ML18100A803

LER 93-013-00:on 931202,DG 2C Declared Inoperable Due to Cracking in 3R Cylinder Liner.All Cylinder Liners Installed in 2C & 1B DGs Inspected & Previously Installed Canadian Allied Diesel Liners Replaced W/Alco liners.W/931230 Ltr

ML18100A803
Person / Time
Site:	Salem
Issue date:	12/30/1993
From:	Pastva M, Vondra C Public Service Enterprise Group
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-93-013-01, LER-93-13-1, NUDOCS 9401110199
Download: ML18100A803 (5)

Text

Public Service Electric and Gas Company P.O. Box 236 Hancocks Bridge, New Jersey 08038 Salem Generating Station December 30, 1993

u. s. *Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 I

Dear Sir:

SALEM GENERATING STATION LICENSE NO. DPR-75 DOCKET NO. 50-311 UNIT NO. 2 LICENSEE EVENT REPORT 93-013-00 This Licensee Event Report is being submitted pursuant to the

• requirements of Code of Federal Regulation 10CFR50.73(a) (2) (i) (A).

This report is required to be issued within thirty (30) days .of event discovery.

Sincerely yours,

~~

-~ M_1~ *\J e-.~h~,__

c. A. Vondra .

General Manager -

Salem Operations MJPj:pc Di~tribution tH30030 9401110199 931230 ~:

PDR ADOCK 05000311 ~

5 PDR ~

Th*- n p*.:.** 1-~ in "')'J'*l*'"'*i"

_ *'-"' j \. \*l...t 1. *** ~\. ._ .1 i..(Ui~"

95*2189 REV 7.9

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISS16-891 APPROVED OMB NO. 3150-0104 EXPIRES: 4/30/92 ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD LICENSEE EVENT REPORT (LER) COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS AND REPORTS MANAGEMENT BRANCH (P~5301. U.S. NUCLEAR REGULATORY COMMISSION. WASHINGTON. DC 20555, AND TO THE PAPERWORK REDUCTION PROJECT 13150-0104). OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.

FACILITY NAME (11 iDOCKET NUMBER (21 I PAGE 131 Salem Generatinsr Station - Unit 2 o 15 Io Io Io 13 I 111 1 loF 0 14 TITLE 141 Non-Valid Failure of 2C Diesel Generator with Subsequent Reactor Shutdown.

EVENT DATE (5) LER NUMBER (61 REPORT DATE (71 OTHER FACILITIES INVOLVED. (8)

~mmr SEQUENTIAL REVISION MONTH MONTH DAV VEAR VEAR NUMBER I(} NUMBER DAY YEAR FACILITY NAMES DOCKET NUMBERISI Salem Unit 1 0 I 5 I O I O I o I 2 I 7 12

- I 113 -

a 0 112 I3 1 I2 ol2 9 3 91 3 0 3lo 9 0 I 5 Io Io I o I I I OPERATING

. THIS REPORT IS SUBMITTED PURSUANT TO THE RkoOUJREMENTS QF 10 CFR §: (Check one or more of rhe following} 1111 MODE 191 1 20.402lbl 20.405(cl

- 50.73(1)(2J(ivl 73.71lbl POWER LEVEL (101 I 11010 20.40511H1 l(il 20.40511111 Hiil 20.405(11(1 )(iii)

....E 60.38(cH11 50.38(cJ(21 50.73(11 l2Hil 50.7311H21M 50.73(1)(2)(viil 60.73(11(2Hviiil(AI 73.71lcl OTHER (S~cify in Absrr*cr below and in Text, NRC Form 366AI 11111111,lllllllllll ....__ 20.405(1)(1)(Jvl 20.405(1111 )(vi

- 60.73(1)(2)(iil 50.73(1)(211iiil 50.73(1)(2)(viiil (Bl

• 50.73(11(211*1 LICENSEE.CONTACT FOR THIS LER (121 NAME TELEPHONE NUMBER AREA CODE J. Pastva. Jr. - LER Coordinator 610 I q 111 I 91- I 51 11 Fi I M

COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED JN THIS REPORT (131 "

