ML20235P391
| ML20235P391 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 09/29/1987 |
| From: | Gridley R TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| NUDOCS 8710070264 | |
| Download: ML20235P391 (4) | |
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o TENNESSEE VAL LEY AUTHORITY CH ATTANOOGA, TENNESSEE 374o1
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SN 157B Lookout Place 8EP 291987 i
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U.S. Nuclear Regulatory Commission d
ATT*1:
Document Control Desk Wssnington, D.C.
20555 Centlemen:
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In the Matter of
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Docket Nos. 50-327 i
Tennessee Valley Authority
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50-328 i
SEQUOYAH NUCLEAR PLANT (SQN) - REMOVAL OF SAFETY PARAMETER DISPLAY SYSTEM
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(SPDS) FROM THE CRITICAL STRUCTURES, SYSTEMS AND COMPONENTS (CSSC) LIST l
Reference:
Letter from L. M. Mills to A. Schwencer dated April 2, 1981 In the reference, TVA committed to include the SPDS on the CSSC list when the system became operational in October 1985.
SQN requests that this commitment be revised to remove SPDS from the CSSC list and place it under the control of SQN's limited Quality Assurance (QA) program as defined in Part I, section 1.3, of TVA's Nuclear Quality Assurance Manual (NQAM).
At the time the 1981 commitment was made, TVA did not have a limited QA program for equipment that required some aspect of QA but less QA control than the 10 CFR 50 Appendix B requirements. As a result of the lack of a limited QA program, TVA agreed to include SPDS on the CSSC equipment list even though SPDS is not a critical system and is not required for the mitigation of 10 CFR 100 events.
SQN proposes to control SPDS under the limited QA program rather than under CSSC rules and requirements.
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The constraints that CSSC requirements place on the maintenance and repair of SPDS equipment significantly increase computer downtime and contribute to the unavailability of the system.
Some of the problems encountered include:
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Circuit board repMcements:
Bad circuit board 6 are returned to the vendor for repair.
The vendor's standard practice is to either repair the circuit board or send a replacement board.
Because of the rapid changes in computer technology, a replacement circuit board typically undergoes configuration upgrades by l
the vendor.
The replacement circuit board performs an identical function as the faulty circuit board.
The vendor, however, occasionally places a new identification number / revision level, etc., on the replacement which slows the material procurement receiving aid inspection process under CSSC controls.
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K An Equal Opportunity Employer
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U,S. Nuclear Regulatory Commission 2.
Troubleshooting and maintenance repairs:
Under CSSC controls, any repairs that are made to SPDS hardware require material procurement for CSSC equipment, review of the work by maintenance planners, and review by QA before the repair work is 1
started.
This high level of procurement and review lowers availability-l and raises the degree of downtime.
Listing SPDS as CSSC defeats the 99-percent availability goals of NUREG-0696.
SQN's alternative to CSSC control is to place the SPDS under the limited QA program, which is defined in TVA's NQAM, section 1.3.
Threo areas of control l
i would be hardware, software, and inputs.
SQN currently provides control in these three subject areas under existing plant procedures for non-CSSC computer systems. A revision to the NQAM to place SPDS under the limited QA program would provide the proper level of control and would remove SPDS from I
the previously selected "CSSC safety-related" status, and correctly relegate j
J it to a non-CSSC nonsafety-related status. After the scope of SQN's limited QA program is defined and established within the NQAM for SPDS, new and existing plant procedures will be written and/or revised to implement the limited QA program.
SQN plans to complete the above actions for both units six months following unit 1 restart but no later than January 1, 1989.
The enclosure contains a i
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description of the commitments made in this letter.
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If you have any questions regarding this subject, please telephone 4
1 D. V. Goodin at (615) 870-7462.
Very truly yours, I
l TENNESSEE VAL
'Y AUTHORITY
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l R. Cr dley, Di ector Nuclear Safety and Licensing Enclosures cc:
see page 3 1
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f U.S. Nuclear Regulatory Commission SEP 291987 cc (Enclosures):
Mr. G. G. Zech, Assistant Director for Inspection Programs Of fice of Special Projects U.S. Nuclear Regulatory Commission 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 i
Mr. J. A. Zwolinski, Assistant Director for Projects Division of TVA Projects Office of Special Projects U.S. Nuclear Regulatory Commission 4350 East-West Highway EWW 322 l
Bethesda, Maryland 20814 Sequoyah Resident Inspector Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy Daisy. Tennessee 37379 l
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e ENCLOSURE SEQUOYAH NUCLEAR PLANT List of Conunitments 1.
Revise NQAM to identify the scope of the limited QA program'for SPDS within six months after unit I restart but no later than January 1, 1989.
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Revise and/or develop plant procedures to incorporate and implement the limited QA program for work affecting SPDS hardware, software, and inputs within six months af ter unit 1 restart but no later than January 1,1989.
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