ML18093B481

LER 89-003-00:on 890205,unit Experienced Rx Trip on Steam Generator 23 Low Level Concurrent W/Steam Flow/Feed Flow Mismatch.Caused by Inadequate Procedures Associated W/ Operating Plant.Procedure AOP-COND-2 revised.W/890302 Ltr

ML18093B481
Person / Time
Site:	Salem
Issue date:	03/02/1989
From:	Miller L, Pollack M Public Service Enterprise Group
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-89-003-01, LER-89-3-1, NUDOCS 8903140524
Download: ML18093B481 (5)

Text

NAC Form 3IG U.ll. NUCLEAR REOULATO .. Y ~IDION 19-831 Al'f'ROVED OMll NO. lll!0--0104 EXPIRES: 8/311115 LICENSEE EVENT REPORT (LER)

DOCKET NU... ER 121 I **u* 131 FACILITY NAME 111 Salem Generating Station - Unit 2 Of5f0f0j0j311Jl ,JoFOJ4 TITLE (41 Rx. Trip - #23 S/G SF/FF Mismatch With Low S/G Level Due To Inad~ Procedures EVENT DATE 181

• LEA NUMBER 1111 REPORT DATE (71 OTHER FACILITIES INVOLVED Ill MONTH QAY YEAR YEAR r::o:o:;:; SEQUENTIAL(:;:;:;:;: REVISION MONTH DAY YEAR FACILITY NAMES DOCKET NUMBERISI r::;:;:;:: NUMBER (:;:;:;:;: NUM!ER oI2 ol s s 9 sI9 - oI ob - oIo oI 3 o ~ s19 THll REPORT 11 IUllMITTED PURIUANT TO THE REOUiREMENTI OF 10 CFR §: (Ch<<lc on* or morw of tlr* following) (111 OPERA TINO

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- ll0.731*1<2)(111 ll0.7311)(2)(1111 LICENSEE CONTACT FOR THIS LEA 1121 ll0.73llll2)(Ylllllll ll0.73(oH2llal NAME TELEPHONE NUMBER AREA CODE M. J. Pollack - LER Coordinator 6 I 0 19 3 13 I 9 I - 14 I 0 I 2 12 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DEICRllED IN THll REPORT (131 MANUFAC* MANUFAC-CAUSE SYSTEM COMPONENT TUR ER TURER B SIB Z I II SI N I I I I I I I B SIB RI VI I Ci 71110 N I I I I I I I SUPPLEMENTAL REPORT EXPECTED 11'1 MONTH DAY YJAR EXPECTED 11 YES (If yn. oompl*to EXPECTED SUBMISSION DATE)

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NO SUBMISSION DATE 115)

I I I On 2/5/8?, following power reduction from 90% to 60%, the Unit experienced a Rx. Trip on No. 23 Steam Generator (S/G) Low Level concurrent witt Ste2m Flow/Feed Flow mismatch. At the time of the even~. Nos. 2J0 a1;d 23b CircuJating Water Pumps and No. 23 Heater Drain Pump were out of servic~.* Four minutes prior to the unit trip, No. 22 S/G Feej Purrp (SG~P) had trir,ped due to low suctioD pressure. It was found that the low suction trip set point for the #22 SGFP responded high due to failure of the low suction pressure switcl,. The root cause of this event has been attributed to inadequate procedures associated with operating the plant with Circ. Water System reduced capacity concurrant with an inoperable Heater Drain Pump. Procedure AOP-COND-2 has been l:evise~ to clarify operator actions with inoperable Circ.

Pumps and Heater Drain Pumps. The SGFP low suction pressure first out annunciator relay was installed and tested. The speed control and electric overspeee were also checked for both SGFPs. The No. 22 SGFP low s~ction pres~urE SKitcl1 w2s repaired and the No. ?1 SGFP switch ~as checked and found satisfactory. The #21 SGFP mechanical overspeed device was checked and the pump was operated to simulate a transient prior to it being pl~c0d ~n service. The 23MS15 va]v~ was adjusteC and tested successfully. Inve~tigation of the 23MS167 Control Roo~

indication probl eE' re\' ea led t.ha t the "close" limit switch was net making prope;- co)1tact. The switch was repaired and the va1 ve tested satisfactorily. This event has been reviewed by Operations management and wi~l be reviewed witn applicable personnel. This event will be incorporated into applicable training programs.

N AC Form 3111 (9-831

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station DOCKET NUMBER LER NUMBER PAGE

Q_Il__:U~--- 2 _____________________ - ---- . -----*--*- ----*.

