05000295/LER-1997-010, :on 960316,reactor Trip Due to Equipment Failure Occurred.Caused by New But Defective Pneumatic Vol Booster on Valve.Pneumatic Vol Booster for 1C Main FW Regulating Valve Replaced

:on 960316,reactor Trip Due to Equipment Failure Occurred.Caused by New But Defective Pneumatic Vol Booster on Valve.Pneumatic Vol Booster for 1C Main FW Regulating Valve Replaced

ML20141H529
Person / Time
Site:	Zion File:ZionSolutions icon.png
Issue date:	05/19/1997
From:	Brennan N, Starkey R COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-97-010, LER-97-10, NUDOCS 9705230332
Download: ML20141H529 (4)

LER-1997-010, on 960316,reactor Trip Due to Equipment Failure Occurred.Caused by New But Defective Pneumatic Vol Booster on Valve.Pneumatic Vol Booster for 1C Main FW Regulating Valve Replaced

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(iv), System Actuation
2951997010R00 - NRC Website

text

Q>mmonwealth fibwin G>mpany Zion Generating Mation 101 Shiloh Ikiulevard Zion, IL 6(W) 2797 Trl H 17 762086 May 19 -1997 U.S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 The enclosed Supplemental License Event Report number 96-010-01. Docket No. 50-295/DPR 39 from Zion Generatirg Station is being transmitted to update both the cause of the event and the corrective action to prevent recurrence of the event.

Very truly yours, MM For Sin /97 R. Starkey Station Manager Zion Generating Station RS/NB/js Enclosure: Licensee Event Report cc:

NRC Region III Administrator f

NRC Resident Inspector J

IDNS Resident Inspector i

INPO Record Center Illinois Department of Nuclear Safety i

a e

230010 9705230332 970519 PDR ADOCK 05000295 lll !.!. a a

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LICENSEE EVENT REPORT (LER)

FAClllTY NAME DOCKET NUMLLR PAGE 0l5l0l0l0l2l9l5 1l0Fl0l3 ll0N STAil0N UNIT 1 TITLE React;.t Trip Due to Equipmerit Failure EVENT DATE LER NUMBER REPORT DATE OTHER FAClllTIES INVOLVED MONTH DAY YEAR YEAR SEQ. NUMBER REVISION MONTH DAY YEAR FACILITV NAMES DOCKET NUMBER (S) l IIIIII 0!3 1!8 9

! 6 9l6 0l1!0 0l1 0l5 1!9 9l7 l l l l l l l

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TH!S REPORT !S SUBMITTED PURGUANT TO THE REQUIREMENTS DF 10 CFR k (CHECK ONE OR MORE OF THE FOLLOWING)

OPERATING MODE 1

20.402M 20.405(el X

50.73(aH2)Gv) 73.71M 20.405(eH1)GI 50.36tcW1) 50.731aH21M 73.71(c)

POWER LEVEL i 1 0l2]O 20.405(aH1)Si) 50.36(c)(2) 50.73(aH2 Hen)

OTHER (Spacdy in Abstract below 20.405(aH1)Giil 50.73(aH2)lil 50 73(sW2HviiiHAl and in Text, NRC Form 366A) 20.405(aH1)Gv) 50.73(aW2)Gi)

M.*2 X2HviiiHB) 20.4051sH1Hv) 50.73(aH2)Glil 50.73(aHWul LICENSEE CONTACT FOR THIS LER NA:7.E TELEPHONE NUMBER Neil M. Brennan, Root Cause est. 2380 8l4l7 7l4l6l-l2l0l8l4 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT

CAUSE

SYSTEM COMPONENT MANUFACTURER

CAUSE

SYSTEM COMPONENT MANUFACTURER TO NPRDS TO NPRDS B

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F 1

3 0 I

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I I I I I I SUPPLEMENTAL REPORT EXPECTED EXPECTED MONTH DAY YEAR SUBMISSION I

YES. ftf yes. complete EXPrCTkD SUBMISSION DATE)

NO DATE ABSTRACT (Umst to 1400 spaces, to.. app,onimately fdtnen single-space typewritten knes).

On March 16,1996, Unit 1 was returning to service. At approximately 20% reactor power, Steam Generator (S/G) fndwater (FW) control was being transferred from the FW Bypass Regulating Valves to the Main FW Regulating vdves. Af ter the transfer,1C S/G level continued to increase despite efforts to close the 1C Main FW Regulating j

ydve (1 LCV-FW520). The reactor subsequently tripped on 1C S/G Level High High although closed valve indication was observed prior to reaching 70% level.

The cause of this event was a new but defective pneumatic volume booster on the valve. The booster spring seat was found to be stuck in a position that would prevent the venting function.

