ML17228A966

LER 94-009-00:on 941122,alarms Indicated SIAS & Cis Had Actuated.Caused by Pressure Transmitters on C & D Channels of Pressurizer Pressure Drifting High,Removing SIAS Block Signal.Operators Verified Component actuation.W/941219 Ltr

ML17228A966
Person / Time
Site:	Saint Lucie
Issue date:	12/19/1994
From:	Sager D, Williams J FLORIDA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
L-94-324, LER-94-009, LER-94-9, NUDOCS 9412290167
Download: ML17228A966 (8)

Text

P RIORITYQ1 (ACCELERATED RII)S PROCI:.SS . G)

REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9412290167 DOC.DATE: 94/12/19 NOTARIZED: NO DOCKET FACIL:50-335 St. Lucie Plant, Unit 1, Florida Power & Light Co. 05000335 AUTH. NAME AUTHOR AFFILIATION WILLIAMS,J.R.

SAGER,D.A.

RECIP.NAME

'lorida PowerAFFILIATION Florida Power & Light Co.

RECIPIENT

& Light Co.

SUBJECT:

LER 94-009-00:on 941122,alarms indicated SIAS & CXS had actuated. Caused by pressure transmitters on C & D channels of pressurizer pressure drifting high, removing SXAS block signal. Operators verified component actuation.W/941219 ltr.

DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR I ENCL TITLE: 50.73/50.9 Licensee Event Report (LER), Tncident Rpt, etc. g BISE:

NOTES:

RECIPXENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD2-2 PD 1 1 NORRIS,J 1 1 INTERNAL ACRS 1 1 AEODJ SPD/~ 2 2 AEOD/SPD/RRAB 1 1 ~FILE CENTE~02 1 1 NRR/DE/ECGB 1 1 NRR/DE/*EELB 1 1 NRR/DE/EMEB 1 1 NRR/DISP/PIPB 1 1 NRR/DOPS/OECB 1 1 NRR/DRCH/HHFB 1 1 NRR/DRCH/HICB 1 1, NRR/DRCH/HOLB 1 1 NRR/DRSS/PRPB 2 2 NRR/DSSA/SPLB 1 1 NRR/DSSA/SRXB 1 1 RES/DSIR/EXB 1 1 RGN2 FILE 01 1 1 EXTERNAL: L ST LOBBY WARD 1 1 LITCO BRYCE,J H 2 2 NOAC MURPHY,G.A 1 1 NOAC POORE,W. 1 1 NRC PDR 1 1 NUDOCS FUIL TXT 1 1 NOTE TO ALL"RIDS" RECIPIENTS:

PLEASE HELP I:S TO REDUCE KVASTE! CONTACT I HE DOCUNIE4T COXTROI.

DESK, ROO!EI P I -37 (EXT. 504-TOS3 ) TO ELI XIIXATEYOUR NAME PRO%I DISTRIBU'I IOY. LIS"I'8 I:OR DOCI'NIL%'I'S YOI.'OX"I'LID!

FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 28 ENCL 28

florida Power & Light Company. P.O. Box 128, Fort Pierce, FL 34854 0128 December 19, 1994 L-94-324 10 CFR 50.73 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Mashington, D. C. 20555 Re: St. Lucie Unit 1 Docket No. 50-335 Reportable Event: 94-009 Date of Event: November 22, 1994 advertent Safet In'ection ctuation so ation Si nal due to an Invalid Hi h Pressurizer Pressure S'l Containme t

~S'a l The attached Licensee Event Report is being submitted pursuant to the requirements of 10 CFR 50.73 to provide notification of the subject event.

Very truly yours, C'MWm~- A~

D. A. Sager Vice President St. Lucie Plant DAS/JWH Attachment cc: Stewart D. Ebneter, Regional Administrator, USNRC Region II Senior Resident Inspector, USNRC, St. Lucie Plant DR P0167 ADOC1. 05000~~~

PDR fggg I an FPL Group company /

KRC FORH 366 U.S. KUCLEAR REGULATORY COMMISSION APPROVED BY OHB MO.. 3150 0104 (5-92) EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COHPLY MITH THIS IHFORHATIOH COLLECTION REQUEST: 50.0 HRS.

rZCENSEE ZWZZrr REPORT (LER) FORllARD COMMENTS REGARDIMG BURDEN ESTIHATE TO THE INFORHATION AND RECORDS HANAGEMENT BRANCH (HNBB 7714), U.S. NUCLEAR REGULATORY COHMISSIOM,

<See reverse for required number of digits/characters for each block) llASHIHGTON, DC 20555-0001 AND TO THE PAPERMORK REDUCTION PROJECT (3150-0104), OFFICE OF HAMAGEMENT AND BUDGET MASHINGTON DC 20503.