5000311

--*----------- 8_~-_Q_Q_3_-::_Q_Q_ -- - ------~___gf__ 1_____

!'~~N'J;' ~Nl2____!?Y~'I'El1 ___I:Q_ENTJ_FI_C::A'J:'ION:

Westinghouse. Pressurized Water Reactor Energy Industry Identification System (EIIS) codes are identified in the text as lxxl*

Reactor Trip - No. 23 S/G Steam Flo~/Feed Flow Mismatch With Low Steam Generator Level Due To Inadequate Procedures Event Date: 2/05/89 Report Date: 3/02/89 This report wa~ initiated by Incident Report No.89-083.

CONDITIONS PRIOR TO OCCURRENCE: **- *--

Mode 1 Reactor Power 60% - Unit Load 700 MWe J2~E-~~_R_If'.I"_l()N OF OCCURRENCE:

On February 5, 1989 at 0307 hours0.00355 days <br />0.0853 hours <br />5.076058e-4 weeks <br />1.168135e-4 months <br />. following power reduction from 90%

to 60~. the Unit experienced a Reactor Trip on No. 23 Steam Generatpr (S/G) Low LevEl concurrent with Steam Flow/Feed Flow mismatch. At the time of the event, Nos. 23a and 23b Circulating Water Pumps and Ne. 23 Heate~ rrain Pump were out of service. Three minutes prior to the unit trip. No- 22 Steam Generator Feed Pum~ (SGFP) had tripped due to low suctio~ pressure.

The Un~t was s~abilize~ in Mode 3 (Hot Standby) and at 0351 hours0.00406 days <br />0.0975 hours <br />5.803571e-4 weeks <br />1.335555e-4 months <br />, the same dav, the Nuclear Regulatory Commissibn was notified of the automatic actu:~tion of the Reactor Protection System (JCl Jn accordance with Cc~e of Federal Regulations 10CFR 50.72(b) (2) (ii)

APPA_REl'{l:'_ <::'.A_l)'S~_QF OCCURRENCE:

The root cause of this event has been attributed to inadequate procedures associated with operating the plant with Circulating Water System reduced =apacity concu~rant with an inoperable Heater Drain

• Pump.

Abncirrnal Operation'" Procedure AOP-COND-2, "Loss of Circulating Water anc_/or Condenser Vacuum" did not adequately address how to operate the unit whe~ bot! citc~lators are out or the 8amc cond~n~er nor with t~e corresponding heater drain pump ou~ of service. The procedure c~r.~ ~- ~{ :: e c '.Jr*~:.T ,_: - :-<~ .__ ~::! l>.:- *:::3.*u_ :*: j ~*:* -~* poi:-~ 1 e L t c, a-:.:- o i ~-3 fl as L.ir:.~~: ~ It 13. i <) .r1 . ; *i_ c;r i-~.; e a specific power reduction. Subsequently, as described in the Analysis of Occu~rence scctio~. th~ SGFPs tripped as a result of flashing

-:aiJ:::;::*O t:*~Y not reO.tJ*::jnc r~or*:e*r* Jow* en<)lJ*~:h ~~}tl1 rJc s. 732_, c::r1-:1 23}:1 1 Circul2-cinc* Pu!f',!)f:: an(;_ No_ 23 Heater Dra:i.n P1Jmp inoperable.

---~--~-----------------------' LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station DOCKET NUMBER .LER NUMBER PAGE Unit 2

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*--- -- --------* ------ -*- ----** *------*--** .. --- 5_Q_Q_Q3_11_ - - ----*. _ ~9-:-_0_Q.}__:-_O_Q ___________ ----~ __9_f_ ~---

!i_N:_ALY_~p:s_ Of'. __ OCCURRENCE:

The Steam Flow/Feed Flow Mismatch coincident with Low S/G Level reactor trip is anticipatory. Its function is to prevent a loss of heat sink capability by sensing conditions which would eventually result in a dry steam generator. By tripping the reactor prior to reaching the Low-Low Level trip setpoint, the requir~d startirig time and capacity requirements for the Auxiliary Feedwater System {BAI are

~educed; thereby, minimizing the thermal transient on the S/Gs and the Reactor Coolant System {AB}.

Investigation revealed that with the Circulating Pumps and the Heater Drain Pump out of service it was possible to flash i~ the 23 Condensate Pump suction line. The operator saw amps on 23 Condensate Pump drop arid fluctuate at the time of the 21 and 22 SGFP_ low suction

• alarms. As flashing continued suction pressure continued to drop until No. 22 SGFP tripped. It was found that the low suction trip set point for the No. 22 SGFP responded high -(conservatively) due to failure of the low suction pressure switch. Additionally, it was found that the relays for the "low feed pump suction pressure first out annunciators were not installed. Therefore, during the transient it could not be determined why tte SGFP tripped. Four minutes prior to the unit trip, the operator red~ced po~er t6 approximately 60%

fiom approximately 90%.

