ML20212B736
| ML20212B736 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 10/21/1997 |
| From: | Kennedy J NRC (Affiliation Not Assigned) |
| To: | Cottle W HOUSTON LIGHTING & POWER CO. |
| References | |
| TAC-M99245, TAC-M99246, NUDOCS 9710280185 | |
| Download: ML20212B736 (5) | |
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October 21, 1997 Mr. William T. Cott'le
. Executive Vice-President &
General Manager, Nuclear Houston Lighting & Power Company South Texas Project Electric Generating Station P 0.-Box 289 Wadsworth, TX 77483
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION ON THE PROPOSED LICENSE AMENDMENT REGARDING REACTOR COOLANT SYSTEM FLOW MONITORING - SOUTH TEXAS PROJECT, UNITS 1 AND 2 (STP) (TAC NOS. M99245 AND M99246)
Dear Mr. Cottle:
The staff has reviewed your September 2, 1997, response to our August 11, 1997, request for additional information (RAI) in support of a proposed amendment to the South Texas Project Technical Specifications regarding use of elbow tap differential pressure flow monitoring for the reactor coolant system flow rate.
The staff has identified a need for additional information as requested in.the enclosed RAI. The staff requests that you respond to the enclosed RAI within 30 days. The staff also suogests that a meeting between the NRC and your staff may be appropriate at this time to review the responses to the enclosed RAI.
If you have any questions regarding this request, phase contact me at (301) 415-3267.
Sincerely, Orig, signed by Janet L. Kennedy, Project Manager Project Directorate IV-1 Division of Reactor Projects III/IV Office of Nuclear Reactor Regulation Docket Nos. 50-498 and 50-499
Enclosure:
RAI cc w/ encl:
See next page
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UNITED STATES j-NUCLEAR REGULATORY COMMISSION g
WAeHINGTON. D.C. 30006 4001 49 October 21, 1997 Mr. William T. Cottle Executive Vice-President &-
General Manager, Nuclear Houston Lighting & Power Company South Texas Project Electric Generating Station P. O. Box 289 Wadsworth, TX 77483
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION ON THE PROPOSED LICENSE AMENDMENT REGARDING REACTOR COOLANT SYSTEM FLOW MONITORING - SOUTH TEXAS
-PROJECT, UNITS 1 AND 2 (STP) { TAC NCS. M99245 AND M99246)
Dear Mr. Cottle:
The-staff has reviewed your September 2, 1997, response to our August 11, 1997, request for additional information (RAI) in support of a proposed amendment to the South Texas Project Technical Specifications regarding use of elbow tap differential pressure flow monitoring for the reactor coolant system flow rate. The staff has identified a need for additional information as-requested in tb enclosed RAI. The staff requests that you respond to the enclosed RAI within 30 days. The staff also suggests that a meeting between the NRC and your staff may be appropriate at this time to review the responses to the enclosed RAI.
If you have any questions regarding this request, please contact me at (301) 415-3267.
Sincerely, A L. fe.nuluy Janet L. Kennedy, Project Manager Project Directorate IV-1 Division of Reactor Projects III/IV Office of Nuclear Reactor Regulation Docket Nos. 50-498 and 50-499
Enclosure:
RAI cc w/ encl: See next page
2 Mr. William T. Cottle Houston Lighting & Power Company South Texas, Units 1 & 2 CC:
Mr. David P. Loveless Jack R. Newman, Esq.
- Senior Resident Inspector Morgan, Lewis & Bockius U.S. Nuclear Regulatory Commission 1800 M Street, N.W.
P. O. Box 910 Washington, DC 20036-5869 Bay City. TX 77414 Mr. Lawrence E. Martin Mr. J. C. Lanier/M. B. Lee General Manager, Nuclear Assurance Licensing
-City of Austin Houston Lighting and Power Company Electric Utility Department P. O. Box 289 721 Barton Springs Road Wadsworth, TX 77483 Austin, TX 78704 Rufus S. Scott Mr. M. T. Hardt Associate General Counsel
'Mr. W.-C. Gunst Houston Lighting and Power Company City Public Service Board P. O. Box 61867 P. O. Box 1771 Houston, TX 77208 San Antonio, TX 78296 Joseph R. Egan, Esq.
Mr. G. E. Vaughn/C. A. Johnson Egan & Associates, P.C.
Central Power and Light Company 2300 N Street, N.W.
