Yes, Humboldt Bay uses attenuation factors. For smears, we had a number of technicians perform smears of alpha contaminated areas and we compared their results to a gamma spec result (60Kev gamma from Am-241, then ratio to Pu-239). IF, they did everything right, no moisture on the smear, no oils, smearing an area of only 100 cm2 rather than a much larger area, etc, we determine a self absorption factor of approximately 1.7. So we add a self absorption factor of 2 into each instruments efficiency calibration. For air samples, we use filter paper calibration standards and use that value for the efficiency calbration.
John Albers Radiation Protection Manager Humboldt Bay Power Plant Pacific Gas and Electric Company 1000 King Salmon Road Eureka CA 707-499-7613 (cell) From: [email protected] [mailto:[email protected]] On Behalf Of Rouse, Raymond Lawrence Sent: Monday, January 23, 2012 7:56 AM To: [email protected] Subject: Powernet: Attenuation factors for alpha Does your facility use an attenuation factor for alpha contamination. Do you use this for air samples, smears or both? If so what factor do you use? What basis from which the factor came from? Raymond Rouse Radiation Protection ALARA Superintendent Watts Bar Nuclear Plant PO Box 2000 Spring City, Tn 37381 (423)-365-1881 [email protected]<mailto:[email protected]>
