ML17223B035

LER 89-009-01:on 891128,containment Purge Valve Local Leak Rate Exceeded Tech Spec Limits.Caused by Valve Closure Stop Out of Adjustment.Testing Frequency Increased to Once Every 6 wks.W/901220 Ltr

ML17223B035
Person / Time
Site:	Saint Lucie
Issue date:	12/20/1990
From:	Mead S, Sager D FLORIDA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
L-90-450, LER-89-009, LER-89-9, NUDOCS 9012260091
Download: ML17223B035 (8)

Text

ACCELERATED DIiRIBUTION DEMONS~TION SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9012260091 DOC.DATE: 90/12/20 NOTARIZED: NO DOCKET FACIL:50-389 St. Lucie Plant, Unit 2, Florida Power & ~

Light Co. 05000389 AUTH. NAME AUTHOR AFFILIATION MEAD,S.C. Florida Power & Light Co.

SAGER,D.A. Florida Power & Light Co.

RECIP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER 89-009-01:on 891128,containment purge valve local leak rate exceeded Tech Spec limits. Caused by valve closure stop out.of adjustment. Testing frequency increased to once every 6 wks.W/901220 ltr.

DISTRIBUTION CODE: IE22T COPIES RECEIVED: LTR ENCL / SIZE:

TITLE: 50.73i50.9 Licensee Event Report (LER), Incident Rpt, etc.

NOTES:

RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD2-2 LA 1 1 PD2-2 PD 1 1 NORRIS,J 1 1 INTERNAL: ACNW 2 2 ACRS 2 2 AEOD/DOA 1 1 AEOD/DS P/TPAB 1 1 AEOD/ROAB/DSP 2 2 NRR/DET/ECMB 9H 1 1 NRR/DET/EMEB 7E 1 1 NRR/DLPQ/LHFB11 1' NRR/DLPQ/LPEB10 1 1 NRR/DOEA/OEAB 1 1 NRR/DREP/PRPBll 2 2 NRR/DST/SELB 8D 1 1 NRR/DST/SICB 7E 1 1 NRR/~ST/vSQLB8D1 1 1 NRR/DST/SRXB 8E RES/DSIR/EIB 1

1 1

1

~EGRGN2 FILE~ 02 FILE 01 1

1 1

1 EXTERNAL: EG&G BRYCE,J.H 3 3 L ST LOBBY WARD 1 1 NRC PDR 1 1 NSIC MAYS,G 1 1 NSIC MURPHY,G.A 1 1 NUDOCS FULL TXT 1 1 NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOM Pl-37 (EXT. 20079) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!

FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 33 ENCL 33

December 20, 1990 L-90-450 10 CFR 50.73 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555 Gentlemen:

Re: St. Lucie Unit 2 Docket No. 50-389 Reportable Event: 89-09 Revision 1 Date of Event: November 28, 1989 Containment Purge Valve Local Leak Rate Exceeds Technical S ecification Due to Valve Closure Sto Out of Ad'ustment The attached Licensee Event Report revision is being submitted pursuant to the requirements of 10 CFR 50.73 to provide an update on the subject event.

Very truly yours, D. A ager Vic resident St. cie Plant I

DAS GRM.kw Attachment cc: Stewart D. Ebneter, Regional Administrator, USNRC Region II Senior Resident Inspector, USNRC, St. Lucie Plant DAS/PSL 4305 9012260091 901220 PDR ADOCK 05000389 8 PDR an FPL Group company

IVIFecal ot U.S. NUCLEAR REGUULTORY COMMISSION IRC Fera Ill APPROVED OM B NO. 315MII04 (IM LlCENSEE EVENT REPORT (LER) EXPIRES BI31/85 FACILITYNAME (1) DOCKET NUMBER (2 PAGE 3 St. Lucie Unit 2 0 5000389 1OF04

" Containment Purge Valve Local Leak Rate Exceeds Technical Specifications Due to Valve Closure Sto Out of Ad'ustment DATE (5) LER NUMBER (6) 'EPORT DATE (7)

'VENT OTHER FACILITIES INVOLVED(8)

