ML20046B473

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LER 93-005-00:on 930630,TS 3.0.3 Entered Due to Both Containment Spray Sys Inoperable.Replaced CCW Outlet Valve Actuator Connecting Link Assembly from Number 11 SDC Heat exchanger.W/930730 Ltr
ML20046B473
Person / Time
Site: Calvert Cliffs Constellation icon.png
Issue date: 07/30/1993
From: Cruse C, Gradle R
BALTIMORE GAS & ELECTRIC CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-93-005, LER-93-5, NUDOCS 9308040253
Download: ML20046B473 (8)
v • d • e


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. ,' B ALTIMORE GAS AND ELECTRIC CALVERT CLIFFS NUCLEAR POWER PLANT 1650 CALVERT CLIFFS PARKWAY

  • LUSBY. MARYLAND 20657-4702 CHARLES H. CRUSE

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c vin rrs July 30, 1993 U.S. Nuclear Regulatory Commission Washington, D.C. 20555 ATTENTION: Document Cc.ntrol Desk

SUBJECT:

Calvert Cliffs Nuclear Power Plant Unit No. 1; Docket No. 50-317; License No. DPR 53 Licensee Event Report 93-005 TS 3.0.3 Entered, Due to Both Containment Spray Systems Inorerable The attached report is being c o nt to you as required under 10 CFR 50.73 guidelines. Should you have any questions regarding this report, we will be pleased to discuss them with you.

Very truly yours,

-f V CHC/RCG/bj d Attachment cc: D. A. Brune, Esquire J. E. Silberg, Esquire R. A. Capra, NRC D. G. Mcdonald, Jr. , NRC T. T. Martin, hTC P. R. Wilson, NRC R. I. McLean, DNR J. H. Walter, PSC Director, Office of Management Information and Program Control 9309040253 930730 030040- 3n f#,#j ADOCK 05000317 PDR >

S PDR gg

  1. N N NRC FORM 366 U. S. NUCLEAR REoVLATORY COMMISSION N *
  • ESTMTED EURDEM FER ESFDPRITo COMFLYWITHTK3 NfC3MATION
  • ** COLLECRON EOUEsT: 500 HFE FCMAFO COMMDRS EGARDWG Bm ESTmTE Tome EMMTON AND RECORDS MMAGEMENT LICENSEE EVENT REPORT (LER) LVWCH (MNBS 7714). U S NUCLEAR FEGULATORV FNMcW(

WASHirGTOtt DC 20'Hr0001. ANDTo THE PAPOWoHK FE. DUCTION PFulECT (See reverse for reauired number of diaits/ characters for each block) Q1500104) OFFICE OF M4%GEMENT AND BUDGET,WASHirGTOf( DC20'in FACILITY NAME (1) DOCKET NUMBER (2) PAGE (3)

Calvert Clif f s, Unit 1 05000 317 1 OF 07 TITLE (4)

TS 3.0.3 Entered, Due to Both Containment Spray Systems inoperable EVENT DA1E (5) LER NUMBER (6) REPORT DATE (7) OTHER F ACILITIE S INVOLVED (8)

^' I MOMTH DAY YEAR YEAR MONTH DAY YEAR NUMBER NUMBER 05000 06 30 93 93 - 005 -

00 07 30 93 05000 OPERATING THff REPORT tS SUDMfTTED PURSUANT TO THE REOUIREMENT9 OF 10 CFR -(Check one or more) f11)

MODE (9)

I 20.402(b) 20 405(c) 50 73(a)(2)(ev) 73 73 gy POWER 73 7DC)

LEVEL 100 20 405(a)(1)@ w.3c(c)(2) 2 73(a)(2)(vii) X mm CD) X 20.405(a)(1)(iii) 50 73(a)(2)(i) 50.73(a)(2)(viii)(A) (Speedy in Atatract below and in 20.405(a)(1)0v) Text, NRC Form 30/A) 50.73(a)(2)0i) 50.73(a)(2)(viii)(B) 20 405(a)(1)(v) 50.73(a)(2)(iii) 50.73(a)(2)(x)

LICENSEE CONTACT FOR THIS LER (12)

NAME TELEPHONE NUMBER Dnclude Area Code)

