05000373/LER-1990-007
| ML20055G843 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 07/18/1990 |
| From: | Diederich G, Tennyson M COMMONWEALTH EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| LER-90-007-07, LER-90-7-7, NUDOCS 9007240223 | |
| Download: ML20055G843 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| 3732090007R00 - NRC Website | |
text
. . - . .. - _- . ~ _ _ . . - _ . ._ __ -
't 4s j TI Commonwoolth Edloon I
[Mc LaSalle County Nuclear Station
.t b _ ;) RuralRoute #1, Box 220 l
4
\ '> Marseilles,lilinois 61341 I
- Telephone 815/357 6761 I
July 18, 1990 j
i Director of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Mail Station P1-137 Nashington, D.C. 20555
Dear Sir:
Licensee Event Report #90-007-00, Docket #050-373 is being submitted to your office in accordance with 10CFR50.73(a)(2)(v).
G. J. Diederich .
ffStationManager ;
LaSalle County Station '
GJD/MT/ls Enclosure
)
l xc: Nuclear Licensing Administrator NRC Resident Inspector '
- _ NRC Region III Administrator l INPO - Records Center l
9007240223 90Q710 PDR ADOCK0500g3f3 K 2.1 19
,s /
LICENSEE EVENT CPORT (LER)
F E0 Facility Name (1) Docket Number (2) Pane (3)
LaSalle County Station unit 1 01 51 01 01 01 31 71 3 1lof!0l4 Title (4) heactor Core Isolation Coolino Trio on Mechanical Overnoeed durino Surveillance Testino Event Date (5) LER thauber (6) hemort Date (7) Other Facilities involved (8)
Month Day Year Year /// Sequential /// Revision Month Day Year Facility Names Docket Number (s) fff fff T// thmber /// Mumber 0151010101 I l 0151010101 l l
- ~~
01 6 11 s 91 0 91 0 01017 010 011 11 8 91 0 THl$ REPORT !$ SUBMITTED PUR$uANT TO THE REQUIREMENTS OF 10CFR 1 (Check one or more of the followine) (II)
M00E W 20.402(b) ,,,,,,, 20.405(c) ,,,,_, 50.73(a)(2)(lv) __,,, 73.7)(b)
POWER ,,__ 20.405(a)(1)(1) ,,_,_ 50.36(c)(1) _X,,,_ 50.73(a)(2)(v) ,,,,,, 73.71(c)
LEVEL ,,_,,, 20.40$(a)(1)(ll) ,_,, 50.36(c)(2) ,,__ 50.73(a)(2)(vil) _,_,
other ($pecify (10) 1! 0! O _,,, 20.405(a)(1)(111) , 50.73(a)(2)(l) ,,,,_ 50.73(a)(2)(vill)(A) in Abstract l ////////////////////////// ,,,,,,, 20.405(a)(1)(lv) ,,,,,,, 50.73(a)(2)(ll) ,,,_,, 50.73(a)(2)(vill)(B) below and in l ////////////////////////// ,,,,,,,, 20.405(a)(1)(v) __,, 50.73(a)(2)(lli) ,,,,,,, 50.73(a)(2)(x) Text)
LICFWSEE CONTACT FOR THIS LFR (12)
Name TELEPHONE NUMBER ,
AREA CODE !
Michael Tennyson. Technical Staff Enoineer. Fat. 2704 8 l 1 15 31 51 11 -l 61 fl 61 1 i C09 TETE ONE LlWE FOR EACH C090NENT FAILURE DESCRIBF0 IN THIS REPORT (13) l CAUSE SYSTEM CO @0NENT MANUFAC- REPORTA8tE CAUSE SYSTEM COMPOWENT MANUFAC- REPORTABLE TURER TO WPRDS TURER TO WPRDS X elN I l l l l l Y l i l l l l l l 1 l l l l l l l l l l l l 1 ,
SUPPLEMENTAL REPORT EXPECTED (14) Expected Month l Day l Year j' Subalssion
~
TlYes (if ves complete EXPECTED SUBMISSION DATE) l N0 110l311l910 l ABSTRACT (Limit to 1400 spaces, i.e, approximately fifteen single-space typewritten lines) (16) ,
1 i On June 18, 1990, at 0838 hours0.0097 days <br />0.233 hours <br />0.00139 weeks <br />3.18859e-4 months <br />, with Unit 1 in Operational Condition 1 (Run) at 1005 power, during the perfonnance of LaSalle Operating Surveillance, LOS-RI-Q4, " Reactor Core Isolation Cooling System cold Q6lck Start
- the Reactor Core isolation Cooling (RCIC) Turbine tripped on mechanical overspeed.
