Re: EPDs

["Sandy Perle" <sandyfl@ix.netcom.com>]

Mike's article regarding issues individuals should be cognizant about 
when using an EPD is a very timely document, and provides a 
significant amount of data analysis. Many HPs are attempting to use 
the EPD as an official dose of record, promarily in the nuclear power 
industry. Their reasons generally evolve around cost savings, 
however, they are in reality false savings. The staff to maintain an 
EPD program when all of the associated costs are included, far exceed 
other forms of dosimetry monitoring. Smoke and mirror budget tracking 
serves no real benefit to anyone. However, even if the cost savings 
were in fact valid, the technical issues in themselves are evidence 
enough that the data is flawed in many instances. To name a few 
issues that affect EPD data: Inability to measure low energy photons 
and most beta energies effectively (including no response for many 
energies), angular dependency issues, RF issues, loss of display in 
high temperature and humidity, loss of power in certain environments, 
dose rate dependency, internal parameters in the microprocessor that 
change in certain work environments, etc. The list is extensive.

While the NRC has remained quiet on the use of the EPD as an official 
dose of record, it is promising that organizations such as NEI 
(Nuclear Energy Institute) ANI (American Nuclear Insurers( and INPO 
(Institute for Nuclear Power Operations) have cautioned the industry 
to go slow, and not to use the EPD as a dose of record. There is too 
much data demonstrating inherent problems with the equipment. 

In summary, does it really make sense to remove a dosimeter that can 
respond accurately within 3 to 5% across an entire energy spectra 
with a dosimeter that is very limited? The only difference between an 
EPD and previous PIC dosimeters is that the precision is better, but 
would we really want to change current business practices? One other 
refreshing note, legal depts for nuclear power utilities have 
unaminously stated that the utility should NOT remove a TLD in favor 
of the EPD as the dose of record. With litigation and liability 
issues, any "pseudo cost savings" would be totally wiped out with one 
suit filed where the jury determines that a "good business decision" 
was not made when accurate and precise dosimetry was removed from 
occupational workers,,, solely to save a few bucks!

Sandy Perle
Director, Technical Operations
ICN Dosimetry Division
Office: (800) 548-5100 Ext. 2306 
Fax: (714) 668-3149

E-Mail: sandyfl@ix.netcom.com