ML17332A331

LER 94-006-00:on 940906,six MSSVs Failed to Meet TS Lift Setpoint Requirements.Caused by Galling Between Valve Disk & Nozzle.Nrr Issued TS Amend 167 to Unit 2 Ts,Increasing MSSV Tolerance on 940909.W/941003 Ltr

ML17332A331
Person / Time
Site:	Cook
Issue date:	10/03/1994
From:	Blind A, Weber G INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-94-006-01, LER-94-6-1, NUDOCS 9410110049
Download: ML17332A331 (6)

Text

wm~mmx (ACCELERATED x i RIDS PROCESSING REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9410110049 DOC.DATE: 94/10/03 NOTARIZED: NO DOCKET FACIL:50-316 Donald C. Cook Nuclear Power Plant, Unit 2, Indiana M 05000316 AUTH. NAME AUTHOR AFFILIATION WEBER,G.A. Indiana Michigan Power Co. (formerly Indiana & Michigan Ele BLIND,A.A. Indiana Michigan Power Co. (formerly Indiana & Michigan Ele RECIP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER 94-006-00:on 940906,six MSSVs failed to meet TS setpoint recpxirements.Caused by galling between valve disk &

lift nozzle.NRR issued TS Amend 167 to Unit 2 TS,increasing MSSV tolerance on 940909.W/941003 ltr.

DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR ENCL SIZE:

TITLE: 50.73/50.9 Licensee Event Report (LER), ncident Rpt, etc.

NOTES RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD3-1 PD 1 1 HICKMAN,J 1 1 INTERNAL: QQg+OAB/DSQ 2 2 AEOD/SPD/RRAB 1 1 FLZZ MENTE~R2 1 1 NRR/DE/EELB 1 1

/DR/E11EB 1 1 NRR/DORS/OEAB 1 1 NRR/DRCH/HHFB 1 1 NRR/DRCH/HICB 1 1 NRR/DRCH/HOLB 1 1 NRR/DRSS/PRPB 2 2 NRR/DSSA/SPLB 1 1 NRR/DSSA/SRXB 1 1 NRR/PMAS/IRCB-E 1 1 RES/DSIR/EIB 1 1 RGN3 FILE Ol 1 1 EXTERNAL: EG&G BRYCE,J.H 2 2 L ST LOBBY WARD 1 1 NOAC MURPHY,G.A 1 1 NOAC POOREIW 1 1 NRC PDR 1 1 NUDOCS FULL TXT 1 . 1

'CLIENT NOTE TO ALL"RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE KVASTE! CONTACT THE DOC! CONTROL DESK, ROOKI Pl-37 (EXT. 504-2083 ) TO ELIXIINATEYOI.tR NAME FROil DISTRIBUTION LISTS I'OR DOCUMENTS YOU DON "I'L'ED!

FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 26 ENCL 26

Indiana Michigan Power Company Cook Nuclear Plant One Cook Place

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Bridgman, Ml 49106 616 465 5901 INDIANA NICHIGiAItiI POWER October 3, 1994 United States Nuclear Regulatory Commission Document Control Desk Rockville, Maryland 20852 Operating Licenses DPR-74 Docket No. 50-316 Document Control Manager:

In accordance with the criteria established by 10 CFR 50.73 entitled Licensee Event Re ort S stem the following report is being submitted:

94 006-00 Sincerely, A. A. Blind Plant Manager

/sb Attachment co J. B. Martin, Region E. E. Fitzpatrick III P. A. Barrett R. F. Kroeger M. A. Bailey - Ft. Wayne NRC Resident Inspector J. B. Hickman NRC J. R. Padgett G. Charnoff, Esq.

D. Hahn INPO S. J. Brewer 9410110049 941003 PDR ADOCK 05000346 PDR

NRC FORM 366 . NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150-0104 (5-92) EXPIRES 5/31/95 ESTlMATED BURDEN PER RESPONSE TO COMPLY WrfH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS, FORWARD LICENSEE EVENT REPORT (LER) COMMENTS REGARDING BURDEN ESTtMATE TO THE INFORMATION AND RECORDS MANAGEMENT BRANCH (MNBB 7714), U.S. NUCLEAR REGUtATORY COMMISSON, WASHINGTON, DC 2055scoot ~ AND TO THE PAPERWORK REDUCTION PRCUECT (31500104), OFFtCE OF (See reverse for required number of digits/characters for each block) MANAGEMENTAND BUDGET, WASHINGTON, DC 20503.

