ML072710590
| ML072710590 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs, Seabrook, Fort Calhoun  |
| Issue date: | 06/01/2006 |
| From: | - No Known Affiliation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| FOIA/PA-2007-0255 | |
| Download: ML072710590 (10) | |
Text
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Junel, 2006 ET/LT BRIEF ON THE STATUS OF THE MEASUREMENT UNCERTAINTY RECAPTURE (MUR) ISSUE JUNE 8, 2006
- GENERIC STATUS STAFF FOUND CALDON CHECK AND CHECKPLUS ACCEPTABLE (ML??, JUNE ??, 2006)
WESTINGHOUSE / ADVANCED MEASUREMENT AND ANALYSIS GROUP (W/AMAG)
REVIEW IS ONGOING. ANTICIPATED STAFF FINDING IS UNACCEPTABLE WE ANTICIPATE FINDING THAT USE OF EXTERNAL UFMs FOR POWER RECOVERY UNDER 50.59 HAS NOT BEEN DEMONSTRATED ACCEPTABLE AND THAT THIS APPLICATION IS AN UNACCEPTABLE USE OF 50.59 PLANT-SPECIFIC STATUS - RECENT LARs STAFF FOUND SEABROOK (CALDON) UFM 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
ACCEPTANCE CRITERIA TRACEABILITY - THE PROCESS WHEREBY A MEASUREMENT IS RELATED TO A STANDARD USUALLY A STANDARD MAINTAINED BY A NATIONAL LABORATORY SUCH AS THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY (NIST)
EACH STEP BETWEEN MEASUREMENT AND STANDARD MUST BE CLEARLY DEFINED AND CAN CONTAIN NO UNVERIFIED ASSUMPTIONS STEPS MUST PROVIDE AN UNBROKEN PATH BETWEEN MEASUREMENT AND STANDARD TOTAL MEASUREMENT UNCERTAINTY MUST REFLECT AGGREGATE UNCERTAINTIES OF EACH STEP ACCEPTANCE CRITERIA (CONTINUED)
APPLICABILITY - INSTRUMENT MUST PROVIDE ACCURATE INFORMATION OVER THE RANGE OF USE
- SOUND BASIS (THEORETICAL UNDERSTANDING OR EQUIVALENT)
- CALIBRATION IS CONSTANT OR ANY CHANGE IS FULLY UNDERSTOOD, PREDICTABLE, AND VERIFIABLE ASSESSMENT
- CALDON CHECK AND CHECKPLUS MEET ALL CRITERIA
- W/AMAG CROSSFLOW HAS NOT BEEN SHOWN TO MEET ANY CRITERIA BUT WE HAVE NOT COMPLETED REVIEW OF ALL SUBMITTED INFORMATION
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 IS 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 TYPICALLY < 0.1%.
CALDON CHECK AND CHECKPLUS ASSESSMENT (CONTINUED)
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 THE WORST UNCALIBRATED CHECKPLUS FLOW RATE ERROR WAS < 0.5%
CALDON CHECK AND CHECKPLUS ASSESSMENT (CONTINUED)
CHECKPLUS PROVIDES AVERAGE VELOCITY IN FOUR PATHS IN EACH OF TWO PLANES PATH LOCATIONS CORRESPOND TO GAUSS QUADRATURE FORMULA AND IS EQUIVALENT TO INTEGRATION OVER 7TH ORDER POLYNOMIAL APPROXIMATION CHECKPLUS OUTPUT INFORMATION FOR 55% SWIRL TEST:
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° CHECKPLUS PROVIDES THE FLOW PROFILE INADDITION TO FLOW RATE
CALDON CHECK AND CHECKPLUS ASSESSMENT (CONTINUED)
ALDEN LABORATORY FLOW RATES WERE LESS THAN SEABROOK'S TEMPERATURES WERE ROOM TEMPERATURE TEST DATA ARE FOR REYNOLDS NUMBER ABOUT A FACTOR OF FIVE LESS THAN FOR PLANT OPERATION CALDON ADDRESSES THIS VIA "FLATNESS RATIO," THE AVERAGE AXIAL VELOCITIES AT THE OUTSIDE CHORDS DIVIDED BY THE AVERAGE AT THE INSIDE CHORDS
CALDON CHECK AND CHECKPLUS ASSESSMENT (CONTINUED)
SEABROOK TESTS PROVIDED:
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THEORETICAL EQUATION AND DATA FIT ARE ALMOST IDENTICAL OPERATION AT SEABROOK IS EXPECTED TO BE BOUNDED BY THESE DATA SIMILAR TESTS HAVE BEEN CONDUCTED FOR 35 CHECKPLUS AND 9 CHECK UFM FLOW ELEMENTS
CALDON CHECK AND CHECKPLUS ASSESSMENT (CONCLUSION)
THERE IS A SUBSTANTIAL THEORETICAL, ANALYTICAL, AND UNDERSTANDING BASIS THERE IS SUBSTANTIAL DATA THAT SUPPORTS OPERATION METER SELF-ASSESSMENT HAS BEEN DEMONSTRATED THERE IS AN UNBROKEN PATH FROM CALIBRATION USED DURING METER OPERATION TO REFERENCE STANDARDS THE CHECK AND CHECKPLUS UFMs PROVIDE THE CLAIMED PRECISION 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 TO BE INCAPABLE OF PROVIDING COMPLETE ASSESSMENT OF HYDRAULIC CONDITIONS CROSSFLOW IS TESTED AT FULL SCALE FACILITY ONLY IF APPLICATION APPEARS TO CAUSE A FLOW PROFILE THAT DIFFERS FROM PREVIOUS INSTALLATIONS GENERIC ALDEN RESEARCH LABORATORY UNCERTAINTY OF 0.25% IS USED.
