Fred, Thank you for the reply. I have a follow-up and clarification for question 2. The question was NOT whether the alarm was "Valid", the question was how you would count it (unanticipated or anticipated).
For a more extreme example, consider the following. if you briefed an employee to expect a dose rate alarm; the dose rate alarm set point was 100 mR/hr; and you expected the person to encounter 125 mR/hr briefly. The person does receive an alarm, as expected. However, after the fact, you determine from the ED histogram that person encountered an actual dose of 950 mR/hr. Would you consider that alarm be "anticipated" or "unanticipated". If, in the above example, you counted the dose rate alarm as "unanticipated" since the dose rate encountered was much greater than expected, at what point would you draw the line for when it goes from anticipated (expected conditions) to unanticipated (unexpected conditions)? That is the question. Thanks again four your reply. Graham From: [email protected] [mailto:[email protected]] On Behalf Of ROSSER, FREDERICK W Sent: Thursday, April 25, 2013 11:00 AM To: [email protected] Subject: Powernet: RE: Unanticipated Dose Rate Alarm Metric (KPI) Grand Gulf Nuclear Station reply 1.This would be classified as a human performance error and treated as such. We would document a condition report to document the circumstances but we would not count it for the PI. Documentation would be used when the NRC or others look at the alarm report. 2. We do not use a band. If the alarm is set at 100 and they get to 100.1, it's a valid alarm. Fred Rosser Radiation Protection Supervisor Grand Gulf Nuclear Station 601 437-6571 From: [email protected]<mailto:[email protected]> [mailto:[email protected]] On Behalf Of Johnson, Graham T Sent: Thursday, April 25, 2013 6:23 AM To: [email protected]<mailto:[email protected]> Subject: Powernet: Unanticipated Dose Rate Alarm Metric (KPI) Duke Energy would appreciate answers to the following questions regarding counting dose rate alarms as anticipated or unanticipated in your site metrics. 1) Scenario: An employee is briefed to expect a dose a rates of between 75 -150 mR/hr in route to a work area. The RWP/Task dose rate alarm setpoint is 75 mR/hr and the employee is briefed to anticipate a dose rate alarm. The employee logs onto the wrong RWP Task and receives a dose rate alarm at 12 mR/hr because he is on the wrong task. The actual dose rates encountered were as briefed. Would you count this as an unanticipated dose rate alarm? 2) Does your site have an acceptance band for variations in briefed dose rate alarms versus actual dose rates encountered and if so, what is the band? For example, if a worker is briefed to receive an anticipated a dose rate alarm of 100 mR/hr, is there a range above 100 that would be acceptable and then a point at which alarm would be called unanticipated? (e.g., if the band was +/- 25%, then 120 mR/hr would be an anticipated alarm but 130 mR/hr would be called an unanticipated alarm.) Thanks, Graham Johnson, CHP Supervising Scientist General Office Radiation Protection Duke Energy
