ML072710599
| ML072710599 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs, Seabrook, Fort Calhoun  |
| Issue date: | 06/05/2006 |
| From: | Lyon W, John Nakoski NRC/NRO/DCIP/CQVB, NRC/NRR/ADES/DSS |
| To: | |
| References | |
| FOIA/PA-2007-0255 | |
| Download: ML072710599 (21) | |
Text
V1fw 6/
USE OF ULTRASONIC FLOW MEASUREMENT TO DETERMINE REACTOR POWER PURPOSE OF THIS PRESENTATION 4
To Inform the ET and the LT of the Status of the Staffs Review of the Application of Ultrasonic Flow Meters (UFMs) in Determining Reactor Power o
MEASURE FOR SUCCESS OF THIS PRESENTATION
+
ET and LT are Aware of Staff Activities
+
ET and LT are Advised of Potential Need for Regulatory Action to Address Deficiencies in the Application of UFMs PRESENTERS: Warren Lyon Presentation Date: June 8, 2006 1
BACKGROUND
/
UFMs Uses: Feedwater Flow Measurement for MURs, Power Recovery, and Venturi Calibration
,/
Appendix K to 10 CFR 50.46 Changed to Allow Decrease in 2% Uncertainty Assumption for Reactor Power Used in LOCA Analyses
/ !Currently, 2 UFM Devices Have Approved Topical Reports Caldon - Check and CheckPlus Westinghouse/AMAG - Crossflow 3
OVERVIEW
,/
Caldon Check and CheckPlus UFMs are Acceptable
/
Westinghouse/Advanced Measurement and Analysis Group (W/AMAG)
Review is Ongoing. Anticipated Staff Finding is Unacceptable
/7 Use of External UFMs for Power Recovery and Venturi Calibration Under 10 CFR 50.59 Has Not Been Shown to be Acceptable 4
PLANT-SPECIFIC STATUS - RECENT MUR LARs
/
Seabrook (Caldon) UFM is Acceptable (ML061360034, May 22, 2006)
".Calvert Cliffs (W/AMAG) is on Hold - an Amended LAR is Anticipated
/!
Ft. Calhoun (W/AMAG) is on Hold Pending Generic Review Completion 5
ACCEPTANCE CRITERIA Traceability - Relating a Measurement to a Standard Standard Maintained by a National Laboratory - National Institute of Standards and Technology (NIST)
Each Step Between Measurement and Standard - Clearly Defined and No Unverified Assumptions Unbroken Path Between Measurement and Standard
- *Total Measurement Uncertainty Reflects Aggregate Uncertainties of Each Step Applicability - Provide Accurate Information Over Range of Use Sound Basis (Theoretical Understanding or Equivalent)
Calibration is Constant or Change is Fully Understood, Predictable, and Verifiable 6
ACCEPTANCE CRITERIA ASSESSMENT
/
Caldon Check and Checkplus Meet All Criteria V
W/AMAG Crossflow Has Not Been Shown to Meet Criteria, but Staff Has Not Completed Review of All Submitted Information 7
CALDON CHECK AND CHECKPLUS ASSESSMENT Theoretical and Analytical Descriptions Cover All Test, Installation, and Operational Conditions Instrument Provides Complete Assessment of Hydraulic Conditions and Operation Within Uncertainty Bounds Every Instrument Tested at Alden Research Laboratory in a Full-scale Mockup of the Installation Configuration Over a Wide Range of Flow Rates Alden Research Laboratory Results are Controlled by NIST-Certified Standards. Test Flow Rate Uncertainty is Typically Approximately 0.1%
Seabrook Tests Included Deliberate. Introduction of Distorted Flow Profile Far Beyond What Would Be Anticipated in Plant 175 Tests with 2000 to 6000 Data Points per Test Were Run Worst Uncalibrated Checkplus Flow Rate Error Was < 0.5%
8
CALDON CHECK AND CHECKPLUS ASSESSMENT (con't)
Check and CheckPlus Provide the Velocity Profile Alden Flow Rates were less than Seabrook's and Tests were Conducted at Room Temperature Consequently, Reynolds Number was About a Factor of Five Less Than For Plant Operation Check and Checkplus Address this by Using Instrument Output that Is Consistent with Theoretical Considerations A Reynolds Number Extrapolation is Not Required Similar Tests Have Been Conducted for 35 CheckPlus and 9 Check UFM Flow Elements 9
CALDON CHECK AND CHECKPLUS ASSESSMENT (CONCLUSION)
V There is a Substantial Theoretical, Analytical, and Empirical Basis for Understanding How the Device Works
/7 There is Substantial Data That Supports Operation
/"
Meter Self-assessment Has Been Demonstrated V
There is an Unbroken Path from Calibration Used During Meter Operation to Reference Standards
/"
Check and CheckPlus UFMs Provide the Claimed Precision 10
W/AMAG CROSSFLOW ASSESSMENT Assessment is Continuing. The Following are Based on Material Reviewed to Date and, are Preliminary and Subject to Change.
