Chris, Palo Verde provides the following response:
We rely mostly on historical data and electronic dosimeter response characteristics relative to the radiation field. On this latter point, we did a lot of in-field testing with TLDs and EDs in a side-by-side configuration and since the vast majority of our actual in-plant conditions for operations and maintenance are in isotropic radiation fields, the selected bias gives us an excellent correlation. It's important to identify those situations in your plant where radiation sources create an anisotropic field. Typically for us (PWR) this is under the Pressurizer or Rx Head during inspections, or where the radiation is predominately from below. The response variation under anisotropic conditions will reveal that amount of angular dependence. Our dosimeters do not exhibit much until incident radiation angles are approximately 75° or more, at this point we see about a 15%-20% difference.. Typically, since the dosimeter is exposed from the all sides, top, bottom, and rear we expect about a 20% under-response and adjust the bias accordingly. Seth ********************************************************************** Seth J. Kanter, CHP, RRPT Sr. Health Physicist Palo Verde Nuclear Generating Station Mail Sta. 7397 5801 S. Wintersburg Rd. Tonopah, AZ 85354 Phone (623) 393-3130 Cell (602) 376-7131 or (602) 402-5764 Fax (623) 393-1853 Unless otherwise noted, all opinions are my own Liviu Librescu ********************************************************************** From: [email protected] [mailto:[email protected]] On Behalf Of Courtenay, Christopher C Sent: Wednesday, March 28, 2012 10:20 AM To: [email protected] Subject: Powernet: Electronic Dosimeter Basis for Bias Duke Energy would like to know what other utilities use as the basis for any bias applied to electronic dosimeters. We consider the following: · Overall station source term · Gamma spectroscopy results during outages · Historical data (particularly TLD/ED correlation) · ED response characteristics Are these similar to what everyone else looks (or looked previously) at? Anyone willing to share white papers or similar? Any and all responses are greatly appreciated. Thanks! Chris Courtenay Engineer, Duke Energy 980-875-5005 "To the optimist, the glass is half full. To the pessimist, the glass is half empty. To the engineer, the glass is twice as big as it needs to be." --- 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.
