ML20087Q057
| ML20087Q057 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 03/30/1984 |
| From: | Tucker H DUKE POWER CO. |
| To: | Adensam E, Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737, TASK-2.K.3.05, TASK-TM GL-83-100, NUDOCS 8404100258 | |
| Download: ML20087Q057 (3) | |
Text
DUKE Powen GOMI%NY P.O. Box 33180 CitAHLOTTE. N.O. 28242 HAL H. TUCKER Ten.zenown vwa enesammt (704)373-4531 mma.saa emonervios March 30, 1984 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D. C. 20555 Attention:
Ms. E. G. Adensam, Chief Licensing Branch No. 4 Re: McGuire Nuclear Station Docket Nos.
50-369 and 50-370 TMI Item II.K.3.5 " Automatic Trip of Reactor Coolant Pumps" (Generic Letter 83-104)
Dear Mr. Denton:
Mr. D. G. Eisenhut's (NRC/0NRR) February 8, 1983 letter (Generic Letter No.83-10d) transmitted the NRC's critaria for resolution of EMI Action Item II.K.3.5, " Auto-matic Trip of Reactor Coolant Pumps".
This letter requested that Duke Power Company provide its plans and schedules for resolution of this issue on McGuire Nuclear Station, along with indicating whether formal submittal of the analyses which sup-port either RCP trip setpoints or the decision to leave the RCPs operational for all events would be made as opposed to having the NRC conduct inspections to examine the 10CFR50, Appendix K and RCP operation mode evaluations.
By my letter dated April' 2 2, 1983. Duke stated that, as a member of the Westing-house Owner's Group, we had authorized generic resolution of this issue. This letter provided detailed plans and schedules for completion of the necessary tasks, which was basically that operator training and implementation was scheduled for completion by June 30, 1984. The letter also indicated that Duke would submit a report (in lieu of inspections) providing the technical justification for treatment of RCPs during transients and accidents by March 31, 1984. The submittals which
' fulfill the established requirements have been transmitted to you by Westinghouse Owner's Group letters OG-110, dated December 1, 1983, and OG-117, dated March 12, 1984. Plant specific items not addressed by these submittals are addressed herein.
Section I of the attachment to NRC letter 83-10d discusses " Pump Operation Criteria Which Can Result in RCP Trip During Transients and Accidents".
Subsection 1 of Section I presents guidelines for estabishing setpoints for RCP Trip. The Westing-house Owners Group response to this section of NRC Letter 83-10d is contained in' Revision'l to the WOG Emergency Response Guidelines, which has been irqued to mem-ber utilities. -Operator training and implementation is currently scheduled for completion by November 1984. This revised date is consistent with the schedule for
-implementation of the Upgraded Emergency Procedures as provided in Revision 1 to the Duke ~ Power Company Response to NUREG-0737 for McGuire Nuclear Station (Ref. My letter dated September 8, 1983).
In the interim McGuire will continue to manually trip reactor coolant pumps based on the existing setpoint of 1500 psig Reactor Coolant System pressure.
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2 The RCP trip criterion being adopted in the McGuire plant specific emergency pro-cedures not only assures RCP trip for all losses of primary coolant for which trip j
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 Westinghouse Owners Group Report entitled, j
" Evaluation of Alternate RCP Trip Criteria", which has been submitted to the h2C for review in letter OG-110.
The Westinghouse Owners Group has also submitted to the NRC, via letter OG-ll7, the report entitled, " Justification of Manual RCP Trip for Snall Break LOCA Events".
As stated above, these submittals completed the WOG documentation comprising a generic reply to NRC Generic Letter 83-10d.
Subsection 2 of Sectior. I of the attachment to NRC Letter 83-10d provides guidance for justification of manual RCP trip. Subsection 2a requires that compliance with 10CFR50.46 be demonstrated in an Appendix K small break LOCA analysis given that the RCPs are tripped two minutes after the onset of reactor conditions corresponding to the RCP trip setpoint. The Iastinghouse Owners Group has generically verified, in the OG-ll7 submittal, that predicted LOCA transients presuming the two minute delayed RCP trip are nearly identical to those presented in Safety Analysis Reports utilizing the WFLASH Evaluation model. Thus, the Final Safety Analysis Report for the McGuire Nuclear Station demonstrates its compliance with the Subsection 2A guide-lines.
The WOG has also performed most probable, best estimate, WFLASH analyses to demon-strate, generically, compliance with the guidelines presented in Subsection 2b of Section I of the attachment to NRC Generic Letter 83-10d. These analyses identify that the minimum time available for operator action for the complete range of LOCA break sizes exceeds the value contained in draft ANSI Standard N660; they show that reactor coolant pumps may be tripped at any time during a LOCA event without result-ing in excessive clad temperatures. The applicability information presented in the generic report affirms the applicability of this best estimate analyses to McGuire.
Therefore, in combination with the Subsection 2a justification cited above, the best estimate analyses justify that manual RCP trip is acceptable for McGuire when RCP trip setpoints consistent with Revision 1 to the Emergency Response Guidelines are in use. Furthermore, the generic report demon >*. rates that no additional contingency emergency procedures are required to address 0.e scenarios which may follow a missed RCP trip setpoint.
Subsection 3 of Section I of the attachment to NRC letter 83-10d requests additional plant specific information concerning RCP trip.
Subsection 3a discusses the level of quality of the instrumentation that will be utilized to signal the need for RCP trip. The RCP trip criterion for_McGuire will be a loss of Reactor Coolant System subcooling. A loss of subcooling is calculated by comparing wide range hot leg tem-perature, core exit thermocouple temperature, and wide range pressure, to an error-adjusted saturation curve. This calculation is provided by the Operator Aid Computer and is displayed on a CRT. The operator can also manually determine a loss of sub-cooling by comparing pressure and temperature to a subcooled margin curve. These instruments have been categorized by Duke as Type A variables as specified by Regulatory Guide 1.97, Revision 2.
As such they are qualified to a level that is.
adequate for the intended function. Subsection 3b requires that timely restart of the reactor coolant pumps be included in the emergency procedure. The McGuire emergency procedures include such guidance where appropriate. Subsection 3e requires
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that the training program provide instruction and emphasis on the responsibility
~ of the operator to trip the reactor coolant pumps on a loss of subcooling.
Such instruction and emphasis will-be provided and is supported by the prominence of the reactor coolant pump trip guidance in the McGuire emergency procedures.
In-summary, the generic information presented by the Westinghouse Owner's Group in the reports entitled " Evaluation of Alternate RCP Trip Criteria" and "Justifi-cation.of. Manual RCP Trip for Small Break LOCA Events", and the plant specific information included in.this-letter, provide the response to NRC Generic Letter
'83-10d for the McGuire Nuclear Station..The implementation of the upgraded emergency procedures which include the reactor coolant pump trip on loss of sub-cooling resolves all issues associated with RCP trip for SBLOCA mitigation.
.Very truly yours, hb.
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-Ha1. B. Tucker PBN:gib'-
cc: _Mr. J. P. O'Reilly, Regional Administrator U. S. Nuclear Regulatory Commission s
Region II 101 Marietta Street, NW, Suite 2900
_ Atlanta,~ Georgia 30303 Mr.' W. T. Orders Senior Resident Inspector
~
McGuire~ Nuclear Station s
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