ML20214Q869

Safety Evaluation Re Interim Operation W/O Bypassed & Inoperable Status Panel

ML20214Q869
Person / Time
Site:	Sequoyah
Issue date:	06/01/1987
From:	NRC OFFICE OF SPECIAL PROJECTS
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Shared Package
ML20214Q867	List: ML20214Q864 ML20214Q869
References
NUDOCS 8706050233
Download: ML20214Q869 (4)

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NUCLEAR REGULATORY COMMISSION 3

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SAFETY EVALUATION BY THE OFFICE OF SPECIAL PROJECTS RELATING TO INTERIM OPERATION WITHOUT BYPASSED AND INOPERABLE STATUS PANEL TENNESSEE VALLEY AUTHORITY SE0VOYAH NUCLEAR PLANT, UNITS 1 & 2 Docket Hos. 50-327/328

1.0 INTRODUCTION

In a September 13, 1982 letter, Tennessee Valley Authority (TVA, the licensee) informed the staff that the status monitoring system (SMS), which provided the automatic bypassed and inoperable status indication (BISI) in the control room per the guidance of Regulatory Guide 1.47, would be permanently removed and replaced by a new BISI system. The licensee, in an October 31, 1986 letter, indicated that plant administrative procedures and indicators would be utilized to assist the operator in determination of the safety system status until the plants' outages in 1990 when a new BISI system would be installed in each unit.

Additionally, in a February 17, 1987, letter, TVA responded to the staff's January 28, 1987, request for additional information and provided a discussion of the specific administrative procedures to be utilized until the new BISI is installed.

The staff has reviewed the interim operation (between restart and the end of cycle 4) of Sequoya.h Units 1 & 2 which would rely on administrative procedures, in lieu of an automatic means, for determination of safety system status and finds it acceptable as discussed below.

2.0 DISCUSSION / EVALUATION Regulatory Guide 1.47 states:

" Current designs of protection systems and engineered safety feature systems are such that certain safety-related functions of a nuclear power plant may be bypassed or made inoperable during the performance of periodic tests or maintenance. Generally, the plant's administrative procedures require that the operator's permission be obtained prior to initiating any activity that would or could affect a safety-related system. The decision to grant such permission should be based on a knowledge of the operating status of the safety-related systems, the extent to which the activity will affect those systems, and whether that effect is permissible within the provisions of the license. Experiences at operating plants, however, indicate that when the measures used to indicate inoperable status consist solely of administrative procedures, the operator is not always fully aware of the ramifications of each bypassed or inoperable component. An acceptable way of aiding the operator's knowledge of plant status is to supplement administrative procedures with automatic indication of the bypass or inoperability of each redundant portion of a system that performs a function important to safety."

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e In Section 7.5.1 of the Sequoyah Safety Evaluation Report, NUREG-0011, the staff stated that the SMS being installed in the plants satisfied the recommendations of Regulatory Guide 1.47 and was therefore acceptable. Since the SMS proved to be unreliable, was subsequently removed, and a new automatic safety system SMS will r.ot be installed until sometime during the 1989-1990 time period, TVA has proposed to implement strict plant administrative procedures, supported by existing channel bypass annunciators and safety system valve alignment monitor lights, for the interim period from restart until the BISI system is installed.

Plant administrative procedures will require that:

(1) The alignment of all systems and components important to safety will be as the reactor coolant system (pressure boundary components) y is defi verified prior to unit startup. Equipment important to safet and associated pressurizer and pressure relief cystems, the residual heat removal system, engineered safety features (ESF) systems, ESF electric power systems, and cooling water systems necessary to operate the above systems. Additional aids will be in place to provide direct feedback to the operator regarding equipment availability such as posting orange stickers on inoperable instrument channels and tagging control room switches to indicate equipment out of service. As an added precaution, operators will be trained to evaluate equipment operability relative to support system availability, and to follow strict authorization and documentation processes prior to removing any safety-related equipment from service.

(2) Changes in the alignment of any system important to safety will be recorded on the applicable status sheet of the configuration control system. The operational status of critical systems, structures and components (CSSC); a record of the status of valves, power supplies, instrumentation, penetrations and structural components; will be required and maintained on the Configuration Log which will be prominently displayed in the control room. The shift supervisor or an authorized senior reactor operator will approve entry of items for removal from and return to normal alignment.

(3) Shift personnel being relieved will communicate information on any abnormal plant condition including temporary conditions. Shift personnel will be required by administrative ir.structions to convey pertinent items or activities in progress, off normal cr unusual conditions, and any limiting conditions for operations. Pre-shift briefings will also be required before each change of control room personnel. This will include the exchange of information such as special tests in progress, significant equipment deficiencies or inoperabilities and significant maintenance in progress.

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l (4) System operability will be demonstrated before a system is returned to service. Provisions will be implemented which verify proper system alignment through the use of status checklists for all modes of plant i

operation. As a final check, once every 24-hour shift, a physical walkdown of the CSSC systems will be conducted to ensure system availability and operability.

(5) Approval by the shift supervisor or his/her representative will be received prior to the performance of any activity on any systems important to safety or any activity that may affect systems important to safety. The shift supervisor or his/her representative will be notified when an activity authorized to be performed on a system important to safety is completed or a change occurs in the scope of the activity.

Plant operating instructions will require completion of a startup checklist before unit startup. This checklist will be used to verify correct alignment I

of systems important to safety. In addition, alignment of systems important l

to safety will be reviewed each shift. Any time a critical component is changed from its normal position or condition an entry will be made on the l

applicable status sheet of the configuration control system. Panel checklists will be reviewed each shift to verify that proper panel alignment exists for all systems important to safety.

i-Independent verification of the alignment of systems important to safety will be performed as required by administrative procedare. The requirements of the administrative procedure apply to the control of valves, breakers, or any component that would, if mispositioned, significantly degrade a safety function or present a safety concern.

Independent verification will be j

applied to placing and removing clearances and the return to service of equipment affected by plant instructions for the following systems:

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(1 Auxiliary building gas treatment system 2

Auxiliary feedwater system 3

Boron injection system 4

Component cooling water system (5

Containment isolation system (6

Containment spray (7) Emergency core cooling system

8) Emergency gas treatment system

9) Engineered safety features actuation system

10) Essential raw cooling water system High pressure fire protection in safety-related areas Post accident sampling system Radiation monitoring systems--Those parts of the system that provide isolation functions to effluent pathways or monitor direct release pathways to the environment 1

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1 (14) Radwaste systems--Those parts that isolate releases to the environment. This includes condensate demineralizer release tanks. This does not include the entire system, but only the valves that isolate the system from the environment.

1 Reactor coolant system l

Reactor protection system Residual or decay heat removal systems I

(18 Standby Diesel Generators (19)HVACDGsupportsystem (20) Upper head injection system (21)ClassIEelectricaldistributionsystemfortheabove-listedsystems j

(22) 125V vital de distribution systems--That part of the system that i

supplies control power essential for the shutdown boards to function

3.0 CONCLUSION

i The staff finds that the above interim procedures and measures provide i

adequate treatment of the concerns of Regulatory Guide 1.47 until,the cycle 4 refueling outage. The staff review of the new safety system SMS will be integrated into the detailed control room design review.

j, Principal Contributor:

F. Burrows Dated: June 1, 1987 e

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