OT: Radiation (RADs & REMs) ** Was: Asian Rice

[Guest guest]

Hey Melissa,

 

Since there is no message traffic now ...

 

I'm sorta reminiscing with the below post .. so them that don't wanna

be bored oughta zap it now. Come to think on it .. its a boring post

so maybe y'all oughta just go ahead and zap it. ;-)

 

>>Thirty days has September, April, June and November .. and a person

>>with 1,000 RADS.

>

> Butch,

>

> Actually, it's less than that. I just finished up second semester Gen.

> Chemistry and our next-to-last chapter was Nuclear Chemistry. Referring

> to my notes, exposures are:

>

> 25 REM (Roentgen Equivalent for Man) - changes to blood cells

> 100 REM - radiation sickness

> 450 REM - 50% death rate at 30 days

> 1000 REM - CERTAIN death (usually w/in 2-3 days)

 

The above is educated guesswork .. the best they can come up with.

And its designed to quantify then speculate effects of total body

exposure. If one has only hands or feet exposed .. they can handle up

to 20 times more dosage without risk of death .. though they are gonna

lose their hands or feet. The link below sorta adjusts the above

figures. I've not studied radiation since the mid 1970s, and prior to

that we had it drummed into our heads weekly because of the possible

threat from the USSR. I'm sure the models have changed since then ..

so I had to refer to on line sources .. which may not be accurate.

 

http://en.wikipedia.org/wiki/Radiation_poisoning#6.E2.80.9310_Sv_.28600.E2.80.93\

1.2C000_REM.29

 

The ditty I quoted is the old Military rule of thumb and its sorta

easy for the troops to remember when its poetic .. plus it would lower

the fear factor while at the same time stressing the importance of

wearing MOP Gear regardless of the temperature. Its like telling them

to have their atropine syringe handy in case of exposure to nerve gas

... odds are slim that an atropine injection could save one who has

been exposed but there is a need to give hope .. or there will be a

natural fear.

 

The entire " science " is based on much assumption. Ehen I had formal

instruction on the subject they told us that first day. I was once

assigned an additional duty as Chemical-Biological-Radiological

officer and had to attend a 2 week school .. I absolutely detested the

entire course .. math is not one of my favorite subjects. ;-)

 

That course was a short course .. those who specialized in CBR went to

school up to a year .. its a VERY COMPLICATED subject. We had no

computers then so it was all worked out with stubby pencil and slide

rule .. which I still hate.

 

It looks like they are using REM instead of RAD to quantify radiation

absorbed dose now .. but its a lot more complicated than choosing the

term to quantify .. it takes in far more factors than just exposure.

Exposure tells one thing but amount of absorption tells another .. so

REM (though as a measurement is pretty much the same as a RAD) doesn't

necessarily tell us what the amount of absorption is .. that can be

affected by many variables.

 

Roentgen Equivalent in Man (REM), is used in formulas in the US, but

regulatory and advisory bodies are pushing for transition to Sievert

(1 REM = 1/100 Sievert) and milliren (mrem) which is 1/1000th of a

REM. The reason is that a REM is a very large amount of radiation, so

the Sievert and millirem better describe dosages commonly encountered,

such as the amount of radiation received from a medical X-ray.

 

RAD is " Radiation Absorbed Dose " . The USA is the only country that

uses this measurement for radiation .. probably because the rest of

the world uses the French Système International d'Unités. Seems like

enough justification to me. ;-)

 

It is possible to survive 1,000 REM or RAD, though its not normal ..

but it has happened so its not a 100% death sentence. Fact is .. all

the calculations for dosage effects are hypothetical .. there is no

way to really test them and using past data like WW II and Chernobyl

is not too efficient due to poor record keeping. But due to a need

for a standard they use what they have .. which is logical.

 

Around 135 emergency workers were close to the fire at Chernobyl in

1986 and they all received high radiation doses (70,000 to 1,340,000

mrem or 700 to 13,400 mSv) - all suffered from acute radiation

sickness but only 20% or so died soon after. Lots of after effects

have been and are still being noted for survivors and their offspring

... thyroid cancers and other effects .. but " true " data is not easy to

get a handle on.

 

However .. its that data and data from the 1945 atomic bombings that

is still used today to calculate rates and incremental increase in

risk. The US Gummit (and other Gummits) use various models to come up

with hypothetical calculations but when they deal with figures below

1000 mrem it is total speculation. The reason is .. they base their

data on rates of cancer but the latent period for cancers that may

develop as a result of radiation exposure are indistinguishable from

those that occur naturally or as a result of exposure to other

chemical carcinogens.

 

Example .. it is claimed that folks living in the Ural Mountain

regions of Russia accumulate up to 500 mSv of radiation over a period

of 30 years and it is claimed that 500-1000 mSv was the rate of " short

term " exposure most atomic bomb survivors experienced in 1945. That

rate is considered to be acute but its not a death warrant. I

personally know Russians who are in their late 80s, never had a

medical problem, and have lived their entire lives in that region ..

my wife's grandmother is but one example.

