05000529/LER-1990-010-01, :on 901110,EDG Jacket Cooling Water Line Inadequately Supported
| ML17305B241 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 12/10/1990 |
| From: | Bradish T, James M. Levine ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 192-00706-JML-T, 192-706-JML-T, LER-90-010-01, LER-90-10-1, NUDOCS 9012140245 | |
| Download: ML17305B241 (17) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 21.21(b)(3) |
| 5291990010R01 - NRC Website | |
text
ACCELERATED I+TRIBUTION DEMONS+ATION SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)
ACCESSION NBR:9012140245 DOC.DATE: 90/12/10 NOTARIZED: NO DOCKET FACIL:STN-50-529 Palo Verde Nuclear Station, Unit 2, Arizona Publi 05000529 AUTH.NAME AUTHOR AFFILIATION BRADISH,T.R.
Arizona Public Service Co.
(formerly Arizona Nuclear Power LEVINE,J.M.
Arizona Public Service Co.
(formerly Arizona Nuclear Power RECIP.NAME RECIPIENT AFFILIATION R
SUBJECT:
LER 90-010-00:on 901110,EDG jacket cooling water line inadequately supported.W/901207 ltr.
DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR ENCL SIZE:
TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.
NOTES:Standardized plant.
05000529 D
A RECIPIENT ID CODE/NAME PD5 LA PETERSON,S.
INTERNAL: ACNW AEOD/DOA AEOD/ROAB/DSP NRR/DET/EMEB 7E NRR/DLPQ/LPEB10 NRR/DREP/PRPB11 NRR/DST/SICB 7E NRR/DST/SRXB SE RES/DSIR/EIB EXTERNAL: EG&G BRYCE,J.H NRC PDR NSIC MURPHY,G.A NOTES:
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ACRS AEOD/DSP/TPAB NRR/DET/ECMB 9H NRR/DLPQ/LHFB11 NRR/DOEA/OEAB NRR DST/SELB SD RR-BSD1 REG 02 RGN5 FILE 01 L ST LOBBY WARD NSIC MAYS,G NUDOCS FULL TXT COPIES LTTR ENCL 1
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NOTE TO ALI. "RIDS" RECIPIEN fS:
PLEASE HELP US TO REDUCE O'ASTE! CONTACT THE DOCUMENT CONTROL DESK, ROO.'~I Pl-37 (EXT. 20079) TO ELlib!INATE YOUR NAb IE FROM DISTRIBUTION LIES FOR DOCUXIENTS YOU DON'T NEED!
FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED:
LTTR 35 ENCL 35
C ff
JAMES M, LEVINE'-
VICE PRESIDENT NJCLEAR PROOUCTIO'I Arizona Public Service Company PALO VERDE NUCLEAR GENERATING STATION P.O BOX 52034
~
PHOENIX. ARIZONA85072-2034 192-00706-JML/TRB/SM December 7, 1990 U.
S. Nuclear Regulatory Commission Attention: Document Control Desk Mail Station Pl-37 Washington, DC 20555
Dear Sirs:
Subject:
Palo Verde Nuclear Generating Station (PVNGS)
Unit 2 Docket No.
STN 50-529 (License No. NPF-51)
Licensee Event Report 90-010-00 File'0-020-404 Attached please find Licensee Event Report (LER) No. 90-010-00 prepared and submitted pursuant to 10CFR50.73.
In accordance with 10CFR50.73(d),
we are forwarding a copy of the LER to the Regional Administrator of the Region V
office.
This report is also being submitted pursuant to 10CFR21 and includes the information requested in 10CFR21.21(b)(3).
If you have any questions, please contact T.
R. Bradish, Compliance Manager at (602) 393-2521.
Very truly yours, JML/TRB/SBJ/dmn Attachment CC:
(all with attachment)
W. F.
Conway J.
B. Martin DE H.
Coe A. C.
Gehr A. H. Gutterman INPO Records Center T.
E. Murley Cooper Energy Services 9012140245 901210 PDR AOOCV~ 0 000529' PLURI:
NRC FORM 366 (6$9)
V.S, NUCLEAR REGULATORYCOMMISSION LICENSEE EVENT REPORT HLER)
APPROVED 0MB NO. 31504)104 EXPIRESr 4/30!92 ESTIMATED BURDEN PER
RESPONSE
TO COMPLY WTH THIS INFORMATION COI.LECTION REQUEST: 50.0 HRS. FOR)YARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS AND REPORTS MANAGEMENTBRANCH (PFe30), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (31500104l, OFFICE OF MANAGEMENTAND BUDGET, WASHINGTON, DC 20503.