MONTH DAY YEAR YEAR FACILITYNAMES DOCKET NUMBER(S)

NUMB R MONTH DAY YEAR NUM ER N/A 0 5000 1 1 2889 8 9 0 0 9 0 1 1 2 2 0 9 0 THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR OPERATING Check one or more of the followln 11 MODE (9) 20.402(b) 20.405(c) 50.73(a)(2)(iv) 73.71(b)

POWER 20.405(a) (1) (i) 50.36(c)(1) 50.73(a)(2)(v) 73.71(c)

LEVEL (10) 1 0 0 20.405(a)(1) (ii) 50.36(c)(2) 50.73(a)(2)(vii) X OTHER (Specify in Abstract 20.405(a)(1 )(iii) 50.73(a) (2)(i) 50.73(a)(2)(viii)(A) below and in Text 20.405(a)(1)(iv) 50.73(a) (2)(ii) 50.73(a)(2)(viii)(B) NRC Form 366A) 20.405(a)(1)(v) 50.73(a) (2)(iii) 50.73(a)(2)(x) VOLUNTARY LICENSEE CONTACT FOR THIS LER (12)

NAME AREA CODE Sandra C. Mead, Shift Technical Advisor 4 0 7 4 6 5-3 550 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT 13 CAUSE SYSTEM COMPONENT MANUFAC- TURER REPORTABLE TO NPRDS CAUSE SYSTEM COMPONENT MIrNUFAC REPORTABLE TO NPRDS SUPPLEMENTAL REPORT EXPECTED 14 EXPECTED M N A SUBMISSION

, YES (lfyes, complete EXPECTED SUBMISSION DATE) NO DATE (15)

ABSTRACT (LImit to 1400 spaces. I.e. approximately fifteen single-space typewritten lines)(16)

On November 28, 1989 at 1345, with Unit 2 in Mode 1 at 100% power, a routine local leak rate surveillance test on Containment Penetration 10 revealed an "as found" leakage rate across FCV-25-5 of 908,970 standard cubic centimeters per minute (sccm). This "as found" leakage rate was in excess of the allowable leakage per Technical, Specification 4.6.1.7.3.

Revision 0 of this Licensee Event Report stated the valve would be disassembled and inspected during the next Unit 2 refueling outage to determine the reason for the failure of the local teak rate test. However, the root cause of this event was not determined during the 1990 refueling outage due to personnel safety concerns over performing maintenance on the 48 inch butterfly valve without a jacking device for the actuator available to hold the valve open.

An attempt was made to obtain this jacking device from the vendor in time to support the outage work, but this was not possible. An Engineering Evaluation was then'performed and'a blind flange re-installed on the penetration to ensure containment integrity is maintained.

This Licensee Event Report was submitted on a voluntary basis. The corrective actions were: 1) Verify other in-line valves FCV-25-4 and FCV-25-6 were closed and de-energized. 2) Blind flange the penetration to ensure containment integrity is maintained. 3) The blind flange was successfullytested after installation. 4) An Engineering Request has been submitted to make permanent the blind flange installation on Penetration 10. 5)

Testing requirements and testing frequency will continue to be on a 6 month frequency in accordance with the St.

Lucie Unit 2 Technical Specifications Surveillance requirements.

AE fecsaW U.S. NUCLEAR REGULATORY COMMISSION 4 IAC Fere APP ROVE 0 0M B NO. 3150010l LICENSEE EVENT REPORT (LER) TEXT CONTINUATION EXPIRES 8/31/85 FACILITYNAME (1) DOCKET NUMBER (2) LER NUMBER (6) PAGE (3)

YEAR SEQUENTIAL NUMBER NUMBFR St. Lucie Unit 2 0 500 0389 8 9 0 0 9 0 1 0 2O" 0 4 TEXT (Ifmore space is required, use additional NRC Form 366A's) (17)

On November 28, 1989 at 1345, with Unit 2 in Mode 1 at 100% power, a routine local leak rate surveillance test on Containment Penetration 10 revealed a leakage across FCV-25-5 (EIIS-ISV) of 908,970 standard cubic centimeters per minute (sccm). Penetration 10 contains a 48 inch exhaust line for the Containment Purge System, with 3 butterfly valves, of which FCV-25-4 and FCV-25-5 are subject to Type C testing per Unit 2 Technical Specification 3.6.1.2.b, Table 3.6-1 and Surveillance 4.6.1.7.3. Local leak rate testing is performed by pressurizing the piping between the inboard (FCV-25-4) and outboard (FCV-25-5) valves. The "as found" leakage of the penetration was in excess of the allowable leakage of 0.05 La, or 48,568 sccm.

