ML18096A638

LER 92-005-00:on 920316,B Reactor Trip Breaker Opened During Solid State Protection Sys Testing.Caused by Procedural Inadequacy.Procedure S2.OP-ST.SSP-0001(Q) Revised by Addition of Caution statement.W/920414 Ltr

ML18096A638
Person / Time
Site:	Salem
Issue date:	04/14/1992
From:	POLLACK M J, VONDRA C A Public Service Enterprise Group
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-92-005-01, LER-92-5-1, NUDOCS 9204210377
Download: ML18096A638 (4)

Text

• Public Service Electric and Gas Company P.O. Box 236 Hancocks Bridge, New Jersey 08038 Salem Generating Station U. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555

Dear Sir:

SALEM GENERATING STATION LICENSE NO. DPR-75 ,DOOKET NO. 50-311 UNIT NO. 2 LICENSEE EVENT REPORT 92-005-00 April 14, .1992 This Licensee Event Report is being submitted pursuant to the of the Code of Federal Regulations lOCFR 50.73(a) (2) (iv). This report is rciquired to be issued within thirty (30) days of event discovery.

MJP:pc Distribution Sincerely yours, C. *A. Vondra General Manager -Salem Operations I / 95-2i89 110M) 12-9 NRC FORM 366 (6-1'91 .* U.S. NUCLEAR REGULATORY COMMISSION APPROVED OMB NO. 3150-0104 EXPIRES: 4/30192 LICENSEE EVENT REPORT (LER) ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS 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 (11 Salem Generating Station -Unit 2 I DOCKET NUMBER (21 I PAGE (31 0 15 I 0 I 0 I 0 I 311 I ii 1 OFI 0 i 3 TITLE (41 Unanticipated Reactor Trip Breaker Opening During Manual SI-Testing EVENT DATE (51 LER NUMBER (6) REPORT DATE (71 O!HER FACILITIES INVOLVED (Bl MONTH DAY VEAR YEAR tr:

MONTH DAY YEAR FACILITY NAMES DOCKET NUMBERISI al 3 6 9 2 9 I 2 -o lo 15. -ol o o I 4 i 14 912 01S1010101 I I OPERATING MODE (Ill THIS REPORT IS SUBMITTED PURSUANT TO THE OF 10 CFR §: (Check on* or more of <h* fol/owing}

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SUPPLEMENTAL REPORT EXPECTED 1141 MONTH DAY YEAR EXPECTED SUBMISSION DATE 1151 n YES (If y*s, compl*t* EXPECTED SUBMISSION DATE} r-xi NO I I ABSTRACT. (Limit to 1400 spaces, i.e .. approximately f(fteen single-space tyPewritten lines} (.16) On March 16, 1992, at 1452 hours0.0168 days <br />0.403 hours <br />0.0024 weeks <br />5.52486e-4 months <br />, the "B" reactor trip *breaker (RTB) opened during Solid State Protection.

System (SSPS) testing. The Unit was in Mode 5 (Cold Shutdown).

At the time of the event, performance of Operations Procedure S2.0P-ST.SSP-0001(Q}, "Manual Safety Injection" was in progress concurrent with the replacement of Rosemount steam flow transmitters under design change package (DCP) 2EC-3078.

The cause of this event is procedure inadequacy.

Procedure did not identify that its performance, concurrent with an unusual plant configuration (i.e., all high steam flow bistables tripped), may cause the'opening of RTBs. Per Operations Procedure S2.0P-ST.SSP-0001(Q), the SSPS Train B Mode Select Switch was turned to "TEST". This resulted in removal of the SI signal block (on high steam flow with low Tav) resulting in the "B" R.TB opening. A safety injection did not occur because the action.of taking the Trairi B Mode Select Switch to TEST the 118 VAC required to pick up the Train & SI relays.

S2.0P-ST.SSP-0001(Q) has been revised by the addition of a "Caution Statement" identifying the consequence of moving the Mode Select Switch to TEST. Other station procedures (both Salem Units) which involve use of this switch will also be reviewed and .revised as appropriate.

