ML051010314
| ML051010314 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 04/01/2005 |
| From: | Warren J Duke Energy Corp |
| To: | James Shea NRC/NRR/DLPM/LPD2 |
| SHea J, 415-1388, NRR/DLPM | |
| Shared Package | |
| ML051010310 | List: |
| References | |
| TAC MC6239, TAC MC6240 | |
| Download: ML051010314 (35) | |
Text
11 ASME Wall Tap Flow Nozzles for MUR Uprate McGuire Nuclear Station Huntersville, North Carolina McGuire Nuclear Station
22 Topics Q Purpose Q Background - why pursue this direction Q Description of ASME Nozzles at McGuire Q Commissioning the ASME Nozzles Q Nozzle Fouling Q DP Flow Measurement Uncertainty Q Operational Advantage of DP Flow Measurement Q Key Elements of DP Flow Measurement Q Moving Forward with DP Flow and MUR Uprate Q Questions, Comments and Open Discussion McGuire Nuclear Station
33 Q This meeting is a first step to explore the viability of use of ASME Nozzles for a MUR uprate at McGuire Nuclear Station.
Q If this concept is favorably received, Duke Power would be interested in pursuing use of ASME Nozzles at Oconee and Catawba Purpose
44 Background
Q Differential pressure based flow measurement has not been reviewed by the NRC for use as the primary flow meter in a MUR uprate 3/4South Texas (STP) included use of venturi based flow measurement when their Crossflow is out of service 3/4STP thermal power measurement uncertainty with venturi is ~1%
3/4EDF uses high Beta ratio orifices in test sections to calibrate venturis used for normal operation
55 ASME Nozzles at McGuire Q ASME nozzle flow metering sections were installed in Unit 1 (Winter 1996) and Unit 2 (Spring 1996) to provide feedwater flow inputs to thermal power calculation 3/4 Venturis had experienced upstream tap erosion 3/4 MWe decreases indicated that flow measurement could be in error Q Duke Power considers these flow meters to be suitable for implementation of a MUR uprate
66 ASME Nozzles at McGuire Q Flow meter section design and construction is per ASME requirements 3/4ASME MFC-3M-1989 3/4ASME Fluid Meters, Sixth Edition Q Refer to drawing handout
77 ASME Nozzles at McGuire
88 ASME Nozzles at McGuire Q Positive control of swirl and hydraulics entering the flow measurement section 3/4A Mitsubishi Plate Type flow straightener
- Eliminates swirl
- Allows restoration of fully developed flow profile in a relatively short length of pipe
99 ASME Nozzles at McGuire Q Positive control of swirl and hydraulics entering the flow measurement section 3/4The ID upstream and downstream of the nozzle element is honed
- Superior surface finish
- Superior circularity of the piping
- Superior axial alignment of the upstream/downstream piping with the nozzle axis
10 10 ASME Nozzles at McGuire Q Low beta ratio (~0.5) ASME nozzle elements that include both wall taps and throat taps for the low pressure measurement Q Four sets of wall taps and four sets of throat taps in each flow section Q The uncertainty of the wall tap and throat tap discharge coefficients is stated to be less than 0.1%
at 95% confidence by Alden Research Laboratory in the calibration report
11 11 ASME Nozzles at McGuire Q Corrosion resistant materials of construction throughout the flow sections 3/4Ensure stability of the beta ratio and geometry of tap edges over operating life 3/4Austenitic stainless steel
- Nozzle element and piping upstream and downstream 3/4Other parts are corrosion resistant Chrome-Moly, P11, material
12 12 ASME Nozzles at McGuire Figure excerpted from ASME Fluid Meters Their Theory and Application, 6th Ed.