IF TEST DATA AGREE TO WITHIN 0.25%, THEN CLAIM IS MADE THAT ONE CANNOT DO BETTER AND NO FURTHER TEST DATA ARE OBTAINED. THIS IS AN INCORRECT, UNACCEPTABLE USE OF STATISTICS.
W/AMAG CROSSFLOW ASSESSMENT (CONTINUED)
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.
THE UNCALIBRATED CROSSFLOW FLOW RATE ERROR WAS - 7%
CALIBRATION FACTOR OBTAINED FROM THESE 4 TESTS IS USED AS THE CALIBRATION FOR WHAT W/AMAG CLAIM IS "STABLE FLOW" W/AMAG CROSSFLOW ASSESSMENT (CONTINUED)
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 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.
W/AMAG CROSSFLOW ASSESSMENT (CONTINUED)
CROSSFLOW PROVIDES A REPRESENTATIVE VELOCITY ALONG A PATH THAT IS PERPENDICULAR TO THE PIPE AXIS VELOCITY LOCATION ALONG THE PATH IS UNKNOWN INDICATED VELOCITY MAY BE A FUNCTION OF VELOCITY PROFILE CORRELATION OF INDICATED VELOCITY TO FLOW RATE, AND HENCE CALIBRATION, ARE UNKNOWN FUNCTIONS OF FLOW PROFILE
W/AMAG CROSSFLOW ASSESSMENT (CONTINUED)
ALDEN TEST DATA ARE AT ROOM TEMPERATURE REYNOLDS NUMBER IS ABOUT A FACTOR OF FIVE LESS THAN FOR PLANT OPERATION W/AMAG EXTRAPOLATES REYNOLDS NUMBER TO OBTAIN PLANT OPERATION CHARACTERISTICS THIS APPEARS TO BREAK THE CALIBRATION REFERENCE TO A STANDARD OUR ASSESSMENT OF THE EXTRAPOLATION VALIDITY IS INCOMPLETE W/AMAG CROSSFLOW ASSESSMENT (CONTINUED)
W/AMAG ASSUMES ALDEN TEST RESULTS AND CALIBRATION MAY BE USED WITHOUT AN UNCERTAINTY OR BIAS IMPACT WHEN CROSSFLOW IS INSTALLED CONSISTENT WITH PRACTICE WITH VENTURIS THIS IS UNACCEPTABLE:
- 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 THE CALIBRATION IS NO LONGER REFERENCED TO A STANDARD W/AMAG CROSSFLOW ASSESSMENT (CONTINUED)
CALVERT CLIFFS HAS ATTEMPTED TO BYPASS THE ABOVE PROBLEM 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 BUT THE CALIBRATION APPLIES ONLY AT THE TIME OF CALIBRATION.
CHANGES IN PLANT CONDITION MAY LATER INVALIDATE THE CALIBRATION.
W/AMAG CROSSFLOW ASSESSMENT (CONTINUED)
W/AMAG APPLY MULTIPLE PROCEDURES AND TESTS TO CIRCUMVENT CROSSFLOW SENSITIVITY AND INABILITY TO INDEPENDENTLY IDENTIFY FLOW PROFILE CHANGES 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 WE ARE CONTINUING TO EVALUATE THESE ACTIVITIES W/AMAG CROSSFLOW ASSESSMENT (CONCLUSION)
THE THEORETICAL, ANALYTICAL, AND UNDERSTANDING BASIS IS WEAK THE DATA BASIS IS WEAK METER SELF-ASSESSMENT DOES NOT APPEAR VIABLE AN UNBROKEN PATH FROM CALIBRATION USED DURING METER OPERATION TO REFERENCE STANDARDS HAS NOT BEEN ACHIEVED THE NRC-APPROVED TOPIC REPORTS ARE NO LONGER VALID NRC REVIEW IS IN THE CLOSING PHASE ALTHOUGH MUCH WORK REMAINS