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To: chimera

How far downwind will people be affected?

Depends on the release term. For example, with the TMI-II release, the safest thing to do, statistically speaking, was to stay put. The millirem-range exposures you might have got if you camped at the plant boundary for the duration of the accident (which no one did), presented a risk smaller than that for driving on the local highways any reasonable distance.

This is a load of CRAP. Don't expect to get the truth from the propaganda ministry. During the TMI release the lamestream media asked "How much radiation are people near the plant being exposed to?" and the comforting answer was "It's equivalent to a chest x-ray." What they didn't tell you was that there's a big difference between the instantaneous dose rate and total accumulated dose. Hanging around TMI was like climbing into an x-ray booth, turning it on, and sitting there for a week with the machine running. No thanks..

256 posted on 01/31/2002 3:03:58 PM PST by agitator
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To: agitator
This is a load of CRAP. Don't expect to get the truth from the propaganda ministry. During the TMI release the lamestream media asked "How much radiation are people near the plant being exposed to?" and the comforting answer was "It's equivalent to a chest x-ray." What they didn't tell you was that there's a big difference between the instantaneous dose rate and total accumulated dose. Hanging around TMI was like climbing into an x-ray booth, turning it on, and sitting there for a week with the machine running. No thanks..

And you're full of that CRAP. You are displaying your ignorance both of the biological effects of ionizing radiation and reading comprehension. The dose estimates were total, accumulated dose for a hypothetical worst-case exposure. You simply integrate the time-dependent dose rate over exposure time to get a total dose. Since it is well-known that the TMI exposures occurred over a relatively short period, it is not invalid to use that to estimate effects from an acute dose. Non-harmful changes in biological functions such as white cell production become statistically significant at between 5 and 10 rems of whole-body exposure. The maximum hypothetical dose at the TMI plant boundary were in the tens of millirem range. Orders of magnitude below observable effects.

Now, use that same exposure to estimate latent effects. Long-term exposure studies indicate that a dose in the range of 10 to 100 millirems results in about one excess cancer death in an exposed population of a million. Now, of that same cohort group, the expected fatal cancer rate is in the range of 160,000 from non-radiation effects. Put another way, a single individual receiving an accumulated exposure in the 100 millirem range increases their fatal cancer risk by about one in one million. The best estimates of average exposure in the TMI cohort group is in the one to 10 millirem range. Adding that into the accumulated total exposure over the average liftetime of a resident of that area, adds about 0.14% to the accumulated total, using the natural background exposure in that area of the country, and excluding medical exposures, which, depending on the individual, can greatly exceed the natural expoures, and dwarf anything a person might get from the accident. So, bottom line, the total added exposure was very, very small, with correspondingly small biological effects.

280 posted on 01/31/2002 4:09:37 PM PST by chimera
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To: agitator
Hanging around TMI was like climbing into an x-ray booth, turning it on, and sitting there for a week with the machine running. No thanks..

BTW, what the hey is "an x-ray booth"? I have some experience in nuclear medicine (going on 25 years now) and I have never heard of such a device. We have x-ray rooms and portable x-ray units, CAT scanners and MRIs, soft x-ray, hard x-ray, and linacs, but nothing in the way of a "booth" for x-rays. Is that something you heard somewhere, or just made up...?

284 posted on 01/31/2002 4:40:29 PM PST by chimera
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To: agitator
Hanging around TMI was like climbing into an x-ray booth, turning it on, and sitting there for a week with the machine running. No thanks..

Well, I thought it might be worth a closer look at this just to see how outrageous a claim this really is. First, lets run a few numbers on what we know about x-ray exposure in diagnostic procedures.

Well-established dosimetry methods will show that the average chest x-ray results in a whole-body expoure of about 30 millirems, depending on filter settings and accelerating potential. Using reasonable quality factors and kerma for converting from tissue-equivalent dose to gamma exposure rate, we get something in the range of 20 to 30 milliroentgens (mR) exposure. Lets go with the higher number of 30 to be conservative.

Now, the beam is only on for a few seconds, maybe two or three, to get this dose. Again, to be safe and overestimate the rate, lets use two seconds. Combining this with the observed exposure, we get and exposure rate for diagnostic machines of about 15 mR/sec, or, converting to the more familiar hourly rate, 54 R/hr.

Now, assuming your "x-ray booth" is just a colloquial term for the conveyor x-ray unit that you see in airport security stations, we will assume, not knowing otherwise, that these machines are similar to medical units. This is reasonable; they are commercially-produced devices that use similar technology. So, you are saying that being around TMI udirng the course of an accident was like being exposed to a source producing an exposure rate in the range of 50 R/hr, and that for days at a time?

Well, if that is so, it is totally outrageous. First, if it were, at that rate, the 24 hour exposure to an individual would be about 1200-1500 rems. You said the exposure time would be one week. That would place the acute dose in the range of close to 30,000 rem. That is a 100% lethal exposure. Since the LD50/60 (look that one up) for human beings is about 450 rem, your assumption would result in everyone dying in that area within about 3 weeks, more likely within a few days. Here's a clue: NO ONE DIED. Further, verified, documented exposure rates at the plant boundary at the peak of the releases were in the millirems per hour range. And you say they were in the tens of R per hour range? Well, you're only off by several orders of magnitude, which, for a Luddite, I guess isn't too bad...

Bottom line, leave the science to scientists. Well, now that we have utterly demolished this incredible bit of sophistry, and other fables to bring up?

291 posted on 01/31/2002 6:00:30 PM PST by chimera
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