FACILITYNAME (Il DOCKET NUMBER (2)
PA E
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REPORT DATE (7I LER NUMBER (6)
EVENT DATE (51 DOCKET NUMBERISI o
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+~P SEQUENTIAL NUMBER FAcrLITYNAMES OAY YEAR YEAR DAY MONTH Pa1o Verde Unit 3 TITLE (4)
EDG Jacket Cooling Mater Line Inadequately Supported 1 0 9 0 0
010 00 12 109 0
0 5
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0 OPERATING MODE (9)
POWE R LEYEL 1
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THIS REPORT IS SUBMITTED PURSUANT T0 THE RLQUIREMENTS OF 10 CFR (I: /Check one or more o/ the /oliowing/ (11 73.71(d) 73.71(cl OTHER ISpecitrrin Aostrect Oelow end in Test, hIIIC Form 366A/
10CFR 21 NAME Thomas R. Bradish, Compliance IIanager TELEPHONE NVMBER AREA CODE 602 393 2 521 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)
CAUSE
SYSTEM COMPONENT MANUFAC TVRER REPORTABLE TO NPADS COMPONENT MANUFAC.
TVRER SUPPLEMENTAL REPORT EXPECTED (14)
YES I/Iyet, COmpiere EXPECTED SU&4SISSIOII DATE/
NO ABSTRACT ILimirto /400 speces, I e., epprosimeteiy Iifteen sinpre speCe tyPewrinen /ines/ (ld)
EXPECTED SUBMISSION DATE (15)
MONTH DAY YEAR On November 8,
- 1990, Palo Verde Units 2 and 3 were in Mode 1
(POWER OPERATIONS) at 100 percent power when cracked tack welds were found on the Unit 3 emergency diesel generator (EDG) "B" jacket cooling water return line support brackets.
Subsequent inspections of Unit 3 EDG "A" discovered similar cracks.
Inspection of EDGs in Unit 1 and 2 discovered varying weld details.
An engineering analysis of each EDG weld configuration completed on November 10,1990 determined that the jacket water return line on both Unit 3 EDGs and on the Unit 2 EDG "A" did not meet seismic qualification requirements.
This could have prevented the EDG from performing as designed in a seismic event.
The brackets on the Unit 2 and 3
EDGs were removed, a full length fillet weld
- made, and the brackets reinstalled.
No other additional corrective action is necessary.
On December 5,
1990 at approximately 0930
- MST, APS determined the insufficient EDG jacket cooling water support bracket welds were reportable pursuant to 10CFR21.
There have been no previous events reported pursuant to 10CFR 50.73.
NRC Form 366 (54)9)
I below includes the information requested by 10CFR21.21(b)(3);
however, it is being formatted to report this event in accordance with the requirements of 10CFR50.73.
DESCRIPTION OF WHAT OCCURRED:
Initial Conditions:
On November 10,
- 1990, Palo Verde Units 2 and 3 were in Mode 1
(POWER OPERATIONS) at 100 percent power.
Reportable Event Description (Including Dates and Approximate Times of Major Occurrences):
Event Classification:
A condition that alone could have prevented the fulfillment of a safety function.
Also reportable'pursuant to 10CFR21.
Note:
This section includes information requested by 10CFR21 concerning the nature of the defect and dates for which information was obtained/developed.
On November 8,
1990 Unit 3 emergency diesel generator(EDG)(EK)
HB" jacket cooling water return line support brackets were found to contain cracked tack welds.
Subsequent inspections of Unit 3 EDG HAH discovered similar cracks.
Inspection of Unit 1 and 2
EDGs did not reveal any cracks, but did reveal that the weld detail varied between units and EDGs.
An engineering analysis of each weld configuration completed on November 10, 1990 determined that the jacket cooling water return line on both Unit 3 EDGs and the Unit 2 EDG HAH did not meet seismic qualification requirements.
This condition could have prevented the EDG from performing as designed in a seismic event.
Each Unit at Palo Verde has two EDGs.
EDG cooling is provided by jacket cooling water.
The jacket cooling water pump takes suction from the jacket cooling water standpipe and pumps the cooling water to the EDG via the jacket cooling water heat exchanger.
The EDG jacket cooling water exits the EDG through.two parallel 10 inch pipes.
Each pipe collects jacket cooling water exhausted from a cylinder bank (e.g., left bank) and returns the jacket cooling water to the jacket cooling water standpipe.
Each 10 inch return pipe is located above a cylinder bank and is supported by six brackets.
