ML20248E172
| ML20248E172 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 09/29/1989 |
| From: | Medford M TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 8910050089 | |
| Download: ML20248E172 (3) | |
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{
TENNESSEE VALLEY AUTHORITY-CHATTANOOGA. TENNESSEE 37401 6N 38A Lookout Place SEPl291989 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C.
20555 Gentlemen:
In the. Matter of Docket Nos. 50-327
)
Tennessee Valley Authority
)
50-328 SEQUOYAH NUCLEAR PLANT (SQN) - NRC INSPECTION REPORT NOS. 50-327/83-14 AND.
50-328/89-14 Enclosed is TVA's response to B. D. Liaw's letter to 0.' D..Kingsley, Jr.,
dated August 31, 1989, which transmitted the subject notice of violation.
If you have any questions concerning this submittal, please telephone M. A. Cooper at (615) 843-6651.
Very truly yours, TENNESSEE VALLEY AUTHORITY d1 C). &
/
Mark 0. Medford, Vice President and Nuclear Technical Director Enclosure cc (Enclosure):
Ms. S. C. Black, Assistant Director for Projects TVA Projects Division U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852 Mr. B. A. Wilson, Assistant Director for Inspection Programs TVA Projects Division U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 j
I NRC Resident Inspector Sequoyah Nuclear Plant g
2600 Igou Ferry Road Soddy Daisy, Tennessee 37379 l
l n e w s s ii3>
An Equal Opportunity Employer
ENCLOSURE 9
RESPONSE TO NRC INSPECTION REPORT NOS. 50-327/89-14 AND 50-328/89-14 B. D. LIAW'S LETTER TO 0. D. KINGSLEY, JR.,
DATED AUGUST 31, 1989 Violation 50-327, 328/89-14-01
" Technical Specification 6.8.1 requires in part that written procedures shall be establif ?d, implemented and maintained covering the activities listed in Appendix A of Regulatory Guide 1.33, Revision 2.
Surveillance Instruction SI-3, Revision 50, approved September 4,1986,. limits the maximum voltage on the 6900 volt Class IE busses at 7240 volts and the 480 volt busses at 504 volts. Corrective. action is required by SI-3 at 7260 volts and 508. volts, respectively, to reduce the voltage to nominal values. The same maximum voltage limits and corrective action were included in SI-3, Revision 68, approved August 23~ 1988.
This latest revision was in place on January 21, 1989.
- General Operating Instruction GOI-6, Revision 28, approved September 16, 1986, page 23, includes maximum voltage limits for normal operation at 7240 volt for the 6900 volt system and 504 volt for the 480 volt system. Corrective action is required by G01-6 at 7260 volts and 508 volts, respectively, to reduce the voltage to nominal values. The same maximum voltage limits and corrective action were included in G01-6, Revision 49, approved January 20, 1988.
This latest revision was in place on January 21, 1989.
System Operating Instruction 501-55-0M26, XX-55-26B, Revision 5, page 14, approved June 24, 1985, requires an alarm setpoint at 105% (7245 volts) and l
also requires immediate action to reduce shutdown board voltage to nominal values when 7245 volts is exceeded.
Contrary to the above, on January 21, 1989, during surveillance testing of emergency diesel generator 2A-A, the licensee failed to follow procedures to reduce voltage at the shutdown board and the board voltage remained at 7400 volts, as determined by calibrated recorder (Visicorder) charts. The overvoltage condition was allowed to persist the following day, January 22, 1989, as evidenced by voltage. recordings on page 140 of Surveillance Instruction SI-26.2A. This is a failure to follow procedures, SI-3, G0I-6, and 501-55-0M-26, as required by Technical Specification 6.8.1.
This is a Severity Level IV violation (Supplement I)."
- Admission or Denial of the Alleged Violation TVA adreits the violation.
I
m
- ;,. o Reason for the Violation The root cause of the violation was failure to follow procedures. A contributing cause was inadequate procedures. As requested by the cover letter, a discussion of the procedural inadequacies is provided below.
Although. General Operating Instruction (G0I) 6, Section G, "Onsite Power System Voltage Limits," provided guidance for responding to overvoltage conditions, the procedures that responded to or recorded overvoltage conditions (i.e., System Operating Instruction [S01] 55-0M26, XA-55-26A and 26B; Surveillance Instruction [SI) 3; Administrative Instruction [AI] 5; SI-7; and SI-7.1) failed to encompass the requirement to notify the lead electrical engineer. The SOI-55 annunciator response did not reference GOI-6, which provides guidance on how to lower the shutdown board voltage.
SI-3 only recorded voltage on a weekly basis.
AI-5, SI-7, and SI-7.1 did not require verification of shutdown board voltage. Also, no guidance was given to Electrical Engineering personnel on how to respond in the event the Operations-personnel contacted them concerning an overvoltage condition.
In addition to the above, Transmission and Customer Services (T&CS) issues a
. voltage schedule for SQN (165 1 kilovolt [kV]) and an operating procedure involving SQN.. This operating procedure restricted the tap on the intertie
" transformer bank (500/161/13 kV) to Tap 11 or less. This restriction did not provide SQN the flexibility needed to control the voltage on the 6,900-volt shutdown boards when Unit 2 was offline.
Corrective Steps That Have Been Taken and Results Achieved Immediate corrective actions consisted of issuance of a night order by Operations to provide adequate guidance for control of grid overvoltage and required action if that voltage is exceeded. Additionally, the lead l
electrical engineer sent a memorandum to all Electrical Engineering supervisors to provide guidance to his personnel of actions required when contacted by the shift operations supervisor of an overvoltage condition.
As long-term corrective actions, the procedures AI-5, SI-3, SI-7, SI-7.1, and S0I-55 have been revised to provide adequate and consistent guidance to Operations personnel. -This guidance includes directing Operations to reduce J
this overvoltage condition and notify the lead electrical engineer when J
overvoltage conditions occur., T&CS operating personnel have performed new j
load flow studies based on additional data and have issued revised operating j
procedures to remove the restriction of limiting the tap setting on the intertie transformer bank to Tap No. 11 or lower when Unit 2 is offline.
The power dispatchers were instructed to closely monitor the 161-kV bus voltage at
]
SQN and coordinate operations with the SQN operators to ensure the voltage i
schedule of 165 il kV is not violated.
Corrective Steps That Will Be Taken to Avoid Further Violations No further corrective actions are planned.
Date When Full Compliance Will Be Achieved I
TVA is in full compliance.
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