RBG-45087, Special Rept:On 990510,LPCI a & LPCS Injected Into Rv for Less than Two Minutes.Caused by Electrical Transient in One of ECCS Power Supplies.Operators Verified Reactor Cavity Level & Closed Injection Valves to Stop Injection

Special Rept:On 990510,LPCI a & LPCS Injected Into Rv for Less than Two Minutes.Caused by Electrical Transient in One of ECCS Power Supplies.Operators Verified Reactor Cavity Level & Closed Injection Valves to Stop Injection

ML20210M766
Person / Time
Site:	River Bend
Issue date:	08/06/1999
From:	King R ENTERGY OPERATIONS, INC.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
RBF1-99-0200, RBG-45087, NUDOCS 9908100172
Download: ML20210M766 (3)

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Ent:rgy Operations. Inc.

' / River Bend Station (6.,-;4l 5485 U S. Highway 61 P. O. Box 220 y St. Francisville, LA 70775 Tel 225 336 6225 Fax 225 635 !068 Rick J. King Dnector Nuclear Safety Assurance August 6,1999 U.S. Nuclear Regulatory Commission Document Control Desk Washington, D.C. 20555

Subject:

River Bend Station - Unit 1 Docket No. 50-458 Special Report: LPCI 'A' and LPCS Injection File No.: G9.5, G9.25.1.7 RBF1-99-0200 RBG-45087 Ladies and Gentlemen:

- This special report is being submitted pursuant to RBS Technical Requirement 5.6.9.2 to report information related to an Emergency Core Cooling System (ECCS) injection into the reactor vessel. The technical requirement requires a special report describing the circumstances of the i event, the total accumulated actuation cycles and the current usage factor for each affected nozzle when that factor exceeds 0.7. This event was previously reported in LER 99-0011-00 dated June 9,1999.

EVENT DESCRIPTION At 1658 on May 10,1999, with the plant in Mode 5 for a refueling outage, Low Pressure Coolant

' Injection (LPCI) 'A' and Low Pressure Core Spray (LPCS) injected into the reactor vessel for less than two minutes. Main control room (MCR) operators appropriately verified reactor cavity level and closed the injection valves to stop the injection. About two inches of water were added to the reactor cavity from the suppression pool. An electrical transient in one of the ECCS power i supplies caused the event.

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9900100172 990006- f / *f- lD PDR ADOCK 05000458 S PM -

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,.l, l Spcial Report: LPCI 'A' and LPCS Injection L August 6,1999 -

RBF1-99-0200 RBG-45087

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Page 2 of 3 The root cause of the electrical transient was determined to be a failed, unsealed capacitor on a Rosemount trip unit. The vendor failure analysis indicated that the capacitor failure' caused a short from the positive 24 volt DC (VDC) power supply to the chassis ground. The short then caused a fuse to blow that initiated the transient to the power supplies.

This event is not safety significant. Shutdown cooling was operating and was not impacted by this event.

f NOZZLE SPECIFIC DATA The cumulative usage factors for the LPCI 'A' and LPCS nozzles are well below the required 0.7.

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The current number of total accumulated actuation cycles since commercial operation is as follows:

LPCI 'A' Nozzle 8 Actuation Cycles

- LPCS Nozzle . 1 Actuation Cycle j l

If thers cre any questions concerning this issue, please contact David Lcrting at (225) 381-4157.

Sincerely, s

.j W

Rick J. King Director-Nuclear Safety Assurance RJK/DLM

Spc cial Report: LPCI 'A' and LPCS Injection -

A'ugust d,1999 RBF1-99-0200

' RBG 45087 Page 3 of 3 -

cc: Mr. Robert Fretz NRR Project Manager U.S. Nuclear Regulatory Commission M/S OWFN 13-D-18 Washington, DC 20555 NRC ResidentInspector P.O. Box 1050 St. Francisville, LA 70775 U.S. Nuclear Regulatory Commission Region IV 611 Ryari Plaza Drive, Suite 400 Arlington, TX 76011 I

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