ML20094B382

Responds to NRC Re Violations Noted in Insp Repts 50-424/95-19 & 50-425/95-19.Corrective Actions:Unit 2 EDG Voltage Regulator T2 & T3 Transformers Will Be Replaced W/ Improved Design as Soon as Practical

ML20094B382
Person / Time
Site:	Vogtle
Issue date:	10/27/1995
From:	Mccoy C GEORGIA POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LCV-0645-B, LCV-645-B, NUDOCS 9511010015
Download: ML20094B382 (8)

Text

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e -' Georgia Power Company

..- - 40 invemess Center Parkwar Post Offce Box 1295

- BJmingham, Alabama 35201

' Telephone 205 877 7122 C. K. Mccoy Georgia Power Vce Presdent, Nuclear i the southem electic system l Vogne Pro;cct October 27, 1995

. LCV-0645-B l

Docket No. 50-424 l 50-425 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555 Ladies and Gentlemen:

VOGTLE ELECTRIC GENERATING PLANT BEPLY TO A NOTICE OF VIOLATION Pursuant to 10 CFR 2.201, Georgia Power Company (GPC) submits the enclosed information for Vogtle Electric Generating Plant (VEGP). This submittal is in response to .

violations identified in Nuclear Regulatory Commission (NRC) Inspection Reports 50-424;425/ 95-19, dated September 29,1995, which documents the inspection conducted at VEGP during August 28 - September 1,1995.

As specifically requested in the NRC Inspection Report and Notice of Violation, this response also indicates the planned short term corrective actions related to GPC's use of the T2 and T3 transformers at VEGP until their replacement.

Should you have any questions feel free to contact this office.

1 Sincerely, C. K. McCoy 1

CKM/AFS i

Enclosure:

Reply to NOV 50-424;425/ 95-19-01 & 02 j t

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' U. S. Nuclear Regulatory Commission -

LCV-0645-B Page 2 ,

r cc: Georgia Power Company Mr. J. B. Beasley, Jr.

Mr. M. Sheibani NORMS U. S. Nuclear Regulatory Commission

. Mr. S. D. Ebneter, Regional Administrator Mr. L. L. Wheeler, Licensing Project Manager, NRR Mr. C. L. Ogle, Senior Resident Inspector, Vogtle l

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ENCLOSURE VOGTLE ELECTRIC GENERATING PLANT- UNITS 1 & 2 REPLY TO A NOTICE OF VIOLATION NRC INSPECTION REPORTS 50-424:425/95-19 VIOLATION A. 50-424:425/95-19-01 The following is a transcription of violation A as cited in the Notice of Violation (NOV):

"During an NRC inspection conducted on August 28 through September 1,1995, violations of NRC requirements were identified. In accordance with the " General Statement ofPolicy and Procedure for NRC Enforcement Actions," 10 CFR Part 2, Appendix C, the violations are listed below:

4 A. 10 CFR 50, Appendix B, Criterion XVI, " Corrective Actions", as implemented by the Vogtle Electric Generating Plant Operations Quality Assurance Policy Manual, Revision 12, requires, in part, that measures be established to assure that conditions adverse to quality, such as failures, malfunctions, deficiencies, defective material and equipment, are promptly identified and corrected.

Contrary to the above, the licensee failed to promptly identify and correct significant conditions adverse to quality, namely the degradation and failure of transformers in safety-related diesel generator voltage regulators. These failures are evidenced by the following l examples: 1 1

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1. Voltage regulator, S/N 3271, failed on March 13,1995. The cause of the failure was determined on May 2,1995 by the manufacturer. However, the licensee failed to take prompt corrective actions to inspect the other diesel generator voltage regulators for defective T3 transformers.

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2. During the performance of Diesel Generator (DG) Operability Test for DGI A per procedure 14980-1 on June 28,1995, severe voltage excursions were noted. Even though conditions adverse to quality were indicated prompt corrective actions were not taken to determine the cause of the voltage excursions. The surveillance was continued and completed as satisfactory.

This is a Severity Level IV violation (Supplement I)"

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RESPONSE TO VIOLATION A (50-424:425/95-19-01) )

l Admission or Denial of the Violation- l Georgia Power Company admits this violation.

