05000278/LER-1984-001, Revised LER 84-001-02:on 840106,turbine Exhaust Rupture Diaphragm Alarm Annunicated Following Startup of HPCI Turbine.Caused by Rupture of Inner Rupture Disc.Inner Rupture Disc Replaced

Revised LER 84-001-02:on 840106,turbine Exhaust Rupture Diaphragm Alarm Annunicated Following Startup of HPCI Turbine.Caused by Rupture of Inner Rupture Disc.Inner Rupture Disc Replaced

ML20091H451
Person / Time
Site:	Peach Bottom
Issue date:	06/01/1984
From:	Brooke Clark, Ullrich W PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	NRC OFFICE OF ADMINISTRATION (ADM)
References
LER-84-001, LER-84-1, NUDOCS 8406050178
Download: ML20091H451 (5)

LER-2084-001, Revised LER 84-001-02:on 840106,turbine Exhaust Rupture Diaphragm Alarm Annunicated Following Startup of HPCI Turbine.Caused by Rupture of Inner Rupture Disc.Inner Rupture Disc Replaced

Event date:
Report date:
2782084001R00 - NRC Website

text

.

e,

.aC Pem ans UA.asWCttan C40whaT04T Ceamsassa0ss APPnowa0 Out me.31e0 0a0m LICENSEE EVENT REPORT (LER) *""**''"

1. aCablTV seatst til 00CEST sguaneta el Pagg 63:

Peach Bottom Atomic Power Station - Unit 3 , , , , , , , ,o , 2 , 7,8 1 lorl 0W

.i68 4, HPCI Turbine Exhaust Line Inner Rupture Disc (PSD3-23-6) Failure -

tVthf OATS tSi tan erweesta ist p4 PORT Daf t 871 OTnta f ACILITIES serWO4Wie see WO4Tse 04Y T8an vtaA :s "[$",'7' T uomTM Dav Vlag PaCassiv naense 00CE4T asweseem684 oislologos ii 0l 1 0l6 84 8l4 0l 0l 1 0l2 0l 6 41 8l4 oisio s oo, s ei opt natisse Tnat atP0mf 68 SwaulTTE0 PunsuamT TO Ynt atowsalutsett OP te4PR l. tchere ow en mee et ene some= met till "aas l') M eMi.) M eMM M.nManuel n.rii.i a M.eetteHIHS M.3sleHit M.78telGIM

_ _ ] _

73.114sl 0 01 l l M.4ASteHilI81 M 3tisilal M.T34sHaltest OTM4A #r a

. M.40$leHIHuel M 334elG1418 M.736eH3HauHal Je64#

g- M.attisH1Hwi M.73neH3Hal M.73eeH3HesGHS1 D > 30.40t telp lM MJ 3telGHassi M.73telGHal LeC8ht48 CONTACT PGA TMel Lim H31 naug 78&tPn048humetA aAtaC008 B. L. Clark, Senior Engineer - Special Projects 2,1,5 8, 4,1 , , 5 , 0, 1,7 C0eart4Tt Oael tsat 30a taCM C0eeP0ntNT f asLWat piscasstD see Twe6 REPORT 113)

"' O L "' O CaWat (Y8Ttu C0esPO4 t m7 "f0 ADS g.

- '4 -;

Caw 84 ST4Tlas C0wP0hthf "fo mN J 7

....v

• .>~

~..w..,v....

.s N ~' "

u-X BtJ i T4 B D CI5I815 Y ' '

I I f f I f f N.. . [/:.$ '

l l l l l l l E l l [ t l l l 'f ea '

SUPPLEMtseTat REP 0af taPECTIO ties WomTM cay TlaA bwtas'888088 14 6 i,7 ree. seaw.es (APf CTd0 $wse#183s04 04 rsJ seo l l l

.uf.ACT,u.s .. . . ..~ .,,,,s,.e e ..,,. ,H.,

Abstract While at power during surveillance testing, the HPCI turbine exhaust rupture diaphragm alarm annunciated following startup of the Unit 3 HPCI Turbine. Investigation revealed that the inner rupture disc, PSD3-23-6, had ruptured. Since the outer disc had not ruptured, the HPCI turbine remained operable until it was intentionally removed from service to replace the inner rupture disc. Prior to removing the turbine from service, the systems i required by Technical Specification 4.5 C.2 (RCIC, ADS , LPCI, and Core Spray) were verified to be operable. Cause of the event is

under investigation. The rupture disc was replaced and HPCI wds l declared operable following surveillance test verification.

...C..e--=. A-1

/

8406050178 840601 #

PDR 6 ADOCK 05000278 PDR .

P ,

e,aC 8eeen asea U.S. IsWCttaa A6GWLaTOAT Cossese86 aces UCENSEE EVENT REPORT (LER) TEXT CONTirJUATION areaovio owe no. me-ei+e taPiA88 613146 pacsut v haut lli 00Gast sevesega t2l LE A sewnesta see Past tal

'saa "t'?.l? T .?:

Peach Bottom Atomic Power m-n +- i n n - n n i +- 1 015 j o l o lo 121718 81 4 -

d011 -

01 2 12 0F 4l n.1m -e . a .c,A m.,nn Description of the Event:

On January 6, 1984, Peach Bottom Atomic Power Station was operating under normal conditions with both Units 2 and 3 at 100%

power. At approximately 10:30 a.m.., while conducting a surveillance test (ST-l.1 'HPCI Logic System Functional Test') on the Unit 3 HPCI system, the turbine exhaust rupture diaphragm alarm annunciated following startup of the HPCI turbine. This alarm senses a pressure of greater than 10 psig between the inner and outer rupture discs located in series in a 16" line which taps off the turbine exhaust line and itself exhausts to the torus room. Investigation revealed that the inner rupture disc, PSD3-23-6 (manufactured by Continental Disc Corporation)', had ruptured. The setpoint of the ~ rupture disc is 175 psig. The outer rupture disc, PSD3-23-7, had not ruptured, and therefore the HPCI turbine was not declared inoperable at that time.

