ML18153D206

LER 92-008-00:on 921215,RCS Leak Identified Near Low Pressure Letdown Flow Transmitter.Caused by Failure of Swagelock Fitting on Flow Transmitter.Root Cause Evaluation in Progress & Fitting & Tube replaced.W/921231 Ltr

ML18153D206
Person / Time
Site:	Surry
Issue date:	12/31/1992
From:	Kansler M VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
92-829, LER-92-008-03, LER-92-8-3, NUDOCS 9301050354
Download: ML18153D206 (5)

Text

, .' A(:CELERAT~ DOCUMENT DISTRIBUTION SYSTEM

'J . REGULAT. INFORMATION DISTRIBUTIO.STEM (RIDS)

~ ACCESSION NBR:9301050354 DOC.DATE: 92/12/31 NOTARIZED: NO DOCKET#

FACIL:50-281 Surry Power Station, Unit 2, Virginia Electric & Powe 05000281 AUTH.NAME AUTHOR AFFILIATION KANSLER,M.R. Virginia Powei (Virginia Electric & Power Co.)

RECIP.NAME RECIPIENT AFFILIATION R

SUBJECT:

LER 92-008-00:on 921215,RCS leak identified near low I pressure letdown flow transmitter.Caused by failure of Swagelock fitting on flow transmitter.Root cause evaluation in progress & fitting & tube replaced.W/921231 ltr. D DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR _l ENCL l_ SIZE: Lf- s TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc:

I NOTES:lcy NMSS/SCDB/PM. 05000281 A

RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL D FD2-2 LA 1 1 PD2-2 PD 1 1 BUCKLEY,B 1 1 D INTERNAL: A.CNW 2 2 ACRS 2 2 A.EOD/DOA 1 1 AEOD/DSP/TPAB 1 1 s A.EOD /ROAB/DSP 2 2 NRR/DET/EMEB 7E 1 1 NRR/DLPQ/LHFBlO 1 1 NRR/DLPQ/LPEBlO 1 1 NRR/DOEA/OEAB 1 1 NRR/DREP/PRPBll 2 2 NRR/DST/SELB 8D 1 1 NRR/DST/SICB8H3 1 1 N~R/DST/SPLB8Dl 1 1 NRR/DST/SRXB BE 1 1

~]!:~ 02 1 1 RES/DSIR/EIB 1 1

"""R:Gm~FILE 01 1 1 EXTERNAL: EG&G BRYCE,J.H 2 2 L ST LOBBY WARD 1 1 R NRC PDR 1 1 NSIC MURPHY,G.A 1 1 NSIC POORE,W. 1 1 NUDOCS FULL TXT 1 1 I

NOTES: 1 1 D

s I

A D

D NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK, s ROOM Pl-37 (EXT. 504-2065) TO ELIMINATE YOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!

FULL TE:XT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 32 ENCL 32

., e 10CFR50.73 Virginia Electric and Power Company Surry Power Station P. O.Box315 Surry, Virginia 23883 December 31, 1992 U. S. Nuclear Regulatory Commission Serial No.: 92-829 Document Control Desk SPS:VAS Washington, D. C. 20555 Docket No.: 50-281 License No.: DPR-37

Dear Sirs:

Pursuant to Surry Power Station Technical Specifications, Virginia Electric and Power Company hereby submits the following Licensee Event Report applicable to Surry Power Station Unit 2.

RRPQRf NUMBER 50-281/92-008-00 This report has been reviewed by the Station Nuclear Safety and Operating Committee and will be forwarded to the Management Safety Review Committee for its review.

Very truly yours, M. R. Kansler Station lv.lanager Enclosure cc: Regional Administrator 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 M. W. Branch NHC Senior Resident Inspector 050043 Surry Power Station 930105035.4~ 921211 PDR ADoc*~ 05000281 S PDR

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION

• APPROVED 0MB NO. 3150-0104 (6-89)

- EXPIRES: 4/30/92 ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD LICENSEE EVENT REPORT (LERI COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS AND REPORTS MANAGEMENT BRANCH (P-530). U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (3150-0104), OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON. DC 20503.

FACILITY NAME (1) DOCKET NUMBER (2) PAGE 13)

TITLE 141 Surry Power Station, Unit 2 Reactor Coolant System Leak Rate Greater Than 10 GP:M Due to Failure of a Io Is Io Io Io 12 1 81 l 1 loF O13 Swagelok Fitting on a Flow Transmitter EVENT DATE (!;I LER NUMBER (61 REPORT DATE (7) OTHER FACILITIES INVOLVED IB)

MONTH DAY YEAR YEAR  :}( SE~~~~~~AL t:t ~~~~~~ MONTH DAY YEAR FACILITY NAMES DOCKET NUMBER(S) 1 I 2 1 Is 9 2 9 I 2 - ol oIs - olo I 1 2 I 3 1 9 I2 THIS REPORT IS SUBMITTED PURSUANT TO THE R~OUIREMENTS OF 10 CFR §: (Chock one or more of th* following) 111)

OPERATING MODE 191 N 20.402lbl

- 20.405lcl

- 50.7311H2Hivl

- 73.71lbl 20.40511)11 )Ii) 20.40511)11)1;1)