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ENCLOSURE VOGTLE ELECTRIC GENERATING PLANT - UNITS 1 & 2 REPLY TO NOTICE OF VIOLATION NRC IN'iPECTION REPORTS 50-424

425/95-19 Reason for the Violation:

A(1). On March 13,1995, EDG 2B voltage regulator #1 was removed during troubleshooting after experiencing a voltage anomaly during post-modification testing. A deficiency card was initiated to address the problem. The EDG 2B voltage anomaly was caused by the modification miswiring of the transfer switch utilized to select either of the redundant

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automatic voltage regulators. Although there were no suspected problems with the voltage regulator, it was sent to the vendor test facility to verify that it was acceptable for

return to warehouse stock. During testing in May 1995, at the vendor test lab, a defective T3 transformer was identified. The voltage regulator with the failed T3 transformer was returned to the site for repair but was inadvertently returned to stock. Actions were initiated to procure and replace the defective T3 transformer.

Since the EDG 2B voltage anomaly had been caused by the modification miswiring and l

the modification miswiring was specific to EDG 2B, there was no sense of urgency nor was it considered necessary to perform a failure analysis on the T3 transformer or to 4 perform inspections of the T3 transformers in the other EDG voltage regulators. It was assumed that the T3 transformer failure could have resulted from the modification .

miswiring. In hindsight, further immediate investigation to determine if the T3 failure was caused by the modification miswiring would have been appropriate, since engineering i-reviews later determined that the modification miswiring could not have caused the T3 failure. The improper material" return-to-stock" also potentially contributed to a missed

opportunity to further investigate the T3 failure mechanism.

! A(2). Within minutes after opestors observed the EDG 1 A voltage anomaly on June 28,1995, the system engineer was dispatched to observe and investigate the problem. A known problem associated with oxidation on the power driven potentiometers was suspected due to similar symptoms. Under the direction of the system engineer, the diesel operator adjusted voltage higher and lower several times, until the problem was no longer evident.

Previous vendor and engineering recommendations to adjust the potentiometer in tiss manner had been proceduralized on an interim basis until replacement potentiometers could be procured and installed.

Following the EDG 1 A voltage anomaly that same morning, corporate and site engineering and management personnel held discussions to further analyze the anomaly and determine a course of action, if required. The adverse voltage condition was recognized and actions were initiated to comply with Technical Specifications (due to the brief period ofinoperability). Upon receipt of a further unexpected EDG trouble alarm, the EDG was immediately declared inoperable and an investigation started to determine the cause of the failure. Subsequent to this failure, an exhaustive event review was conducted.

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ENCLOSURE VOGTLE ELECTRIC GENERATING PLANT - UNITS 1 & 2 REPLY TO NOTICE OF VIOLATION NRC INSPECTION REPORTS 50-424:425/95-19 Corrective Steos Which Have Been Taken and the Results Achieved:

1. A successful surveillance test was performed utilizing the other redundant automatic voltage regulator and EDG 1 A was returned to service on June 29,1995. The redundant automatic voltage regulator with the failed T3 transformer which caused EDG 1 A to experience the severe voltage excursions, was replaced on July 7,1995. The "Information only" LCO was cleared on the same day after satisfactory completion of the EDG's operability test.

2. The automatic voltage regulator power driven potentiometers (PDP) for all EDGs were replaced and a preventive maintenance checklist has been generated to insure EDG PDPs are replaced periodically. l

3. Since all the EDG's voltage regulator's PDPs have been replaced, the EDG operability test procedures have been revised to remove the steps which were added pending their replacement. These procedures had previously directed operators to manually adjust voltage in order to " wipe-clean" the potentiometer prior to EDG loading.

4. All of the EDG's T2 and T3 transformer voltage taps were tested to detect improper I voltage output. EDG 1B voltage regulator # 1 was replaced because of a low voltage measurement on the 600V tap and all of the other EDG voltage regulator T2 and T3 transformer tap settings were found to have acceptable voltage output on all of their taps.

5. Materials Department personnel have been trained concerning the inadequate handling practices as identified in this violation and personnel have been made aware of the applicable material control procedure revisions.

Corrective Steos Which Will Be Taken to Avoid Further Violations:

1. The Unit 2 EDG voltage regulator T2 and T3 transformers will be replaced with an improved design as soon as practical. Material delivery to support installation is anticipated by February 29,1996. The Unit 1 EDG transformers will be replaced during the next refueling outage, which is currently scheduled to begin March 10, l 1996.

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2. Until the new transformers are installed, the planned short term corrective action includes performing preventive maintenance to ensure the T2 and T3 transformers are tested for proper output voltage. This will begin by October 31,1995, and periodically tisxeafter until replacement.

