05000304/LER-1986-005, :on 860219,diesel Generators 2A & O Tripped During Performance of PT-11 Loading Tests.Caused by Inadvertent Partial Fuel Supply Valve Closure & Faulty Kurman Instrument Relay.Relay Replaced

:on 860219,diesel Generators 2A & O Tripped During Performance of PT-11 Loading Tests.Caused by Inadvertent Partial Fuel Supply Valve Closure & Faulty Kurman Instrument Relay.Relay Replaced

ML20155J219
Person / Time
Site:	Zion File:ZionSolutions icon.png
Issue date:	05/16/1986
From:	Pliml G, Sassaman S COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF ADMINISTRATION (ADM)
References
0274D, 274D, LER-86-005, LER-86-5, NUDOCS 8605220261
Download: ML20155J219 (4)

LER-1986-005, on 860219,diesel Generators 2A & O Tripped During Performance of PT-11 Loading Tests.Caused by Inadvertent Partial Fuel Supply Valve Closure & Faulty Kurman Instrument Relay.Relay Replaced

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(iv), System Actuation 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(viii)(8) 10 CFR 50.73(a)(2) 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(x)
3041986005R00 - NRC Website

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1 LICENSEE EVENT REPORT (LER)

Facility Name (1)

Docket Nuder (2)

Pace (3)

Zion. Unit 2 01 51 01 01 01 31 01 4 1lof!0!3 Failure of 0 diesel generator while 2A diesel generator was inoperable Event Date (5)

LER Neber (6)

Report Date (7)

Other Facilities Involved (8)

//j Revision Month Day Year Facility Names Docket Nueer(s) fj/j/ Sequential

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Month Day Year Year

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Nueer f

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Nueer

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01 51 01 01 01 I I 012 119 816 816 010 15

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Oli 0 15 116 816 0151010101 l l THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10CFR OPERATING (Check one or more of the followine) (11) 1 20.402(b) 20.405(c) 50.73(a)(2)(iv) 73.71(b)

Polder 20.405(a)(1)(i) 50.36(c)(1) 50.73(a)(2)(v) 73.71(c)

(10) 0l9 l8 20.405(a)(1)(ii)

_X_ 50.36(c)(2) 50.73(a)(2)(vii)

Other (Specify l

LEVEL 1

i 20.405(a)(1)(iii) 50.73(a)(2)(viii)(A) in Abstract below

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20.405(a)(1)(iv) 50.73(a)(2)(i) 50.73(a)(2)(viii)(8) and in Text)

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20.405(a)(1)(v) 50.73(a)(2)(ti)

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50.73(a)(2)(iii) 50.73(a)(2)(x) j j jj LICENSEE CONTACT FOR THIS LER (12) vn-gs4 AREA CODE n

Steven W. Sassaman. Technical Staff Engineer. Extension 320 3l1l2 714161-l210181 COMPLETE ONE LINE FOR EACH COMPONEN FAILURE DESCRIBED IN THIS REPORT (13)

CAUSE

SYSTEM COMPONENT MANUFAC-REPORTABLE

CAUSE

SYSTEM COMPONENT MANUFAC-REPORTA8LE TURER TO NPRDS TURER TO NPRDS X

ElK l Rll lY Cl6 l 314 Y

l l l l l l l A

ElK l 115 lV C16 l 314 N

l l l l l l l SUPPLEMENTAL REPORT EXPECTED (14)

Expected Month l Day 1 Year Submission j

lyes (If ves couplete EXPECTED SUBMISSION DATE)

X l NO l

l l

l APSTRACT (Limit to 1400 spaces, i.e, approximately fifteen single-space typewritten lines) (16) l On 2/19/96, 2A diesel generator was started for a perfonnance test (PT-11 Diesel Generator Loading Tast). Two minutes after starting, at 2030, 2A diesel tripped off due to a partially closed fuel oil day i

tink supply valve. O diesel was started for a PT-il test in response to 2A diesel inoperability. At 2117 0 diesel came up to rated speed, then tripped. A generating station emergency plan event was declared until 2A l

diesel had successfully coupleted PT-11 at 0030, 2/20/96. On 0 diesel, investigation found that a relay in I

the starting circuit failed to remain sealed in with one of its own contacts after the initial starting signal was given. The contact was off center and intennittently failed. Before the relay problem was found, a subsequent failure occurred at 2135 on 2/20/96 during a PT-11 test.

Safeguards starting was available through relays that would have bypassed the faulty relay. The relay was replaced and 0 diesel was successfully tested and back in service by 1040, 2/23/96.

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8605220261 860516 PDR ADOCK 05000304 ffcN S

PDR u

i ib 02.

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LICENSEE EVENT REPORT (LER) TEXT CONTINUATION

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l FACILITY NAME (1)

DOCKET NUMER (2)

_ LER NUMER (6)

Pace (3)

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Sequential

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Nueer

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Nueer Zion. Unit 2 0 l 5 1 0 1 0 1 0 l 310 14 8l6 010l5 0l1 012 0F 013 TEXT Energy Industry Identification System (EIIS) codes are identified in the text as [xx]

A.

PLANT CONDITIONS PRIOR TO EVENT:

i Unit 1:- MODE 1 - Power Operation RX Power - 98%

Unit 2: MODE 1 - Power Operation RX Power - 98%

B.

DESCRIPTION OF EVENT

On 2/19/96, 2A diesel generator was started for a perfonnance test (PT-11 Diesel Generator Loading Test).

