ML20092N506
| ML20092N506 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 06/26/1984 |
| From: | Kammer D TENNESSEE VALLEY AUTHORITY |
| To: | Adensam E Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0737, TASK-2.K.3.05, TASK-TM GL-82-33, GL-83-10D, NUDOCS 8407030220 | |
| Download: ML20092N506 (2) | |
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TENNESSEE VALLEY AUTHORITY a
CHATTANOOGA TENNESSEE 37401 400 Chestnut Street Tower II c,
June 26,1984 Director of Nuclear Reactor Re6alation Attention:
Ms. E. Adensam, Chief Licensing 3 ranch No. 4 Division of Licensing U.S. Nuclear Regulatory Commission Washington, D.C.
20555 De tr Ms. Adensam:
In the Mutter of
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Docket Nos. 50-327 Tennessee Valley Authority
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50-328 Enclose,! for our Sequoyah Nuclear Plant is the final response to the February 8,1983 letter from D. G. Eisenhut to All Licensees with Westinghouse Designed Nuclear Steam Supply Systems (Generic Letter 83-10d) regarding the resolution of TMI Action Item II.K.3.5, automatic trip of mactor coolant pumps. Previous submittals were made to the NRC by L. M. Mills' April 20, 1983 and January 6,1004 letters to you. This submittal provides the justification for utilization of manual reactor coolant pump trip.
If you have any gaestions concerning this matter, please get in touch with Jerry Wills at FTS 858-2683 Very truly yours, TENNESCEE VALLEY AUTHORITY pS h D. S. Kammer j
Nuclear Engineer Sworn tg ppd subscrfbed before me this h9 day of W1ALL 1984
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Notary Public My Commission Expires Enclosure cc:
U.S. Nuclear Regulatory Commission Region II Attn:
Mr. James P. O'Reilly Administrator 101 tiarietta Street, NW, Suite 2900 Atlanta, Georgia 30323 DR P
1983-TVA 5OTH ANNIVERSARY
/ t' Equal Opportunity Employer
ENCLOSURE SEQUOYAH NUCLEAR PLANT (SQN) UNITS 1 AND 2 FINAL RESPONSE FOR TMI ACTION ITEM II.K.3.5 e
Previous letters from L. M. Mills to E. Ade1 sam dated April 20, 1983, and January 6,1984, prssented the plan for demonstrating compliance with the criteria for resolution of TMI action plan requirements in item II.K.3 5, established in NRC Generic Letter 83-10d dated February 8,1983, from Darrel G. Eisenhut (NRC) to All Licensees with Westinghouse Electric Corporation (W) Designed Nuclear Steam Supply Systems. The submittals which fulfill the established requirements have been transmitted to you by Westinghouse Owners' Group (WOG) letters OG-117 dated March 12, 1984, and OG-110 dated December 1, 1983 Section I of the attachment to NRC letter 83-10d discusses " pump operation criteria which can result in reactor coolant pump (RCP) trip daring transients and ' accidents." Subsection 1 of section I presents guidelines for establishing setpoints for RCP trip. The WOG response to this section of NRC letter 83-10d is contained in revision 1 to the WOG emergency response guidelines, which has been issued to member utilities. TVA's plans and schedule for implementing revision 1 WOG emergency response guidelines at SQN are provided in our April 15, 1983 letter from L. M. Mills to NRC regarding supplement 1 to NUREG-0737, Requirements For Emergency Response Capability (Generic \\ Letter 82-33).
The RCP trip criterion being adopted in the SQN plant-specific procedure not only ensures RCP trip fcr all losses of primary coolant for which trip is considered necessary, but also permits RCP operation to continue during most non-LOCA accidents, including steam generator tube rupture events up to the design basis double-ended tube rupture. The generic applicability of the RCP trip criterion selected has been documented by the WOG report entitled, " Evaluation of Alternate RCP Trip Criteria," which has been submitted to NRC for review in letter 00-110.
The WOG has also submitted to NRC, in the letter OG-117, the report entitled, " Justification. of Manual RCP Trip for Small Break LOCA. Events."
As stated, these submittals completed the WOG documentation. comprising a generic reply to NRC Generic Letter 83-10d.
Subsection 2 of section I of the attachment to NRC leter 83-10d provides guidance for justification of manual RCP trip. Subsection 2a requires that compliance with 10 CFR 50.46 be demonstrated in an Appendix K small break LOCA analysis provided that the RCPs are tripped two minutes after the onset of reactor conditions corresponding to the RCP trip setpoint. The WOG has generically verified, in the 00-117 submittal, that predicted LOCA transients, presuming a two-minute delayed RCP trip, are nearly identical to those presented in safety analysis reports utilizing the EFlash evaluation model. Thus, the final safety analysis report for SQN demonstrates its compliance with the subsection 2A guidelines.
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The _WOG has also performed most probable, best estimate, WFlash analyses.
to demonstrate, generically, compliance with the guidelines presented in subsection 2b of section I of the attachment to NRC Generic Letter 83-10d.
These analysos identify that the minimum time available for operator action
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for the complete range of LOCA ' break sizes exceeds the value contained in American National Standards Institute ( ANSI) draft standard N660. They show that mactor. coolant pumps may be tripped at any time during a LOCA event without resulting in' excessive clad temperatures. The information-presented in the generic report affirms the applicability of this best estimate analyses to SQN; -therefore, in combination with the subsection 2a
. justification cited, the best estimate analyses justify the acceptability of manual RCP trip for SQN when RCP' trip setpoints are consistent with revision 1 in the emergency msponse guidelines. Furthermoro, the generic report demonstrates that to additional contingency emergency procedures are mquired to address the scenarios which may follow a mLased RCP trip set-point. We have previously provided in ~ a letter from L. M. Mills to NRC dated April 20,- 1983, responses to subsections 3a and 3c of section I of the attachment to NRC-Generic Letter 83-10d.
In summary, the generic information presented by the WOG in the reports entitled, " Evaluation of Alternate RCP Trip Criteria" and " Justification of Manual RCP Trip for Small 3reak LOCA Events" provides the response to NRC Generic Letter.83-10d for SQN. The implementation of revision 1 to the emergency msponse guidelines in the plant-specific procedures with an.
appropriate RCP trip setpoint specified resolves all issues associated with automatic tripping of the reactor coolant pumps.
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