 

Dose will always depend on time of exposure .. and soldiers had to

learn to operate in contaminated environments .. theory wise, if one

pops a tactical nuke its not necessarily to kill the enemy .. but to

restrict his movements by either keeping him in place or denying

terrain to him. That is why we used to teach youngsters to get out of

the area as soon as possible after initial fallout. You can't stay

hunkered down forever and while you are there the enemy is going to

concentrate fire on you.

 

When we talk REM and RAD we're normally talking skin exposure but if

one breaths in dust or drinks water after the fallout we get into

Committed Effective Dose Equivalent (CEDE) .. pertains to ingestion or

inhalation. Roughly it describes the rate of absorption or affect on

various organs of the body (which vary in sensitivity). Its possible

to have no outer skin damage but die from a damaged liver, etc. I'm

talking ionizing radiation, which is what is used to fight tumors,

etc., and its also what we get from X-Rays. It can be dangerous in

large doses even in short term exposure .. and in smaller doses over a

long period of time because of the accumulative effects of radiation.

There are MANY commercial/industrial uses for ionizing radiation ..

like to make smoke detectors. In excess this form of radiation has

the capability to sterilize and cause mutations. At low dose its

great for sterilizing instruments, etc.

 

Non-ionizing radiation (microwaves & radio waves) are generally

harmless but some forms can be harmful if they accumulate but that

normally takes lots of time .. not short term exposure. This too can

be measured in REM or RAD.

 

Background Radiation like Cosmic and Solar, etc., can also be harmful

if exposure is chronic .. like in skin cancers. The EPA and other

Gummit agencies have a general rule of thumb that says 1% of the US

population will develop cancer in their life due to natural and

manmade sources of radiation .. but that figure is challenged by many

private agencies.

 

In a nuclear war (which is what your class is most likely relating

to), if one is a fair distance from the flash bang (infrared risk

decreases greatly as distance increases) or has a fair amount of

shielding (which depends on the thickness .. even a rubber poncho can

protect from Beta and Gamma fallout particles) .. they'll survive the

initial flash bang blast and if they move out of the area they might

come out smelling like a rose .. but without that degree of protection

the fallout is likely to knock them out as it will cause the greatest

number of casualties. Those who are exactly downwind of a detonation

(matters not so much what the yield is), can get doses up to 300 Gy

per hour (thus, the need to get out of the area as soon as possible).

 

The average annual " Background " level of radiation exposure (solar,

etc.) is roughly 4.5 Gy .. 300 Gy is roughly 15,000 times that rate

and it is estimated that this rate would kill roughly half those

exposed to it in a very short period of time .. those who survived

would have greatly increased risks of cancer.

 

Also .. many calculations are for short term/high dose (acute)

exposure but one can slowly accumulate REM/RAD over a period of time

(chronic). There is scientific support for persons living up to a

month after having been accidentally exposed to a dose of 1,000 REM/RAD.

 

Back when we used military formulas to determine exposure we dealt

with time/distance factors vs yield vs temperature vs humidity vs

downwind drift vs air to ground burst ratio vs shielding (a piece of

cardboard can afford some protection), and half lives/decay rates and

even color of fabric a person is wearing .. light colors reflect more

infrared than dark colors. All of these variables (and others) play a

key role in determining exposure and thus, rate of absorption or dose.

 

> We learned some fascinating things about radiation.

 

I'm glad it was fascinating .. what I learned was boring. ;-)

 

I got into this post after so many years and I started to go into a

long drawn out set of formulas but as I started doing it I became

bored .. so odds are it would bore others too. ;-)

 

Best it is to say that odds are great that up to 1,000 REM/RAD a

person is gonna go under snakes in 2 weeks to a month .. and with far

more than 1,000 REM/RAD they are certain to go under in 2 weeks or

less. But as you will see from the link above a fellow did absorb

8,000 REM/RAD and lived for two days .. though he probably didn't know

he was alive.

 

A good rule of thumb today might be .. don't let Outlaw Nations have

nuclear weapons .. and hope that some day we can have a real, valid

disarmament .. but odds are that will never be the case. If Iran goes

Nuke then many Middle East countries will go Nuke .. and we have China

and Russia and Pakistan and Israel who are Nuke capable now .. before

one of those countries allowed themselves to be overrun or destroyed

they would certainly start popping Tactical Nukes and odds are it

would escalate to Strategic Nukes .. and we would be back to the old

Mutual Assured Destruction (MAD) mode. Perhaps First Strike is

justified when dealing with Nukes in the hands of Outlaw Nations. Not

necessarily an opinion .. just a consideration.

 

One thing for sure .. all this makes Global Warming sound like a

stroll through the park.

 

Y'all keep smiling. :-) Butch http://www.AV-AT.com