Not sure where to post this question, please advise if you know a better place.
I live near a massive quarry and in conversation with one of my neighbours, they said that they thought that there was uranian being dug up. I did'nt like the sound of that so I bought a cheap Portable Dose Rate Meter (A plessey PDRM 82 (off ebay for under £20 to check for myself. The meter was brand new in the box, manufactured in the
60/70's. The problem is I do not know what levels are safe and even if this meter is sensitive enough. It reads 0.0 after going through a test procedure. The units of measurement are in cGy/h (in air), does anybody know about this meter and is it any good for what I want?
I don't think that model is sensitive enough to detect what you are looking for. If you get any kind of reading run fast....
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Quote: As mentioned, the only downside with the PDRM 82 is that its digital reading is from 0.1 cGray/hr 300 cGray/hr (remembering that a CentiGray is equal to a REM) making the scale too high for use with most nuclear accidents (but ideal for nuclear war use). END Quote.
So lets work some numbers...
1 CentiGray = 1 Roentgen = REM = 10mSievert.
...so your meter starts reading at 1m Sievert per Hour.
So lets google for safe levels...
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Quote: At present, the Australian dose limit for an activity such as uranium mining is 1 mSv per year to a member of the public, and 20 mSv per year (averaged over 5 years) for a worker at the mine. End Quote
Note that's 1mSv per YEAR where as your meter only detects anything above
1mSv per HOUR. Thats a factor of about 8760. or look at it this way... That mine could be exceeding the safe level by a factor of 8760 before your meter would start to detect it.
At least I think I've got my sums right (too hot here today).
Yes its hot here too, I thought it might have been the Uranium kicking in. Joking apart thanks for taking the time to answer my question. Back on Ebay it goes, regards.
In the radiation protection biz, dose is measured in REM (roentgens equivalent to man), or commonly millirem (mR). Roentgens are more or less equivalent to REM. So it would be good to have a meter that reads in those units.
Most common meters are sensitive to gamma, the most common and penetrating type of radiation, but some are also sensitive to beta and alpha. Gamma is probably the all-around best thing to be measuring.
On average, you'll get about 360 mR per year from natural sources. That will vary pretty widely with your location though. Several times that shouldn't be a major concern.
The NRC limits radiation workers to 5 REM per year, whole body. (More to specific regions.) As a "member of the public" (non-radiation worker), I sure wouldn't want to be getting that much.
Another issue is direct dose versus internal contamination. Uranium puts off alpha particles. They are massive and easily stopped (shielded) by a few inches of air or your outer layer of skin. But if you get the stuff internal to your body, it can be a problem. So if your neighbor were stirring up uranium dust, you wouldn't want to be breathing it. That's why radiation workers wear those coveralls and respirators. Not to protect against radiation, but to keep from getting an internal dose.
Another acceptable meter would be one that reads in counts per minute (or maybe disintegrations per minute, same thing). This is like the clicky geiger counter of 50s prospectors. Here, you are looking at relative readings. Survey some locations pretty far from your mine. Say you read from 25 to 200 CPM at these suspected "normal" locations. Now survey the area of the mine. If you're getting say, 1000 CPM or more, there's some activity there in excess of normal background. Maybe not hazardous, but still it's there. If you get way more than that, you might want to figure out what's going on.
A more direct approach might be to ask. If they are mining uranium, they probably are working under some standards for protection for the workers. (Are you in the US?) Ask them.
Thanks Nick, thats all the information I needed, I am in Spain, the quarry digs up brown earth for making ceramic tiles, but it is massive. Does anybody know where I can get a suitable meter at a suitable price?
"However, concentrated uranium ores are found in just a few places, usually in hard rock or sandstone."
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Spain Spain is, apart from Ukraine, the only country in Europe with an increasing uranium production. The company ENUSA (Empresa Nacional del Uranio SA) has taken into operation a new uranium mill at Saelices el Chico near Ciudad-Rodrigo (Salamanca province) close to the Portuguese border, and produced a total of 270 tonnes of uranium in 1994. Production shall be maintained at this level in the future. Spain thus can meet one fifth of its reactor needs [NF 16 January 1995]. The final design capacity of the plant is 800 tonnes of uranium per year.
I suspect you are wasting money but f you really want a meter....
I think we worked out that you need one that reads around 20 x 10^-3 Sv/year (20mSv/year). That's about 2.5 x 10^-6 Sv/hour (=2.5uSV/hour)
Perhaps the meter at the middle of this page?.... LOW COST RADIATION MONITOR Cat. #A783) . $159.95
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It appears to have a range of 0.05 to 9.9uSv/hour.
but best have someone check my figures before you spend your money.
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