ML16272A346
| ML16272A346 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 08/10/2016 |
| From: | Randy Hall Dominion |
| To: | Office of Nuclear Reactor Regulation |
| Benney B, NRR/DPR, 301-415-2767 | |
| Shared Package | |
| ML16209A375 | List: |
| References | |
| Download: ML16272A346 (6) | |
Text
Estimate of BADGER* System Uncertainty using Millstone Unit 1 Calibrations (2013)
R. A. Hall Dominion, Nuclear Engineering and Fuel 8/10/2016 NEI / NRC Meeting on NEI 16-03
- Boron-10 Areal Density Gauge for Evaluating Racks 1
Background Data 2013 Millstone Unit 1 BADGER campaign Non flux trap rack (single panel between cells)
Improved BADGER equipment Multiple B-10 calibration standards 0.0078, 0.0099, 0.0203, 0.0305, 0.0505 g B-10/cm2 AD Multiple independent calibrations (13) 2
Goal of Analysis Exercise Estimate BADGER uncertainty Use ONLY calibration data Standards have known B-10 content Determine uncertainty Use multiple measurements of standards Assess uncertainty for typical B-10 loading 0.0203 AD (Standard #3)
Estimate is not definitive, but is representative Goal is to better understand what to expect 3
Typical BADGER Process Collect calibration stand count rate (CR) data Multiple AD standards Calculate calibration transmission ratio (TR)
Absorber region CR / Unpoisoned region CR Construct calibration curve A function of areal density Determine interpolation method Measure in-rack TR Calculate measured AD using calibration curve 4
2013 Calibrations 0
10000 20000 30000 40000 50000 60000 70000 80000 90000 0
10 20 30 40 50 60 70 Total Counts (45 seconds count time)
Axial Position (Inches)
MP1 Typical BADGER Calibration Result CAL 3 DET 3 Unpoisoned region Outofrack Standard1 Standard2 5
Uncertainty Estimation Process Obtain Calibrations Non flux trap rack design (one absorber panel)
Each calibration TR is the average of 4 or 5 measured axial points on the AD standard 2 detectors Create calibration curves Average multiple measurements Independent curve for each detector Measure B-10 in known standard One value for each calibration measurement 0.0203 AD 6
Calibration Results 7
Calibration Curves 8
Standard #3 Measured B-10 AD (Detector 2) 9 Cal.#
Measured TR Measured B10AD Difference vs.Known 1
4.135 0.0165 19%
2 4.673 0.0203 0%
3 4.255 0.0173 15%
4 4.219 0.0171 16%
5 4.690 0.0205 1%
6 4.881 0.0219 8%
7 4.898 0.0221 9%
8 4.105 0.0163 20%
9 4.902 0.0221 9%
10 5.005 0.0229 13%
11 5.218 0.0246 21%
12 4.580 0.0196 3%
13 5.133 0.024 18%
Average 4.669 0.0203 0%
Standard #3 Measured B-10 AD (Detector 3) 10 Cal Measured TR Measured B10 Difference 1
4.090 0.017 16%
2 4.519 0.02 1%
3 4.152 0.0174 14%
4 4.138 0.0173 15%
5 4.604 0.0206 1%
6 4.784 0.022 8%
7 4.991 0.0236 16%
8 3.781 0.0149 27%
9 4.670 0.0211 4%
10 4.774 0.0219 8%
11 5.024 0.0238 17%
12 4.336 0.0187 8%
13 4.968 0.0234 15%
Average 4.526 0.02 1%
Conclusions Average of multiple independent measurements can be reliable Uncertainty of the average is reasonable Individual independent measurements reflect system measurement uncertainty Individual low measured B-10 values within the uncertainty of the measurement are not reliable indicators of B-10 loss Individual high measured B-10 values within the uncertainty of the measurement are not reliable indicators of B-10 gain System uncertainty will produce a distribution of results, even for pristine absorber material If low uncertainty is required, multiple independent measurements are needed.
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