ML052570651
| ML052570651 | |
| Person / Time | |
|---|---|
| Site: | Turkey Point  |
| Issue date: | 07/31/2005 |
| From: | Jarosh D, Suggs C, Vaughn Thomas Westinghouse |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| L-2005-171 WNA-LI-00049-FPL-NP, Rev 0 | |
| Download: ML052570651 (18) | |
Text
L-2005-1 71 B B Florida Power and Light Companv Turkey Point Units 3 and 4 Supplemental Licensinq Input for Deletion of Steam / Feedwater Flow Mismatch Reactor Trip WNA-LI-00049-FPL-NP
WI Westinghouse Non-Proprietary Class 3 Florida Power & Light Turkey Point Units 3 & 4 Supplemental Licensing Input for Deletion of Steam / Feedwater Flow Mismatch Reactor Trip WNA-LI-00049-FPL-NP Revision 0 July 2005 Westinghouse
Westinghouse Non-Proprietary Class 3 Florida Power & Light Turkey Point Units 3 & 4 Supplemental Licensing Input for Deletion of Steam I Feedwater Flow Mismatch Reactor Trip WNA-LI-00049-FPL-NP Revision 0 July 2005 APPROVALS Function Name dgSigure IDate Authors V. M. Thomas 7115f200 Principal Engineer, Desig Basi ngineeng7 Reviewed C. W. Suggs C&/.
7/15/2005 Principal Engineer asis Enineen Approved D. A. Jarosh 7/1512005 Manager. e a
gineering Westinghouse Electnc Company, LLC P.O. Box 355 Pittsburgh, PA 15230-0355 C 2005 Westinghouse Electric Company LL C All Rights Reserved
Florida Power & Light Turkey Point Units 3 & 4 Supplemental Licensing Input for Deletion of Steam I Feedwater Flow Mismatch Reactor Trip LIST OF CONTRIBUTORSIREVIEWERS Name Date E.Lozito, FPL 7/2005 W.Busch, FPL 7/2005 D.Tomaszewski, FPL 7/2005 REVISION HISTORY RECORD OF CHANGES Revision Revision Made By Description Date 0
V. M. Thomas Initial Issue 07/15/05 DOCUMENT TRACEABILITY & COMPLIANCE Created to Support the Following Document(s) l Document Number Revision None DETAILED RECORD OF CHANGES Revision Date
==
Description:==
Rev 0: Initial issue.
7/2005 WNA-LI-00049-FPL-NP, Rev. 0 i
Florida Power & Light Turkey Point Units 3 & 4 Supplemental Licensing Input for Deletion of Steam I Feedwater Flow Mismatch Reactor Trip TABLE OF CONTENTS Section Title Page LIST OF CONTRIBUTORS/REVIEWERS...............................
i TABLE OF CONTENTS...............................
ii ACRONYMS AND TRADEMARKS...............................
iii GLOSSARY OF TERMS...............................
iii REFERENCES..................................
SECTION 1 SECTION 2 PURPOSE AND SCOPE OF DOCUMENT.................................
1-1
SUMMARY
OF REVIEW AND CONCLUSION.................................
2-1 APPENDIX A RESPONSE (REQUEST 2).............................................
A-1 WNA-LI-00049-FPL-NP, Rev. 0 ii
Florida Power & Light Turkey Point Units 3 & 4 Supplemental Licensing Input for Deletion of Steam /
Feedwater Flow Mismatch Reactor TriD ACRONYMS AND TRADEMARKS The following abbreviations and acronyms are defined to allow an understanding of their use within this document.
Acronyms Definition FPL MSS PTN SG RPS Florida Power & Light Median Signal Selection Plant Turkey Point Steam Generator Reactor Protection System All other product and corporate names used in this document may be trademarks or registered trademarks of other companies, and are used only for explanation and to the owners' benefit, without intent to infringe.
GLOSSARY OF TERMS The following definitions are provided for the special terms used in this document.
Term Definitions None.
REFERENCES Following is a list of references used throughout this document.
- 1.
WNA-LI-00038-FPL-P, Revision 1, 'Licensing Input for Deletion of Steam I Feedwater Flow Mismatch Reactor Trip", February 2005 (Last Page of Front Matter)
WNA-LI-00049-FPL-NP, Rev. 0 iii
Florida Power & Light Turkey Point Units 3 & 4 Supplemental Licensing Input for Deletion of Steam I Feedwater Flow Mismatch Reactor Trio SECTION 1 PURPOSE AND SCOPE OF DOCUMENT The purpose of this document is to provide review and concurrence of the FPL response to an NRC request for supplementary information relative to their review of Reference 1, and to determine the appropriate proprietary designation for the response.
The scope is limited specifically to Request 2 and the corresponding response as shown in Appendix A.
