Radiation 101

We are exposed continuously to radiation.
You actually are exposed to around 70 to 100rem of radiation over a year. Unless you are aircrew or medical rad tech of some sort. Then it's more.
That 80 to 100rem dose we get every year would actually be not good.
I have informed anti nuclear libtards of this fact and they were legitimately horrified, one even started to display symptoms of acute radiation poisoning LOL.
So some how through our failed educational system and lie based news media some people are being convinced that all radiation is some unnatural, nuclear age man made horror. Almost as if radiation didn't exist at all before the 20th century.

 

I still believe in an ounce of prevention.

 

The rad calculator says almost 600 for me from naturally occurring sources.
Then my wife says she get an additional +200 to +500 from work per year.

 

Worked around nukes and reactors a very little in USAF back in 1950's. Beat very deeply into my head for safety was the heck with shielding, radiation, etc, the real danger was ingestion or wounds. That and plutonium burns quite well. Rocky Flats outside of Denver had a fire that scared heck out of my bosses in 1957 and although somewhere around a pound escaped, it was in fine particles. They had a second fire later in 1969 that was contained, but one report said there were 7500 pounds of plutonium in the building that caught fire and that was somewhere around 20 miles out of Denver. You could hold the metal in your hands, but a small flake of it in a cut or your lungs could kill you so we always used glove boxes when handling it. I would want a very good mask and protective suit for some period after any major event.

 

Alpha particles are bad mmmk.

 

https://xkcd.com/radiation/


And here is something I wrote....


What Is a “Half-Life”?


The short answer is that a half-life doesn't mean the time it takes for something to become safe, it's the time it takes for half of something to become different.

Picture a jar with 100 red marbles in it, and each marble has a half-life of 1 day, and the marbles convert (spontaneously) to green marbles.

Tomorrow (1 day later), the jar will have around 50 red marbles, and some number (not 50, for reasons I will shortly explain) of green marbles. We don't know at all which individual marbles will turn from red to green, or exactly when in the last day they will turn: We just know that after a day, half of them turned.

Now, let’s say the green marbles have a half-life of 1 minute, and turn to blue marbles. Our jar, after 1 day, has 50 red marbles, some green marbles, and some blue marbles. We can calculate statistically how many there should be of green and blue, but it will change with time, and we can't tell when any particular marble will change.

Lets say that once they turn blue, they quit changing...eventually, all the marbles will turn blue.

Thats how radionuclides decay. Call the red marbles tellurium, (which actually started as 235-Uranium in a reactor), and after some time turns into 131-Iodine (the green marbles). 8 days and a little change (the half-life of 131-I is 8.02 days) turns into 131-Xenon (the blue marbles).

So, we have some 131-Iodine in the jar. We take all the marbles out, and fill the jar up again with JUST green marbles. 8 days later, half are blue, right?

Well, in the process of turning from red to green to blue, they give off energy, in the form of ionizing radiation. That is the kind of radiation we worry about.

So, we have our jar giving off energy. Some of it happens very quickly, some not so quickly, but on average, half of the 131-Iodine will turn to 131-Xenon every 8 days.

After 8 days (1 half life), we have 50 green marbles, and 50 blue ones, right? But the jar is still giving off energy, same as last week, just not quite as much of it, right (because after another 8 days another half-life), we have 25 green marbles (half of 50). They're still giving off energy, though. So, another half life, another 8 days, and we have 12 or 13 green marbles, still giving off ionizing radiation. Another 8 days or half life and we're down to (lets say) 6. Still giving off ionizing radiation. Thats been 4 half lives, so far, and while the total amount of ionizing energy is lower, it's still giving off some, right? Let’s go another half-life, another 8 days, and we're down to 3 green marbles. Quite a step down after 5 half-lives (call it 40 days), but still a little bit of radiation.

And with radiation, its' all a matter of chance. How much is safe? How much is none at all? We could wait 1000 years, and not be conclusively sure that there was no radiation at all, because there will probably still be an atom (a marble) or two of 131-I in there, because there aren't 100 marbles in the jar, there are literally trillions and trillions in the kilogram (theres a number we can use to calculate about how many, trust me: It’s a LOT).

We like at least 5 half-lives reduction in intensity to call something kind of safe. Some say 10 half-lives.

Some radionuclides have half-lives that are measured in microseconds (I wrote a paper in college, for chemistry class, on one of the shortest lived, 215-Francium with a half-life of 85 nanoseconds), to (again) 128-Tellurium, the longest at 2.2x1024 years (160 trillion times longer than the existence of the universe). Quite a spread.

Which ones give off their energy fastest? The ones that 'pop' at 85 nanoseconds, or the ones that 'pop' at 160 trillion times the existence of the universe? Generally, the shorter-lived ones are more worrisome.