In accordance with Technical Specification 3.6.1.7, action statement "c", action was undertaken to restore the leakage rate to within the specified limit within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. In accordance with Technical Specification 3.6.3, FCV-25-4 and FCV-25-6, both of which are in series with FCV-25-5, were verified to be closed and de-energized, ensuring containment isolation.

Technical Specification 3.6.1.2 also limits containment leakage rate to a combined leakage rate of less than or equal to 0.60 La for all penetrations and valves subject to Type B and C testing. Based on guidance from ANSI 56.8 for a combined test, one-half of the leakage is assigned to each valve, thus the 0.60 La limit was not exceeded.

Following the adjustment of the valve seat travel stop adjustment screw, the leakage rate across FCV-25-5 was reduced to 400 sccm. Technical Specification 3.6.1.7 was exited within the required time limit at 1720 when the valve was returned to service after the successful retest. The valve was retested on January 5, 1990 and passed its local leak rate test. The valve was subsequently retested on February 15, 1990 and March 28, 1990 and both times failed to pass its initial local leak rate test. The valve stop had to be adjusted in both cases and was successfully retested after doing so.

The first time leakage problems were experienced on this valve was following work on the Bettis actuator during the 1989 refueling outage. The work performed was the 5 year overhaul on the Bettis actuator. The valve passed its pre-maintenance test but failed the post-maintenance test following the Bettis actuator work. The valve seat was adjusted and the valve passed its retest. Three months later on June 5, 1989 it failed its leak test again, without having been operated. The seat was adjusted, and the valve passed its retest. LER ¹389-89-004 was submitted on this event. The valve passed its next test on August 30, 1989, but failed on the next scheduled test on November 28, 1990. The seat was adjusted, and the valve passed its retest. The valve was put on the "frequent failure" list as required by the ASME code. The testing frequency was increased to every 6 weeks to ensure continued tightness. It demonstrated repeated failures, as documented above, and on May 8, 1990 a blind flange was installed because of concern over valve seating reliability.

The root cause of these failures cannot be conclusively determined without disassembly of the valve. The valve and acuator were to be disassembled during the 1990 Unit 2 refueling outage, but due to personnel safety concerns over performing maintenance on the 48 inch butterfly valve without a jacking device for the actuator available to hold the valve open, it was not performed. Attempts were made to obtain a jacking device from the vendor in time to support the outage work but this was not possible. An Engineering Evaluation was performed and a blind flange installed on the penetration to ensure containment integrity is maintained.

fPL Fecersle ol US. NUCLEAR REGULATORY COMMISSION WC fera Xl (I4$) APPROVED 0MB NO. 31500I04 LICENSEE EVENT REPORT (LER) TEXT CONTINUATION EXPIRES 8/3 I/85 FACILITYNAME (1) DOCKET NUMBER (2) LER NUMBER (6) PAGE (3)

I YEAR

', SEQUE(NTIAL RF VISION NUM ER St. LLICie Unit 2 0500038989 0 0 9 0 1 0 3 o 04 TEXT (Ifmore space is required, use additional NRC Form 366A's)(1 7)

An Engineering Request has been submitted which will make permanent the blind flange installation on Penetration 10.

This Licensee Event Report was written on a voluntary basis. This event is not considered reportable per 10CFR50.73 because the time limitations of the applicable Technical Specification action statements were not exceeded. The integrity of the penetration was maintained at all times.

Technical Specification 3.6.1.2 limits containment leakage rates for combined leakage of less than or equal to 0.60 La for all penetrations and valves subject to Type B and C testing. Based upon guidance from ANSI 56.8, for a combined test one-half of the leakage is assigned to each valve, thus the 0.60 La limit was not exceeded.