At 4:44 p.m. on January 6, 1984, the HPCI turbine was intentionally removed from service and declared inoperable in order to replace the inner ru'pture disc. At 8:31 p.m. on January 6, 1984, the HPCI turbine, which was out of service for three hours and forty-seven minutes, was declared operable and returned to service following surveillance test (ST-6. 5) verification.

As of January 1,1984, the newly imposed 10CFR50.72 (b) (2) (iii) requires reporting an inoperable HPCI system within four hours on the Emergency Notification System (ENS). Administrative Procedure A-31, Rev. 8 " Procedure for Notification of NRC",

addresses this new reporting requirement; however, the four hour report was not made. The notification error was due to an administrative oversight as a result of an unfamiliari'ty with the new reporting requirements. The NRC Site Inspector was notified of the reporting error. Senior station personnel were informed on January 9,1984 of the importance of being familiar with the new reporting requirements.

...... A.2

/

'o a .

e e e

..C f.ee ansa

'" v.8. soutttaa a46W6 AlemT Conneus54086 UCENSEE EVENT REPORT (LER) TEXT CONTINUATION arenovio on s e.o. siw-oios larmats S/31s06 eassur y .aast p. Occati eswesete las tsa sewn.sga sS4 #A44 838 Peach Bottom Atomic Power . . . u m ,a 5y,1; Station - Unit 3 1 . ,,, - . ..C ,

• m., n s.

o is lo lo lo l217 l8 8l 4 -

0l l1 -

Op l3 or 4l Conseguences of tiie Event:

The outer rupture disc, PSD3-23-7, did not rupture therefore the HPCI system remained in service at the time of the occurrence.

Prior to blocking the HPCI system out of service, the Reactor Core Isolation Cooling 0 / stem, Automatic Depressurization System, Low Pressure Coolant Injection System, and Core Spray systems ,

were verified as operable as required by. Technical Specification '

l 4.5.C.2. The HPCI system was returned to service within four hours after being declared incperable.

Cause of the Event:

Determination of the cause remains under investigation. A Problem Analysis has been performed by representatives from the station staff, Mechanical Engineering, Quality Assurance, and the Nuclear Safety Section. This Problem Analysis included: (1) verifying the proper material of the rupture disc, (2) a review of the piping configuration of the turbine exhaust line, (3) investigating the performance of the vacuum breakers between the torus air space and turbine exhaust line, (4) investigating the turbine exhaust stop/ check valve performance, and (5) reviewing dynamic pressure test data of the turbine exhaust system. The conclusions of the Problem Analysis show that the most probable cause of the . failure is due to intermittent sluggishness of the check valves in the exhaust line. The check valves will be inspected at the next out, age of sufficient duration to accomplish the inspection. A supplemental report will be submitted following completion of the investigation.

.. . . . . no A2

o =

.aCfoem Jose W4, NWCLEAR AGGW4ATOAT COnamesS6604 LICENSEE EVENT REPORT (LER) TEXT CONTINUATION areaovso ome ma siu.eie.

Earsais +13846 pass 6stv maws sig 00Catt hueseta633 ,404 83 48a asunsete tot Peach Bottom Atomic Power "** " tM E= 7#8 .

Station - Unit 3 o s l o l o o ;,, l.7 l 8; 4 q0l1 0l 2 l4 or 4l r . , ,,, . . ..e , A m., ei >>

Corrective Actions:

ST 6.5 HPCI Pump, Valve, Flow, Cooler Test verified the operability of the HPCI system after the inner rupture disc was replaced. Turbine exhaust pressure indicated normally during the test and the system was returned to service. A subsequent ST-6.5 was successfully completed on January 30, 1984 with all functions indicating normally.

Previous Similar Occurrences LER's: 3-33-15/3L-0, 3-82-23/3L-0.

....e. . A-2

m. g o

PHILADELPHIA ELECTRIC COMPANY 23O1 MARKET STREET P.O. BOX 8699 PHILADELPHI A. PA.19101 1215)841-4000 June 1, 1984 Docket No. 50-278 Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555

SUBJECT:

Licensee Event Report

Dear'Dr. Murley:

This LER deals with the failure of the Unit No. 3 HPCI turbine exhaust inner rupture disc, PSD3-23-6, while performing surveillance testing on the HPCI system.

Reference:

Docket No. 50-278 Report Number: 3-84-01 Revision Number:- 02 Event Date: January 6, 1984 .,,

Report Date: June 1, 1984 Facility: Peach Bottom Atomic Power Station RD #1, Delta, PA 17314 This LER is submitted pursuant to the requirements of 10 CFR 50.73 (a) (2) (v) . The revised portion of this LER is identified by a vertical bar in the margin.

Very truly yours, h "

f / . . Ullrich Superintendent l Nuclear Generation Division cc:- Mr. A. R. Blough, Site Inspector l Dr. Thomas E. Murley, USNRC

[

h,

\\

l l

--. ._ _ _ _ _ .