Theoretical and Analytical Descriptions Do Not Cover Test, Installation, and Operational Conditions Crossflow Appears Unable to Provide Complete Assessment of Hydraulic Conditions Crossflow Tested at Full Scale Facility Only if Application Appears to Cause a Flow Profile That Differs from Previous Installations Generic Alden Data Agree to Better and No Unacceptable Research Laboratory Uncertainty of 0.25% is Used. If Test Within 0.25%, Then Claim is Made that One Cannot Do Further Test Data are Obtained. This is an Incorrect, Use of Statistics.
11
WIAMAG CROSSFLOW ASSESSMENT (con't)
Initial Full Scale Tests were Limited to What was Believed to Be Fully Developed Flow Conditions 8 Tests with 30 to 40 Data Points per Test Were Run 4 Tests were Later Rejected Essentially as Outliers. Still Later, W/AMAG Found the Reason for Poor Data was Noise Contamination.
Uncalibrated Crossflow Flow Rate Error was - 7%
Calibration Factor Obtained from These 4 Tests is Used as the Calibration for What W/AMAG Claims is "Stable Flow" 12
W/AMAG CROSSFLOW ASSESSMENT (con't)
An Additional Correction Factor is Obtained from Tests for Single and Multiple Elbows, and for a Few Plant-specific Configurations There are Sometimes Insufficient Data to Acceptably Substantiate the Claimed Representation. Further, W/AMAG Use of the 0.25% Uncertainty Argument to Claim Converged Conditions Have Been Achieved.
Further Tests Have Been Run at Facilities Other than Alden These are Claimed to Substantiate Crossflow Calibration. These Claims are Not Always Valid.
13
WVAMAG CROSSFLOW ASSESSMENT (con't)
Crossflow Provides a Representative Velocity along a Path That is Perpendicular to the Pipe Axis Velocity Location along the Path is Unknown Indicated Velocity is a Function of Velocity Profile, but Relationship has Not Been Demonstrated Correlation of Indicated Velocity to Flow Rate, and Hence Calibration, are Unknown Functions of Flow Profile Alden Test Data are at Room Temperature 14
a Reynolds Number is about a Factor of Five Less Than for Plant Operation 15
W/AMAG CROSSFLOW ASSESSMENT (con't)
"W/AMAG Extrapolates Reynolds Number to Obtain Plant Operation Characteristics This Appears to Break the Calibration Reference to a Standard a
Our Assessment of the Extrapolation Validity is Incomplete W/AMAG Assumes Alden Test Results and Calibration May Be Used Without an Uncertainty or Bias Impact When Crossfiow is Installed Consistent with Practice with Venturis 16
W/AMAG CROSSFLOW ASSESSMENT (con't)
Problems with In-Plant Installations:
Swirl Causes a Venturi to Over-predict Flow Rate but Causes Crossflow to Under-Predict Flow Rate Venturis are less Sensitive to Swirl than Crossflow There is No Proof the Installations are Identical Calibration is No Longer Referenced to a Standard 17
W/AMAG CROSSFLOW ASSESSMENT (con't)
Calvert Cliffs has Attempted to Bypass the Above Problems by Using Chemical Tracer Tests for Full Power Calibration in the Plant Ft. Calhoun is Using the Same Approach with Recently Calibrated Venturis These Appear to Be Acceptable but Uncertainty Has Not Been Determined
- 0 But the Calibration Applies Only at the Time of Calibration. Changes in Plant Conditions May Later Invalidate the Calibration.
18
WlAMAG CROSSFLOW ASSESSMENT (con't)-
W/AMAG Apply Multiple Procedures and Tests to Circumvent Crossflow Sensitivity and Inability to Independently Identify Flow Profile Changes 0
Power Level and Feedwater Configuration are Constrained to Fixed Limits Data are Compiled and Processed in Many Ways to Determine Acceptability Comparisons are Sometimes Made with All Other Available Plant Parameters that Provide Insight Staff is Continuing to Evaluate These Activities 19
W/AMAG CROSSFLOW ASSESSMENT (con't)
Potentially Effected Measurement Uncertainty Recapture Power Uprates:
Plant
% Uprate MWt I ncrease Salem '.&2 1.4 48 x 2 = 96 Hope Creek 1.4 46 SONGS 2&3 1.42 48 x 2 = 96 STP 1 &2 1.4 53 x 2 = 106 Plant
% Uprate MWt Increase
'Pilgrim 1.5 30 Hatch 1&2 1.4 48 x 2 =96 Kewaunee 1.4 23 Palisades 1.4 35.4 Total MWt increase from Use of Crossflow based MURs =
This equates to about 185 MWe Use of Crossflow for Power Recovery is Unknown 528 MWt 20
W/AMAG CROSSFLOW ASSESSMENT (CONCLUSION)
/
Theoretical, Analytical, and Understanding Basis is Weak
/
Empirical Data Basis is Weak
/r Meter Self-assessment Does Not Appear Viable An Unbroken Path from Calibration Used During Meter Operation to Reference Standards Has Not Been Achieved NRC-approved Topic Report is No Longer Valid
/
NRC Review is Nearing Completion Although Work Remains
,/
Regulatory Action May Be Required to Address the Use of Crossflow and Other External UFMs for MURs, Power Recovery, and Venturi Calibration Applications 21