# 7-10 Rule



## UncleJoe (Jan 11, 2009)

I've seen this in several of Jerry's stories and didn't know what it meant so I finally looked it up. In a nutshell:

*The "seven-ten" rule* - For every sevenfold increase in time after the initial blast, there is a tenfold decrease in the radiation rate. For example, a 500 rad level can drop to 50R in 7 hours and down to 5R after 2 days (49 hours). In other words, if you have shelter with good shielding and stay put for even just 7 hours ... you've really increased your chances of survival. Your detection devices, emergency radio or cell phone [if the last 2 are working, that is] can assist you in knowing when it's safe to come out.


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## kogneto (Feb 23, 2010)

yeah but you still have to worry about radiation coming down on your shelter, I've heard it described like ash in the air or sooty snowflakes. So long as you don't have too much around your shelter you would be pretty safe from initial blast radiation after 2 weeks to go out and brush anything off the roof.

What I'm wondering though, is about what to do with your outdoor clothes in this type of situation. Obviously you can't bring them into your shelter, but you also don't want them just sitting out exposed to the elements, and if you need to wear special clothes you don't want to be stripping outside and exposing yourself to beta-burns. I was thinking maybe a decontamination shower at the entrance, or maybe _an_ entrance, with like lead drawers to put work stuff.

In this type of situation, what happens to farming and livestock? And water supplies?


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## Expeditioner (Jan 6, 2009)

Just one little clarifciation. Too many people confuse radioactivitity with radiation. Radiation is energy and is emitted by radioactive material aka radiaoctive contamination. You cannot wash away radiation but you can wash away the contaminated particles that emit radiation.

Another way to look at it is radioactivity is the cow manure you step in....radiation is the smell.


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