ML17305B724
| ML17305B724 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 09/03/1991 |
| From: | James M. Levine ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 192-00737-JML-T, 192-737-JML-T, 3-SR-91-006, 3-SR-91-6, NUDOCS 9109110005 | |
| Download: ML17305B724 (7) | |
Text
I ACCELERATED DISTRIBUTION DEMONSTION SYSTEM C
REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)
ACCESSION NBR:9109110005 DOC.DATE: 91/09/03 NOTARIZED: NO DOCKET FACIL:STN-50-530 Palo Verde Nuclear Station, Unit 3, Arizona Publi 05000530 AUTH;NAME AUTHOR AFFILIATION
-LEVINE,J.M.
Arizona Public Service Co.. (formerly Arizona Nuclear Power RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)
SUBJECT:
Special Rept 3-SR-91-006:on 910829,Class 1E inverter C
failed during maint evolutions. Caused by momentary ground on 120-volt Channel C vital ac electrical bus.Inverter returned to svc
& bus reenergized from associated inverter.
DISTRIBUTION CODE:
IE22D COPIES RECEIVED:LTR l ENCL J SIZE: ~
TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt,- etc.
D NOTES:Standardized plant.
05000530 A
(
INTERNAL:
EXTERNAL:
NOTES:
RECIPIENT ID CODE/NAME PD5 LA TRAMMELL,C ACNW AEOD/DOA AEOD/ROAB/DSP NRR/DET/EMEB 7E NRR/DLPQ/LPEB10 NRR/DREP/PRPB11 NRR/DST/SICB8H3 NRR/DST/SRXB 8E RES/DSIR/EIB EG&G BRYCE,J.H NRC PDR NSIC POORE,W.
COPIES LTTR ENCL 1
1 1
1 2
2 1
1 2
2 1
1 1
1 2
2 1
1 1
1 1
1 3
3 1
1 1
1 1
1 RECIPIENT
~
ID CODE/NAME PD.5 PD THOMPSON,M ACRS AEOD/DSP/TPAB NRR/DET/ECMB 9H NRR/DLPQ/LHFB10 NRR/DOEA/OEAB NRR/DST/SELB 8D
/D~S SPLB8D1 EG F 02 RGN FILE 01 L ST LOBBY WARD NSIC MURPHY,G.A NUDOCS FULL TXT COPIES LTTR ENCL 1
1 1
1 2
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 D
D D
NOTE TO ALL"RIDS" RECIPIENTS:
PLEASE HELP US TO REDUCF, O'ASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOM Pl-37 (EXT. 20079) TO IiLIiIINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!
TOTAL NUMBER OF COPIES REQUIRED:
LTTR 35 ENCL 35 A
D D
Arizona Public Service Company PALO VERDE NUCLEAR GENERATING STATION P.O. BOX 52034
~
PHOENIX. ARIZONA85072-2034 JAMES M. LEVINE VICE PRESIDENT NUCLEAR PRODUCTION 192-00737-JML/TRB/KR September 3,
1991 U.
S. Nuclear Regulatory Commission Attention: Document Control Desk Mail Station Pl-37 Washington, D.C.
20555
Dear Sirs:
Subj ect:
Palo Verde Nuclear Generating Station (PVNGS)
Unit 3 Docket No.
STN 50-530 (License No. NPF-74)
'pecial Report 3-SR-91-006 File:
91-020-404.
Attached please find Special Report 3-SR-91-006 prepared and submitted pursuant to Emergency Plan Implementing Procedure (EPIP-03).
This report discusses a condition requiring the declaration of a NOTIFICATION OF UNUSUAL EVENT due to a reactor shutdown required by Technical Specifications.
If you have any questions, please contact T. R. Bradish, Compliance Manager at (602) 393-2521.
Very truly yours, JML/TRB/KR Attachment cc:
~
W. F.
J.
B.
D. H.
A. C.
A. H.
Conway Martin Coe Gehr Gutterman (all with attachment) 9109110005 910903 PDR ADOCK 05000530 5
0
Palo Verde Nuclear Generating, Station Unit 3 Notification of Unusual Event Docket No. 50-530 License No. NPF-74 Special Report 3-SR-91-006 This Special Report is being submitted pursuant to Emergency Plan Implementing Procedure (EPIP-03), "Notification of Unusual Event Implementing Actions" to report a condition which required the declaration of an Unusual Event for Palo Verde Unit 3 at 2015 MST on August 30, 1991.
The Unusual Event was terminated at 0132 MST on August 31, 1991..
On August 29, 1991, at approximately 2032 MST, Palo Verde Unit 3 was operating at approximately 87 percent power in Mode 1
(POWER OPERATION) when the Class 1E Inverter C failed during maintenance evolutions due to a momentary ground on the 120-volt Channel C Vital A.C. electrical bus.
Technical Specification (TS) 3.8.3.1 Limiting Condition for Operation (LCO) requires that:
"The following electrical busses
[120-volt Channel C Vital A.C.
bus) shall be energized in the specified manner
[from its associated inverter connected to the D.C. Channel C bus) with tie breakers open between redundant busses within the unit."
TS 3.8.3.1 ACTION b requires that:
"with one A.C. vital bus either not energized from its, associated inverter, or with the inverter not connected to its associated D.C. bus:
(1) reenergize the A.C. vital bus within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br /> and (2) reenergize the A.C.
vital bus from its associated inverter connected to its associated D.C. bus within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />."
At approximately 2032
- MST, TS 3.8.3.1 ACTIONs b(1) and b(2) were entered.
TS 3.8.3.1 ACTION b(l) was immediately exited when the 120-volt, Channel C Vital A.C. electrical bus successfully auto-transferred to the Voltage Regulator following the inverter failure.
However, efforts to restore the inverter to operable and reenergize the A.C. vital bus from the inverter within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> were not successful.
Emergency Plan Implementing Procedures require the declaration of an Unusual Event for a reactor plant shutdown required by TS.
By 2016 MST, on August 30,
- 1991, the appropriate state and local agencies were notified of the conditfon requiring the declaration of an Unusual Event (i.e.,
shutdown required by TS).
At approximately 2023 MST on August 30,
- 1991, the Nuclear Regulatory Commission (NRC) Operations Center was notified.
At approximately 2330 MST on August 30, 1991, Unit 3 Control Room personnel commenced a plant shutdown as required by TS 3.8.3.1 ACTION b(2).
At
NRC Document Control Desk Page 2
Special Report 3-SR-91-006 approximately 0119 MST on August 31,
- 1991, the reactor was shut down in accordance with the shutdown procedure.
At'pproximately 0132 MST on August 31, 1991, the Unusual Event was terminated in accordance with EPIP-03.
By 0142 MST on August 31,
- 1991, the appropriate state and local agencies and the NRC Operations Center were notified of the termination of the Unusual Event.
Following corrective maintenance, at approximately 1902 MST on August 31,
- 1991, TS 3.8.3.1 ACTION b(2) was exited when the Class lE Inverter C was returned to service and the 120-volt Channel C Vital A.C. electrical bus was reenergized from its associated inverter.
The ACTION requirement to be in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br /> was no longer necessary.
Further investigation into the circumstances surrounding this event is being performed in accordance with the PVNGS Incident Investigation Program.