REPORTABLE 1::::-:-:-:-:*:*:*:*:*:*:*:*:*:*:-:*:*>:*: ',;.; MANUFAC*

MANUFAC* REPORTABLE CAUSE SYSTEM COMPONENT TUR ER TO NPRDS *::*:*:*:*:*:*:*:*:':*:*:*:*:'/""*"'""'""

CAUSE SYSTEM COMPONENT TUR ER TO NPR.DS 1Jjj:j"jjj,.:*:*:J:i::,li:l::::J,::.':.::::=:::::i:=

LIN I RI

J! :~:~:i:!:~:i:~:~:J:! i! !~:i:~:~!i!~!l! ! !~:~:i: I I jJJ:,*1=jj*j!j:=*:.*:*j:"":"j:*':l.*:*:i:::,:J:::

B V IJ A I 115 12 y  :;:;:::::::::::::::::::::::::::::::::::::::::::;:;:;: I I I I I

/{:}} ::::::::::::::::::::: *:*:*:*:*:*:"

I I I I I I I """"""""""

                                                                               '"*'""*'"""""""""'""'""                                      I          I I I                 I I I                             *:-::*:*:-:-:*:<*:*::*:* :*:*:*:*:*:*:*:*:*:*

SUPPLEMENTAL REPORT EXPECTED (141 MONTH DAY YEAR EXPECTED bi SUBMISSION il YES (If yes. comp/ere EXPECTED SUBMISSION DATE! NO DATE 1151 I I I ABSTRACT (Limit to 1400 spacss, i.e., approximately fifttJBn single*sfMce typewritten lines) 1161 On 12/2/93, 2C Diesel Generator (D/G) was declared inoperable due to cracking in 3R cylinder liner. This was discovered while investigating a jacket-water leak following a successful post-maintenance operability run. The flange portion of the cylinder liner had several through-wall radial cracks and the flange had separated completely around. its circumference from its cylindrical base. Repairs to the D/G could not be completed within the 72 hours allowed by Technical Specifications and on 12/3/93 a controlled shutdown was initiated and Mode 5 (cold shutdown) was entered on 12/5/93 ,* at 1944 hours. 2C D/G was disassembled to check other cylinder liners for signs of cracking. Because lB D/G (Salem Unit 1) was the only other Salem D/G with Canadian Allied Diesel (CAD)-supplied liners, it wa*s disassembied and inspected. The liners of lB D/G did not have any relevant indications. *The root cause of this event is attributed to "Design, Manufacturing, construction/ Installation," as per NUREG-1022. The most plausible cause of the 3R cyl*inder liner failure was* a combination of lack of liner flange flatness and perpendicularity, under-sized upper o-ring groove radius and possible presence of a flaw in the upper o-ring groove area. A contributor to this failure was less than adequate definition of critical characteristics at time of liner dedication (flange flatness, flange perpendicularity, and upper o-ring groove radius) . All previously installed CAD liners have been removed from Salem D/Gs and replaced with ALCO liners. Appropriate changes will be made to the receipt, inspection, and maintenance activities involving P/G cylinder liners. NRC Form 366 (6*891

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station DOCKET NUMBER LER NUMBER PAGE Unit 2 5000311 93-013-00 2 of 4 PLANT AND SYSTEM IDENTIFICATION: Westinghouse - Pressurized Water Reactor Energy Industry Identification System (EIIS) codes and Institute of Electrical and Electronics Engineers, Inc. (IEEE) are identified in the text as {xx/xx} IDENTIFICATION OF OCCURRENCE: Non-Valid Failure Of 2C Diesel Generator (D/G) With Subsequent Reactor Shutdown Event Date: 12/2/93 Report Date: 12/30/93 This report was initiated by Incident Report No. 93-491. CONDITIONS PRIOR TO OCCURRENCE: Salem Unit 1: 11th Refueling Outage in progress Salem Unit 2: Mode 1 Reactor Power 100 % - Unit Load 1160 MWe DESCRIPTION OF OCCURRENCE: On December 2, 1993, 2C D/G {VJ} was declared inoperable following identification of cracking in 3R cylinder liner {VJ/LNR}. This was discovered while investigating a jacket-water leak following a successful post-maintenance operability run. Examination revealed that the flange portion of the cylinder liner had several through-wall radial cracks and that the flange itself had cracked completely around its circumference from its cylindrical base. Repairs to the D/G could not be completed within the 72 hours allowed by Technical Specifications (TS) Action Statement 3.8.1.1.a. On December 3, 1993 a control.led Reactor shutdown was initiated and Mode 5 (cold shutdown) was entered on December 5, 1993, at 1944 hours. ANALYSIS OF OCCURRENCE: When 2C D/G was overhauled in April 1993 all 18 cylinder liners were removed and replaced with 10 new Canadian Allied Diesel (CAD) liners and 8 refurbished GE/ALCO liners previously removed from other Salem