FACILITY NAHE (1) DOCKET KlNBER (2) PAGE (3)

St. Lucie Unit 1 05000335 1OF5 TITLE (4) Inadvertent Safety Injection Actuation Signal Containment Isolation Signal EVENT DATE (5) LER NUMBER (6) REPORT 'DATE (7) OTHER FACILITIES INVOLVED (B)

SEQUENTIAL REVISION FACILITY NAHE DOCi<ET NUMBER HONTH DAY YEAR YEAR HUHBER KUHBER MONTH DAY YEAR N/A

'2 94 94 --009-- 12 19 94 FACILITY NAME N/A DOCKET NUMBER OP ERAT I KG THIS REPORT IS SUBHITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR 5: (Check one or more) (11)

MODE (9) 20.402(b) 20.405(c) ~ 50.73(a)(2)(iv) 73.71 (b)

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

LEVEL (10) 20.405(a)<1)(ii) 50.36(c)(2) 50.73(a)(2)(vii) OTHER 20.405(a)(1)(iii) 50.73(a)(2)(i) 50 '3(a)(2)(viii)(A) (Specify in 20.405(a)(1)(iv) 50.73(a)(2)(ii) 50.73(a)(2)(viii)(B) Abstract below and in Text 20.405 (a) (1) (v) 50.73(a)(2)(iii) 50.73(a)(2)(x) NRC Form 366A)

LICEHSEE CONTACT FOR THIS LER (12)

HAHE TELEPHONE NUMBER (Include Area Code)

James R. Williams, 'Shift Technical Advisor (407) 465-3550 K3151 COMPLETE ONE LIME FOR EACH COMPOHENT FAILURE DESCRIBED IN THIS REPORT (13)

REPORTABLE REPORTABLE CAUSE SYSTEM COMPONEHT MANUFACTURER CAUSE SYSTEH COMPONENT MANUFACTURER TO NPRDS TO NPRDS I JC SUPPLEMENTAL REPORT EXPECTED (14) EXPECTED HONTH DAY YEAR SUSHI SS ION X (If yes, YES complete EXPECTED SUBHISSION DATE).

HO DATE (15) 3 22 1995 ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typeMritten lines) (16)

On November 22,1994, Unit 1 was in mode 5 with utility licensed operators in the process of filling Pressurizer pressure at and venting the Reactor Coolant System. At 2137, with approximately 65 psia the control room operators received alarms indicating a Safety Injection Actuation Signal (SIAS) and a Containment Isolation Signal (CIS) had actuated. The operators noted that C and D channels of Pressurizer pressure were indicating 2300 psia and 1840 psia respectively. All components actuated as recpired. At 2229, the 1B Emergency Diesel Generator (EDG) loaded onto the 1B3 safety related bus due to a loss of voltage on the 1B3 bus tha developed from the SIAS actuation while the plant was in an electrical line-up onl used during outages. All B train components sequenced onto the EDG as rectLLired.

Offsite power remained available throughout the event.

The cause of the event was due to the pressure transmitters on C and D channels of Pressurizer pressure drifting high and allowing the SIAS block signal to become removed. The cause of pressure transmitters drifting high is still being investigated.

Corrective actions: 1) Operators verified all components had actuated to their required position. 2) Operators restored offsite power to the B electrical train.

3) Instrument and Control (I&C) personnel reset the SIAS block permissive signal.

4) Operators reset all affected components to their normal state. 5) IEZ replaced v

HRC FORM 366 ( 92)

HRC FORM 366A U.S ~ NUCl.EAR REGULATORY COMMISSION APPROVED BY CSIB NO. 3150.0104 (5-92) EXP I RES 5/31/95 ESTIMATED BURDEN PER RESPOHSE TO COMPLY UITH THIS INFORMATION COLLECTION REOUEST: 50.0 HRS.

r XCENSEE ZWZm REPDRT (Zm) FORNARD COMMENTS REGARDING BURDEN ESTIMATE TO THE IHFORHATIOH AMD RECORDS MANAGEMENT BRANCH TEXT CONTXÃKTlON (NNBB 7714), U.ST NUCLEAR REGULATORY COMMISSION, NASHIHGTON, DC 20555 0001 AND TO THE PAPERMORK REDUCTION PROJECT (3180-0104), OFFICE OF MANAGEMENT AHD BUDGET UASHIMGTOM DC 20503.

