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

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Mail Stop MG03A2
Huntersville, NC  28078
Office: 980-875-6893
Mobile: 803-627-4832




From: Voss, Tom [mailto:tv...@lanl.gov]
Sent: Thursday, August 10, 2017 10:19 AM
To: Powernet@hpspowernet.org
Cc: Mclean, Thomas Donaldson
Subject: [powernet] Questions on neutron detectors and calibration methods



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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

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