ML072710663
| ML072710663 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs, Byron, Braidwood, Fort Calhoun  |
| Issue date: | 06/06/2006 |
| From: | Lyon W, John Nakoski NRC/NRO/DCIP/CQVB, NRC/NRR/ADES/DSS |
| To: | |
| References | |
| FOIA/PA-2007-0255 | |
| Download: ML072710663 (12) | |
Text
WLA/ýi[ Or'A USE OF ULTRASONIC FLOW MEASUREMENT TO DETERMINE REACTOR POWER
-PURPOSE OF THIS PRESENTATION.
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 MEASURE FOR SUCCESS OF THIS PRESENTATION
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ET and LT are aware of staff activities
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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
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BACKGROUND
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UFMs uses: Feedwater flow measurement for MURs and power recovery v/ Appendix K to 10 CFR 50.46 changed to allow decrease in 2% uncertainty assumption for reactor power used in LOCA analyses V
Importance is tied to compliance with the licensed thermal power upon which accident and transient analyses are conducted V
Currently, 2 UFM devices have approved topical reports Caldon - Check and CheckPlus Westinghouse/AMAG - Crossflow 3
CROSSFLOW UFM HISTORY 1999 Generic Crossflow UFM topical report approved. Licensees beging requesting MURs January 2003 - Byron/Braidwood operating above rated thermal power (RTP). Region III requests NRR assistance on review of allegation related to Crossflow application at Byron/Braidwood.
July 2003 - Ft. Calhoun submits first MUR LAR based on Crossflow August 2003 - Byron/Braidwood reduce power, staff begins assessment of basis for operating above RTP. Power recovery application of Crossflow UFM.
January 2004 - NRC approves Ft. Calhoun MUR LAR February 2004 - NRC establishes task group to review UFMs May 2004 - Ft. Calhoun licensed RTP returned to pre-MUR level July 2004 - NRC task group identifies issues and recommends actions.
January 2005, Calvert Cliffs and March 2005, Ft. Calhoun submit MUR LARs based on Crossflow August 2005 - Westinghouse, Calvert Cliffs, & Ft. Calhoun provided issues related to Crossflow 4
CROSSFLOW UFM HISTORY (con't)
September 2005 - New issue identified with Crossflow use at Calvert Cliffs. Swirl in feedwater flow adversely affects Crossflow measurement.
October 2005 - Staff places Calvert Cliffs and Ft. Calhoun MUR reviews on hold October 2005 to January 2006 - Calvert Cliffs, Ft. Calhoun, W/AMAG, Owners Group, & NRC continue interactions on issue resolution. NRC obze.es tracer testing at Calvert Cliffs.
February 2006 - NRR staff completes theoretical assessment of Crossflow uncertainty claim.
Additional RAIs provided to W/AMAG March 2006 - NRC & W/AMAG meet to discuss RAI responses April 2006 - NRC provides detailed RAls on issues that must be resolved for use of Crossflow.
NRR issues User's Need memo to RES to peer review theoretical assessment. W/AMAG describe model being developed that confirms original bases. Staff informs W/AMAG of schedule for and issues to be resolved for completion of reviews.
May 2006 - RES provides response to NRR User's Need memo. RES substantiated NRR position that Crossflow does not obtain sufficient information to support uncertainty analyses.
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June 2006 - W/AMAG provide additional information on theoretical and empirical bases for Crossflow uncertainty claim.
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OVERVIEW Caldon Check and CheckPlus UFMs are acceptable Westinghouse/Advanced Measurement and Analysis Group (W/AMAG) review is ongoing. Anticipated staff finding is unacceptable. RES supports NRR position on capability of Crossflow UFM.
Use of external UFMs for power recovery under 10 CFR 50.59 has not been shown to be acceptable 6
PLANT-SPECIFIC STATUS - RECENT MUR LARs
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Seabrook (Caldon) UFM is acceptable (ML061360034, May 22, 2006)
V Calvert Cliffs (W/AMAG) is on hold - an amended LAR is anticipated V
Ft. Calhoun (W/AMAG) is on hold pending generic review completion 7
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 8
ACCEPTANCE CRITERIA ASSESSMENT V
Caldon Check and Checkplus meet all criteria
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VW/AMAG Crossflow has not been shown to meet criteria, but staff has not completed review of all submitted information 9
Ultrasonic Flow Meter Comparison Caldon Check & CheckPlus W/AMAG Crossflow m
rn I~.A M -7.7; 1-IJ
.LL
- 1 4:.
,4:
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- W/AMAG CROSSFLOW REGULATORY IMPACT Potentially effected measurement uncertainty recapture power uprates:
Plant
% Uprate MWt 1
Increase Salem 1&,
8 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 = 528 MWt This equates to about 185 MWe Regulatory impact from the use of Crossflow for power recovery has not been fully assessed 11
W/AMAG CROSSFLOW CONCLUSIONS
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Theoretical, analytical, and understanding basis is weak
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Empirical data basis is weak
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Meter self-assessment does not appear viable S"'An unbroken path from calibration used during meter operation to reference standards has not been achieved
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NRC-approved topic report is no longer valid
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NRC review is nearing completion although work remains
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Regulatory action may be required to address the use of Crossflow and other external UFMs for MURs and power recovery applications 12