ML17285A542

LER 89-015-00:on 890512,three-quarter-inch High Point Vent Line Failed During Performance of HPCS Sys Operability Procedure.Caused by Reverse Bending Fatigue Caused by Vibration.Design Change Implemented

ML17285A542
Person / Time
Site:	Columbia
Issue date:	06/08/1989
From:	Arbuckle J WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:
Shared Package
ML17285A541	List: ML17285A540 ML17285A542
References
LER-89-015, LER-89-15, NUDOCS 8906140264
Download: ML17285A542 (4)

Text

NRC Form 3M U.S. NUCLEAR REGULATORY COMMISSION (94)3)

APPROVED 0M B NO. 3)500104 EXPIRES: BI31/88 LICENSEE EVENT REPORT (LER)

FACILITY NAME (1) DOCKET NUMBER (2) PAGE 3I Washington Nuclear Plant - Unit 2 o 5 o o o3 97 i oFO 4 lg ressure ore pray ys em ree- uar er- nc one rea urging Surveillance Testing While Plant was Shutdown - Component Failure EVENT DATE(5) LEA NUMBER (6) REPORT DATE (7I OTHER FACILITIES INVOLVED (8)

SEGVENT IAL AcvlsioN OAY YEAR FACILITY NA DOCKET NUMBER(5)

MONTH DAY YEAR YEAR NUMBER NUMBER MONTH 0 5 0 0 0 0 5 12 89 015 0 0 6 0 8 8 9 0 5 0 0 0 OPERATING THIS AEPOAT IS SUBMIT'TEO PURSUANT T 0 THE AEOVIAEMENTS OF 10 CFR $ ; fChtch oi t or moit of tht foi(oivinpf (ll MODE (9) 20.402(5) 20 405(cl 50.73( ~ ) (2)(iv) 73.71(5)

POWE R 20.405( ~ ) (1)(i) 60.35(c)(1) 50,73( ~ )(2)(vl 73.71(c)

LEYE(.

0 0 0 20AOS( ~ )(1)(iil 60,35(cl(2) 50,73(s)(2)(vsl OTHKR ISPtcify in AOttrstt osfovr snd in Ttvt ffRC Form 20AGS I ~ ) (I l(ili) 50.73( ~ l(21(il 60.73(o) (2)(viill(A) 35SA) 20,405( ~ l(1) (lv) 50.73( ~ ) (2) l ii) 60,73( ~ i(2) I viiil(BI 20A05 (~ I(1) (v) 50,7 3(v ) (2) I liI I 50.73( ~ ) (2)(s I LICKNSEE CONTACT FOR THIS I.EA (12I NAME TELEPHOtvE NUMBF R AREA CODE J.D. Arbuckle, Compliance Engineer 50 937 7- 211 5 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCAIBEO IN THIS REPORT (13)

MANUFAC CAUSE SYSTEMI COMPONEIvT MANVFAC

'TVRKR cIEPORTABI.E TO NPADS CAUSE SYSTEM COMPOIvENT TVRER REPORTABLE TO NPRDS ': v "i r<*

SUPPLEMENTAL REPORT EXPECTED (14I MONTvr DAY YEAR EXPECTED SUBIVIISSIO "II DATE ',"l5i YES fff yN Comport EXPECTED S(fBMISSION OA TEI ABSTRACT fLimit to tt00 totctf I~ toorommtrtry fiftttn Iinpit ttlttt tyotvrrrittn finttf (15)

On Hay 12, 1989 during the performance of the High Pressure Core Spray (HPCS) System operability procedure, a three-quarter-inch high point vent line failed approximately one-ha'if inch above the fillet weld. The vent line is on the 12-inch HPCS test return line to the suppression pool and is located on approximately the 466'levation of the Reactor Building. At the time of the event the Plant was shutdown for the annual maintenance and refueling outage.