R. C. Gradle, Compliance Engineer 401 260-3738 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

CAUSE SYST E M COMPONENT ABE M CAUSE SYSTEM COMPONENT TURER NPRDS TURER NPRDS B CC V M120 Y SUPPLEME NTAL REPORT f YPECTED (14) EXPECTED MONTH DAY YEAR YES 8 "8 " '**' "

X No (if yes complete FXPFCTFD SUBMISSION DATF) DATE (15)

ABSIRAC1 (LJmit to 1400 spaces,i.e , approxamarely15 single 4p < t, pewntien hnes) (10) on June 30, 1993, at 2:00 p.m., Calvert Cliffs Unit 1 entered Technical Specification 3.0.3 for 45 minutes because both independent Containment Spray (CS) Systems were inoperable. No. 12 CS System was inoperable for scheduled maintenance. No. 11 CS System was determined to be inoperable because the outlet valve for component cooling water supplying its shutdown cooling heat exchanger was broken. Immediate corrective action restored No. 11 CS System to OPERABLE status while the Unit was at 100 percent power. This event l resulted in no public health or safety consequences.

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l The affected valve actuator had disconnected. We believe the actuator connecting linkage separated due to pivot locking plate failure. The replacement plcte subsequently cracked. Similar cracked plates were found on two identical Unit 2 valves. Plate material was a sintered alloy. The cracked plates were replaced with carbon steel plates. We plan to install carbon steel pivot locking plates on similar style valves. This report satisfies 10 CFR Part 21 requirements.

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PRC Form 3E pg5

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NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 31504104 f! Lea EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE To COMPLY W!TH THIS INFoRMATioN CoufCTloN REQUEST: 50.0 HRS FORWARD LICENSEE EVENT REPORT (LER) COMMENTS REGARCMG BURDEN ESTIMATE To THE INFoRMATON AND RECORDS MANAGEMENT BRANCH (MNBB 7714L U.S NUCLEAR TEXT CONTINUATION REcutAToRy CoMMssON. WASHINGTON. DC aosssmoi. AND To THE PAPERWORK REDUCTON PROJECT (31sG 0104L oFFCE oF MANAGEMENT AND BUDGET, WASHINGTON. DC 20503 F ACluTY NAME (1) DOCKET NUMBER A LER NUMBER @ PAGE (4)

Calvert Cliffs, Unit 1 05000 3 1 7 93 -

005 - 00 02 OF 07 TtxT y mo. .p.c. w.a. .m on.i wp.= or NRC ro, 38eA3 ci7)

I. DESCRIPTION OF EVENT On June 30, 1993, at 2:00 p.m. Calvert Cliffs Unit 1 entered Technical Specification (TS) 3.0.3 for 45 minutes because both independent Containment Spray (CS) Systems were inoperable. No. 12 CS System was inoperable for scheduled maintenance. No. 11 CS System was subsequently determined to be inoperable because the outlet valve for Component Cooling Water (CCW) supplying its shutdown cooling (SDC) heat exchanger was broken. Immediate corrective action restored No. 11 CS System to OPERABLE status while the Unit was at 100 percent power.

Technical Specification 3.6.2.1 Limiting Condition for Operation (LCO) for the CS System requires that two independent CS Systems and associated SDC heat exchangers be OPERABLE in Modes 1-3. The associated ACTION requirement for this LCO allows one CS System to be inoperable for up to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> ACTION limit for No. 12 CS System was entered on June 30, 1993, at 2:50 a.m.

when No. 12 Saltwater (SW) loop was removed fron service for scheduled maintenance. The removal of No. 12 SW loop also rendered one group of containment air coolers out of service.

On June 27, 1993, at 4:00 a.m., SDC was secured with No. 11 SDC heat exchanger CCW outlet control valve (1-CC-3828-CV) shut. This is the last time this valve was operated prior to June 30, 1993.

On June 30, post-maintenance flow testing of No. 13 CCW pump was in progress.

Control Room operators were aware that Control Room valve position indication for 1-CC-3828-CV was inoperable due to a broken open position indicator limit switch. When 1-CC-3828-CV was opened an expected increase in CCW flow did not occur. Immediate inspection of the valve, revealed that the connecting link from the actuator stem had disconnected from the vane arm. This failure rendered the valve inoperable in the shut position. The Control Room was immediately informed of the valve failure. With both CS Systems inoperable, the Snift Supervisor entered TS 3.0.3 at 2:00 p.m.