The LGO for Technical Specification 3.6.1.7 was entered at 1345 on November 28, 1989 due to the excessive leakage found after performing the local leak rate test. The valve was successfully retested following adjustment of the valve stop. Action statement "c" of Technical Specification 3.6.1.7 was exited within the required time limit at 1720 on November 28, 1989, when the valve was returned to service.

The limits for containment leakage rates in the Technical Specifications are from the requirements of 10CFR50 Appendix J. The leakage rate measured from testing is higher than that which could actually occur under hypothetical accident conditions due to the conservative manner in which the test results are evaluated. When calculating local leak rates, it is assumed that for a given pair of isolation vvalves, the valve having the lower leakage rate fails fully open. Thus the leakage across the penetrations is governed by the valve having the higher leakage rate. In reality, with both FCV-25-4 and FGV-25-6 closed and de-energized, which are both in series with FCV-25-5, the integrity of the penetration was maintained. The satisfactory test result (leakage rate: 400 sccm) for FCV-25-4 was an assurance that containment intergrity for Penetration 10 was maintained at all times during the degraded condition of FCV-25-5. Therefore, at no time was the health and safety of the public endangered.

This same valve failed its local leak rate test 6 months earlier (June 5, 1989) due to the valve closure stop out of adjustment due to personnel error. LER ¹389-004 was written on this event. The same valve also failed its local leak rate test 3 months prior (March 5, 1989) when the post-maintenance/surveillance test was performed. With this most recent failure of the valve, it has been speculated that the correct root cause of the problem may not have been determined. Due to this, corrective actions are being undertaken which will ensure the continued tightness of the valve seat until the valve can be disassembled and the root cause for these failures determined with certainty or blind flanges are permanently installed. The installation of the blind flange was determined to be the most effective way to ensure the continued integrity of the penetration. Operating with the blind flange (passive barrier) installed on Penetration 10 is superior to using flow control valves (active components) from a containment isolation standpoint. A Engineering Request has been submitted which will make permanent blind flange installation on Penetration 10.

(PL $ aae4s L.S. NVCLEAR REGULATORY COMMISSION

(( l((C /ena Al($45) APP AOVE0 0M B NO. 31500(04 LICENSEE EVENT REPORT (LER) TEXT CONTINUATION EXPIRES 8/31/85 FACILITYNAME (1) DOCKET NUMBER (2) LER NUMBER (6) PAGE (3)

YEAR SEQUENTIAL @ REVISION NUMBER @ NUMBER St. LUCie Unit 2 r

0 500 0389 8 9 0 0 9 0 1 0 4 OF 0 4 TEXT (lfmore space ls required, use additional NRC Form 366A's)(1 7)

1) The series redundant valves for Penetration 10, FCV-25-4 and FCV-25-6, were verified to be closed and de-energized.

2) FCV-25-4 was verified to have a leakage rate well within the acceptance criteria for the Technical Specifications.

3) Instrument & Controls personnel adjusted the valve seat travel stop adjustment screw for the closing of the valve.

4) Technical Staff Test Group personnel retested FCV-25-5.

5) Prior to installation of the blind flange, the testing frequency on FCV-25-5 was increased to once every

,6 weeks to ensure continued tightness. With the blind flange installed, the testing frequency of the valve has been returned to once per 6 months in accordance with the St. Lucie Unit 2 Technical Specification Surveillance requirements.

6) An Engineering Request has been submitted which will make permanent the blind flange installation on Penetration 10.

Manufacturer: Henry Pratt Co.

Valve Model: NR1A Valve Size/Type: 48 inch Carbozinc 11lButterfly Actuator Type: Bettis Cylinder Air Operated Actuator Model: T-520B-SR2 For the most recent similar event, see Licensee Event Report ¹389-89-004, which pertains to excessive penetration leakage across FCV-25-5 on Unit 2 due to valve closure stop out of adjustment due to personnel error. For another similar event, see LER ¹335-87-005 which pertains to excessive leakage discovered during performance of a local leak rate test on a containment purge valve on Unit 1.