The brackets are constructed out of three 3/8 inch thick carbon steel flat bars welded together (see attached'669)
U.S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT ILER)
TEXT CONTINUATION
~-
APPAOVED OMB NO. 3)504)04 E XPIR ES: 4/30/92 ESTIMATED BURDEN PER
RESPONSE
TO COMPLV WTH THIS INFORMATION COLLECTION REQUEST: 50A) HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS AND REPOA'TS MANAGEMENTBRANCH IPS30). U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, ANDTO THE PAPEAWOAK REDUCTION PROJECT (3)504)104). OFFICE OF MANAGEMENTAND BUDGET, WASHINGTON,DC 20503.
FACILITYNAME (1)
DOCKET NUMBER (2)
VEAR LER NUMBER (6)
SEQUENTIAL SSFE REVISION
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The S-bar in the center is bolted to the EDG and to a lug welded to the jacket cooling water return pipe.
On November 6,
1990 at approximately 1703 MST, Unit 3 EDG HB" was declared inoperable in order to perform scheduled maintenance.
On November 8,
1990 cracks in tack welds of the jacket cooling water return line support brackets were discovered by maintenance personnel working on the EDG.
The bracket had approximately three (3) inch long quarter inch fillet welds connecting the flat bars on the bottom portion but only tack welds at the top.
A similar configuration was discovered on Unit 3 EDG "AH.
Inspections of the Unit 1 and Unit 2 EDGs discovered different variations in weld details between EDGs.
Unit 2 EDG "AH had quarter inch fillet welds approximately 3.5 inches to 5 inches long on both sides of the bottom of the support bracket.
The top of the support bracket had two half inch tack welds on each side of the support bracket.
Unit 2 EDG "B" had quarter inch fillet welds approximately 5
inches long on both sides of the top of the support bracket.
The bottom of the support. bracket was welded with quarter inch fillets between 3 and 5inches long.
Both Unit 1 EDGs weld detail was similar to Unit 2 EDG HB".
Vendor specifications were reviewed to determine weld requirements.
No detailed weld specifications could be found. It was decided to provide full length fillet welds in place of the cracked tack welds in order to return Unit 3 EDG HB" to service while the as found condition was analyzed.
The support brackets were removed, fillet welded the full length of the bracket, and reinstalled on Unit 3 EDG HBH.
Unit 3 EDG HBH was declared operable at approximately 1742 MST on November 9,
1990.
Unit 3 EDG "AH was removed from service at approximately 1840 MST on November 9, 1990 and the support brackets welded the full length.
Unit, 3 EDG HAH was declared operable at approximately 0013 MST on November 10, 1990.
Unit 2 EDG HB" was declared inoperable at approximately 2131 MST on November 9, 1990 in order to weld the jacket cooling water support bracket.
The EDG was returned to service at approximately 0100 MST on November 10, 1990.
On November 10, 1990, engineering analysis determined that the as found weld configuration on both Unit 3 EDGs, and Unit 2 EDG HAH resulted in the jacket cooling water line not being seismically qualified.
The analysis determined that a minimum of 3 inches of quarter inch fillet weld was required on both sides and the top and bottom of the support bracket; Subsequently, Unit 2 EDG HAR was declared inoperable.
The existing weld configuration for Unit 2
EDG HB" and both Unit 1 EDGs was determined to be acceptable to meet seismic qualification requirements.
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U.S, NUCLEAR REGULATORY COIAMISSION LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION APPROVEO 0MB NO,31500104 EXPIRES. 4/30/92 ESTIMATED BURDEN PER
RESPONSE
TO COMPLY WTH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS AND REPORTS MANAGEMENTBRANCH (P4)30). U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (31500104). OFFICE OF MANAGEMENTAND BUDGET, WASHINGTON,OC 20503.
FACILITYNAME (I)
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YEAR LER NUMBER (6)
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On December 5,
1990 at approximately 0930 MST APS determined that the insufficient welds on the EDG jacket water support brackets were reportable under 10CFR21.
Status of structures, sy'stems, or components that were inoperable at the start of the event that contributed to the event:
~
r Unit 3 EDG RBN was inoperable for scheduled maintenance when the condition was discovered.
No other structures,
- systems, or components were, inoperable at the start of event which contributed to the event.
D.
Cause of each component or system failure, if known:
Not applicable
- - no component or system failures were involved.
Failure mode, mechanism, and effect of each failed component, if known:
Not applicable
- - no component failures were involved.
For failures of components with multiple functions, list of systems or secondary functions that were also affected:
Not applicable
- - there were no failures of components with multiple functions.
For a failure that rendered a train of a safety system inoperable, estimated time elapsed from the discovery of the failure until the train was returned to service:
No failures occurred which rendered a train of a safety system inoperable;
- however, on November 10, 1990 at approximately 0724 MST, Unit 2 EDG HA" was declared inoperable based on the results of the engineering analysis of the condition.
