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Radiation health hazards with field nuclear densiometer test 4
- Thread starter geoindeo
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Nuclear density gauges emit low levels of radiation, but because of their relatively continuous close proximity and use by the operator, generally require monitoring by the use of dosimeters, film badges or similar.
That's not to say that the radioactive isotopes contained within the shielding of the gauge are not dangerous. They are. Cesium and Americium are commonly used isotopes, but they are usually also in a "strength" or activity range in picocuries, as compared to the radioactive isotopes used for welding NDT which can be 100 curies.
Bottom line is that anyone using a nuclear density gauge should be trained in basic radiation safety, transportation of radioactive isotopes, and monitoring schemes for radiation exposure. Each person should also be monitored from an outside source with reporting on at least a monthly basis so that radiation exposure levels can be checked and action taken if necessary.
That's not to say that the radioactive isotopes contained within the shielding of the gauge are not dangerous. They are. Cesium and Americium are commonly used isotopes, but they are usually also in a "strength" or activity range in picocuries, as compared to the radioactive isotopes used for welding NDT which can be 100 curies.
Bottom line is that anyone using a nuclear density gauge should be trained in basic radiation safety, transportation of radioactive isotopes, and monitoring schemes for radiation exposure. Each person should also be monitored from an outside source with reporting on at least a monthly basis so that radiation exposure levels can be checked and action taken if necessary.
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Ron gives the good basics. In Canada when I first immigrated there, we were required to have badges (but the company sometimes used the same one for different people!?) - but at some point, the badges (dosimeters) were discontinued. I know of only one that ever shown a reading - the guy had the machine in his hotel room and sat his badge on the unit (in the box).
Good operating procedure should be followed. You drive the rod to form the hole, then sit your machine over the hole, then extend the rod into the hole (yes, it takes a bit of practice). I have seen many who make the rod hole, then extend the probe a bit to get it into the hole, then sit the machine down. Not the way to do it!
When I was in India, they were all so scared of it that some even wore a lead vest! They were very careful not to be within 1 m of the machine during operation - except to hit the button and pull up the probe . . . Once, there were about 8 guys standing around and I went up to the machine (during its count) - looked at it rather investigatively, then took a quick two steps back - talk about scattering like a bunch of rabbits!![[bigsmile]](/data/assets/smilies/bigsmile.gif "[bigsmile] [bigsmile]")
They are safe but you do need to follow proper safety protocols.
Good operating procedure should be followed. You drive the rod to form the hole, then sit your machine over the hole, then extend the rod into the hole (yes, it takes a bit of practice). I have seen many who make the rod hole, then extend the probe a bit to get it into the hole, then sit the machine down. Not the way to do it!
When I was in India, they were all so scared of it that some even wore a lead vest! They were very careful not to be within 1 m of the machine during operation - except to hit the button and pull up the probe . . . Once, there were about 8 guys standing around and I went up to the machine (during its count) - looked at it rather investigatively, then took a quick two steps back - talk about scattering like a bunch of rabbits!
They are safe but you do need to follow proper safety protocols.
- Thread starter
- #4
Thanks Ron and BigH both, for sharing your understanding and some interesting observations!
For someone who is seeking to enter the Canadian job market in geotech(after a long gap due to recession), I really don`t know what the current safet protocols are for such tests.
Maybe I will follow the example of your Indian friends and keep clear of the instrument !!
As you both said, one would surely want to get the safety issue out of the way before getting into the correct procedure and data interpretation !!
For someone who is seeking to enter the Canadian job market in geotech(after a long gap due to recession), I really don`t know what the current safet protocols are for such tests.
Maybe I will follow the example of your Indian friends and keep clear of the instrument !!
As you both said, one would surely want to get the safety issue out of the way before getting into the correct procedure and data interpretation !!
Do as BigH notes. Troxler often has representatives in various area who conduct basic radiation safety training and issue certificates for such. This is often free, depending on whether your company owns several Troxler gages. Campbell Pacific (CPN), now Instrotek, did similar at one time. Not sure about now.
Here's a link to an online course...
Online Nuke Gage Course
Here's a link to an online course...
Online Nuke Gage Course
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I just completed this training provide by Nuclear Gage provided by Troxler(see link below). A user is required to train every three years in the US as well as other reporting an paper work requirements to utilize nuclear gages. Either a state agency or the NRC is the regulatory agency depending on your state. If used properly they do not pose much of a risk. Three keys to protection distance, time, and shielding.
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Hwy guys: I used some of the first "gages" developed as a grad student. One device was hung on a cable for down the hole use. Of course I was hanging on the cable and the radiactive part was within 1 foot of me for hundreds of tests.
At 83 now, and in good health, I'd not get too excited about these devices.
At 83 now, and in good health, I'd not get too excited about these devices.
OG...same here. Took one of the old Troxler 2401 gauges apart once because of an electronic problem. Pulled the source tube (completely unshielded) and let it sit in a concrete cylinder mold on the table where I was working until I changed out a circuit board.
The source strength if I remember correctly is on the order of 10 milliCuries. Compare that to the source strength we used in industrial radiography of 100 Curies of Iridium 192...and I still don't glow in the dark.
The source strength if I remember correctly is on the order of 10 milliCuries. Compare that to the source strength we used in industrial radiography of 100 Curies of Iridium 192...and I still don't glow in the dark.
As OG, Ron and I know, the use of the nuclear guage is quite safe - far too much is being made - regulations and Safety, I guess. I used the troxlers that you had to look up on a table And we all know that stop signs have some nuclear materials in the paint, eh?
The first ones I found on the commercial market were by Nuclear- Chicago. Then Troxler came along with what I termed a piece of junk compared to Nuclear Chicago's, but it was cheaper so they took over the market. Earlier ones were surface gages depending on back scatter. No rod into the ground for those.
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