-X 50.38lcH11 50.38(c)(21 B) 50.73111121M 50.73(1112Jlvii) -- 73.71(cl OTHER (Spt1cify in Abstr*ct below *nd in Text, NRC Form 20.40511111 Hilil 20.40511111111*)

- 50.131111211n (

150.7311112Hiil

- 50.7311)(2llvi111CAI 50.73(11(21(vliil(BI 366A) 20.405111111M

- 50.7311H2Jliiil

- 50.73(111211*)

LICENSEE CONTACT FOR THIS LER (121 NAME TELEPHONE NUMBER AREA CODE M. R. Kansler, Station Manager COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (131 MANUFAC- MANUFAC-CAUSE SYSTEM COMPONENT TURER TURER I I I I I I I X y I I I I I I I SUPPLEMENTAL REPORT EXPECTED 1141 MONTH DAY YEAR EXPECTED

~

SUBMISSION I YES (If yos, com,olot* EXPECTED SUBMISSION DATE) NO DATE 115)

I I I ABSTRACT (Limit to T400 spaces, i.e., approxim*toly fiftetm singltJ*SJ>>Ctl typawritttln /intJs) (181 On December 15, 1992, at 0858 hours0.00993 days <br />0.238 hours <br />0.00142 weeks <br />3.26469e-4 months <br />, with Units 1 and 2 at 100% reactor power, Radiological Protection technicians notified the Unit 2 Senior Reactor Operator (SRO) that a Reactor Coolant System (RCS) leak had developed near the Low Pressure Letdown Flow Transmitter. The leak was determined to be in excess of the maximum RCS leakage rate permitted by Technical Specification (TS) 3.1.C.5.

A Limiting Condition for Operation (LCO) requiring hot shutdown within six hours was entered at 0858 hours0.00993 days <br />0.238 hours <br />0.00142 weeks <br />3.26469e-4 months <br />. The LCO was exited at 0901 hours0.0104 days <br />0.25 hours <br />0.00149 weeks <br />3.428305e-4 months <br /> once letdown was isolated. A four hour LCO was entered at 0901 hours0.0104 days <br />0.25 hours <br />0.00149 weeks <br />3.428305e-4 months <br /> to identify the leak in accordance with TS 3.1.C.2. RCS leakage was verified to be less than 1 gallon per minute (gpm) at 0940 hours0.0109 days <br />0.261 hours <br />0.00155 weeks <br />3.5767e-4 months <br /> and the LCO was exited. The leakage occurred when a section of drain valve tubing for the Low Pressure Letdown Flow Transmitter separated from its fitting. It was determined that the release of radioactivity to the environment was negligible based on indications from the Ventilation System Process Radiation Monitors; therefore, the health and safety of the public were not affected. A Root Cause Evaluation (RCE) is being conducted to determine the exact cause of this event. Recommendations will be implemented from the RCE, as appropriate. This event is reportable pursuant to 10CFR50.73(a)(2)(i)(B).

NRC Form 366 (6-89)

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (6-89) APPROVED 0MB NO. 3150-0104 EXPIRES: 4/30/92 E* ATEO BURDEN PER RESPONSE TO COMPLY WTH THIS LICENSEE EV'T REPORT (LER) INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS t TEXT CONTINUATION AND REPORTS MANAGEMENT BRANCH (P-5301. U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (3150-01041. OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.

FACILITY NAME (1) DOCKET NUMBER (21 PAGE (31 LER NUMBER (61

SEQUENTIAL ::::::::::: REVISION YEAR  ::::::::::: NUMBER  :::::::::: NUMBER Surry Power Station, Unit 2 o Is I o I o I o 12 I s 11 91 2 - oIo 1s - o I o o I 2 oF o 13 TEXT /If mom space is required, use additional NRC Form 356A '*I (171 Jl. 0 DESCRIPTION OF THE EVENT On December 15, 1992, at 0858 hours0.00993 days <br />0.238 hours <br />0.00142 weeks <br />3.26469e-4 months <br />, with Units 1 and 2 at 100% reactor power, a Reactor Coolant System (RCS) [EIIS-AB] leak was identified near the Low Pressure Letdown Flow Transmitter (2-CH-FT-2150) [EIIS-CB-FIT]. While performing decontamination activities in a high radiation area, a decontamination technician noticed water and boric acid on a "Swagelok" fitting on the flow transmitter. He wiped the boric acid off and saw water dripping out of the fitting.

While the technician was placing a leak catch container around the drain line tubing, the drain tubing separated from a Swagelok fitting, significantly increasing the leakage. Radiological Protection (RP) technicians immediately notified the Unit 2 Senior Reactor Operator (SRO) of the leak. The SRO determined that the leakage met entry conditions for Abnormal Procedure, "Excessive RCS Leakage," (AP-16).