NRC Form 366 (6-891 I

• LICENSEE EVENT REPORT (LER) TEXT CONTINUATION S.alem Generating Station DOCKET NUMBER LER NUMBER PAGE PLANT AND SYSTEM IDENTIFICATION:

Westinghouse

-Pressurized Water Reactor Energy Industry Identification System (EIIS) codes are identified in the text as {xxf IDENTIFICATION OF OCCURRENCE:

Unanticipated Reactor Trip Breaker opening during Manual Safety Injection testing Event Date: 3/16/92 Report Date: 4/14/92 T.his_ report was initiated by Incident Report No.92-187. CONDITIONS PRIOR TO OCCURRENCE:

Mode 5 -Gth Refueling in progress DESCRIPTION OF OCCURRENCE: .cin March 16, 1992, at 1452 hours0.0168 days <br />0.403 hours <br />0.0024 weeks <br />5.52486e-4 months <br />, the "B" reactor trip breaker {RTB) {JC} opened during Solid State Protection System (SSPS} {JG} testing. The Unit was in Mode 5 {Cold Shutdown).

At the time of the event, performance of Operations Procedure S2.0P-ST.SSP-0001(Q), "Manual Safety Injection" was in progress concurrent with the replacement of Rosemount steam flow transmitters under design change package {DCP) 2EC-3078.

Due to the actuation of the Reactor Protection System {JEI RTB opening), the Nuclear Regulatory Commission (NRC) was notified in ** accordance with the requir.ements of the Code of Federal Regulations lOCFR 50.72(b)(2)(ii).

APPARENT CAUSE OF OCCURRENCE:

The cause of this event is procedure inadequacy.

Procedure S2.0P-ST.SSP-0001(Q) did not identify that its performance, concurrent with an unusual plant configuration

{i.e., all high steam flow bistables tripped), may cause the opening of RTBs. Steam flow Rosemount transmitter replacement design change work was in progress.

In support of the this work, the high steam flow bistables were tripped thereby satisfying safety injection logic for "high steam flow coincident with low Tav".* However, since the Unit was below permissive P-12 {Tav < 541°F), the SI signal was blocked. Per-of Operations Procedure S2.0P-ST.SSP-0001{Q), the SSPS Train B Mode Select Switch was turned to "TEST". This resulted in of the SI signal block *high flow coincident with

• *

• LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station Unit 2 APPARENT CAUSE OF OCCURRENCE:

DOCKET NUMBER 5000311 (cont'd) LER NUMBER 92-005-00 PAGE 3 of 3 low Tav) *. The previous procedure step, 5.2.3, required closure of *the RTBs. Consequently, the "B" RTB opened asper design upon implementation of step.5.2.4.

A safety injection did not occur because the action of taking the Train B Mode Select Switch to TEST *removes the 118 VAC required

• to pick up the Train B SI*. relays. ANALYSIS OF OCCURRENCE:

There are two (2) reactor trip. breakers ("A" and "B"J in series which connect.the output of the rod drive motor generator (MG). sets to the rod control power cabinets.

In the event of a reactor trip signal, these breakers open, removing power from the control rod drive mechanisms allowing the control rods to drop into the reactor core. The opening of either breaker will cause this to occur. Two (2) Reactor Trip Bypass Breakers are provided to allow surveillance testing at power. No control rod movement occurred as a result of the "B" RTB opening. At the time of this event, the control rods were not capable of . withdrawal since their MG sets were cleared and tagged. The SSPS is not required to be operable in Mode 5 even though it was functional.

The "B" RTB and the SSPS functioned as designed; therefore, this did not affect the health or safety of the public. However, since the reactor protection system was actuated, this event.is reportable to the NRC in accordance with Code of Federal Regulations lOCFR 50.73(a) (2) (iv). CORRECTIVE ACTION: Pro6edure S2.0P-ST.SSP-000l(Q) has been revised by the addition of a "Caution identifying the consequence of movirig the Mode Select Switch to TEST. Other station procedures (both Saiem Units) which involve use of this switch will also reviewed and revised as appropriate.

MJP:pc SORC Mtg.92-045 General Manager -Salem Operations