect safety. Indeed, it isn't even against the standard of safety it is against the standard of public fear. We mustn't play into that. We should acknowledge the poor decisions and the need for improvement while at the same time repeatedly demonstrating that the real actual harm done is miniscule. The harm done by fear mongering over the safety of nuclear power is orders of magnitude larger than the actual damage done.

Quote:
The engineering decision to produce nuclear waste of slightly used fuel was an economic decision to reduce the cost of the light water reactor. This fuel was store on site in Fukushima where its containment system failed.


By the way, do you know what the public health impact is from the waste stored at Fukushima? I agree that we could have done better but please don't feed the false rumors that somehow the spent fuel at Fukushima harmed anyone or released any radiation to the environment.


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