FACILITY MANE (1) DOCKET NUMBER (2) LER NINBER (6) PAGE (3)

St. Lucie Unit l 05000335 YEAR 94 SEQUENTIAL NUMBER

--009--

REVISIOH NUMBER 2 OF 5 TEXT (lf more space is required, use additional copies of HRC Form 366A) (11')

On November 22, 1994, Unit 1 was in mode 5 with utility licensed operators in the process of raising Pressurizer (ElIS:AB) pressure during filling and ventinq the Reactor Coolant System (RCS) . The Engineered Safety Features

-Actuation +stem (EIIS:QZ) consists of four measurement channels NA, NB, NC, ND and requires two of four measurement channels to be in trip for an actuation to occur. At this time, all four measurement channels of Pressurizer pressure were providing a block signal which prevents a Safety Injection Actuation Signal (SIAS) from occurring for low Pressurizer Pressure. This is a normal configuration when Pressurizer pressure is intentionally reduced below 1600 psia which is the low Pressurizer pressure SIAS trip setpoint. At 1725 psia increasing, the low Pressurizer pressure SIAS block is automatically removed and will allow a SIAS to occur four channels are below the low Pressurizer pressure trip setpoint of 1600 if two of psia. A SIAS actuation also causes a Containment Isolation Signal (CIS) to occur.

At 2137, with Pressurizer pressure at approximately 65 psia, utility licensed operators in the control room received alarms indicating a SIAS had occurred.

At 2138, the control room licensed operators noted that C channel of Pressurizer pressure was indicating 2300 psia and D channel was indicating 1840 psia and continuing to drift higher. With both C and D channels of Pressurizer pressure above the 1725 psia block permissive setpoint the SIAS block signal was automatically removed. With channels A and B indicating less than the 1600 psia low Pressurizer pressure trip setpoint the two of four logic was satisfied and a SIAS/CIS was initiated. All SIAS components responded as expected includinq the start of both Emergency Diesel Generators (EDG) (EIIS:EK) . However, offsite power was available at the time of the event and neither EDG was required to load on to the Class 1E safety buses (EIIS:EB) .

At 2229, the 1B EDG output breaker closed and provided power to the 1B3 4160 volt safety related bus concurrent with the opening of the 1B2 4160 volt non-safety related bus tie breaker to the 1B3 4160 volt bus. This tie breaker opened in response to an undervoltage condition on the 1B2 480 volt (EIIS:ED) safety related bus. At the time of the undervoltage condition the 1B2 -480 volt safety related bus was being supplied power frcm the 1A2 480 volt safety related bus via the 1AB 480 volt safety related bus. This line-up is only used during outaqes in modes 5 and 6. Prior to the event only outage loads were being supplied ky the 1B2 480 volt safety related bus. However, when the SIAS actuated additional loading was placed on the 1B2 480 volt bus. Over a period of time this caused an overcurrent condition to be detected by one of the tie breakers which caused the tie breaker to open. When this occurred a loss of voltage sensed on the 1B2 480 volt bus provided a signal to open the 1B2 4160 volt non-safety related bus tie breaker to the 1B3 4160 volt safety related bus. This caused a loss of voltage signal to be sensed HRC- FORM 66A ( -92)

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSIOH APPROVED BY OMB NO. 3150-0104 (5.92) EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPOHSE TO COMPLY WITH THIS INFORMATION COLLECTION RECUEST: 50 ' HRS ~

FORWARD COMMENTS REGARDIHG BURDEN ESTIMATE TO

. Z,XCENSEE mZNT REPORT (LER) THE INFORMATION AHD RECORDS MAHAGEMEHT BRANCH TEXT CONTINUATION (MHBB 7714), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555-0001 AHD 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)

SEQUEHT IAL REVISION St. Lucie Unit 1 YEAR NUMBER NUMBER 05000335 --009-- 3 OF 5 TEXT (If more space is required, use additional copies of NRC Form 366A) (17) on the 1B3 4160 volt safety'related bus which provided a signal for the 1B EDG output breaker to close on to the 1B3 4160 volt bus.

At 2242, offsite power was restored to the 1B3 4160 volt bus and the 1B Emergen(7 diesel generator output breaker was opened. At.0109 on November 23, utile.ty Instrument and Control Maintenance personnel reset the block permissive signal for the low Pressurizer pressure Safety Injection Actuation Signal (SIAS) by lifting lead YYY1 on PT-1102D.

The cause of the event was due to pressure transmitters PT-1102C and PT-1102D output signals drifting h3gh which removed the SIAS block signal.

The Emergency Response Data Acquisition and Display System (ERDADS)

(EIIS:IU) indicated that the C channel began drafting up at 2122 and that the D channel began drifting up at 2132. Both of these channels continued to drift upwards until both channels pegged out high. The cause of these -two pressure transmitters drifting high xs still under investigation.