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ENCLOSURE )

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VOGTLE ELECTRIC GENERATING PLANT - UNITS 1 & 2 REPLY TO NOTICE OF VIOLATION NRC INSPECTION REPORTS 50-424:425/95-19 I

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3. This event will be included in the Licensed Operator Requalification Program. All applicable individuals will be made aware of this event by December 31,1995.

. I Date When Full Compliance Will Be Achieved:

Full compliance was achieved on July 7,1995, when the defective voltage regulator which had been inadvertently re-installed, was replaced and a satisfactory EDG operability surveillance test  !

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) VIOLATION B. 50-424:425/95-19-02 The following is a transcription of violation B as cited in the Notice of Violation (NOV): )

"During an NRC inspection conducted on August 28 through September 1,1995, violations of l 3

NRC requirements were identified. In accordance with the " General Statement of Policy and l Procedures for NRC Enforcement Actions," 10 CFR Part 2, Appendix C, the violations are listed  !

l below: l B. 10 CFR 50, Appendix B, Criterion XV, " Nonconforming Materials, Parts, or Components", as implemented by the Vogtle Electric Generating Plant Operations Quality Assurance Policy Manual, Revision 12, requires, in part, that measures be established to I control materials, parts, or components which do not conform to requirements in order to prevent their inadvertent use or installation.

Contrary to the above, on May 26,1995, measures to control a defective voltage regulator, S/N 3271, were not clearly established to prevent its return to warehouse stock and subsequent issue for installation in diesel generator DGI A June 29,1995.

i This is a Severity Level IV violation (Supplement I)."

RESPONSE TO VIOLATION B (50-424:425/95-19-02)

Admission or Denial'of the Violation: ,

1 l Georgia Power Company admits this violation.

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I ENCLOSURE i

VOGTLE ELECTRIC GENERATING PLANT - UNITS 1 & 2 )

REPLY TO NOTF S CJ ,10LATION  ;

NRC INSPECTION REPO[iTS 50-424:425/95-19 Reason for the Violation: i On March 13,1995, EDG 2B's voltage regulator #1 was removed due to a voltage drop experienced during post-modification testing. On March 27,1995, EDG 2B voltage reguh lor #2 l was removed following a voltage drop during Engineered Safety Features Actuation System (ESFAS) testing. As part of the investigation to determine the cause of the voltage anomalies, both voltage regulators were shipped to the vendor for testing. Since the vendor no longer had an approved 10 CFR 50 Appendix B Quality Assurance program in place, testing was conducted and documented through VEGP Work Order (WO) practices and procedures. Vogtle Electric i Generating Plant maintenance support personnel were present during all testing.

On May 2,1995 the voltage regulators were unpacked by VEGP maintenance support personnel

at the vendor's facility. Testing indicated that one voltage regulator was working properly while the other had a defective T3 transformer. The VEGP maintenance support personnel present during the testing were not qualified to perform the work needed to replace the T3 transformer; therefore both the acceptable and the defective voltage regulators were shipped back to VEGP.

VEGP material control procedures did not adequately provide a method to control safety-related material being sent and received from an offsite vendor with work being controlled by VEGP procedures and personnel. Procedures did not address receipt of defective material designated to be repaired by VEGP personnel and procedures. Additionally, specific guidance for control of the safety-related material was not adequately documented or included with the voltage regulator return shipment to VEGP. 1 l

Corrective Stcos Which Have Been Taken and the Results Achieved

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1. The defective voltage regulator which had been inadvertently re-installed on EDG 1 A was replaced and a satisfactory EDG operability surveillance test was performed on July 7,1995.

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2. VEGP material control procedures have been revised to incorporate specific instruction and guidance for performing repairs / testing of safety-related materials sent offsite using VEGP work control procedures. l

3. Materials Department personnel have been trained concerning the inadequate materials handling practices as identified in this violation and personnel have been made aware of the applicable new material control procedure revisions.

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r ENCLOSURE VOGTLE ELECTRIC GENERATING PLANT - UNITS 1 & 2 REPLY TO NOTICE OF VIOLATION NRC INSPECTION REPORTS 50-424:425/95-19 Corrective Steos Which Will Be Taken to Avoid Further Violations:

No further corrective actions are planned at this time.

Date When Full Comoliance Will Be Achieved:

Full compliance was achieved on September 13,1995, when the Materials Department personnel were trained on the applicable material control procedure revisions.

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