ML18005A773

Forwards Response to Generic Ltr 88-17, Loss of Dhr. Standpipe Indication Will Be Modified to Include hard-piped Configuration,Replacing Currently Used Hoses & Control Room Indication W/Completion Expected by Second Quarter of 1991

ML18005A773
Person / Time
Site:	Harris
Issue date:	02/01/1989
From:	Mcduffie M CAROLINA POWER & LIGHT CO.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
GL-88-17, NLS-89-028, NLS-89-28, NUDOCS 8902070226
Download: ML18005A773 (9)

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ACCESSION NBR:8902070226 DOC.DATE: 89/02/01 NOTARIZED: YES DOCKET FACIL:50-400 Shearon Harris Nuclear Power Plant, Unit 1, Carolina 05000400 AUTH. NAME AUTHOR AFFILIATION MCDUFFIE,M.A. Carolina Power & Light Co.

RECXP.NAME RECIPIENT AFFILIATXON Document Control Branch (Document Control Desk)

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SUBJECT:

Forwards response to Generic Ltr 88-17, "Loss of DHR."

"/"'"""" D NOTES:Application for permit renewal filed. 05000400 S

RECIPIENT COPIES RECXPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD2-1 LA 1 0 PD2-1 PD 1 1 h BECKER, D 1 1 INTERNAL: ACRS 6 6 ARM/DAF/LFMB 1 0 NRR BALUKJIAN,H 2 2 NRR TRAMMELL,C 1 1 NRR/DEST/ADE 8H 1 1 NRR/DEST/ADS 7E 1 1 NRR/DOEA/TSB 11 1 1, NUDOC~S- BSTRACT 1 1 OGC/HDS1 RES SPANO,A 1

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.1 CMiL Carolina Power 4 Light Company P. O. Box 1551 ~ RaIeIgh, N.C. 27602 FEB Oi )989 M. A. McDUFFIE Sentor VIce Prestdent NucIear Generation SERIAL: NLS-89-028 10CFR50.54(f)

United States Nuclear Regulatory Commission ATTENTION: Document Control Desk Washington, DC 20555 SHEARON HARRIS NUCLEAR POWER PLANT DOCKET NO. 50-400/LICENSE NO. NPF-63 GENERIC LETTER 88-17 LOSS OF DECAY HEAT REMOVAL Gentlemen:

Carolina Power 6 Light Company hereby submits the Shearon Harris Nuclear Power Plant (SHNPP) response to the programmatic actions required by Generic Letter 88-17 "Loss of Decay Heat Removal".

The generic letter provides recommendations for expeditious actions and programmed enhancements to assure protection from loss of shutdown cooling while in a reduced inventory condition. Licensees are required to submit their plan to implement each expeditious action recommendation within 60 days of receipt of the generic letter, and to submit their plans and schedule for implementation of the programmed enhancement recommendations within 90 days of receipt. The enclosure to this letter provides a description of the actions taken and planned at SHNPP to implement the programmed enhancements specified in the generic letter.

Please refer any questions regarding this submittal to Mr. Steven Chaplin at (919) 836-6623.

Yours very truly, M. A. McDuffie MAM/SDC Enclosure cc: Mr. R. A. Becker Mr. W. H. Bradford Mr. M. L. Ernst SSSSSPSIISsr M. A. McDuffie, having been first duly sworn, did depose and say that the ~~>'py~ 'aa, information contained herein is true and correct to the best of his i+>co~a oo,,4/~'~~

information, knowledge and belief; and the sources of his information employees, contractors, and agents of Carolina Power & Light/' aI~~o'fficers, 90

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Enc sure to NLS-89-028 Page 1 Item 1 Instrumentation Action Provide reliable indication of parameters that describe the state of the RCS and the performance of systems normally used to cool the RCS for both normal and accident conditions. At a minimum, provide the following in the CR:

(a) two independent RCS level indications (b) at least two independent temperature measurements representative of the core exit whenever the RV head is located on top of the RV (We suggest that temperature indications be provided at all times.)

