And then there is the benefit of comparing ED to your Dose of Record dosimeter.
----------------------------------- Sander C. Perle President Mirion Technologies Dosimetry Services Division 2652 McGaw Avenue Irvine, CA 92614 +1 (949) 296-2306 (Office) +1 (949) 296-1130 (Fax) Mirion Technologies: http://www.mirion.com/ "Protecting people, property and the environment" From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: Tuesday, December 20, 2011 12:16 PM To: [email protected] Subject: RE: Powernet: Tracking electronic dosimeter dose to tenths? Palo Verde displays electronic dosimeter dose in tenths of mrem. For us there are some ALARA benefit for displaying the 1/10 of a mrem. First, we use the 1/10 of a mrem chirp feature; therefore, the worker has an audible and visual indication of accumulated dose. Secondly, during the Sentinel Access Control system log out radworkers get a visual display of total dose (in tenths) plus maximum dose rate. Without the tenth display, if they get 4/10s of a mrem, the dosimeter will display 0 mrem; however, if the max rate field is populated, e.g., 10 mR/hr, they think that the small fraction of dose received is being ignored regardless of the fact that the system will truncate it and report a zero. With the tenths on, they will see 0.4 mrem for the entry. This may be more of a PR issue rather than an ALARA one, but the workers like the fidelity between recorded and indicated dose. Note, when you use the tenths display the dose alarm will not occur until the entire value is reached. For example, if the dose alarm is set to 25 mrem and you use tenths, a display of 24.9 will not give you a dose alarm. It will not alarm until it gets to 25.0 mrem. Without the tenths display, when the dose reaches 24.5 the displayed value will be 25 mrem (you would still have to accumulate the other 0.5 mrem to reach the alarm), but if a worker is looking at their dose and they see 25, they may question the ED operation. Seth From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: Tuesday, December 20, 2011 11:55 AM To: [email protected] Subject: Powernet: Tracking electronic dosimeter dose to tenths? San Onofre currently tracks electronic dosimeter dose to integer mrem (a deliberate decision when we implemented the MGPI DMC-2000S dosimeters). We understand that some plants track dose to tenths of an mrem. Reportedly, there is an ALARA benefit for this additional precision. I have two questions: How many plants/fleets are tracking ED dose to tenths of a mrem? How does such precision impact ALARA performance? In other words, what worker behaviors change when a worker sees 4.4 mrem instead of 4, or 4.7 mrem instead of 5? Thanks and Happy Holidays from sunny (today) California, Eric Eric M. Goldin, CHP Southern California Edison <[email protected]<mailto:[email protected]>> ----------------------------------- Powernet - a service of the Health Physics Society Power Reactor Section Powernet archives at http://www.mail-archive.com/[email protected]/ Reply to: [email protected]<mailto:[email protected]> If Questions, contact Mike Russell, CHP at [email protected]<mailto:[email protected]> --- NOTICE --- This message is for the designated recipient only and may contain confidential, privileged or proprietary information. If you have received it in error, please notify the sender immediately and delete the original and any copy or printout. Unintended recipients are prohibited from making any other use of this e-mail. Although we have taken reasonable precautions to ensure no viruses are present in this e-mail, we accept no liability for any loss or damage arising from the use of this e-mail or attachments, or for any delay or errors or omissions in the contents which result from e-mail transmission.
