Earthquake Drill

What is being said is that there aren't that many big hurricanes that hit the US mainland, so you are looking at a Poisson distribution of fairly rare events, and can't say too much about the nature of that distribution.

If you look at the population as a whole, you have more data to work with. Hurricanes do have a continuous distribution of intensity, and putting in an arbitrary cut-off at Category 3 isn't all that clever.

--
Bill Sloman, Sydney

Cat

er

ing

It wasn't a particularly intense hurricane, but it went straight over Galve rston Island and killed a lot of people. They didn't have any kind of sea w all and had chosen not to learn from the fate of Indianola, which had been destroyed by a similar hurricane some 25 years earlier.

Low frequency events on the tail of the bell curve don't happen all that of ten. If you want to work out whether the bell curve is getting wider, it ma kes more sense to look at the more frequent events clustered around the mea n intensity.

Statistics does seem to have been one of those course that John Larkin didn 't monitor all that closely.

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Bill Sloman, Sydney

Earthquake drill? This is my earthquake drill:

We can expense most tenant improvements. Of course, like all tax stuff, it's complex.

--

John Larkin         Highland Technology, Inc 

lunatic fringe electronics

People often fail to grasp the significance of the failure. It is not that this resulted in any real problem for the plant. The issue is that there were unanticipated failures that could have resulted in catastrophic failures had conditions been only slightly worse.

The biggest issue was that the plant was designed so there would be no single point of failure which could result in catastrophe. But procedures can be a single point of failure as in this case where the same procedure was used to maintain each of the backup generators. One bad procedure and all generators could fail in the same way.

There were other issues in how the plant specifications were developed including a lie by the power company on the original application regarding the presence of a geological fault. This lie was discovered and the power company was fined some $32,000 dollars. Woo hoo! They only cared about the fine as it gave them a record, not the fine itself.

This near miss has resulted in better regulations on nuclear plants in this country, but it well illustrates how an industry can not be allowed to regulate itself. There are other issues waiting to be discovered. There is no reason to believe that the US will never suffer a similar accident to the one in Japan. There have been other plants built that were similarly on the edge of accident. In fact, one plant was not allowed to renew their license because of that.

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Rick C 

Viewed the eclipse at Wintercrest Farms, 
on the centerline of totality since 1998

You are confused about the purpose of the features. They are *exactly* the same as insurance, they are there in *case* you have an accident. The fact that you have no accident is not the issue. Insurance paying for others' care is *not* why anyone buys insurance.

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Rick C 

Viewed the eclipse at Wintercrest Farms, 
on the centerline of totality since 1998

As long as it doesn't affect you it's ok?

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Rick C 

Viewed the eclipse at Wintercrest Farms, 
on the centerline of totality since 1998

No, that is completely incorrect! Well, maybe it is true in countries like the USA, but over here it certainly isn't. We care for others, and we pay together for the health costs that other people have.

Insurance is based on the sharing of costs that will occur for some people with a large group of people paying the premium. Due to scale and statistics it is quite accurately known what costs will occur. Every year, a certain percentage of the sum of the paid insurance premium is paid out to the insured people, much like a lottery pays a certain percentage of its ticket sales as prize money. (another part goes to overhead in the company, profit, etc)

When spending money on earthquake-proof building, there is no such spreading. Everyone effectively pays his own costs, and when an earthquake occurs in part of the country there is no aspect of other people paying for the damage that occurred in the affected area.

What did humans cause in Tokyo? It is a quite earthquake-prone area and it has been hit quite severely in the past, but I wasn't aware of any human cause in that. Berlin is not affected by earthquakes, when we are talking about the same Berlin that is (there probably are a couple of them in the USA).

Of course in a system that has redundancy added by duplication of functionality, it is always best to use different types of equipment for each of the items. So certainly not 3 generators of the same type from the same manufacturer, but at the very least generators from different manufacturers and preferably even using different technology.

Another example: when some form of computer control is used, the redundant systems should use different computers running different, independently developed software. Just installing two identical computers running the same software is only redundant against hardware component failure, not software bugs or hardware design errors like sensitivity to external events (voltage spikes/drops, radiation, etc).

In practice this is not always done because it increases cost of system design and integration, maintenance, etc. But some well-known failures in "redundant systems" have occurred because some circumstances occurred that made all the supposedly independent subsystems fail in the same way at about the same time.

Um, didn't the date 1945 in my earlier post ring a bell?

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC 
Optics, Electro-optics, Photonics, Analog Electronics 

160 North State Road #203 
Briarcliff Manor NY 10510 

hobbs at electrooptical dot net 
http://electrooptical.net

So you design three independent systems that redundantly do the same job. The specification is still a single point of failure. If there is an error in the spec, potentially all three systems will still all fail.