At 0858 hours0.00993 days <br />0.238 hours <br />0.00142 weeks <br />3.26469e-4 months <br />, Unit 2 was placed in a six hour Limiting Condition for Operation (LCO) to hot shutdown (HSD) in accordance with Technical Specification (TS) 3.1.C.5 which allows a maximum unidentified leakage of 10 gallons per minute (gpm) from the RCS. In accordance with AP-16, level control valves (2-CH-LCV-2460A!B and 2-CH-HCV-2200A!B/C) [EIIS-CB-LCV] were closed to isolate letdown. Motor Operated Valve (2-CH-MOV-2289B) [EIIS-CB-FCV] was shut to isolate normal charging. Subsequent review determined that leakage was approximately 11 gpm calculated from a level drop noted on the control room recorder for the Volume Control Tank (VCT) [EIIS-CB] level. The LCO was exited at 0901 hours0.0104 days <br />0.25 hours <br />0.00149 weeks <br />3.428305e-4 months <br />. In accordance with TS 3.1.C.2, which limits unidentified leakage to less than 1 gpm, a four hour LCO to identify the leak was entered at 0901 hours0.0104 days <br />0.25 hours <br />0.00149 weeks <br />3.428305e-4 months <br />. Operating Procedure, "Shifting From Normal Letdown To Excess Letdown," (2-0P-8.8.1) was used to place excess letdown in service. An operator was dispatched to determine the exact cause of the leak. The operator reported that a section of drain valve tubing for the flow transmitter had separated from a Swagelok fitting, creating the RCS leak. The operator isolated the leak by closing the high side isolation valve to the transmitter. At 0940 hours0.0109 days <br />0.261 hours <br />0.00155 weeks <br />3.5767e-4 months <br />, RCS leak rate was verified to be less than 1 gpm. VCT and Pressurizer [EIIS-AB-PZR] trends had stabilized and the four hour LCO was exited.

2.0 SIGNIFICANT SAFETY CONSEQUENCES AND IMPLICATIONS A limited amount of leakage from the RCS is expected. The maximum allowable TS values for RCS leakage are 1 gpm from unidentified sources and 10 gpm for identified sources. These values are sufficiently low to ensure corrective actions are taken prior to the leakage becoming excessive. Leak rate calculations are performed once per day, or more often if required. During this event, normal charging was in service and was able to compensate for RCS leakage. RP technicians immediately evacuated personnel from the affected area and notified the Control Room of the leak. The leak was immediately isolated in accordance with AP-16. The amount of radioactive gases released into the Auxiliary Building basement during this event, as indicated on the Ventilation System Process Radiation Monitors [EIIS-VF-MON],

NRC Form 366A (6-89)

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION APPROVEO 0MB NO. 3150-0104

• (6-89)

EXPIRES: 4/30/92 E

• ATED BURDEN PER RESPONSE TO COMPLY WTH THIS LICENSEE EVIT REPORT (LER) INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS TEXT CONTINUATION AND REPORTS MANAGEMENT BRANCH (P-530), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (3150-0104), OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.

FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (6) PAGE (3)

Surry Power Station, Unit 2 o Is I o I o I o 12 I 811 91 2 - oI o 18 - o Io o I3 OF oI 3 TEXT (If mom SfJllctJ is n,qu;md, use 1JdditiofllJ/ NRC Form 366A '*) (17) was negligible. Access to the Auxiliary Building was promptly restricted and filtered exhaust was placed in service. The affected area was reclaimed at 1115 hours0.0129 days <br />0.31 hours <br />0.00184 weeks <br />4.242575e-4 months <br />. Local air sample testing detected minimal airborne radioactivity which was rapidly removed via the Auxiliary Building ventilation system. Therefore, the health and safety of the public were not affected.

3. 0 CAUSE OF THE EVENT While performing decontamination activities in a high radiation area, a decontamination technician noticed water and boric acid on a Swagelok fitting on the Low Pressure Letdown Flow Transmitter. He wiped the boric acid off and saw water dripping out of the fitting. While the technician was placing a leak catch container around the drain line tubing, the drain tubing separated from a Swagelok fitting, significantly increasing the leakage from the RCS. A Root Cause Evaluation (RCE) is in progress to determine the exact cause of the event.

4.0 IMMEDIATE CORRECTIVE ACTION{S)

Prompt and accurate communication between RP personnel and the Control Room enabled operators to immediately control and isolate the leakage. RP technicians immediately evacuated the area. The operations shift performed the required procedures and isolated the leakage path. The fitting and tubing were replaced by maintenance personnel and at 1332 hours0.0154 days <br />0.37 hours <br />0.0022 weeks <br />5.06826e-4 months <br /> normal letdown was returned to service.

5 .1D ADDITIONAL CORRECTIVE ACTION{S)

A RCE is being performed to determine the exact cause of failure.

Recommendations from the RCE will be implemented, as appropriate.

Instrumentation and Control technicians are currently checking similar fittings to ensure correct assembly.

6. 0 ACTIONS TO PREVENT RECURRENCE Actions to prevent recurrence will be based on the results of the RCE.

7. 0 SIMILAR EVENTS LER Sl-90-08, "RCS Leakage Exceeds 10 gpm Due to Gage Sensing Line Break".

8.0 MANUFACTURER/MODEL INFORMATION Crawford Fitting Company Swagelok Tube Fitting SS-812-1 NRC Fann 366A (~9)