No 23b Circulating Pumps was removed from service at approximately 0220 hours0.00255 days <br />0.0611 hours <br />3.637566e-4 weeks <br />8.371e-5 months <br />. An Operator had been stationed at the vicinity of the Condensate Pumps. No. 23a Circulating Pump had been out of service for pump replacement previously. Hot Well levels were maintained at approximately 24. When No. 23~ Circulating Pump was removed from service power was reduced to approximately 90% from 96%. They operated in this condi~ion until No. 22 SGFP tripped at 0303 hours0.00351 days <br />0.0842 hours <br />5.009921e-4 weeks <br />1.152915e-4 months <br /> Just prior to the reactor trip, enqineering investigation, although not conclusive, determined that No. 21 SGFP had also tripped from low feed pump suction pressure. This has been substantiated by the drop in feed water flow by over 50% 2 seconds prior to the reactor trip.

No. 21 SGFP tripped from low suction pressure because of the continuing suction problems with No. 23 Condensate Pump (i.e.,

flashing in the suction line\. With both SGFPs tripped S/G level dropped to the trip setpoint coincident with the SF/FF mismatch.

It could not be determined why the "low feed pump suction pressure" first out annunciator rel~ys were not installed.

During the pdst trip recovery, No, 23MS15 (Main Steam Safety Valve) lifted. The valve has a lift set point of 1070 psia. However, it appeared to open at 1030 psiq. It could not be positively determined at w~at p~essur~ i~ jid lift due to inc~rrect installation of the lift assist apoaratus. The cause of the lift has been attributed to set point drift.

The Reactor Protection Sistem functiofied as designed. However,

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station DOCKET NUMBER LER NUMBER PAGE lJ_l}_:L_~---~~ -------------------------------------- ______?_ 9_9_Q_ 3_JJ,.___ ___ _ __ ~_C}._:-_ Q_ O_J_:-_O_ O_______ ~___qJ ___4___

ANALYSIS

• - -- OF OCCURRENCE: -. (cont_' d)

Control Room indication of closure of the 23MS167 valve (Main Steam Isolation Valve) was not immediately received. Post trip investigation revealed that it did close within the required time frame.

This occurrence did not affect the health or safety of the public.

Due to the automatic actuation of the Reactor Protection System, this event is reportable in accordance with Code of Federal Regulations 10CFR 50.73(a)(2)(iv).

CORRECTIVE ACTION:

Procedure AOP-COND--2 has been revised to clarify operator actions with inoperable Circulating Pumps and Heater Drain Pumps. The procedure now details specific power reductions as well as maintaining a specific hot~ell levsl, placing the hotwell sprays in service, requiring an operator to be kept in the area, and other requirements to ensure the secondary side operates properly in this condition.

The SGFP low suction pressure first out annunciator relay was installed and tested. The speed control and electric overspeed were also checked for both SGFPs. The No. 22 SGFP low suction pressure switch was re~aired and the No. 21 SGFP switch was checked arid found satisfactory.

The No. 21 SGFF m~chanical oveispeed device was checked and the pump was operated to simulate a transient prior to it being placed in service. Results were saiisfactory.

Tte 23M~l::. vaJvc '). .... ~

J.io.;,;,-

...... been adjusted and tested successfull~.

Investigation oi the 23MS167 Con~rol Room i~dication problem has revealed tL2_ t thio: "ciose" limit switch was r;ot making proper con tact.

The switch was repaired and the valve was tested satisfactorily.

The Unit was returned to operation on February 8, 1989.

This event has_ been reviewed by Operations management and will be reviewed with applicable Operation~ Departmen~ personnel.

This event will be reviewed by the Nuclear Training Center for incorooration into applicable training programs.

Gene~a l r.-:a::-:iac-:>:-

Salem Operations M,Jl=':pc SOF.C Mtg. 89-0J.6

PS~G*

Public Service Electric and Gas Cornpanv P.O. Box E Hancocks Br*idge, New Jersev 08038 Salem Generating Station March 2, 1989 U. S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555

Dear Sir:

SALEM GENERATING STATION LICENSE NO. DPR-75 DOCKET NO. 50-311 UNIT NO. 2 LICENSEE EVENT REPORT 89-003-00 This Licensee Event Report is being submitted pursuant to the requireme~ts of the Code of Federal Regulations 10CFR 50.73

{a) (2) 1 iv). 'I'his report is being submitted within thirty (30} days of discovery.

Sincerely yours, J

l~rL L. K. Miller General Manager -

Salem Operations M,Jp: pc Distributior;