J Corrective actions include response time testing the Unit 2 Main FW Regulating valves and conducting a bench test br:ak in period on similar components prior to issuing them for use.

Thi safety significance of this event is minimal.

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i ZLERi96013,ler(1)

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LICENSEE EVENT REPORT (LER) TEXT CONTINUATION FACRJTY NAME DOCKET NUMBER LER NUMBER PAGE YEAR SED. NUMBER REVIS!0N LON NUCLEAR POWER STATION UNIT 1 l

ol5lololol2lsl5 sls ol1l0 ol1 ol2 ol3

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0F TEXT Energy industry identdcaten Syston (Ells) codes are identdud in the test es [XX)

A.

PLANT CONDITIONS PRIOR TO EVENT Unit 1 MODE,,l_ - Power Ooerations Rx Power 70%

RCS [AB] Temperature / Pressure 550*F/2235 psig B.

DESCRIPTION OF EVENT

On March 16,1996, Unit 1 was returning to service. The unit was placed on line at approximately 2215 hrs.

j At approximately 20% power, Nuclear Station Operator (NSO) began transferring Steam Generator [SB) (S/G) feedwater [SJ) (FW) control from the FW Bypass Regulating Valves to the Main FW regulating valves. The NSO l

reported that the 1C (1LCV-FW520) and the 1D (1LCV-FW530) Main FW Regulating valves appeared to be i

sluggish but responding sufficiently to allow the transfer to continue. After the transfer, the NSO began to experience difficulty in controlling the 1C S/G level,1C S/G level continued to increase despite the NSO's j

efforts te close the 1C Main FW Regulating valve (1LCV-FW520). The NSO observed closed valve indication l

prior to reaching 70% level at which time the reactor tripped on 1C S/G Level High High (2256) water level.

Emergency Procedure E-0, " Reactor Trip or Safety injection," was entered and the unit stabilized.

C.

CAUSE OF EVENT

The cause of this event was a defective pneumatic volume booster on the valve. The booster spring seat was found to be stuck in a position that would prevent the venting function. This would cause a slow responding i

valve. The 1C Main FW Regulating valve was tested. It took approximately 3 minutes for the 1C Main FW Regulating to begin to respond to a change in demand. Typical response time is expected to be 3 to 10 i

seconds.

The spring seat surface finish was found to have a roughness average value of 125 micro-inches. This finish was verified to be the specification finish per Fisher Control. Fisher also specifies lubrication of the spring seat.

i The failed component, which was new and had been installed prior to the startup, was found with the proper surface finish and lubricated. Bench testing was able to duplicate the failed condition several times. However, after some " break in" time, the valve performed properly on subsequent tests. Therefore, though the valve was j

within the manufacturer's tolerances, the cause of the sticking appears to be related to the need to exercise the components to remove any final surface irregularities.

i D.

SAFETY ANALYSIS

1 l

This event is reportable pursuant to 10 CFR 50.73(a)(2)(iv) which requires a 30-day written report when any l

event or condition resulted in a manual or automatic actuation of any engineered safety feature.

l 1

l S/G high high level is intended to provide protection against S/G overfill and the potential for moisture carry over l

to the main turbine. In this event, the high high level on 1C S/G was reached due to a failure of the pneumatic l

volume booster on the 1C Main FW Regulating Valve (1LCV-FW520). The unit responded as expected with a turbine trip and reactor trip. Therefore, this event had no impact on the health and safety of the public.

ZLER\\96013.ler(2)

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l LICENSEE EVENT REPORT (LER) TEXT CONTINUATION l

i FACILITY hAME DOCKET NUMBER LER NUMBER PAGE l

YEAR SEQ. NUMBER

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HEVISION Il0N NUCLEAR POWER STATION UNIT 1 o l s l o l a l o l 2ls ls s le olilo oli ol ola i

or ttXT Energy industry identificaten System (Ells) codes are identifed in the text es IXX)

E.

CORRECTIVE ACTIONS

1. The pneumatic volume booster for the IC Main FW Regulating valve was replaced.

t

2. All four Unit 1 Main FW Regulating valves were response time tested.

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3. The Unit 2 Main FW Regulating valves will be response time tested at the next cpportunity.

(295-180-96-013-01) l

4. Material Management placed the spare volume boosters on hold until bench testing is conducted.

i

5. Volume booster installation practices will include a bench testing break-in period prior to issuing the I

component for use. (295-180-96-013-03).

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F.

PREVIOUS EVENTS SEARCH AND ANALYSIS No previous events were identified from the results of a search of Zion's Nuclear Tracking System database.

G. COMPONENT FAILURE DATA

Manufacturer Nomenclature Model i

Fisher Controls Volume Booster Type 2625 r

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