From the research project studying survivors of Hiroshima and Nagasaki:
Tumor registries were initiated in 1957 in Hiroshima and 1958 in Nagasaki. During the period from 1958 to 1998, 7,851 malignancies (first primary) were observed among 44,635 LSS survivors with estimated doses of >0.005 Gy. The excess number of solid cancers is estimated as 848 (10.7%) (Table). The dose-response relationship appears to be linear, without any apparent threshold below which effects may not occur (Figure 1).
Table. Excess risk of developing solid cancers in LSS, 1958-1998
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Now, 0.005 grays is not a spectacular dose. 5 grays causes death within 14 days. Hiroshima and Nagasaki were small enough yield to irradiate a lot of survivors. Primary radiation is usually limited to about 8000 feet. Big bombs kill by setting things (including people) on fire and blast damage.
Fallout is the big risk. I suspect many who may be exposed to fallout will die before cancer becomes an issue. "One hour after a surface burst, the radiation from fallout in the crater region is 30 grays per hour (Gy/h)" I am guessing that downwind fallout is going to be less than going to the crater. ("Let's go sightseeing!") Fallout in your food likely is a bigger risk.
Building a shelter is a good idea, but with the current shortage of materials and construction workers, preparing an expedient shelter and stocking up on canned food and water will make more sense, especially if you are over 50.
A reader points out the need to mask out fallout. Does anyone know fallout particle size. N95 respirators are at least 95% efficient for .3 micron sized particles. It appears that particles greater than 20 microns are local fallout (which is what we are worrying about); smaller particles will stay aloft likely until they decay. I bought some potassium iodide tablets because radioiodine is vapor and thus would pass through dust particle masks.
You need shelter and food/water for about 30 days post explosion Fallout is generally very "hot" and the half-life is often hours or days.
ReplyDeleteAs a rule, the drop in intensity of gamma from fallout averages to about one half per day.
So in other words, it's intensity falls off by about half every day (varies some, but it is a good rule of thumb).
So the really "hot" stuff fades away quickly. The biggest worry (if you have shelter) is the dust containing alpha emitters, as these tend to stick in your lungs.
YMMV
Shelter construction and more:
ReplyDeletehttps://www.oism.org/nwss/
and the rule of 7
http://www.falloutradiation.com/johnwayne7
WRT respirators, one good for radionuclides (a purple filter) is considered the standard.
ReplyDeleteAnd while airborne fallout falls slowly, it does fall - leading to contamination hundreds to thousands of miles downwind. Remember that some of the decay particles are long-lived. Being in the Boise area there is a minimal chance of fallout reaching you from upwind unless Mountain Home AFB is targeted.
I chose the Flathead valley of Montana because it's upwind of the missile fields, and far enough away from Fairchild AFB (likely a target) that local fallout is not an issue, and distant fallout is likely going to pass by
The seminal work on this topic is 'Effects of Nuclear Weapons' by Glasstone. Free copies are available for download, unfortunately not with the fallout calculator slide rule.
https://atomicarchive.com/resources/documents/pdfs/effects/ggi.pdf