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Re: EPDs for personnel monitoring and surveys
Steve,
Since January 10, 1996 all radiography cameras in use in NRC space and in most Agreement States must meet performance requirements for radiography equipment. Specifically, they must meet ANSI N423-1980. To wit, they must have a "lock box" and mechanism to lock the source in the device when it is cranked in. This includes a signaling device to indicate source position. They also have to meet a bunch of other requirements. (See 10 CFR Part 34.20)
This is all neat stuff but nothing replaces the survey meter and a good survey.
Jim
>>> steve hand <hand@wam.umd.edu> 01/22 1:48 PM >>>
Why do radiographic devices not have an interlock that either signals the operator that the source is shielded (not out), for example similar to an X-ray shutter, or that the source is in a safe position ? Is there no way to build into the unit any type of visual or audible warning that the source is still out ?
steve hand
radiation safety
university of maryland
James Myers wrote:
> Sandy,
>
> Don't forget those fellas in Alaska who had the EPD under their "layered" clothing......
>
> Wes is also correct that several of the states, among others, were against the mandated use of EPDs in radiography based on their regulatory experience. Manditory certification of radiographers has had more positive impact on the safety. Also, the requirement for two person crews has also provided an improvement in safety. In my experience we have come a long, long way in radiograpy safety thanks to these requirements.
>
> Comment: To me, isotopic radiography is a lot like handling guns. Its always the "unloaded" one that gets you. Visually inspecting a gun to assure that the chamber is clear, the magazine out and weapon on "safe" EVERY TIME YOU PICK IT UP is the best technique to assure that the gun is safe. After that, treat it as if it IS LOADED. In radiograpy the analogy is the survey of the device before handling it and after every "shot." Always treat a camera as if the source is out.....unless you absolutely know for sure, positively the source is in a safe position...assume nothing.
>
> EPDs can also produce a "lulling" effect. Since they go off from time to time when the source is out during use, the radiographer may tune them out and disregard a real emergency. (Now take this self test.....did you really hear that key in ignition and seat belt buzzer in your car when you fired up this morning???? How about all those lights on the dash....did they all come on or could one of them, just maybe... been out? Nothing critical...just the oil pressure light..... Now that I've reminded everone they will listen and look next time..... :) )
>
> EPDs are like gunshots By the time you hear it (if you do!) there's probably already damage. Yep! that "report" just told me the bullet is now down range or worse.....
>
>
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information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html