(Last Page of Section 1)
WNA-LI-00049-FPL-NP, Rev. 0 1 -1
Florida Power & Light Turkey Point Units 3 & 4 Supplemental Licensing Input for Deletion of Steam I Feedwater Flow Mismatch Reactor Trip SECTION 2
SUMMARY
OF REVIEW AND CONCLUSION Request 2 as shown in Appendix A requests a descripton of the existing feedwater instrumentation from a reactor protection and control point of view relative to control and protection system interaction, and the role of the Median Signal Selector (MSS).
Westinghouse concurs with the response shown in Appendix A and has no additional comments.
Relative to proprietary designation, it is understood that the response in Appendix A has been developed based upon section 5.4.2.7 of the FPL Reactor Protection System Design Basis Document, which was originally issued as a Westinghouse Class 2 document. The material also corresponds to the type of information which had been provided previously in submittals for other plants, and which had been considered as Westinghouse Proprietary Class 2 in such submittals.
As a result, Westinghouse requires that the attached response be bracketed as shown and considered proprietary for submittal to the NRC.
(Last Page of Section 2)
WNA-LI-00049-FPL-NP, Rev. 0 2-1
Florida Power & Light Turkey Point Units 3 & 4 Supplemental Licensing Input for Deletion of Steam /
Feedwater Flow Mismatch Reactor Trip APPENDIX A RESPONSE (REQUEST 2)
WNA-LI-00049-FPL-NP, Rev. 0 A-1
Florida Power & Light Turkey Point Units 3 & 4 Supplemental Licensing Input for Deletion of Steam I Feedwater Flow Mismatch Reactor TriO Request 2.
Provide an explanation of the existing feedwater instrumentation system, from the reactor protection and control point of view, including the limitations of the existing system for which the proposed TS change has been requested, specifically addressing adverse effect of the existing control and protection system Interaction and how it will be eliminated by the new Median Signal Selector (MSS).
Response: r a, c WNA-LI-00049-FPL-NP, Rev. 0 A-2
Florida Power & Light Turkey Point Units 3 & 4 Supplemental Licensing Input for Deletion of Steam /
Feedwater Flow Mismatch Reactor Trip a, c WNA-LI-00049-FPL-NP, Rev. 0 A-3
Florida Power & Light Turkey Point Units 3 & 4 Supplemental Licensing Input for Deletion of Steam I Feedwater Flow Mismatch Reactor Trip a, c (Last Page of Document)
WNA-LI-00049-FPL-NP, Rev. 0 A-4
L-2005-1 71 Page 1 of 4 Westinghouse Nuclear Safety Advisory Letter NSAL-96-004 Control and Protection Interaction August 14, 1996
d Westinghouse Energy Systems Business Unit NUCLEAR SAFETY ADVISORY LETTER m
THIS IS ANOTIFICATION OFA RECENTLY IDENTIFIED POTENTIAL SAFETYISSUE PERTAINING TO BASIC COMPONENTS SUPPUED BYWESTINGHOUSE. THIS INFORMATION IS BEING PROVIDED TO YOU SO THAT AREVIEW OFTHS ISSUE CAN BE CONDUCTED BY YOU TO DETERAINE IF ANY ACTION IS REQUIRED.
P.O. Box 355, Piltsburgh, PA 15230-0355
Subject:
Control and Protection Interaction fNumber NSAL-96-004 Basic Component:
Instrumentation Tapnp ulse Line Da= WI4196 Plants:
Westinghouse NSSS Plants per uSummanP Below SubstantalSafetyHazardorFaluretoComplyPursuant l1OCFR21.21(a)
Yes El No Transfer of Informatlon Pursuant to 10 CFR 2121(b)
Yes El Advisory Information Pursuanto 1o0 CFR 21.21 (c)(2)
Yes LI
Reference:
SUMMARY
This NSAL is only applicable to those plants wth three narrow range steam generator water level channels that have removed the low feedwater flow trip function on the basis that a median signal selector (MSS) on the level control signal Input precluded the need for this back-up protection for a control/ protection Wnteraction scenario. This design did not address the failure of a common tap for steam flow and narrow range steam generator level for which the low feedwater flow also provided back-up protection to satisfy IEEE-279 requirements.
Westinghouse has determined that this Issue Is not reportable pursuant to 10 CFR Part 21.
Recommended actions are provided for plants using either an analog MSS or the Advanced Digital Feedwater Control System.
Addlional Information, If required, maybe obtained from the originator. Telephone 412-374-5036.