This event is reportable under the requirements of 10CFR50.73.a.2.iv as "any event that resulted in manual or automatic actuation of any Engineered Safety Feature."

This event did not adversely affect plant operations because: 1) The utility licensed operators in the control room quickly recognized the SIAS/CIS actuation and secured the Charging Pumps (EIIS:CB} as the SIAS actuation caused letdown (EIIS:CB) to isolate. ERDADS indicated that Pressurizer ressure increased to a maximum of 72 psia during the event which is well low the Low Temperature Overpressure Protection (LTOP) setpoint of 350 psia for the Power Operated Relief Valves (EIIS:AB) at the time of the event.

2) Section 15.2.9 of the St. Lucie Unit 1 Final Ujxhted Safety Analysis Report (FUSAR) "Loss of Offsite Power to the Station Auxiliarxesn is defined as a camplete loss of offsite electrical power with a concurrent turbine trip. Ties event is more conservative than that described in the FUSAR due to the Unit being in cold shutdown and only one of two electrical trains being lost for approximately 2.5 seconds. 3) Shutdown cooling (EIIS:BP) remained available during this event.

Therefore, the health and safety of the public were not affected by this event.

HRC FORM 366A ( -92)

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB HO. 3150.0104 (5-92) EXPIRES 5/31/95 ESTIMATED BURDEH PER RESPONSE TO COMPLY MITH THIS INFORMATION COLLECTIOH REQUEST: 50.0 HRS.

FORNARD CONEHTS REGARDIHG BURDEH ESTIMATE TO Z,XCmSZZ ZVENT aszeRr (Z ER) THE INFORMATION AHD RECORDS MANAGEHENT BRANCH TEXT CONTINUATION (MNBB 7714), U.S. NUCLEAR REGULATORY COMMISSIONS MASHINGTON, DC 20555-0001 AND TO THE PAPERNORK REDUCTION PROJECT (3150.0104), OFFICE OF MANAGEMENT AND BUDGET NASHINGTON DC 20503.

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

SEQUENTIAL REVISION YEAR St. Lucie Unit 1 NUMBER NUHBER 4OP5 05000335 94 --009-- 0 TEXT (lf more space is required, use additional copies of NRC Form 366A) (17)

1) Utility licensed operators verified all components had actuated to their required position after the event by performing table 1 and 2 of Emergency Operating Procedure (EOP)-99, which is the component actuation list for SIAS and CIS.

2) Utility licensed operators restored offsite power to the B electrical train following the opening of the 1B2 480 volt us tie breaker.

3) I&C maintenance personnel reset the SIAS block signal by lifting lead YYY1 on PT-1102D.

4) Utility licensed operators reset the affected components to their normal

. state.

5) I&C maintenance peisonnel performed loop calibrations on PT-1102C and PT-1102D. The results of this testing revealed the pressure transmitters were slow to responded to an input signal. Both pressure transmitters were replaced and tested satisfactorily.

6) I&C maintenance personnel tested pressure transmitters PT-1102A and PT-1102B for slow response time. Both pressure transmitter tested satisfactorily.

7) I&C maintenance personnel in conjunction with the original equipment manufacture are currently performing a root cause analysis."

8) Electrical Maintenance personnel reviewed the action of the breakers and the ED" and determined that all equipment functioned as required.

NRC FORH 366A U.S. HUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150-0104 (5-92) EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COMPLY MlTH THIS INFORMATION COLLECTIOH REQUEST: 50.0 HRS.

FORMARD COMMENTS REGARDIHG BURDEN ESTIMATE TO X.XCZmSEZ EVZm REPORT (ZZR) THE INFORMATIOH AHD RECORDS MAHAGEHEHI BRANCH TEXT CONTINUATION (MHBB ??14), U.S NUCLEAR REGULATORY COMMISSION MASHIHGTOH, DC 20555-0001 AND TO THE PAPERMORK REDUCTION PROJECT (3140-0104), OFFICE OF MANAGEMENT AND BUDGET MASHINGTON DC 20503.

FACILITY NAME (1) DOCKET NUMBER (2) 'ER NUMBER SEQUENTIAL (6)

REVI SION PAGE (3)

YEAR St. Lucie Unit 1 NUMBER NUMBER 5 OF 5 05000335 --009-- 0 TEXT (It sore space is required, use additional copies ot NRC Form 366A) (1?)

Manuf acture: Rosemount Inc.

Model Number: 1153GD9PB Device: Pressure Transmitters PI'-1102C and PT-1102D Serial Numbers: PT-1102C (411711A} PT-1102D (408929A}

There are no previous similar events at St. Lucie involving simultaneous drifting of pressure transmitters and causing an inadvertent ESFAS actuation.