.P. 0.-Box 289 Washington, DC 20037 Mail Code:
N5012 Wadsworth, TX 74483 Office of the Governor ATTN: John Howard, Director INPO Environmental and Natural Records Center Resources Policy 700 Galleria Parkway P. O. Box 12428 Atlanta, GA 30339-3064 Austin, TX 78711 Regional Administrator, Region IV Arthur C. Tate, Director U.S. Nuclear Regulatory Commission Division of Compliance & It.spection 611 Ryan Plaza ~ Drive, Suite 400 Bureau of Radiation Control Arlington, TX ' 76011 Texas Department of Health 1100 West 49th Street Dr. Bertram Wolfe Austin, TX 78756 15453 Via Vaquero Monte Sereno, CA 95030 Texas Public Utility Commission ATTN: Mr. Glenn W. Dishong Judge, Matagorda County 7800 Shoal Creek Blvd.
Matagorda County Courthouse Suite 400N 1700 Seventh Street Austin, TX 78757-1024 Bay City, TX 77414 L
l
u REDMES1 FOR ADDIT 10NAL INFORMATION
-PROPOSED AMENDMENT TO ALLOW USE OF ELBOW TAPS TO MEASURE REACTOR COOLANT' SYSTEM FLOW RATE 1.-
Provide the~ analytical model:used including nodalization diagram,
-equations-used, etc.'.
2.
.Does the 0.4% repeatability include repeatability of loop instruments?
3.
Is the 0.4% repehtability accounted for in the uncertainty calculations?
4.
Is the elbow tap method (and its uncertainties) included in the revised therst/l-design procedure (RTDP)?
c 5.
Justify not including a 0.1% fouling factor in the venturi uncertainty j
calculations 6.
11s the analyti:a1 model controlled by your 10 CFR Part 50, Appendix B Qyility Assurance program?
7.
((egarding verification that the flow coefficients for each elbow tap Jreraain constant, explain the statement, "a change to K will-not be considered unless a trend were defined by more than a-single measurement."
8.
Provide the following in your proposed Technical Specification (TS).
changes:
/(v
- delta-P),
a.
equation: Future Cycle Flow - BCF--
/(v
- delta-P)3 and the following fixed constants for each elbow tap:
4 Baseline Calorimetric Flow (BCF)
Specific Vo?ume (v )
3 delta-P3 b.
A periodic surveillance to verify that the individual correlation coefficients for each of the elbow taps. remain constant. Explain how your proposed method would -verify this assumption and provide the c-iteria that would be used to detect char.ges in this coefficient.
Provide the
-individual elbow tap flow coefficients.
A statement requiring a 100% calorimetric-heat balance flow
- c..
measurement at the.beginning of each cycle.
d.
A commitment to:
(1) notify the NRC of any known changes to the hydraulic flow model; and (2) contact the NRC for further review of the methodology if the correlation
-coefficients change' or if the elbow tap flow-rate exceeds the best estimate flow rate.
. ENCLOSURE
-. =.
L 2-9.
Provide the entire derivation of the proposed methodology (above equation) from the fundamental equation Q = K*/(delta-P*v) in the TS Bases.
10.
The Westinghouse report SAE/FSE-TGX/THX-0152, currently referenced in the prososed TS Bases, has not been submitted to the NRC for review and should >e deleted from the Bases.
11.
Provide further justification of the use of an average of the delta-Ps from all elbow taps instead of individual elbow tap delta-Ps (i.e.,
individual flow measurements from each elbow tap).
Provide this by starting with the summation of the flows from all elbow taps (as if you were to use individual elbow tap measurements of flow) and deriving the equation using an average delta-P.
12.
Explain your conclusion that the analytic model can predict flow to a 2%
accuracy but can predict changes in flow to a 0.2% accuracy.
13.
Justify your use of the analytic ratio R' from the perspective that this would lead to reliance on an analytically derived flow versus measured flow. The staff believes that while the analytic model can be used for verification, it should not be used for flow measurement to meet the TS requirement.
14.
In response to Question 5 of the staff's August 11, 1997, RAI, you stated that use of an average delta-P simplifies the process while imposing no penalty or loss of flow measurement accuracy.
Specify and quantify all benefits that would be gained from the averaging approacle.
15.
Provide the basis-(including calculations) for your conclusion that the elbow tap measurement is a 95/95 value.
16.
Provide an evaluation of the effects that crud deposits would have if they were to get into the taps and how this was addressed in your methodology. Should this occur, how will it be detected at South Texas?
17.
Explain the increase in calorimetric heat balance flow measured for cycles 2 and 3 for Unit I and justify, for both units, the use of calorimetric data that were higher than the best estimate flow predictions in your baseline cycle flow average.
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