The procedure was being performed as part of normal surveillance testing. During the course of the surveillance, Plant Operators noted vibration on the test line while the Full-Flow Suppression Pool Test Return Valve (HPCS-V-23) was open. At 0315 hours0.00365 days <br />0.0875 hours <br />5.208333e-4 weeks <br />1.198575e-4 months <br /> the high point vent line failed, spraying water on two Equipment Operators and a Health fg Physics Technician. However, none of the personnel were contaminated. At 0330 hours0.00382 days <br />0.0917 hours <br />5.456349e-4 weeks <br />1.25565e-4 months <br />, roofs Plant Operators secured and partially drained the HPCS System to stop the leak.

DOQ.

40 DO Oi IA The cause of the HPCS vent line failure was due to reverse bending fatigue caused by FJ0 vibration. The vibration was due to turbulence caused by high flow rates in the 12-inch 4O test return line. Although primary containment was open for refueling activities, an (MID HPCS high point vent line failure during operation would have been considered to be a GA breach of containment (open to the submerged portion of the suppression pool). However,

<CC had this occurred during operation, the line failure would only have affected the HPCS DiC test mode. The normal injection mode would not have been affected.

O'A CEIL.(FP Corrective actions consisted of 1) implementing a design change to strengthen the high point vent piping, and 2) performing an Engineering evaluation of similar (vents and drains) piping failures at the Plant.

NRC Form 356 (9 83(

NRC Form 355A V.S. NUCLEAR REGULATORY COMMISSION (94)3)

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION APPROVED OMB NO. 3150-0(04 EXPIRES: 9/31/SB FACILITY NAME (1) DOCKET NUMBER (3) LER NI/MBER (5) PAGE (3)

SEOUENTIAL '~P.'EVISION YEAR )N NUMBER NUMBER Washin ton Nuclear Plant - Unit 2 0 5 0 0 0 3 9 7 8 9 0 1 5 000 2 0 4 TEXT /I/ moro FINco lr rooulrod, uro oddkr/onrr////IC Form 36SA'4/ (IT)

Abstract (continued)

This event did not effect the health and safety of either the public or Plant personnel.

Plant Conditions a) Power Level - 0%

b) Plant Node - 5 (Refueling)

Event Descri tion On Hay 12, 1989 during the performance of Plant Procedure (PPII) 7.4.5.1.11, "High Pressure Core Spray (HPCS) System Operability Test," a three-quarter-inch high point vent line t.HPCS (55-1-7): containing val ves HPCS-V-83/84] failed approximat'ely one-half inch above the fillet weld. The vent line is on the HPCS test return line to the suppression pool and is located on approximately the 466'levation of the Reactor Building (in the HPCS pump room). At the time of the event, the Plant was shutdown for the annual maintenance and refue'ling'utage.

The procedure was being performed as part of normal survei 1 lance testing. In accordance with the procedure, Plant Operators had aligned the system, proper ly vented and filled the piping and started the HPCS pump (HPCS-P-1). During the course of the surveillance they noted vibration on the test line while the Full-Flow Suppression Pool Test Return'alve (HPCS-V-23) was open. At 0315 hours0.00365 days <br />0.0875 hours <br />5.208333e-4 weeks <br />1.198575e-4 months <br /> the high point vent line failed, spraying water on two Equipment Operators and a Health Physics Technician. However, none of the personnel were contaminated.

At 0326 hours0.00377 days <br />0.0906 hours <br />5.390212e-4 weeks <br />1.24043e-4 months <br />, Plant Operators tripped pump HPCS-P-1. The control fuses for the pump were removed at 0330 hours0.00382 days <br />0.0917 hours <br />5.456349e-4 weeks <br />1.25565e-4 months <br /> and the system was secured and partially drained to stop the leak.

Immediate Corrective Action Plant Operators secured HPCS-P-1 and isolated the HPCS System to stop the leakage.