Originator(s):
R. B. Mler Regulatory & Licensing Initiatives J. S. Galembush, Acting Manager Regulatory& Licensing Initiatives NSAL-96-004 Sheet I of 3
TECHNICAL DESCRIPTION ISSUE DESCRIPTION Some plants with three narrow range steam generator level channels have Installed a median signal selector (MSS) on the control side and deleted the low feedwater flow trip function. This trip function was necessary to provide a back-up to prevent a control and protection Interaction scenario involving level channel failures. The MSS precluded an Inadvertent control action from a postulated level channel failure and, therefore, it was determined that the back-up trap was not required. This design did not address a failure of the common tap for a steam flow channel and a narrow range steam generator level channel for which the low feedwater flow trip was also a backup. If this tap or Impulse line were to sever, a low steam flow signal would begin to close the feedwater control valve and the level channel would fail high. The level control demand signal would not have a sIgnificant Impact on the rapid transient and there is a high probability that a low-low steam generator level trip would be required. IEEE-279 Section 4.7.3 states that a second random failure be considered In this situation. Since only three level channels are provided, the second postulated failure of a level channel would not satisfy the trip logic. Plants with four level channels (using separate taps) providing the low-low steam generator level trip are not impacted by the scenario.
TECHNICAL EVALUATION Westinghouse provided guidance in the early 1970s on the installation of impulse lines for the steam flow and steam generator level channels via l&C Standards. Later plants utilze Level Systems Installation Schematics. The common tap connection is shown on these drawings.
Two steam flow channels are provided for each loop, only one of which shares a tap connection with a narrow range steam generator level channel In a three level channel system.
The original design that eliminated the low feedwater flow trip could be accomplished with either an analog or digital MSS. The digital MSS Is part of the Advanced Digital Feedwater Control System, which also provides either a MSS or an Arbitrator for the steam flow Inputs. Although the same certification was not performed on the Arbitatorfunctlon as was done for the MSS for the steam generator level signal, redundant signal validation on steam flow provides confidence that the failure of a steam flow channel wilt not perturb the control system. Plants with an analog MSS on the level channels also have a selector switch for the steam flow control signal.
Selecting the steam flow transmitter that Is not connected to steam generator narrow range level will also preclude the problem.
ASSESSMENT OF SAFETY SIGNIFICANCE To determine the signIficance of this Issue, a search of INPO records was performed and no Instances of tap or Impulse line severance had been reportod. The probabilIty of a tap/impulse line failure coupled With another level channel of the same redundant set falling high Is extremely low. Therefore, this Issue is not considered to be a substantial safety hazard and will not be reported pursuant to 10 CFR Part 21. However, as stated In 10 CFR 50.55a(h), the design must meet IEEE-279 and certain actions are required to comply with the controlprotection Interaction section of that standard.
NSAL-96-004 Sheet 2 of 3
RECOMMENDED ACTiONS These actions apply only to plants with a three channel low-low steam generator water level trip function that have Incorporated a MSS for the control signal from these level channels and removed the low feedwater flow trip function.
The plants with an analog MSS, must either, 1) remove the steam flovi control signal selector switch and connect directly to the steam flow transmitter that does not sharm a tap, or 2) Include a statement m the Technical Specification Bases section for the Steam Generator Water Level Low-Low function to thb effect that: 'The steam flow selector switch must normally select the steam flow transmitter that does not share a tap conne6tion with a narrow range steam generator water level transmitter."
For plants with the Advanced Digital Feedwater Control Systems, Westinghouse will supplement the original licensing documentation to Include the MSS/Arbltrator for the steam flow signals.
There Is no plant action required except a review of this documentation against their licensing bases for removal of the low feedwater flow protection function.
NSAL--004 Sheet 3 of 3
L-2005-1 71 B Page 1 of 11 B FPL Letter ENG-LCM-04-256 PTN 3 Engineerinq Evaluation PTN-ENG-SEIJ-04-073 for Section 4.2 Platform Considerations For Westinghouse Licensing Report WNA-LI-00026-FPL Regarding Steam/Feedwater Flow Mismatch Reactor Trip December 17. 2004
L-2005-1 71 B Page 2 of 11 700 UnIvene Boulevard Juno Beach, FL 33408 FPL ENG-LCM-04-256 December 17, 2004 Mr. P.J. McDonough Customer Projects Manager Westinghouse Electric Company Nuclear Services P.O. Box 355 Pittsburgh, Pennsylvania 15230-0355 USA
Subject:
PTN 3 Engineering Evaluation PTN-ENG-SEIJ-04-073 for Section 4.2 Platform Considerations for Westinghouse Licensing Report WNA-LI-00026-FPL Regarding Steam IFeedwater Flow Mismatch Reactor Trip.
Dear Mr. McDonough:
Attached are subject Engineering Evaluation and Platform Considerations for Incorporation into Revision B of the subject document identified by Westinghouse as Dated November, 2004.
If you have any questions regarding this matter please feel free to contact Warren Busch at 561-691-2963, or Samuel C. Moore at 561-691-2652.
Sincerely, Dan Tomaszewski LCM Project Manager cc: Warren Busch Steve Hetrick Samuel Moore Gary Wood Ralph Cholewinski Paul Collette, Westinghouse w/ attach