But, that isn't all there is to it - the types of energy they give off is an issue as well. Is it an alpha particle? Relatively low energy, not able to penetrate a sheet of paper, or unbroken skin, but able to damage skin or tissue in near proximity or contact? A beta particle, more energetic, able to penetrate skin? Gamma rays, very energetic, able to penetrate lots of things? Some or all of these together?

And what happens is important, too. 131-Iodine turns into 131-Xenon, which is stable (doesn't undergo any decay, or turn into anything else). Other products of fission inside a nuclear reactor (or detonation) turn into other isotopes, some of which are very bad news, some of which are not so bad (relatively speaking), and a few of which are stable. Ultimately, 239-Plutonium decays (through Uranium, Thorium, Proctactinium, Actinum, and others to lead, and that is the end of the line....after a long, long time over all, but some of the intermediate steps are quite short (a few milliseconds). Each of the intermediates has to be analyzed and considered separately for its risk.

So, it's not a matter of waiting a single half-life period for radiation to become 'safe'. Personally, for radioactive Iodine from nuclear reactors or detonations, I plan on taking KI for at least 41 days (5*8.02 half lives). Of course, I'm old enough that I don't really have to worry about thyroid cancer anyway, but why take chances?


Hope this helps.

 

My pen dosimeter in my tee shirt pocket is currently reading.... .07 uSv/hr. Have taught myself to convert to mille rems if necessary.

I have three spare dosimeters and two counters...

I have taken readings about town to the places I frequent for business...grocery store..., gas station....bank....Lowes...Home Depot Bass Pro...etc etc et al. I do this as a base line to know when something radical changes.

Radiation techs do this often...and make a map of conditions.

Good thing to do if you have a dosimeter....take readings in a mental average of the places you tend to frequent..and keep an eye on any seasonal changes....throughout the year. Averages..

But you members decide for yourselves....for your reasons...as you shepherd your flocks.

Orangetom
Not an Ishmaelite.

 

Had mine on driving and an unmarked truck passed me that was rather radioactive. Don't know what was it it. Could have been phosphate tailings for all I know. Or an iridium 141 source rolling around on the floor inside the truck.

 

I have KI here in my daily BOB/Get home bag...also other stashes...of KI here at home.

The Radiation techs at work have it in stock but I have learned not to depend on them as well...which is why I have my own dosimeters....and counters.....at my expense....as well as KI.

Again...you members make up your minds for your reasons.....

Some good information on this thread...

Will be recharging my pencil dosimeter today while I use and carry my spare at work.


Orangetom
Not an Ishmaelite.

 

The old swimming pool reactors were used to test electronic units etc for radiation. Had a beautiful glow in the water around unit. About 20 feet of water cut radiation down to point you could work in area. Impressed me on the effects shielding had on radiation. Thousands of Rem in core, just about background in work area

Swimming pool reactor - Wikipedia

Ours used enriched as it was USAF and had a tank of a solution that if you hit the kill switch would flood the core and kill the reaction in seconds as well as cool it. Control rods were held by magnets and any excess radiation or manual action would cut magnets and they would drop in place and kill the reaction. Had counters for hot end, work areas and "mickey mouse" badges for exposure over time on chain next to dog tags. We also had hand held counters to check for residual radiation on objects that had been in reactor or that we thought might have been in reactor. Like woodworking, measure twice, cut once, always checking. Base had 2 methods of calibration. One was about the size of a floor chest freezer and had a calibrated source of several hundred rem that was used for high units. Other was small sample that had minimal shielding and was used for probes and mickey mouse badges. Put object to be tested a measured distance from sample and had measured dose. High right against source, would trigger alarms, at 3 feet in mils and allowed adjusting meters. High end meters used gieger tubes, lower valued ones often used crystals and a light detection system. Low end crystal ones 60 years ago were more rugged and smaller probe as you didn't need such high voltages.

The samples were like these.

Civil Defense Museum - Radiation Instruments and Kits - Photos From Two State Radiological Maintenance And Calibration Shops

Most states used to have a place where civil defense would calibrate an individual on for free or a few bucks. Haven't done it in years myself. Went to key chain style and back ground count indicates that it is working and general level. Comes calibrated and I have never checked its accuracy. Hope I never find out if old one is still good. Self checks worked and the last time I checked it about 20 years ago it was good. Checked out good over previous 30 years so I guess it is pretty fool proof. Only wood use it for high end any way. Trust key chain for actual working exposure. Don't plan to be working 100 rem any way.

I use this one. Cheaper ones out there, but I use these and replace them at about 7 years, say good for 10..Always on so you can check them with back ground radiation and know they work. Haven't calibrated it so I really can't prove it works at higher levels. Back ground count does check out when compared with expensive calibrated lab unit how ever and it doesn't seem to give false positives. Doesn't seem to have anything easy to break either like the gieger units. Thicker the glass the less they can read on low end.

NukAlert Personal & Compact Key Chain Attachable Radiation Monitor & Alarm