The EDG was returned to service at approximately 2227 MST on November 10,
- 1990, 15 hours1.736111e-4 days <br />0.00417 hours <br />2.480159e-5 weeks <br />5.7075e-6 months <br /> after being declared inoperable'RC Form 366A (6691
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NRC FOAM 366A (64)9)
U S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION, APPROVED OMB NO. 31500104 EXPIRES) 4/30/92 ESTIMATED BURDEN PER
RESPONSE
TO COMPLY WTH THIS INFORMATION COLLECTION REQUEST( 50.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS AND REPORTS MANAGEMENTBRANCH (F430), U.S. NUCLEAR AEGULATOAYCOMMISSION, WASHINGTON, DC 20555. ANDTO THE PAPERWORK REDUCTION PROJECT (3)504)(04). OFFICE OF MANAGEMENTANDBUDGET. WASHINGTON,DC 20503.
FACILITYNAME (II DOCKET NUMBER (2)
LER NUMBER (6)
PAGE (3)
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Method of discovery of each component or system failure or procedural error:
Not applicable
- - there have been no component or system failures or procedural errors identified.
(
I.
Cause of event
Note:
This section includes information requested by 10CFR21 concerning the nature of the defect and dates for which information was developed.
The jacket water lines were seismically unqualified because of insufficient support bracket welds.
The EDG supplier, Cooper-
- Bessemer, did not complete the required support bracket welds after tack welds were made for fitup of the flat bars.
The inadequacy of the jacket cooling water support bracket weld configuration was determined on November 10, 1990 by an APS engineering analysis.
No unusual characteristics of the work location (e.g., noise,
- heat, poor lighting) directly contributed to this event.
The event was not a result of personnel or procedural errors.
Safety System Response:
Not applicable
- - there were no safety system responses and none were necessary.
Failed Component Information
Note:
This section includes information requested by 10CFR21 concerning the identification of the firm supplying the basic component.
There were no failed components.
- However, the jacket cooling water support brackets were supplied with the EDG.
The EDG, utilized at Palo Verde Units 1, 2, and 3 are manufactured by Cooper-Bessemer division of Cooper Energy Services.
The model number is KSV-20-T.
Each unit utilizes two (2)
EDGs (six total).
Each EDG has two jacket cooling water return lines.
Each return line is supported by six brackets (twelve per EDG).
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NAC FORM 366A (6 4>S>
US, NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION APPROVEO OMS NO. 31500104 EXPIRES: 4/30/92 ESTIMATED BURDEN PE'R
RESPONSE
TO COMPLY WTH THIS INFORMATION COLLECTION REQUEST: 600 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS AND REPORTS MANAGEMENTBRANCH (P-530>. U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, OC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (31504>104>, OFFICE OF MANAGEMENTAND BUDGET, WASHINGTON. OC 20503, FACILITYNAME (I>
DOCKET NUMBER (2>
YEAR LER NUMBER (6>
$EQVENTIAI NVM$$ R REVISrQN NVM $ R PAGE (3)
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II.
ASSESSMENT OF THE SAFETY CONSEQUENCES AND IMPLICATIONS OF THIS EVENT:
Note: This section contains the information requested by 10CFR21 concerning the nature of the safety hazard which is created or could be created.
The EDGs are required to supply power to components necessary to maintain the reactor in a safe shutdown condition in the event offsite power is lost.
The insufficient jacket cooling water support bracket welds could have resulted in the failure of the jacket cooling water line during a seismic event and subsequently prevented the EDG from functioning.
In Unit 3, the condition could have prevented both EDGs from functioning after a seismic event. If offsite power was lost after the seismic event, the ability to maintain Unit 3 shutdown could have been compromised.
The condition only adversely affected one EDG in Unit 2.
Therefore, this condition alone would not have affected the ability to maintain Unit 2 in safe-shutdown.
This condition did not affect either EDG in Unit l.
III.
CORRECTIVE ACTION
Note:
This section contains information requested by 10CFR21 concerning the 'corrective action(s) which have been taken.
A.
Immediate:
The brackets on both EDGs in Unit 2 and both EDGs in Unit 3 were
- removed, fillet.-welded the full length of the bracket, and reinstalled.
Information on the condition was supplied to other utilities with Cooper-Bessemer EDGs by APS engineering.
IV.
PREVIOUS SIMILAR EVENTS
There have been no previous similar events reported pursuant to 10CFR50.73 by APS.
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NRC FORM 356A (669)
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