We had Mirion perform a passive monitoring study at DCPP on our GEMS to prove the ability of the monitors to detect less than 1% of an ALI for an inhalation intake of a mixture of C0-60 and Cs-137. We also ratioed the impact from hard to detect (HTD) nuclides into the mixture that also resulted in the ability to detect less than 1% of an ALI. We follow up every two years or when parameters are changed.
Scott Stoffel Senior Engineer 119/1/123 (805) 545-4422 From: Powernet [mailto:[email protected]] On Behalf Of Nasser Rashidifard via Powernet Sent: Friday, October 11, 2019 8:02 AM To: [email protected] Cc: Nasser Rashidifard <[email protected]>; Jordan, H. Brandon <[email protected]> Subject: Re: [Powernet] Passive Monitoring *****CAUTION: This email was sent from an EXTERNAL source. Think before clicking links or opening attachments.***** Hi Michelle, Hope all is well. ANI Engineering Inspection Criteria Section 8.5 provides guidance on passive monitoring for gamma (GEM 5 or equivalent) and alpha/beta (ARGOS or equivalent) at RCA or PA boundaries. This is the big one and they specifically mention areas with potential for alpha. There is guidance on when to employs such as the DAC levels or potential for greater than 10 mrem CEDE, etc. With the setup you would need to establish some sort of sensitivity basis for the minimum detectable dose. We have done several of these types of evaluations, if you want to talk more in detail about the process let me know. Nasser Nasser Rashidifard, MS, CHP Supervisor of Technical Services Radiation Safety & Control Services Inc. 93 Ledge Rd, Seabrook NH, 03874 [email protected]<mailto:[email protected]> Office: 603-778-2871 x240 Direct: 603-474-6740 Cell: 781-856-2180 From: Powernet <[email protected]<mailto:[email protected]>> On Behalf Of Williams, Michelle Lewis via Powernet Sent: Thursday, October 10, 2019 08:21 To: [email protected]<mailto:[email protected]> Cc: Williams, Michelle Lewis <[email protected]<mailto:[email protected]>>; Jordan, H. Brandon <[email protected]<mailto:[email protected]>> Subject: [Powernet] Passive Monitoring In support of Vogtle Unit 3 and 4 construction we have been tasked with developing monitoring at temporary Protected Area Boundaries. We are looking for information on the standard practice for gamma monitoring at the Protected Area Boundary. We are trying to determine the need for this monitoring ,i.e. GEM 5s, and what specific regulatory guidance governs monitoring at the PA Boundaries. The only radioactive sources that will be on site during the time period in question will be new fuel and the sealed exempt sources in our RMS monitors. Any designated RCA areas will have will have monitoring upon exit. The time period will only be until fuel load into the vessel and at that time we will have full Protected Area monitoring in place. We would like to have any input from industry professionals with experience with this area. Thanks in advance for information and clarification on this issue. Regards, Michelle Williams RP Superintendent Support Services Plant Vogtle Units 1&2 706.848.4236 tel 919.770.7138 cell [southern_nucl_h_rgb]
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