The RClc turbine trip is set to actuate at $625 +/- 50 rpm. The turbine tripped at 5650 rpm, which is within l the design limits. The exact cause of the turbine overspeed is uncertain at this time. An investigation ,
into the root cause is continuing. I The RCIC system was declared inoperable, and work request LOO 513 was initiated to investigate and repair the problem. The High Pressure Core Spray System was fully operable throughout the event.
Initial corrective actions included the disassembly and cleaning of the Electronic Governor actuator, flushing of the oli system, changing the oil, and re-adjustment of the limit switch for the RCIC Steam Supply stop Valve IE51-F045. These measures brought the initial speed spike down to 4750 rpm, and the RCic system was declared operable on June 20, 1990 at 2025 hours0.0234 days <br />0.563 hours <br />0.00335 weeks <br />7.705125e-4 months <br />. Any further corrective actions will be reported in a supplement to this report.
This event is reported to the Nuclear Regulatory Canaission as a Licensee Event Report in accor' dance with 10CFR50.73(a)(2)(v) due to the RCic System being declared inoperable (loss of a safety system function).
_- - - . - - . - - - - - - ~ _ . - - -.- . - - -
vo
- l Lle8m88 EVENT KPERT (1H) TEXT CONTitnahiltal Fem Rev 2.0 i FAtttlTY IIRfE (1) DOCKET GRpWER (2) LER lapeER (6) Pane (3) !
Year /// Sequential //j/ Revision I fff ff
/// Humber /// Ihater l w ile County statlan unit 1 o 1 5 1 o I o i o 1 31 71 3 910 - oIol7 - oIo 01 2 0F of4 !
TEXT Energy ladustry identification System (Ells) codes are identified in the text as [XX] ;
PLANT A410 SYSTEM IDEWilFICATION General Electric - Dolling unter Reactor !
EnergyIndustryidentificationSystem(Ells)codesareidentifiedinthetextas(XX). [
l A. CONDITION PRIOR TO EVENT Unit (s): 1 Event Date: 6/18/90 Event flee: 0838 Hours Reactor Mode (s): 1 Mode (s) teams: Run Pouer Level (s): J9gE
- 8. DESCRIPilolf 0F EVENT :
On June it, 1990, at 0834 hours0.00965 days <br />0.232 hours <br />0.00138 weeks <br />3.17337e-4 months <br />, while Unit I was in Operational Condition 1 (Run), at 1005 power, the L Reactor Core Isolation Cooling (RCIC) [011] Turbine tripped on mechanical overspeed during the perfomance of LaSalle operating Surveillance, LOS 4t!-Q4, " Reactor Core Isolation Coollng System told Quick Start." This surveillance is perfomed every quarter to demonstrate the quica start capal ality of the RCIC system.
A Startrec recorder thigh speed data acquisition system) monitors the RCIC pump dischaNe pressure, pep suction pressure, pump flow rate, turbine speed, rang generator signal converter, : seam demand signal, j and the opening of the stem supply stop valve IE514045. The startrec recorder was initiated upon ?
opening of the RCIC Stem Supply Stop Valve IE514045 and the Full flow Test Return Stop valve IE514059. The RClc turbine went from zero rpm to 5650 rpm, which resulted in the mechanical overspeed trip system actuation and a RCic tusine trip as designed. The mechanical overspeed trip assembly is set to actuate at 125% of rated speed (5625 +/- 50 rpm). ;
Decing power operation, the RCIC system is nomally lined up in standby condition with the RClc turbine ;
gove nor valve IE514360 fully open. The surveillance requires that the RCIC turbine stem supply stop '
valve IE514045, and the RCIC full flow test return to the condensate Storage Tank (CST) stop valvo IE514059 to be opened simultaneously. Stem at rated pressure and temperature enters the turbine, and ,
during the first 2 seconds, a speed spike nomally ranging from 4000 to 4500 revolutions per minute-(rpm) occurs before the RCIC control system takes control to place the system in a steady state.
After the overspeed trip, the RCIC system Was lamediately declared Inoperable. An entry was made in the. ,
Degraded Equipment Log, (DEL 327 89-1-134) and work request LOO 513 was initiated to investigate and repair the problem.
No other inoperable equipment / systems contributed to this event. too automatic or manual safety system actuations occurred and none were required.
This event is reported to the lisclear Regulatory Commission as a Licensee Event Report in accordance with 10CFR50.73(a)(2)(v) due to the RCic System being declared inoperable (loss of a safety system function).