• D/Gs. The 3R liner of 2C D/G was a CAD liner, dedicated as a Commercial Grade Item by the Procurement Engine*ering Group in June 1991. Replacement liners were obtained from a vendor other than GE/ALCO after GE/ALCO decided not to maintain a dedication process

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station DOCKET NUMBER LER NUMBER PAGE Unit 2 5000311 93-013-00 3 of 4 ANALYSIS OF OCCURRENCE: (cont'd) in accordance with the requirements of 10CFR50 Appendix B or the* commercial grade dedication process. The investigation of the 3R liner failure focused on 3 areas to determine what caused the liner to fail. Areas examined were operations, installation, and materials. In-depth reviews.of D/G operations _and installation requirements did not identify any conditions which may have contributed to failure. Extensive metallurgical examinations.by two metallurgical labs did not identify a.nY significant non-conformance or deviations from the vendor material specification requirements. A detailed finite element stress analysis was performed to estimate the stresses in the cylind.er liner to assess the potential for cracking. Based on the cases evaluated, it was determined that under worst case stresses, it is possible that local failure or damage could occur. 2C D/G was disassembled to check other cylinder liners for signs of

  *cracking. Because lB D/G (Salem Unit 1) was the only other Salem D/G with CAD-supplied liners, it was disassembled and inspected. The liners of lB D/G did not have any relevant indications.

This event is classified as a non-valid failure in accordance with Regulatory Guide 1.108. As such, no change in the D/G testing interval is required. This report of the D/G failure is submitted for information purposes, in accordance with TS Surveillance Requirement 4.8.1.1.4. APPARENT CAUSE OF OCCURRENCE: The root cause of this event*is attributed to "Design, Manufacturing, Construction/Installation," as per NUREG-1022. The investigation team concluded the most plausible cause of the 3R cylinder liner failure was a combination of lack of liner flange flatness and perpendicularity, under-sized upper o-ring groove radius, and possible presence of a flaw in the upper o-ring groove area. A contributor to this failure was less than adequate definition of critical characteristics at time of liner dedication (flange flatness, flange perpendicularity, and upper o-ring groove radius). PREVIOUS OCCURRENCES: There are no previously identified occurrences involving cracked D/G cylinder liners at Salem. SAFETY SIGNIFICANCE: This event did not affect the health or safety of the public. It is

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station DOCKET NUMBER LER NUMBER PAGE Unit 2 5000311 93-013-00 4 of 4 SAFETY SIGNIFICANCE: (cont'd) reportable to the NRC in accordance*with 10CFR50.73(a) (2) (i). Operability of the D/Gs assures that* sufficient emergency power is available for operation of safety related equipment during normal as well as accident and transient conditions. With the unit in Mode 1, three D/Gs are required to be operational as per TS 3. 8 .1.1. With one D/G inoperable, TS Action Statement 3.8.1.1.a requires that the D/G be restored to operability within 72 hours, or else be in Hot Standby within 6 hours and in Cold Shutdown within the next 30 hours. During this event 2A and 2B D/Gs were operable and, as such, TS requirements were met. CORRECTIVE ACTION: All cylinder liners installed in 2C and lB D/Gs were inspected for liner flange flatness and perpendicularity, under-sized upper o-ring g~oove radius, and possible presence of a flaw in the upper o~ring groove area. All previously installed CAD liners have been removed from Salem D/Gs and replaced with ALCO liners. To preclude future similar occurrences, appropriate changes will be made to the receipt, inspection, and maintenance activities involving D/G cylinder liners. General Manager - Salem Operations MJPJ:pc . rt~J~N\6-'-'\L*.c;__ SORC Mtg. 93-109 t~ G~'-~*~ Vc-*j_,\_c~}}