(c) the capability of continuously monitoring DHR system performance whenever a DHR system is being used for cooling the RCS (d) visible and audible indications of abnormal conditions in temperature, level, and DHR system performance Response - (a) At least one of the two Reactor Vessel Level Inventory System (RVLIS) channels and a reactor vessel standpipe are required to be available prior to mid-loop operations by our present plant procedures'he standpipe indication will be modified to include a hard-piped configuration, replacing the currently used hoses, and control room indication. This modification will be completed by the end of the third SHNPP refueling outage, currently scheduled for the second quarter of 1991.

(b) At least two incore thermocouples are required to be available prior to mid-loop operations with reactor head installed by our present plant procedures. The procedures will be revised prior to the next refueling outage to ensure that the two thermocouples are independent, i. e ~ from different trains.

(c) The following indications were determined to be necessary to monitor Residual Heat Removal (RHR) System performance: flow rate, pump suction and discharge pressures, and pump motor amperage. Currently, indications of RHR pump discharge pressure, flow rate and motor amperage are available on the main control board. Control room indication will be provided for RHR pump suction pressure. This modification will be implemented by the end of the third SHNPP refueling outage'

Page 2 (d) Visible indication of parameters identified in (a) through (c) is addressed above. The capability to provide an audible indication of abnormal conditions for these parameters will require plant modifications.

The specific design for alarms or other audible indications will be dependent on several factors, such as the analyses of specific transient scenarios, human factors considerations and the existing design. These modifications are currently being evaluated, and modifications resulting from this evaluation will be implemented by the end of the third refueling outage.

Item 2 Procedures Action Develop and implement procedures that cover reduced inventory operation and that provide an adequate basis for entry into a reduced inventory condition. These include:

(a) procedures that cover normal operation of the NSSS, the containment, and supporting systems under conditions for which cooling would normally be provided by DHR systems.

(b) procedures that cover emergency, abnormal, off-normal, or the equivalent operation of the NSSS, the containment, and support systems if an off-normal condition occurs while operating under conditions for which cooling would normally be provided by DHR systems.

(c) administrative controls that support and supplement the procedures in items (a), (b), and all other actions identified in this communication, as appropriate.

Response- SHNPP has as active representative on the Westinghouse Owners Group (WOG) Operations Subcommittee, which is conducting a three phase project (MUHU-1106) to provide generic guidance on mid-loop operation for Westinghouse plants. Phase 1 of the project was completed in November 1988 with issuance of interim procedural guidance and a two-day workshop which the SHNPP representative attended.

SHNPP plant procedures are currently being revised to incorporate this interim guidance. As part of this revision process, the plant's On-site Nuclear Safety (ONS) unit will provide an independent review of these procedures. This revision process will be completed prior to the next refueling outage at SHNPP, currently scheduled for November 1989.

SHNPP will continue to participate in the WOG subcommittee project on mid-loop operations and will implement additional

Page 3 generic guidance as appropriate. The remaining phases of the project include development of procedures to mitigate and recover a loss of decay heat removal, guidance for actions associated with RCS drain down to mid-loop conditions, and analytical verification and background documentation.

Item 3 E ui ment Action - (a) Assure that adequate operating; operable, and/or available equipment of high reliability is provided for cooling the RCS and for avoiding a loss of RCS cooling.

(b) Maintain sufficient existing equipment in an operable or available status so as to mitigate loss of DHR or loss of RCS inventory should they occur. This should include at least one high pressure injection pump and one other system. The water addition rate capable of being provided by each equipment item should be at least sufficient to keep the core covered.

(c) Provide adequate equipment for personnel communications that involve activities related to the RCS or systems necessary to maintain the RCS in a stable and controlled condition.

Response (a) Plant Technical Specifications already require two operable RHR loops in mode 6 when the water level is less than 23 feet above the reactor vessel flange. In mode 5, a reduced inventory condition would also require the operability of two RHR loops due to the unavailability of the steam generators for RCS heat removal.

(b) Plant Technical Specifications require one operable charging/safety injection pump (CSIP) in modes 5 and 6.

