Re[2]: RF Interference of GM Instruments ** AND EPDs

[sandy_perle@email.fpl.com]

     Electronic Dosimetry is also affected by electromagnetic interference. 
     Field use as well as laboratory testing has validated this. Here are a 
     few excerpts form NUREG/CR-6354 "Performance Testing of Electronic 
     Personal Dosimeters"
     
     "Permanence of record is an issue with the EPD since electronic 
     failure could lead to loss of data. Many EPDs periodically write the 
     dose data to a nonvolatile EEPROM memory. Transfer of data on the 
     Siemen's unit occurs every 15 minutes."  The proposed standard 
     therefore recommends that the write be performed every 15 minutes, 
     since most vendors are setup as such. If the EPD is only used as a 
     dosimeter for estimation of dose until the primary dosimeter is 
     processed, no problem. The issue arises when the facility decides to 
     use the EPD as a "primary dose of record" and the potential to lose 
     dose exists, as allowed by the Standard. This should not be 
     acceptable.
     
     " Susceptibility of the EPD to electromagnetic interference (e.g., 
     r.f. emissions) is a common problem and virtually impossible to 
     eliminate in intense fields such as pulsed radar or radio/TV 
     transmitters. In some cases manufacturing mistakes have led to 
     increased susceptibility."
     
     My philosophy is that when one understands the electromagnetic 
     interference capabilities of the instrumentation being used for 
     conducting surveys, they can be handled. It is a far different story 
     when the same technology interferes with a "dose of record" 
     instrument, and, the loss of record dose is possible and condoned, all 
     at the same time.
     
     Sandy Perle
     Supervisor Health Physics
     Florida Power and Light Company
     Nuclear Division
     
     (407) 694-4219 Office
     (407) 694-3706 Fax
     
     sandy_perle@email.fpl.com