FACILftYNAME (I) DOCKET NUMBER (2) PAGE (3)

D. C. COOK NUCLEAR PLANT UNIT 2- p5ppp 316 1OF4 FAILURE OF THE UNIT TWO MAIN STEAM SAFETY VALVES TO MEET TECHNICAL SPECIFICA'TION LI EVENT DATE 5 LER NUMBER 6 REPORT NUMBER 7 OTHER FACILITIES INVOLVED 8 REVISION FACIUTYNAME DOCKET NUMBER SEQUENTIAL MONTH DAY YEAR YEAR MONIH DAY NUMBER NUMBER 05000 FACIUlYNAME DOCKET NUMBER 09 06 94 94 006 00" '10 03 94 05000 OPERATING THIS REPORT IS SUBMITTED PURSUA NT TO THE REQUIREMENTS OF 10 CFR %: Check one or m ore MODE (9) 20.402(b) 20.405(c) 50.73(a) (2) (iv) 73.71(b)

POWER 20A05(a) (1)(i) 50.36(c) (1) 50.73(a) (2) (v) 73.71(c)

LEVEL (10) 00 20.405(a) (1) (ii) 50.36(c) (2) 50.73(a) (2)(vii) OTHER 20.405(a) (1) (iii) 50.73(a) (2) (i) 50.73(a) (2) (viii)(A) (Specity tn Atetract below and in Text, NRC 20.405(a) (1)(iv) 50 73(a)(2)(ii) 50.73(a) (2) (viii)(B) Form 388A) 20.405(a) (1) (v) 50.73(a) (2)(iii) 50.73(a)(2) (x)

LICENSEE CONTACT FOR THIS LER 12 NAME TELEPHONE NUMBER include Area Code)

G. A. WEBER PLANT ENGINEERING SUPERINTENDENT 616-465-5901 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT 13 REPORTABLE REPORTABLE CAUSE SYSTEM MANUFACTURER CAUSE SYSTEM COMPONENT MANUFACTURER TO NPRDS TO NPRDS X SB RV D243 Y SUPPLEMENTAL REPORT EXPECTED 14 EXPECTED MONTH DAY YEAR YES NO SUBMISSION 0f yea, complete EXPECTED SUBMISSION DATE) DATE (15)

X ABSTRACT (Umit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) (16)

On September 6, 1994, with the Unit .2 Reactor in Mode 3 (hot standby), routine surveillance testing found the initial lift pressures for six of twenty Main Steam Safety Valves (MSSVs) outside the +/.-, one percent setpoint tolerance established by Plant Technical Specifications. Five of the valves lifted above the allowable setpoint range; one lifted below the allowable range.

However, all six initial lifts were within +/- three percent of their nominal lift setpoint. Three of the MSSVs had acceptable subsequent lifts andis did not lift require adjustment. Based on previous events, the high initial believed to be caused by mild galling between the valve disk and nozzle, along with mechanical "keying" and/or chemical bonding of the three mixed oxides on the valves did disk with the chromium oxide on the nozzle. The other were partially require adjustment to restore them to within tolerances. These attributed to setpoint drift.

On September 9, 1994, D. C. Cook was granted a Technical Specification amendment which increased the MSSV setpoint tolerances to +/- three percent.

The as-found condition reported here under the more stringent Technical Specifications in effect previously, has already been analyzed as onpart of the licensing submittal and determined not to have an adverse impact the health and safety of the public.