Plant engineering and maintenance personnel inspected the valve actuator linkage and discovered that the pivot locking plate, which resembles a square washer, was missing from the pivot screw (see Figure 1). The pivot screw is part of an assembly that connects the actuator connecting link to the valve vane arm.

Emergency maintenance was conducted on 1-CC-3828-CV. Replacement parts were obtained off a similar spare valve actuator and the valve was repaired and returned to service. Technical Specification 3.0.3 was exited at 2:45 p.m.

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . _ _ _ . _ _ _ _ _ _ _ _ . _ _ _ _ _ _ _ . _ _ _ _ _ _ _ . _.._____.___-__-.__-.__.___m_ _ _ . _ _ _ _ _ - _ _ . _ _ - - - _ .__._

NRC [ORM 36CA U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150-0104 per) EXPIRES 5/31/95 l ESTIMATED BURDEN PER RESPONSE To COMPLY WITH THIS INFORMATON CoLLECTON REQUEST 60.0 HRS. FORWARD UCENSEE EVENT REPORT (LER) couuENTs ReGARaNo BURoEN ESTuATE To TwE mroRuATON  :

AND RECORDS MANAGEMENT BRANCH (MNBB 7714), U 8. NUCLEAR TEXT CONTINU ATION REGutATony couussON, wAsMuGroN. oC rosssoooi, ANo To THE PAPERWORK REDUCTON PROJECT (315CLO104), OFFICE oF j MANAGEMENT AND BUDGET, WASHINGTON, oC 20603.

F ACILITY NAME (1) DOCKET NUMBER (4 LER NUMBER (3) PAGE (4) ;

Calvert Cliffs, Unit 1 05000 3 1 7 93 -

005 - 00 03 OF 07 TEXT Of more space a requited, use aoMonal copees of NRC Form 366A) (17)

II. CAUSE OF EVENT The immediate cause of this event was the separation of the valve actuator connecting link from the valve vane arm. We believe that the pivot locking .

plate on 1-CC-3828-CV cracked in half allowing the connecting linkage to slip  !

free of the vane arm. ,

l On June 30, 1993, a visual inspection was conducted on the identical Unit 2 valves (2-CC-3828-CV and 2-CC-3830-CV). Both valves were found to have cracks in their pivot locking plates. The Shift Supervisor was informed and maintenance orders were issued to replace these pivot locking plates.

Ten other similar style safety-related valves were identified in the Unit 1 and  ;

Unit 2 CCW and Service Water (SRW) Systems. These valves were visually inspected on June 30, 1993, and no cracks were found.

On July 9 and 10, 1993, the cracked pivot locking plates on 2-CC-3828-CV and i 2-CC-3830-CV, were replaced. The old cracked plates were mistakenly discarded, i so the opportunity was lost to perform a metallurgical failure analysis. l I

Replacement plates were purchased from the vendor as non-stock commercial grade  ;

and were dedicated for use as safety-related items. Critical characteristics for the plate described the material as either carbon steel or sintered iron copper alloy. The same part number (370295-111-779) applies to both materials.

During receipt inspection both plates were verified to be ferrous material.

Discussions with the vendor revealed that they currently supply only carbon steel pivot locking plates with improved ductility characteristics under this part number. They stated that in October 1989, a drawing change was made to include carbon steel as a material for the plates.

On July 2 a small crack in the replacement pivot locking plate for 1-CC-3828-CV was discovered. This plate had been obtained from a similar spare valve assembly on June 30. A maintenance order was issued to replace this pivot locking plate. ,

On July 22, 1993, the cracked pivot locking plate on 1-CC-3828-CV was replaced with a carbon steel pivot locking plate. The replaced plate had two cracks oriented 90 degrees apart and was verified to be sintered alloy material. A detailed failure analysis on the replaced plate identified the brittle nature of the material as susceptible to this type of inservice failure.

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NRC FORM 36CA U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150-0104 (sea EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE To COMPLY WW THIS INFoRMATON CodICTON REQUEST 50 0 HMS FORWARD ,

LICENSEE EVENT REPORT (LER) CouuEwTS ReoARDiNG BURDEN tsnuATE To THE iNFoRuaTON i AND RECORDS MANAGEMENT BRANCH {MNBB 7714L U.S. NUCLEAR  !

