05000269/LER-1983-005, Forwards LER 83-005/03L-0.Detailed Event Analysis Encl

Forwards LER 83-005/03L-0.Detailed Event Analysis Encl

ML20069L370
Person / Time
Site:	Oconee
Issue date:	04/18/1983
From:	Tucker H DUKE POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20069L372	List: 05000269/LER-1983-005, Forwards LER 83-005/03L-0.Detailed Event Analysis Encl 05000269/LER-1983-005-03, /03L-0:on 830316,engineering Evaluation Revealed That Double Isolation Criteria Not Met for Standby Shutdown Facility Makeup Water Pump tie-ins to Fuel Transfer Tubes. Caused by Design Deficiency.Procedures Will Be Revised
References
NUDOCS 8304280181
Download: ML20069L370 (3)

LER-1983-005, Forwards LER 83-005/03L-0.Detailed Event Analysis Encl

Event date:
Report date:
2691983005R00 - NRC Website

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DUKE POWER GOMPANY P.O. BOX 33189 CHARLOTTE, N.o. 28949 HAL B. TUCKER TELEP95ME vuon rosesmawr (704) DNMI April 18, 1983

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Mr. James P. O'Reilly, Regional Administrator U. S. Nuclear Regulatory Commission

'3 Region II Mi 7

101 Marietta Street, NW, Suite 2900 g

'r Atlanta, Georgia 30303

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Re: Oconee Nuclear Station u

Docket No. 50-269

Dear Mr. O'Reilly:

Please find attached Reportable Occurrence Report R0-269/83-05. This report is submitted pursuant,to Oconee Nuclear Station Technical Specification 6.6.2.1.b(2) which concerns operation in a degraded mode permitted by a limiting condition for operation, and describes an incident which is considered to be of no significance with respect to its effect on the health and safety of the public. My letter of April 15, 1983 addressed the delay in preparation of this report.

Very truly yours, g

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v Hal B. Tucker JCP/php Attachment cc: Document Control Desk U. S. Nuclear Regulatory Commission Washington, D. C. 20555 INPO Records Center Suite 1500 1100 Circle 75 Parkway Atlanta, Georgia 30339 Mr. J. C. Bryant

- NRC Resident Inspector Oconee Nuclear Station Mr. E. L. Conner, Jr.

' Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission

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Washington, D. C. 20555 60

\\C of 8304280181 830418 gDRADOCK 05000269 6 d7 PDR

Duke Power Company Oconee Nuclear Station Report Number:.R0-269/83-05 Report Date: April 15, 1983 Occurrence Date: March 16,-1983 Facility: Oconee Units 1, 2, and 3, Seneca, South Carolina

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Identification of Occurrence: Failure to meet double isolation criterion for the SSF RC Makeup System Conditions Prior to Occurrence: Oconee 1:

100% FP-Oconee 2:

100% FP Oconee 3: 100% FP Description of Occurrence: On March 16, 1983, an Engineering evaluation conducted as part of follow-up actions concerning adequate containment isolation provided by containment isolation valves determined that the double isolation criterion was.not met for the Standby Shutdown Facility (SSF) Reactor Coolant Makeup Pump tie-in'to the Fuel Transfer Tubes. The. valves are identified on Attachments 1, 2, 3,Jand 4.

At the time of this determination the status of the valves inside the RB containment could not be confirmed. Later, during the course of the investigation, the position of the valves was determined by documentation review.

This is a violation of the Final. Safety Analysis Report (FSAR) General Design Criterion 53, and a degraded mode of operation per Technical Specification (T.S.)

.3.6.. Criterion 53, containment Isolation Valves, states that piping that requires closure under accident conditions is provided with double isolation valves, and all isolation valves inside the Reactor Building (RB) regriring remote operation are electrically operated.

T.S. 3.6 requires that containment integrity be maintained, that all non-automatic containment valves are closed as required, and in this case means that two valves on the RB side are to be closed.

The SSF was' designed to provide'an alternate means of shutting down each Oconee unit to hot shutdown condition and maintaining the' unit (s) at this condition for'approximately three days. It is nc ' yet. operational.- The design for the

~SSF was submitted in February 1.978 to the NRC, and Duke received their conceptual

- approval in December 1978.

In' July 1981, work was started on the SSF Reactor Coolant:(RC) Makeup System.on Unit 1 during its refueling outage.

Similarly, work was started on the' same system on Units 2 and 3 in January 1982 and May 1982, respectively. The tie-ins were completed during each unit's outage.

Apparent Cause of Occurrence: The cause of this occurrence was design deficiency resulting from inadequate review on the part of-the designers and other responsible qualified personnel. The system was not designed correctly nor properly aligned

- once installed to satisfy the required design criterion.

It was not recognized

that the-connection to the transfer tubes required double isolation. A possible contributing ~ factor is that most Reactor Building' penetrations teve one isolation valve inside the-RB and one' isolation valve outside the RB.

Manually operated

- valves (HP-428 and SF-97) will be changed to electrically operated valves to

satisfy the' double. isolation requirement before the system becomes operational.

Analysis of Occurrence: After investigation, the status of the manual isolation valves inside the RB was confirmed to be. closed, and also the system's piping was seismically _ qualified. Therefore, actual containment integrity was not violated..By verifying shut Transfer Tube "A" and "B" isolation valves (SF1 and SF2) on all three units, and since valves SF-97 and HP-428 on all three units were locked shut, double isolation was achieved on each transfer tube.

The entire SSF RC Makeup' System was designed as a seismic system so, in.the event of an earthquake or severe transient, the line is not postulated to break.

The likelihood of an earthquake or a severe transient in conjunction with a Loss of Coolant Accident is very small.

In the unlikely event radioactive leakage through the inside containment isolation valve occurred it would have to enter the bottom of the Spent Fuel Pool and rise through several feet of_ water to the Spent Fuel Pool room. The Spent Fuel Pool room has a separate ventilation system that is capable of being manually started after a Radiation Indicator Alarm. Area monitors exist in the Spent Fuel Pools to alert the operators to any abnormal radiation condition.

The health and safety of the general public were not endangered.by this incident.

Corrective Action

SF 1 and 2 on all three units were verified shut and tagged shut. Also, the handwheel operators were removed and locked up.

HP-428 and SF-97 will be. changed from manual to electric motor operated valves during the forthcoming refueling outages of each unit. Relief valve 3HP-429 will be removed.

Relief valves 1HP-429 and 2HP-429 which were scheduled for future installation will not be installed.1 A listing of SSF RC makeup isolation valves and their current ~ position is contained in Attachment 1.

Line drawings of these current valve arrangements and positions for each unit-are shown in Attachments 2, 3, and 4.

Design Engineering has revised their procedure to require a concept review by the Safety Review and Licensing (SRAL) group before a design may be released.

The SRAL group will also complete all design Safety-Evaluation Checklists. A program will be developed at.Oconee-Nuclear Station to train all qualified reviewers on their responsibilities as qualified reviewers. A task force, at the Oconee Station, has.been formed to study methods to prevent recurrence of

. incidents dealing with containment integrity.