Tom, I can answer the instrument detector portion of this. Someone else in Duke Energy will have to answer the dosimetry part. See answers below: Which are the most typical types (models) of neutron detectors being used by your organization ?
· Duke Energy uses Ludlum 12-4 survey meter with a 9-Inch moderated neutron detector (Ludlum Model 42-31H) using a He-3 detector · The answer is the same for 6 sites 11 reactors. Which are the most typical types (models) of neutron DOSIMETERS being used by your organization? · Duke Energy Fleet Dosimetry group will need to answer dosimetry question. What is a typical uncertainty in the calibration of neutron detectors and neutron dosimeters ? · Duke Energy neutron detectors are currently calibrated by Ludlum Measurements using a moderated Cf-252 source to +10% tolerance. · Duke Energy Fleet Dosimetry group will need to answer the dosimetry portion of this question. Which regulations drive the requirements to calibrate neutron detectors ? · Previously ANSI N323-1997 currently swapping over to ANSI N323AB - 2013. This regulation does allow for wider tolerance than +10% currently used. Per ANSI N323AB - 2013: 5.2.2 Neutron dose equivalent instruments Instruments designed to read out in units of neutron dose equivalent or dose equivalent rate shall be calibrated as in 5.2.1.1 through 5.2.1.2; except that the calibration accuracy shall be ±x of the CTV for the following ranges: a) 0 to 100 μSv/h or 0 to 100 μSv (0 to 10 mrem/h or 0 to 10 mrem); ±x = ±30% b) 100 μSv/h or 100 μSv (10 mrem/h or 10 mrem) and above; ±x = ±20% · RP Instrument calibrations are also, tied to 10CFR20 regulations for meeting survey and posting requirements as well as INPO 05-008. Which national/international calibration laboratory accreditation organization is followed ? · Duke Energy Central Calibration Facility for instrument detector calibration is not part of any calibration laboratory accreditation program (our recent poll of the industry found this to be typical in the industry). · Ludlum Measurements does state that they have American Association for Laboratory Accreditation (A2LA) accreditation. · Duke Energy Fleet Dosimetry group will need to answer the dosimetry portion of this question. Thanks, Bill Faulkenberry, NRRPT Supervising Scientist, EnRad Labs Duke Energy [EnRad Logo.jpg] 13339 Hagers Ferry Rd Mail Stop MG03A2 Huntersville, NC 28078 Office: 980-875-6893 Mobile: 803-627-4832 From: Voss, Tom [mailto:[email protected]] Sent: Thursday, August 10, 2017 10:19 AM To: [email protected] Cc: Mclean, Thomas Donaldson Subject: [powernet] Questions on neutron detectors and calibration methods *** Exercise caution. This is an EXTERNAL email. DO NOT open attachments or click links from unknown senders or unexpected email. *** Hello All I am looking for input on neutron detectors used by yourself and the calibration methods for those neutron detectors. This may provide us with an idea of the consistency of our neutron measurement techniques. I have 5 questions but please do provide more input where needed. The tabulation after the questions is nowhere near complete so please add to that. Which are the most typical types (models) of neutron detectors being used by your organization ? Which are the most typical types (models) of neutron DOSIMETERS being used by your organization? What is a typical uncertainty in the calibration of neutron detectors and neutron dosimeters ? Which regulations drive the requirements to calibrate neutron detectors ? Which national/international calibration laboratory accreditation organization is followed ? Neutron Detectors Gas filled such as HPI Rem 500 Fuji NSN3 Liquid such as BTI Bubble NE213 Solid such as Polyethylene Moderated Lithium-doped glass Neutron spectrometers Neutron Dosimeters CR-39 Thermoluminescent albedo dosimeters Bubble dosimeters Instrument Calibration Methods NIST traceable Radioactive sources DD and DT generators Transfer instruments First Principles Exposure in a well-characterized operating nuclear reactor Typical isotopes used for neutron detection helium-3, lithium-6, boron-10, and uranium-235 best regards Tom James Tom Voss, NRRPT, CHP