Further Evaluation and Corrective Action A. Further Evaluation This event is being reported per the requirements of 10CFR50.73(a)(2)(.ii) as an event or condition that resulted in the condition of the nuclear power plant, including its principle safety barriers, being seriously degraded. Although primary containment was open for refueling activities, an HPCS high point vent line failure during operation would have been considered to be a breach of primary containment (open to the submerged portion of the Suppression Pool).

2. With the exception of the line break, there were no structures, systems or components contributed to the event.

that were inoperable at the start 'f this event that NRC FORM 355A ~ U.S. CPOI 1955-330-959 00010 (943)

NRC Form 366A U.S. NUCLEAR REGULATORY COMMISSION (943)

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION APPROVED OMB NO. 3)50-0104 EXPIRES: 6/31/SB FACILITYNAME (ll DOCKET NUMBER (2) LER NUMBER (61 IIAGE (3)

SEOUENTIAL REVrelON NUMBER NUMBER Washington Nuclear Plant - Unit 2 0 s o 0 0 397 89 0 1 5 0 0 3 OF 0 4 TEXT /// mors cpsse is Nrr/oirsd. oss sdde'one ///IC Form 36SA's/ (17)

3. On tray 15, 1989 a field examination of the failed HPCS vent line was performed. As previously stated, the line failed one-half inch above the fillet weld. The failure was due to reverse bending fatigue caused by vibration. The vibration was due to turbulence caused by high flow rates in the 12-inch test return line. The line that failed is a three-quarter-inch, Schedule 160, SA105 (Grade B) pipe (Carbon steel:

ASHE III/2).

B. Further Corrective Action

1. A design change has been implemented to strengthen the high point vent piping. Specifically, one-inch butt we'id piping was used (coming off the 12-inch test return line) and reduced to three-quarter inch to connect to the valves (which have been close-coupled and an elbow deleted), and a gusset plate was installed to rigidly support the vent valves to the 12-inch test return line.

2. Generation Engineering has performed an evaluation of similar (vents and drains) piping failures at WNP-2. Extensive efforts have been ongoing to preclude repetitive failures of similar connections. The Supply System will continue to focus on eliminating the causes of these failures through improved design configuration and minimizing the source of cyclic loading.

Safet Si nificance There are no unacceptable consequences associated with this event. At the time of the event, the reactor vessel head was removed and reactor water level was greater than 22 feet above the reactor vessel flange. In addition, the Residual Heat Removal (RHR) System was in service for shutdown cooling. Furthermore, the HPCS was not required for trode 5 (Refueling).

If this event had occurred during operation, the failure of the HPCS high point vent line would have been considered to be a breach of primary containment (between the subsurface of the suppression pool and the outside containment atmosphere).

However, had this occurred the l.ine failure would have only affected the HPCS test mode. The normal HPCS injection mode would not have been affected.

Accordingly, this event did not affect the health and safety of either the public or Plant personnel.

Similar Events

\

LERs 85-011-00 and 85-011-01 NRC FORM 366D ~ O.e. CPcr Ieee-Sc<-eee One;I IS Ser

NRC Form 3BSA U.S. NUCLEAR REOULATORY COMMISSION (943)

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION APPROVED OMB NO. 3150&)04 EXPIRES: 8(3) i88 FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (6) PACE (3)

$ SEQUENTIAL pili REVISION YEAR g+ NUMBER B:X. NUMBBR Washington Nuclear Plant - Unit 2 o s o o 0 3 9 7 89 01 5 0 0 0 Q OF 0 4 TEXT iilmors spsssis ~Irirsd. oss sddnerel NRC Form 3SSA'si (ll)

EI I S Information Text Reference EIIS Reference System Component High Pressure Core Spray (HPCS) System BG HPCS High Point Vent Line [HPCS (55-1-7): containing HPCS-V-83/84] BG Pump HPCS-P-1 BG P Valve HPCS-V-23 BG TV Residual Heat Removal (RHR) System BO Primary Containment NH NRC FORM SBBA ~ II.S. CPOI )BBP-S2O-SBPrOOO'IO (9 83)