We have a procedure that says:
Beta-gamma contamination activity in dpm/100cm2 may be estimated assuming a constant dpm/100cm2 per mrad/hr conversion factor with RC Supervisor concurrence. Reference 2.7 uses 28,000 dpm/100cm2 per mrad/hr after application of a beta correction factor. Use 100,000 dpm/100 cm2 per mrad/hr for uncorrected activity values. Our number came from a benchmark of another utility but the 28,000 dpm has been verified to be reasonable based on several smears counted at my facility (RO-2 and a L-177/44-9). From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: Tuesday, September 27, 2011 5:15 PM To: [email protected] Cc: [email protected] Subject: Powernet: Off Scale Count Rate Instrument Rules of Thumb Palo Verde requests information on the following: If a count rate instrument's reading exceeds the measurement capability (i.e., off-scale), do you use or have a thumb rule to convert dpm to mrad? I have seen some mrad to dpm conversions such as 25,000, 28,000, and 50,000 dpm per mrad; however, I have not seen any technical justification or limitations for these thumb rules. If you have such guidance in your program what value do you use? Do you have any precautions or limitations for the thumb rule usage, e.g., qualitative measurement only, specified measurement height above smears, etc. Thanks, 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 Fax (623) 393-1853 Unless otherwise noted, all opinions are my own Liviu Librescu ********************************************************************** --- 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. ________________________________ This e-mail contains Omaha Public Power District's confidential and proprietary information and is for use only by the intended recipient. Unless explicitly stated otherwise, this e-mail is not a contract offer, amendment, or acceptance. If you are not the intended recipient you are notified that disclosing, copying, distributing or taking any action in reliance on the contents of this information is strictly prohibited.