TEXT CONTINUATION REovuToRY Couw SSON. WASHINGTON. oC asseooi, AND To ,

THE PAPERWORK REDUCTON PROJECT Cit 60-0104), OFFICE OF j UANAGEMENT AND BODGET, WASHINGTON. DC 20$C3 F ACluTY NAME (1) DOCKET NUMBER (a LER NUMBER (3) PAGE (4)

Calvert Cliffs, Unit 1 05000 3 1 7 93 -

005 -

00 04 0F 07 TEXT y mo,. .o.r a,.o. o .ooit on.i cop or Nrc Form assA) tit) t A review of previous maintenance orders was conducted for the eight similar CCW  ;

control valves, but did not identify any previous valve inoperability due to -

failed pivot locking plates. We also conducted two historical queries of the Nuclear Plant Reliability Data System (NPRDS) under the general valve model number (34000) and the valve actuator (Case No. 18L, 37-18), but no pivot t locking plate failures were identified. ,

III. ANALYSIS OF EVENT The CS System is designed to provide sufficient heat removal capability to ,

maintain containment pressure and temperature below established design values i following a loss-of-coolant accident (LOCA). Each CS System consists of a 50 percent capacity pump, a SDC heat exchanger, and a spray header. The SDC heat exchanger is cooled by the CCW System. After a LOCA, suction for the CS pumps is taken directly from the refueling water tank and discharged through the SDC heat exchangers to containment.

The CS System is redundant to the Containment Air Cooling System which consists of two independent groups of containment air coolers, with two units in each  ;

group cooled by a SRW System. With three of four cooling units in operation, the Containment Air Cooling System provides the same heat removal capability as ,

the two CS Systems.

The short time that both CS Systems and one group of containment air coolers was inoperable resulted in no public health or safety consequences. The safety significance of this event was minimized based on the following.

The scenario of concern is a LOCA concurrent with a loss of offsite power (IDOP), a highly unlikely scenario. We have identified that 1-CC-3828-CV was shut from the Control Room on June 27, 1993. Thus, the maximum hypothetical time of CS System inoperability concurrent with one group of inoperable containment air coolers is limited to the approximate 12-hour period following the securing of No. 12 SW loop and the restoration of 1-CC-3828-CV to OPERABLE status. The probability of such an event occurring in so short a period of time was extremely low.

This event is considered reportable in accordance with 10 CFR 50.73(a)(2)(1)(B),

10 CFR 50.73(a)(2)(v), and 10 CFR Part 21.

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 313 0104 f5 e2) EXPIRES 5/31/95 ESTIMATED BURDEN PER NBPoNSE TO COMPLY WlTH THIS INFoRMATiON COLLECTON REQUEST: SO 0 HRS. FORWARD LICENSEE EVENT REPORT (LER) CouuCNTs REsAmNG BURDEN EsTiuaTE To THE iNroRuAfoN AND RECoRDB MANAGEMENT BRANCH (MNBB 7714), U.S. NUCLEAR TEXT CONTINUATION REGULATORY COMMSSON. WASHWGToN, DC 205554xH, AND TO THE PAPERWORK REDUCTON PROJECT (31500104), oFFtCE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20$03.

F ACluTV NAME (1) DOCKET NUMBER (2) LER HUMBER (3) PAGE (4)

Calvert Cliffs, Unit 1 05000 3 1 7 93 -

005 -

00 05 0F 07 TtxT e mm..p.c ..w.o. .amons cop or NRC r awn on IV. CORRECTIVE ACTIONS Immediate corrective actions are completed as follows:

A. The CCW outlet valve actuator connecting link assembly from No. 11 SDC heat exchanger was replaced and TS 3.0.3 was exited at 2:45 p.m. on June 30, 1993.

B. The pivot locking plates on Unit 2 CCW valves for 21 and 22 SDC heat exchangers were replaced with carbon steel pivot locking plates on July 9 and 10,1993.

C. The appropriate maintenance personnel were sensitized to the importance of retaining the replaced, cracked pivot locking plate  ;

for failure analysis.

Actions to prevent recurrence include:

A. On July 22, 1993, a carbon steel pivot locking plate was installed on 1-CC-3828-CV. I 1

B. Sintered alloy plates will be replaced with carbon steel pivot locking plates on other similar style safety-related valves in the plant.