Howard S. Bean editor, ASME ©1971
13 13 ASME Nozzles at McGuire Q The flow measurement for input to the thermal power calculation is derived from the wall taps Q Each wall tap and throat set share a common upstream pressure tap Q The throat taps are not instrumented at this time
14 14 ASME Nozzles at McGuire Wall taps were selected for flow measurement to avoid deleterious effects experienced by throat taps when fouling accumulation causes boundary layer changes that affect the pressure sensed by the throat tap
15 15 ASME Nozzles at McGuire Q Wall taps are considered to be insensitive to fouling effects 3/4 EPRI Report TR-101388, November 1992
- Two utilities reported use of wall tap nozzles without venturi fouling" effects 3/4 Low pressure wall tap is upstream of the nozzle discharge plane
- Chaotic eddy region where classic boundary layer flow should not exist
16 16 ASME Nozzle Commissioning Q For both McGuire units, placing the flow nozzles in service involved precision flow measurement during plant startup Q Flow was measured using wall taps and throat taps
17 17 ASME Nozzle Commissioning Q Flow measured by the wall taps was compared to that of the throat taps during power escalation 3/4Provide empirical confirmation that the extrapolation of the wall tap discharge coefficient to full power conditions was correct
- Greater emphasis in technical writings on the superior accuracy of ASME throat tap 3/4Wall tap measurement was shown to be within
~0.1% of the throat tap measurement
18 18 Fouling of Nozzles Q After one cycle of operation, one flow element was removed for visual inspection which revealed accumulation of a thin layer of fouling on the nozzle element Q Monitoring for the first few cycles following installation showed no tendency of the wall taps to be affected by fouling
19 19 DP Flow Measurement Uncertainty Q ASME, ANSI, ISO standards define:
3/4 Flow calculation methods using differential pressure producers 3/4 Method for determining uncertainty Q No proprietary information associated with:
3/4 Meter design 3/4 Flow calculation 3/4 Calibration process 3/4 Commissioning requirements
20 20 DP Flow Measurement Uncertainty Q Flow measurement inputs:
3/4Discharge coefficient 3/4Differential pressure 3/4Temperature of the flowing fluid
- Pressure also needed but small influence 3/4Beta ratio at cold conditions (pipe and nozzle diameters)
21 21 DP Flow Measurement Uncertainty Q Discharge coefficient 3/4The uncertainty of the discharge coefficient is derivable from laboratory calibration data and can be confirmed by comparison of wall tap to throat tap flows during commissioning testing 3/4Industry standards define requirements for acceptable calibration results and extrapolation methods
22 22 DP Flow Measurement Uncertainty Q Temperature and Differential Pressure 3/4Currently available technology provides very low measurement uncertainties 3/4Temperature sensor plus string accuracy ~0.8 ºF 3/4Differential pressure sensor plus string accuracy
~3.1 inches water (0.31% URL) 3/4Instrument strings are assumed to be digital
23 23 DP Flow Measurement Uncertainty Q Beta ratio at cold conditions (pipe and nozzle diameters) 3/4Measured by manufacturer 3/4Manufacturers QA program required to meet ANSI and purchasers requirements with traceability to NIST 3/4Fluid temperature measurement and thermal expansion curves impact influence of Beta ratio at operating conditions
24 24 DP Flow Measurement Uncertainty Q Use of redundant sensors and use of digital signal transmission from the sensors to the plant computer provides a large improvement in total uncertainty Q Redundancy in sensors also improves thermal power measurement uncertainty
25 25 DP Flow Measurement Uncertainty Q 2001 uprating study for Oconee showed total thermal power measurement uncertainty can be reduced to as low as 0.25% using flow nozzles 3/4FDW Flow ~0.22%
3/4FDW Enthalpy ~0.05%
3/4Steam Enthalpy ~0.06%
26 26 Operational Advantage of DP Flow Measurement Q DP based flow 3/4Based on mature processes and techniques for measurement 3/4From operational perspective, DP based flow is more robust than ultrasonic options
- Rapid response
- Flow profile is controlled for control of hydraulics in the measurement section 3/4No impact on Operations Staff
27 27 Key Elements of DP Based Flow for MUR Uprate Q Careful design and construction of differential pressure producer in accordance with standards Q Elimination of error associated with signal transmission hardware
28 28 Key Elements of DP Based Flow for MUR Uprate Q Calibration and commissioning testing 3/4 The independence of the wall taps and throat taps permits the throat tap measurement to be viewed as an in-situ calibration of the wall tap measurement Q Careful design of thermal power calculation to include redundancy in all inputs 3/4 Independence of inputs used by thermal power calculation and control system
29 29 Moving Forward with DP Flow and MUR Uprate Q Independent consultant to review McGuire nozzle design Q Development of requirements for submittal of DP based flow for MUR uprate Q Definition of additional actions to support McGuire MUR uprate submittal
30 30 Moving Forward with DP Flow and MUR Uprate Independent Consultant Richard W. Miller, Ph. D Served on US and international standards committees Holds several patents on flow measurement devices Authored several publications including Flow Measurement Engineering Handbook Recognized expert on flow measurement Dr. Millers initial impression of our objectives is positive and viewed as probably doable
31 31 Moving Forward with DP Flow and MUR Uprate Objective of Dr. Millers review will be to:
3/4Evaluate the nozzle calibrations 3/4Perform a literature review of fouling effects 3/4Identify mitigating strategies for fouling effects or other bias errors induced by operation 3/4Review and assist in development of uncertainty calculation for MUR uprate 3/4Develop/expand technical justification for use of ASME Wall Tap Nozzle for MUR uprate
32 32 Moving Forward with DP Flow and MUR Uprate Evaluation of actions in addition to Dr. Millers review to support the McGuire MUR uprate submittal 3/4Define necessary modifications and PMs to demonstrate health and condition of nozzles in support of MUR submittal 3/4Define special testing or data collection needs
33 33 NRC Expectations for Proving DP Based Flow for MUR Q How does Duke Power proceed in working with the NRC to develop justification for DP based flow with MUR uprate?
3/4RIS provides guidance for use of UFMs and MUR 3/4UFM vendors have provided Topical Reports to facilitate the MUR uprate review process
34 34 NRC Expectations for Proving DP Based Flow for MUR Q What are NRC expectations for this process and for this flow measurement option?
3/4Technical content of submittal 3/4Schedule for review 3/4Other concerns with respect to DP based flow measurement?
35 35 McGuire Nuclear Station Questions and Comments