Originally posted by Escrotumus
I was under the impression that a ground burst creates far more fallout than an air burst because of the particulate matter that it throws into the
air and then this fallout comes back to earth and settles on everything.
It does create a lot more particulate matter. On the other hand, the particles are heavier, and don't travel as far. Sort of a fifty fifty
trade-off.
For anyone caught in a major city when something like this happens your chances of survival have almost nothing to do with planning, but have
everything to do with luck and how quickly (if at all) you can make it to your shelter.
I disagree. I doubt that terrorists can get their hands on, or build a bomb with more than a 50 kiloton explosion.
Suppose, for the sake of argument, this is what you are presented with. Again, that's a fireball less than a kilometer across. If you are 5 miles
from the blast, and there's 15 mph wind, and you are
directly downwind of the blast, you've still got 20 minutes to prepare. I can imagine a
dose of 500 rads when the cloud reaches you. The 7/10 rule means it will drop to 50 rads after 10 hours, and 5 rads at 49 hours.
In my thread about a non-electronic fallout meter
(link) I provide a link to
Kearny's original brochure, here's a quote from that pamphlet:
A healthy person who previously has received a total accumulated dose of no more than 100 R distributed over a 2-week period should realize that:
100 R, even if all received in a day or less, is unlikely to require medical care - provided during the next 2 weeks a total additional dose of no
more than a few R is received.
350 R received in a few days or less results in a 50-50 chance of being fatal after a large nuclear attack when few survivors could get medical care,
sanitary surroundings, a well-balanced diet, or adequate rest.
600 R received in a few days or less is almost certain to cause death within a few days.
Now, if you can get your *cough* inside a shelter with 18 inches of dirt around you,
This Handy pamplet from the UK shows that you reduce the radiation to 16 rad for
the first hour, which is means less that 100 rad in the first seven hours. After that, your exposure in the shelter effectively drops below
2 rads
per hour.
But suppose you are on the highway, doing 70. You'll get pretty serious dose if you can see the blast. But suppose you happen to be in a small
valley when it goes off. If traffic just keeps going, and you can drive out from under the fallout in 10 minutes. Then you'd be somewhere around
the 350 rad level. Youd
still have a 50/50 chance of survival.
So yes, by my calculations, you
could survive a terrorist's tactical nuke, if you take measures to increase time, distance, and shielding.
In the US, a lot of public buildings are still technically classed as a fallout shelter, even if they have taken their signs down.
But if you just stand there, you are correct--you are most certainly doomed.
.
[edit on 28-5-2007 by dr_strangecraft]