I
4o -*
j
. i Lietmss EVENT rep 0RT (LER) TEXT CONTINuAfl0N Fore Rev 2.0 FACILITY NRE (1) DOCKET NU SER (2) __ L1R NU SER (6) Paes (3)
Year /// Sequential //j/ Revision l fff
/// Number ff/
/ Nueer I w ile County Station unit 1 0 1 5 1 0 1 0 1 0 1 31 71 3 9Io - 01017 - 01 0 01 3 0F 01 4 TEXT Energy industry identification System (Ells) codes are identified in the text as [XX]
C. APPARENT CAUSE OF EVENT The cause of the RCIC turbine overspeed trip during the performance of the surveillance is uncerteln at this time, it is believed the cause is related to dirt / rust in the RCIC governor and/or the Ilmit switch setting of the RCic Stem supply stop valve It51-F045. Further investigations to determine the root causes of the event are ongoing, j l
D. SAFETY ANALYSIS OF EVENT The mechanical overspeed assembly trips the RCic Turbine at 125 percent of the rated speed, %25 +/- 50 rpm. Actuation of the trip assembly requires a reset of the RCIC Turbine locally at the tuttine. i During the performance of the surveillance the RCIC system overspeed trip occurred at %50 rpm. The mechanical overspeed assembly actuated as designed.
At the time of this incident tre High Pressure Core Spray (HPCS) System and the other amergency core cooling systems were fully operable. The HPCS System was operable for the entire time period from the last successful performance of LOS41-Q4 on April 12, 1990 until the RCIC System was declared operable >
again. Therefore, the consequences of this event were minimal.
I E. CORRECTIVE ACTIONS i
- The RCic $3 stem was declared inoperable and Work Request #L00513 was written to investigate and repair L the problan. .
The Electroth Governor - Type R (EG-R) actuator was removed and during the inspection rust was found in the housing on the top of the governor. The rust discovered in the oil at the EG 4 actuator may have been the result of rusting at the governor valve stem.
The governor travel will be observed during the next RCIC surveillance test. It will be compared with I the governor travel from the Unit 2 RCic System tests and frou earlier startup tests. The oil to the governor comes from the RCic oil system. The dirt that accisuulated with the rust may have come from the oil ssp. The last oil change to the RCic oil system was performed on July 11, 1999.
The EG-R was disassee led and cleaned. The oil to the RCic system was removed and the oil system was flushed with hot oil. The tuttine sep was filled with fresh oil, and a slow start was performed. 1 To help prevent future occurrences of this problem, the RCIC oil system will be flushed during each outage, and the EG4 actuator will be disassembled, inspected and cleaned. The LaSalle general !
surveillance progrm will be updated to include these corrective actions and will be tracked by Action item Record (AIR) 373-200-90-04601.
l l The operating department performed LaSalle Operating Surveillance LOS-RI-43, " Reactor Core Isolation Cooling Pop Operability Test,' satisfactorily. LOS41-44 was also perforned later that day, and the first speed spike for the RCIC turbine was 4950 rpm. The speed spike was at the acceptance limit of
</= 4950 rpm, however it was decided to continue to troubleshoot and another work request was written to inspect the limit switch that interlocked the RCIC steam supply stop valve IE51-F045 and the rang generator signal converter.
e t.
- l* _ !
Llem8 EVENT EpcRT (L1R) 1 EXT CEnftimmilmi Form tev 2.0 I FACILITY lilWE (1) 00CKE1 InpWER (2) LER mileER (6) Pane (3) 1 Year /// Sequential ffj //j
/ nevision
/// tousber /// thaber l uulle County station unit 1 o I 5 1 0 I o I o 1 31 71 3 9Io - oIoI7 - oI o 01 4 or el 4 :
TEXT Energy Industry identification System (Elis) codes are identified in the text as [KK) i E. CORRECilVE ACitows (Continued) 1he inspection of valve IE51-F005 found the limit switch set in accordance with the previous revision of the valve maintenance procedure LEP-GM-102, 'Limitorque Valve Actuator Electrical Maintenance." The maintenance on this valve was last performed on July 28, 1987 per the maintenance schedule. The settine forclosureofthelimitswitchwasreadjustedbythecurrentprocedurerevision,andthelleltswitches for the ramp generator signal converter and the steam supply stop valve were re-aligned. Opening of the stem supply valve and actuation of the ramp generator signal converter would occur between zero and two i percent.
Af ter 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, another cold quick start was performed..the first speed spike was reduced to 4750 rpm.
Following this surveillance, the RCIC system was declared operable on June 20, 1990 at 2025 hours0.0234 days <br />0.563 hours <br />0.00335 weeks <br />7.705125e-4 months <br />.
1 Additional actions to reduce the initial speed spike will be pursued to provide additional margins to the overspeed trip. The results of these actions will be reported in a supplement to this report and tiacked by Action item Record AIR 373-200-90-04602.
, 1 F. PREVIOUS EVENT 5 LER Number iltle 373/84-054-02 RCic Inoperable and stem Line Isolation I
G. COMPONENT FAILURE DATA Ir l
-- .-- - .