7 The engine started at 2030, reached rated speed, but began to decelerate. The operator attempted to raise the engine speed, but the engine continued to decelerate until it tripped at 2032._ The first-out annunicator trip flag was "Overspeed". Due to the 2A diesel inoperability, O diesel was started for a i

PT-il test. At 2117, O diesel came up to rated speed, then tripped. The first-out annunciator trip flags were " Lube Oil Pressure, Vibration, and Overspeed". A generating station emergency plan (GSEP) unusual event was declared and the NRC was notified at 2143. The GSEP event remained in effect until 2A diesel had successfully coupleted PT-11 at 0030, 2/20/96.

I i

At 0117 on 2/20/86, a PT-11 test was successfully perfonned on 0 diesel generator. At this point however, j

the cause of the original 0 diesel generator failure was unknown. Therefore, at 1045, O diesel generator was taken out of service for troubleshooting. After approximately 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> of investigation, the engineer felt that he had located the problem. Following several successful maintenance starts, PT-ll test was attempted at 2135 on 2/20/85. During this test, O diesel generator again came up to rated speed and tripped off. At this point, another investigation of the entire starting system was perfonned. The source of the trouble was found on 2/22/86, and 0 diesel generator was given a successful PT-ll on 2/23/86 i

and placed back in service.

l l

The engine is a Cooper Bessemer KSV-16-T diesel that runs an emergency 4 megawatt generator.

C.

CAUSE OF EVENT

4 After an inspection of 2A diesel generator's fuel system was made, a partially closed fuel oil day tank l

supply valve was found. The valve is a plug type which is turned 90 degrees to go from full closed to full open. It was probably closed accidentally by stationmen cleaning the engine following a February 18th, 1986 PT-11. The fuel oil supply valves on the other diesel generators were inspected and verified open.

A faulty relay, in the Cooper Bessemer En-tronic Control system, caused the O diesel engine to trip soon after starting. The relay failed intemittently, thus trouble shooting involved intensive investigation j

of the entire starting system. The second failure to start, which occurred on February 20th at 2135 during a subsequent PT-ll test, led to discovery of the relay problem. A movable contact was found off center thus not always providing the continuity needed to keep the relay energized after the initial start signal was given. Without this self sealing action, the engine would trip itself and indicate a nonnal engine shutdown on the annunciator.

t The "Overspeed" annunciation for 2A diesel and the " Lube Oil Pressure, Vibration, and Overspeed" annunciations for 0 diesel were erroneous indications. The small pneumatic pistons for the annunciator l

flags may be scratched, thus preventing them from being locked out when the true flag is up. During maintenance runs while troubleshooting the engines, Technical Staff engineers saw the "Nonnal Panel Shutdown" flag come up first followed by other flags which did not lock out, i

i 02740 4

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LICENSEE EVENT REPORT (LER) TEXT CONTINUATION e

FACILITY NAME (1)

DOCKET NUPBER (2)

LER NbpBER (6)

Page (3)

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Ntaber f

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Number Zion. Unit 2 0 l 5101010131014 8l6 0l0l5 0 l1 0l3 0F 013 TEXT Energy Industry identification System (Ell 5) codes are identified in the text as [xx]

0.

SAFETY ANALYSIS

After each failure of 0 diesel generator, all engineered safety feature (ESF) buses were verified to have nonnal power. Diesels lA and 18 for Unit I and diesel 28 for Unit 2 were verified operable by PT-il testing. Diesel 2A was verified operable by PT-il testing at 0030 on 2/20/86 thus ending the GSEP condition.

lhe troubleshooting group discovered that at the time of its PT-ll failures, O diesel would still have started for a loss of power or safeguards actuation condition, because an independent set of relays would have bypassed the faulty relay. Therefore, O diesel was only inoperable for manual starts. Since the bypass relays would have started 0 diesel on a safeguards actuation, and since 2A diesel was back in service while O diesel was out of service for troubleshooting, there were always at least 2 diesel generators available to provide emergency power if needed.

E.

CORRECTIVE ACTIONS

Due to the location of the engine fuel oil isolation valves and the possibility of a recurrence, the valve handles have been removed on all engines. A caution card has been attached to each engine fuel oil isolation valve with instructions to leave the valve in the open position and to remove the valve handle.

lhe faulty relay in the O diesel generator control cabinet was replaced with a new one. Additional starts were perforred using a brush recorder to monitor key portions of the starting circuits. No other problems were indicated. The diesel was given a successful PT-il test on February 23rd and placed back in service.

Work Requests have been written to rebuild all diesel generator first-out annunciator panels. No further corrective actions are required.

F.

PREVIOUS OCCURRENCES

1 lhere have been no previous occurrences of fuel oil supply valves being accidentally closed.

1 A search of the NPRDS computer files did not indicate previous relay trouble of this kind in the Cooper Bessemer En-tronic control system.

G.

COMPONENT FAILURE DATA

I MANUFACTURER NOMENCLATURE MODEL NUPBER MG PART NUPEER Kunnan Instrument 3 Pole, Double threw Kurman Instrument Cooper Bessemer Corp. (made for 11 pin plug relay, Corp. No.: 2603C Co. No.: 2-04E-158-001 Cooper Bessemer) 1 3/8" X 1 3/8" X 2 1/4",

clear plastic cover 02140

r O Zi;n Gen:riting Stition Commonw::lth Edi:on 101 Shiloh Blvd.

Zion, Illinois 60099 Telephone 312/746-2084 May 16, 1986 t

U.

S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555

References:

10CFR50

Dear Sir:

The enclosed Supplemental Licensee Event Report from Zion Generating Station is being transmitted to you to add additional information to the event description.

This report is number 86-005-01, Docket No. 50-304/DPR-48.

Very trul

yours,

/

lG.

f<

J.' P iml Station Manager Zion Generating Station GJP/gn

Enclosure:

Licensee Event Report No. 86-005-01 Attachment cc:

J. G. Keppler, NRC Region III Administrator M.

Holzmer, NRC Resident Inspector INPO Record Center CECO Distribution List