A specification failure also happened at the North Anna power plant. Earthquake design limits are actually developed in terms of the strength of the vibrations experienced at the plant, not the Richter scale rating of the earthquake. The facility was designed to withstand the shaking expected from a nearby 6.2 magnitude earthquake and the earthquake in 2011 was only a

5.8 magnitude, however the shaking experienced was twice the level the plant was designed to. Had the earthquake been as strong as the maximum anticipated, the shaking would have been 5 times the design specification for the plant. Again, a single point of failure, but not in the architecture, in the specifications!

--

Rick C 

Viewed the eclipse at Wintercrest Farms, 
on the centerline of totality since 1998

The sharing of costs is not why people buy insurance. They buy insurance because they want *others* to share their own costs *if* they have a loss. Insurance is not altruistic, it is practical, based on the fact that it is affordable to pay the certain cost of insurance while it is not affordable to pay for the loss. In that sense, paying the affordable cost of earthquake proofing instead of the much higher cost of suffering a building collapse in an earthquake is exactly the same as buying insurance.

In the end the money spent on the building was recouped when the now more valuable building was sold. Even if they wanted to tear it down, they had to pay for what the building was worth. So the money was not wasted, it was stored in a way that provided protection to the occupants of the building.

--

Rick C 

Viewed the eclipse at Wintercrest Farms, 
on the centerline of totality since 1998

As I wrote: maybe that is true in the USA, but it is not true here. Here, health care insurance is mandatory. Everyone is insured and together we pay all the healthcare costs covered by that insurance. As far as I understand, such a system has been established in the USA under the previous administration, but it was not very popular becuase the Americans are such an antisocial bunch of people and the head of that clan claimed that he would turn it over. After studying the matter in a bit more detail, he turned back on that path. He should do that more often (think before he shouts).

Yes, that problem still remains. However, the problem that a subsystem does not adhere to all (implicit or explicit) specification is reduced, because it is less likely that all 3 implementations fail in the same way. E.g. in this case there was some problem with oil pressure/sealing under shaking in the generators, and maybe this was not specified or not well tested for compliance. Having a different type of generator greatly reduces the chance that it suffers the same failure under the same circumstances.

The Richter scale is an expression of the magnitude of the shaking, so that cannot be true. However, as usually people call it "the Richter scale" without knowing what they are talking about, and it fact it was probably a 5.8 magnitude earthquake on the moment magnitude scale, and it may well have exceeded 6.2 on the Richter scale.

Not sure if you are talking about the North Anna failure or not.

Shaking at the epicenter is one number, shaking at the power plant is another. That's the issue at question. The way the power of the earthquake is transferred to the plant is the unknown that screwed the pooch in this case. The plant was 11 miles from the epicenter. My house which was about

3 more miles lost one brick off the chimney. Other houses about the same distance lost their entire chimneys. I also had a plant fall out of a window into the kitchen sink. I can't report on others' plants. The point is my house obviously felt a *lot* less shaking than the power plant did where multi-ton dry storage casks moved and pipes ruptured. Shaking can't be determined from the magnitude of the earthquake without a lot of knowledge of the geology.

--

Rick C 

Viewed the eclipse at Wintercrest Farms, 
on the centerline of totality since 1998

You aren't talking about insurance, you are talking about healthcare. Yes, I agree that healthcare is a right for all. You may have decided insurance was the best way to provide the healthcare, but that doesn't apply to auto insurance, home insurance, life insurance, etc. It isn't about the insurance, it is about the healthcare.

I don't know what you are talking about and I believe you don't either. The US has never had anything other than private healthcare insurance. It can be paid for by individuals, or by employers or in some cases by the government (even if only in part), but it is still a choice. If you are talking about the Obamacare "mandate" you have not looked at it properly. It is a token, not unlike receiving a driving penalty. I expect it has virtually no impact on anyone's decision to pay for insurance and we still have millions without healthcare insurance.

Before you insult an entire country try getting your facts straight. Otherwise you come across as an idiot not unlike some of the people we have in government at the moment.

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Rick C 

Viewed the eclipse at Wintercrest Farms, 
on the centerline of totality since 1998

I see, you don't suffer earthquakes, you *make* them.

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Rick C 

Viewed the eclipse at Wintercrest Farms, 
on the centerline of totality since 1998

I am talking about the financing of health care. Health care exists, but it has to be paid for. Insurance pays for the health care, but it does not provide it.

Here it is mandatory to get a health care insurance that covers a standard level of health care (which includes all gp and all essential hospital care) at a commercial company, and when you don't abide to that you will get a fine (much higher than the insurance premium you "save") and a lot of trouble. It is not a choice that you can voluntarily make, in practice the only people in this situation are the homeless and unregistered. When you don't earn enough to pay the mandatory health insurance, you will receive a grant to cover that via the tax system. It is similar to the Obamacare but I don't think that covers the "what if you can't pay" aspect. Then, of course, you will have a lot of people that cannot afford the insurance and still are left uninsured.

Well, when the party that represents about half of the country's voters is so firmly against a system for health care payment, I don't think my observations are wrong.