C. The stock description for this pivot locking plate has been revised I such that only carbon steel pivot locking plates will be accepted in the future.

D. An Issue Report was generated concerning the inadvertent discarding of the cracked locking plates for 2-CC-3828-CV and 2-CC-3830-CV.

Corrective action to preclude this problem from recurring will be taken in accordance with our corrective action process. )

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' NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150-0104 maa EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE To COMPLY WITH THIS INFoRMATION COLLECTION REQUEST: 20 HRS. FORWARD UCENSEE EVENT REPORT (LER) CouuENTs REcAFoNG BuRoEN tsTiuATE To THE iNroRMATiON AND RECORDS MANAGEMENT BRANCH (MNB0 7714), U.S. NUCLEAR TEXT CONTINUATlON REGULATORY COMMISS40N, WASHINGTON, DC 2055540, AND To THE PAPERWORK REDUCTION PROJECT (3150 c104). OFFICE oF MANAGEMENT AND BUDGET, WASHINGTON, DC 23503, F ACILITY NAME (1) DOCKET NUMBER (33 LER NUMBER (3) PAGE (4)

Calvert Cliffs, Unit 1 05000 3 1 7 93 -

005 - 00 06 0F 07 TEXT pf more space is requued, peo addMkmal copese of NRC Form 36eA) (17)

V. ADDITIONAL INFORMATION A. Identification of Components and Systems referred to in this LER:

IEEE 803A/83 IEEE 805/84 Component or System Function ID System ID Containment Spray System N/A BE Component Cooling Water System N/A CC Saltwater System N/A BI Service Water System N/A BI' Containment Fan Cooling System N/A BK Pump P N/A Valve V N/A  ;

Heat Exchanger HX N/A Cooler CLR N/A B. Previous Similar Events: I There has been one previous similar event involving entry into TS <

3.0.3 due to a concurrent inoperability of both CS Systems, but the  !

cause is not related to this event. Details of the previous event I were provided in LER 318/92-002.

The valves which experienced pivot locking plate cracking are Masonellan model number 37-34211. The part number for the pivot locking plate is 370295-111-779. The vendor stated that carbon steel pivot locking plates have square edges and pivot locking plates made of sintered iron carbon alloy have rounded edges.

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HRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO.3150-0104 as21 EXPIRES 5/31/95 ESTIMATED BUFOEN PER e4ESPONSE TO COMPLY WriH THIS it#0RMATON COLLECTON REQUEST: 50 o HHS. FORWARD LICENSEE EVENT REPORT (LER) coMuEurs REaAroNo suRDEN EsTiMAtt TO THE wORuATON AND RECORDS MANACEMENT BRANCH (MNBB 7714) U.S. NUCLEAR TEXT CONTINUATION HEGULATORY COMMIC3ON WWUNGTON. DC 20555@01, AND TO THE PAPERWORK REDUC'ON PROJECT (31BC104). OFFCE OF MANAGEMENT AND BUDGET. W ASHINGTON. DC 20$03.

F ACluTY NAME (9) DOCKETNUMBER Q LER NUMBER (3) PAGE l4)

Calvert Cliffs, Unit 1 05000 3 1 7 93 -

005 - 00 07 0F 07

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FIGURE 1 34000 Butterfly Valves with 1-1/2" -- 4" Stroke Actuators PARTS REFERENCE No. Part Name No. Part No. No. Part No.

1. Body 13 Lock Washer 25. Clevis I
2. Vane 14. Body Cap Screw 26. Lock Nut

'3. Elastorner Liner 15 Bushing 27. Actuator Stem

4. Vane Shaft 16. Setscrew 28. Actuator Mounting Plate
5. Teper Pina 17. Key 29. Cap Screw

'6. Vane Shaft Bushing 18. Vane Arm 30. Lock Washer

'7. Pm nng 19. Pivot Screw 31. Nut

8. Pe:6ng Box Gland 20. Pivot Locking Plate 32. Cotter Pin
9. Gland Flange Stud 21. Castle Nut
10. Giand Fiange 22. Cotter Pan
11. Gland Flange Nut 23 Connecting Lie -
12. Actuator Mounting Bracket 24 Clevis Psn

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