A second pump is not allowed to be operable due to potential for overpressurization of the RCS beyond the relief capability of the system. The only other available means of adding water to the RCS using existing equipment other than the RHR pumps is a gravity feed from the Refueling Water Storage Tank through the RHR piping into the RCS. Availability of the gravity feed path will be implemented by plant procedures as a prerequisite to reduced inventory operation prior to the next SHNPP refueling outage.

(c) Procedural requirements for reduced inventory operations will include availability of communications equipment as needed to implement both normal and emergency actions. These procedure revisions will be completed prior to the second SHNPP refueling outage.

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Enclosure to NLS-89-028 Page 4 Item 4 Anal sis Action Conduct analyses to supplement existing information and develop a basis for procedures, instrumentation installation and response, and equipment/NSSS interactions and response. The analyses should encompass thermodynamic and physical (configuration) states to which the hardware can be subjected and should provide sufficient depth that the basis is developed. Emphasis should be placed upon obtaining a complete understanding of NSSS behavior under nonpower operation.

Response- As stated in the response to item (2), SHNPP is participating in the WOG Operations Subcommittee study MUHU-1106. Phases 2 and 3 of this project will address this item. A methodology similar to that used in the WOG development process for Emergency Response Guidelines is to be used. The analyses developed will provide the basis documents for SHNPP procedures and modifications addressed in our response to the Generic Letter.

Item 5 Technical S ecifications Action Technical specifications (TSs) that restrict or limit the safety benefit of the actions identified in this letter should be identified and appropriate changes should be submitted.

Response Technical Specification 3.9.8.2 requiring 2500 GPM RHR flow in mode 6 challenges the RHR pump reliability during reduced inventory conditions when the flow rate should be reduced to minimize the potential for vortexing at the pump hot leg suction connection to the RCS. A change to this requirement will be submitted to the NRC for implementation at the next SHNPP refueling outage, currently scheduled for November 1989.

SHNPP will evaluate a change to Technical Specifications to permit a second CSIP to be operable during reduced inventory conditions. If appropriate,'this change will be submitted to the NRC for implementation at the end of the third refueling outage.

As a participant in the WOG Technical Specification Subcommittee, SHNPP is aware of the analysis to support removal of the RHR suction valve Automatic Closure Interlock (ACI) on high RCS pressure. Upon completion of this generic study, SHNPP will evaluate the benefit to RHR reliability of

Page 5 ACI deletion and consider implementation of this modification and Technical Specification change.

Item 6 RCS Perturbations Action Item (5) of the expeditious actions should be reexamined and operations refined as necessary to reasonably minimize the likelihood of loss of DHR.

Response- Cautions currently exist in the operating procedures to provide control or prevention of perturbations to the RCS or support systems. As noted in the response to item 2, the SHNPP ONS Unit will review the next procedure revisions currently in progress to be implemented prior to the next refueling outage. This item will specifically be addressed, and any enhancements to current procedures and practices will be implemented at that time. The training provided to each operating shift crew prior to reduced inventory conditions, as previously committed to in our response to expeditious action 1 of the Generic Letter, will continue to emphasize the safety implications of such perturbances and the need to control or limit such evolutions during reduced inventory operations.

1 Excerpt from CP&L letter NLS-88-293 dated January 3, 1989 Ex editious Actions Item 5 Administrative Control of Plant Activities Action - Implement procedures and administrative controls that generally avoid operations that deliberately or knowingly lead to perturbations to the RCS and/or to systems tPiat are necessary to maintain the RCS in a stable and controlled condition while the RCS is in a reduced inventory condition.

If the operations that could perturb the RCS must be conducted while in a RCS or systems supporting reduced inventory condition then additional measures should be taken to assure that the PCS will remain in a stable and controlled condition.

Such additional measures include both prevention of a loss of DHR and enhanced monitoring requirements to ensure timely response to a loss of DHR should such a loss occur.

Response - A caution presently exists in the operating procedures to provide control/prevention of perturbations to the RCS and/or systems needed for control of the RCS. The training lesson described in Item 1 also emphasizes the need to control evolutions in progress during periods of mid-loop operation.

Planning for outages at SHNPP zdentifies the reactor vessel level on the timeline schedule, and Operations personnel are involved in determining the scheduling of concurrent activities during reduced inventory conditions. No further action is required.