NRC FORM 388 (5-92)

NRC FORM 355A U.S. NUClEAR REGULATORY COMMISSION (54) 9) APPROVED OMB NOi 3)504)(04

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I EXPIRES: 4/30/92 ATED BURDEN PER RESPONSE TO COMPLY WTH THIS LICENSEE EVENT REPORT (LER) ES INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD COMMENTS REGARDINQ BURDEN ESTIMATE TO THE RECORDS TEXT CONTINUATION ANO REPORTS MANAGEMENT BRANCH (P4)30), U.S. NUCLEAR REGULATORY COMMISSION. WASHINGTON, OC 20555, AND TO 1HE PAPERWORK REDUCTION PROJECT (31500104), OFFICE OF MANAGEMENTANO BUDGET, IYASHINGTON, DC 20503.

FACILITYNAME 0) DOCKET NUMBER l2) I.ER NUMBER (5) PAGE (3)

YEAR @jj. SEQUENTIAL

.9 NVMBER '..;:

/PE<

REVISION NVMEE R D. C. COOK NUCLEAR PLANT UNIT 2 0 5 0 0 0 3 94 00 6 00 0 2 OF 0 4 TEXT ///mom 4P444 /4 IPEP/RNL II44 d/I/PfM/HRC FPmi 355AQ/ ()7)

Conditions Prior to Occurrence:

Unit Two - Mode 3 (hot standby)

Descri tion of Event:

September 6, 1994, six of the twenty Main Steam Safety Valves (MSSVs)

On (EIIS/SB-RV) tolerance lift setpoints were found outside of the +/- one percent limits established in Unit Technical Specification 3.7.1.1. Five of the six out-of-tolerance percent high. One MSSV had a MSSVs had a lift 2

lift setpoint between one and three setpoint that was 1.5 percent low.

The MSSVs at Cook are Dresser Model 3707RA Safety Valves. Based on operating experience and vendor input, the valve maintained within +/- one percent tolerance limits.

lift setpoints cannot be consistently The required relief pressu're setpoint ranges and the as-found setpoints for the MSSVs found out of specification are listed below:

Valve T/S Allowable As Found Percent Date I.D. No Stm. Gen. ~net nint 09"06"94 2"SV-1B-1 1 1065 1054-1075 1094 2.7 09-06"94 2"SV-2B-1 1075 1064-1086 1107 3.0 09-06-94 2"SV-2A-2 2 1075 1064-1086 1059 1.5 09"06-94 2"SV"1A"3, 3 1065 1054"1076 1086 2.0 09-06-94 2-SV-1A-4 1065 1054-1076 1084 1.8 09-06"94 2-SV" 1B-4 1065 10S4-1075 1087 2.1 Retests were performed on the MSSVs to make necessary setpoint adjustments and ensure as-left lift setpoints vere acceptable. The subsequent MSSV'tests revealed that some sticking was experienced on the initial lifts and was not indicative of the actual setpoint values. Three of the MSSVs with high initial lifts required no adjustment as subsequent lifts were acceptable.

MSSV 2-SV-1A-2 (Steam Generator No. 2) had an acceptable setpoint, but subsequent retests revealed that the lift as-found lift setpoint was erratic and this valve was not returned to service. The Action Statement of Technical Specification 3.7.1.1 was met as the Power Range Neutron Flux High Trip Setpoint was reduced prior to testing of the MSSVs.

Cause of Event:

Three of the five valves that lifted high were retested and found to within the allowable range without adjustment. Based on the investigation of lift similar previous events, the tendency of the valves to initially believed to be caused by mild galling between the valve disk and nozzle, along lift high is with mechanical "keying" and/or chemical bonding of the mixed oxides on the disk with the chromium oxide on the nozzle. It is believed these combined effects over time caused the elevated lifts. The other three valves did require adjustment lift setpoint on the MSSV's initial to restore them to within tolerances. These deficiencies vere partially attributed to setpoint drift.

NRC Form 355A (559)

NAC FORM 355A U.S. NUCLEAR REGULATORY COMMISSION APPROVED OMB NO. 31504104 154)9)

EXPIRESI'4/30/92 EST) TFO BUROFN PEA RESPONSE TO COMPLY WTH THIS LICENSEE EVENT REPORT (LER) INFORMATION COLLECTION REOUESTI 500 HAS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS TEXT CONTINUATION AND REPORTS MANAGEMENT BRANCH (P4)30). U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, OC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (31500104), OFFICE OF MANAGEMENTAND BUDGET, WASHINGTON, OC 20503.

FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER 15) PAGE (3)

YEAR SEOUENTIAL P@S REVISION g@ NUMSER NUMSER D. C. COOK NUCLEAR PLANT UNIT 2 0 5 o o o 3 1 6 9 4 0 0 6 00 03 OF 0 4 TEXT /I/more y>>oe /4 eeqtu/red, uee edd/dor>>///RC Form 85/AB/ (IT)

Cause of Event continued:

As the result of previous events, several MSSV discs were sent to an independent laboratory for analysis. Results of the analysis indicated that the contact surfaces of the discs were found to have been covered with mixed iron-chromium oxides over most of their, surfaces except for islands of nozzle-material. The nozzle material transfer most likely occurred by a galling or adhesive wear mechanism rather than a diffusion bonding process.

The'ixed oxides on most of the sealing surface are postulated to have developed from normal oxidation of the disk alloy along with possible deposition of iron-oxide particulates from the steam. (This cause was previously identified in LER 315/94-01, Revision 1.)

Previous testing data has indicated that there is a correlation between the number of MSSV failures and the main steam pressure transients/unit trips.

With fewer transients occurring during an operating cycle, more MSSV failures would occur. The Unit 2 MSSVs were last tested in February, 1994, and a unit trip occurred on August 15, 1994.

Anal sis of Event:

This event is reportable via the provisions of 10CFR50.73(a)(2)(i)(B) as an operation prohibited by Plant Technical Specification 3.7.1.1. The Technical Specification 3.7. 1.1 requires that the Main Steam Safety Valves be operable in Modes 1 through 3. Operability requires that all twenty Main Steam Safety Valves lift within +/- 1 percent of the Technical Specification Setpoints.

The Safety Evaluation revealed that the MSSV as-found have resulted in exceeding the design rating of the steam generators.

lift setpoints would not This event would not be reportable in the future as the out-of-specification MSSVs had lift setpoints within three percent of the Technical Specification value.

On September 9, 1994, the NRR issued Amendment No. 167 to the Unit 2 Technical Specifications, increasing the MSSV tolerance to + three percent.

Corrective Action:

Three of the six MSSVs with the initial. lift setpoint ranges retested satisfactorily and did not require any adjustment.

setpoints outside the acceptable Three of the out-of-tolerance MSSVs required adjustment to return the setpoint to acceptable values.

MSSV 2-SV-1A-2 had erratic lift setpoints and was declared inoperable. This valve will be repaired during the current Refueling Outage. One additional MSSV (2-SV-2B-2) required adjustment.

retests indicated a slightly low lift The initial setpoint.

lift was acceptable, but Failed Com onent Identification:

Main Steam Safety Valve Manufacturer: Dresser Consolidated Valves Model: 3707RA-RT22 EIIS Code: SB-RV NRC Form 355A (589)

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (689) APPROVED 0 M 8 NO, 31500104 6 XP IR ES: O/30/92 ES . TED BURDEN PFR RESPONSE TO COMPLY WTH THIS LICENSEE EVEN REPORT {LER) INFORMATION COLLECTION REOUESTI SOB) HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS TEXT CONTINUATION AND REPORTS MANAGEMENT BRANCH (P430), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO 1HE PAPERWORK REDUCTION PROJECT (3(50010E), OFFICE OF MANAGr E MENT AND BUDGET, WASHINGTON, DC 20503.

FACILITY NAME (1) DOCK ET NUMBER l2) LER NUMBER (8) PAGE (3)

YEAR SEQUENTIAL 4EVISION

'45 PÃv'UMBE4 NUMBER D. C. COOK NUCLEAR PLANT UNIT 2 o 5 o o o 3 1 6 9 4 0 0 6 0 0 0 4 OF 0 4 TEXT /I/more epooe /en/lrrwerL oee //6rnnr/HRC Form 366AB) llT)

Previous Similar Events:

50-315/94-01 50-316/92-03 50-315/92-06 50-316/90-06 50-315/90- 13 50-316/88-04 50-315/89-02 50-315/87-11 50-315/86-20 NRC Form 388A (689)