05000286/LER-2009-004, Regarding Automatic Reactor Trip Due to High Steam Generator 32 Water Level Caused by Inadequate 31 Main Feedwater Pump Governor Valve Setting and 32 Main Steam Generator Level Controller Set-Up

Regarding Automatic Reactor Trip Due to High Steam Generator 32 Water Level Caused by Inadequate 31 Main Feedwater Pump Governor Valve Setting and 32 Main Steam Generator Level Controller Set-Up

ML092330119
Person / Time
Site:	Indian Point
Issue date:	07/27/2009
From:	Pollack J Entergy Nuclear Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NL-09-0746 LER 09-004-00
Download: ML092330119 (7)

LER-2009-004, Regarding Automatic Reactor Trip Due to High Steam Generator 32 Water Level Caused by Inadequate 31 Main Feedwater Pump Governor Valve Setting and 32 Main Steam Generator Level Controller Set-Up

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(1), Submit an LER, Invalid Actuation 10 CFR 50.73(a)(2)(iv)(A), System Actuation
2862009004R00 - NRC Website

text

Entery Indian Point Energy Center 450 Broadway, GSB P.O. Box 249 Buchanan, N.Y. 10511-0249 Tel (914) 734-6700 i

J. E. Pollock Site Vice President NL-09-074 July 27, 2009 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Stop O-P1-17 Washington, D.C. 20555-0001

SUBJECT:

Licensee Event Report # 2009-004-00, "Automatic Reactor Trip Due to a High Steam Generator 32 Water Level Caused by Inadequate 31 Main Feedwater Pump Governor Valve Setting and 32 Main Steam Generator Level Controller Set-up" Indian Point Unit No. 3 Docket No. 50-286 DPR-64

Dear Sir or Madam:

Pursuant to 10 CFR 50.73(a)(1), Entergy Nuclear Operations Inc. (ENO) hereby provides Licensee Event Report (LER) 2009-004-00. The attached LER identifies an event where the reactor automatically tripped, which is reportable under 10 CFR 50.73(a)(2)(iv)(A).

As a result of the reactor trip, the Auxiliary Feedwater system was actuated which is also reportable under 10 CFR 50.73(a)(2)(iv)(A). This condition was recorded in the Entergy Corrective Action Program as Condition Report CR-IP3-2009-02494 and CR-IP3-2009-02710.

There are no new commitments identified in this letter. Should you have any questions regarding this submittal, please contact Mr. Robert Walpole, Manager, Licensing at (914) 734-6710.

Sincerely, JEP/cbr cc:

Mr. Samuel J Collins, Regional Administrator, NRC Region I NRC Resident Inspector's Office, Indian Point 3 Mr. Paul Eddy, New York State Public Service Commission LEREvents@inpo.org e'

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Abstract

On May 28, 2009, the Control Room received 32 MBFP vibration alarms and reduced power to approximately 65% and removed the 32 MBFP from service.

The 31 MBFP was unable to supply sufficient feedwater (FW) flow to maintain Steam Generator (SG) levels which resulted in all four main FW regulating valves (FRV) opening.

SG-31, 33, 34 water levels recovered but the SG-32 water level increased and continued increasing after the 32 FRV was placed in manual.

The 32 SG level reached the high level trip initiating a turbine trip that resulted in a reactor trip.

All control rods fully inserted and all required safety systems functioned properly.

The Auxiliary Feedwater System automatically started as expected.

The root cause was improper MBFP governor valve stroke due to poor vendor oversight of a maintenance work order which was performed without completing MBFP governor valve stroke readings, and 32 SG level controller set-up due to inadequate programmatic control of controller settings.

Contributing causes included 1) an inadequate MBFP turbine inspection procedure which did not specify a check of governor linkage clearances,

2) failure of vendor to adhere to procedure by not documenting 31 MBFP governor valve settings, 3) Ineffective corrective action due to failure to check HP governor stroke as planned.

Significant corrective'actions include: adjustment of the 31 MBFP governor and coaching of Maintenance personnel on requirements for contractor oversight, and including the event in maintenance training.

Procedure 0-TUR-402-MFW will be revised to require stroke measurement of governor valves and linkage clearance check, and SG Level Control settings will be reviewed for adequacy.

The event had no effect on public health and safety.

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There were no significant potential safety consequences of this event under reasonable and credible alternative conditions.

A RT and the increase in SG level is a condition for which the plant is analyzed. This event was bounded by the analyzed event described in FSAR Section 14.1.10, "Excessive Heat Removal Due to Feedwater System Malfunctions."

Excessive FW additions is an analyzed event postulated to occur from a malfunction of the FW control system or an operator error which results in the opening of a FW control valve.

The analysis assumes one FW valve opens fully resulting in the excessive FW flow to one SG.

For the FW system malfunction at full power, the FW flow resulting from a fully open control valve is terminated by the SG high level signal that closes all FW control valves and trips the MBFPs and the main turbine.

A TT initiates a RT.

The analysis for all cases of the excessive FW addition initiated at full power conditions with and without automatic rod control, show that the minimum DNBR remains above the applicable safety analysis DNBR limit, the primary and secondary side maximum pressures are less than 110% of the design values, and all applicable Condition TI acceptance criteria are met.

For this event, rod control was in automatic and all rods inserted upon initiation of the RT.

The AFWS actuated and provided required FW flow to the SGs.

RCS pressure remained below the set point for pressurizer PORV or code safety valve operation and above the set point for automatic safety injection actuation.

Following the RT, the plant was stabilized in hot standby.