Friday, April 08, 2011

Fukushima

Vero Beach
27 39.80 N 080 22.39 W

Pardon me for a departure from the normal cruising life theme on this blog. I know that a number of friends and readers have been waiting for me to write about the situation at the nuclear plants at Fukushima Japan.

You see, I know a bit about the subject. For 17 years, I wrote models of those BWR type plants for use in simulators used to train the plant operators. Think of flight simulators used to train pilots.  I've modeled just about every aspect of the plants, from the nuclear physics in the reactor, to electrical distribution, even the plumbing in the basements, and refueling operations when things are disassembled.

How to explain things simply to non-engineers? That's a challenge. Let me use my best analogy.

Imagine that I have a spray can of very lethal red paint. There is enough paint in the can to form one million tiny droplets, and one droplet is enough to kill a person if inhaled. Now suppose I threw that can on my backyard charcoal grill in Chittenen County Vermont. There are 152,000 people in Chittenenden county. If that can exploded, there could be enough toxic drops to kill every person six times over. Pretty scary huh?

But it would only kill all those people if the droplets are distributed evenly over the whole county and inhaled, leaving almost no drops left behind in my back yard. That's not reasonable. Common sense tells us that almost all the drops will paint my grill and my back yard. Even a person standing in my back yard might not inhale a drop.  Dividing the can size by the smallest droplet size is a very very bad way to estimate the real risk to public heath, but that is exactly the method used to scare people about the dangers of radioactivity.

Now suppose, that the grill was covered. Even though the cover is not air tight, and even if the cover might be blown open by the explosion, it would still capture amost all those paint drops. How many drops would you expect to drift all around the county? Common sense says almost none.

The BWR reactors have three levels of covers. First, the steel pressure vessel. Second, a steel and concrete primary containment designed specifically to keep the bad stuff inside. Third a sheet steel building designed only to keep weather out, not bad stuff in.

Now the point. Those three containments, even if imperfect, and even if they have leaks or cracks, will still manage te keep almost all of that radioactive stuff inside and away from the public.

Chernobyl, was different. It had only the sheet steel exterior building, and that was blown away at the very start leaving the core exposed to weather. That's why so much radioactivity leaked out.

What about the radioactive spent fuel in the pools? That stuff is contained only by the water in the pools that cover it. As long as they can keep it covered by water, very little of that radioactive suff will escape to the environment.

So every day, we read more scary stuff in the media reports. Much of it is contradictory. The containment is intact, no it is not intact. Are the spent fuel pools cracked or do they still hold water? No information on that.

The Japanese utility and government have done a terrible job in gathering and publicising accurate information. Part of the problem is that there are 6 reactors and 6 spent fuel pools on the site -- making 12 simultaneous and interrelated critical news stories to be told.

So, what is my prognosis? A number of the utility workers who bravely exposed themselves to do their duty will die from radiation related causes. Bless their hearts; they are true heroes.  Among the general public, there will be zero or almost zero cases of radiation related illness or death. However, the nocebo effect is very powerful (the opposite of the placebo effect). Countless people all over the world, will imagine themselves exposed, and that will cause them great suffering. That was the net result of Three Mile Island. I expect that the incident at Fukushima will cause the demise of nuclear power everywhere on the globe. Mere physics and engineering can never overcome that nocebo effect.

2 comments:

  1. Nice explanation, Dick. Thanks.

    ReplyDelete
  2. Excellent overview. Although I regard myself as somewhat clever ;) - I am very confused by the media reports. This comment was tweat worthy!

    ReplyDelete

Type your comments here.