ML18096B350

LER 93-005-00:on 930218,experienced Reactor Protection Sys Reactor Trip/Turbine Trip Signal,When 12 SG Level Decreased. Caused by Personnel Error.Event Will Be Reviewed for Incorporation in Applicable Training program.W/930322 Ltr

ML18096B350
Person / Time
Site:	Salem
Issue date:	03/22/1993
From:	Pastva M, Vondra C Public Service Enterprise Group
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-93-005, LER-93-5, NUDOCS 9303250090
Download: ML18096B350 (5)

Text

Public Service Electric and Gas Company P.O. Box 236 _ Hancocks Bridge, New Jersey 08038 Salem Generating Station March 22, 1993 U. S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555

Dear Sir:

SALEM GENERATING STATION LICENSE NO. DPR-70 DOCKET NO. 50~272 UNIT NO. 1 LICENSEE EVENT REPORT 93-005-00 This Licensee Event Report is being submitted pursuant to the requirements of the Code of Federal Regulations 10CFR 50.73(a) (2) (iv). This report is required to be iss.ued within*

thirty (30) days of event discovery.

Sincerely yours, fJ/W~c?r f'c. A Vondra General Man~ger -

Salem Operations

• MJPJ:pc Distribution 250020 9303250090 930322 PDR ADOCK 05000272 S PDR ~\

95-2189 REV 7 *92

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION (6-89) APPROVED OMB NO. 3150-0104 EXPIRES: 4/30/92 ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS INFORMATION. COLLECTION REQUEST: 50.0 HRS. FORWARD LICENSEE EVENT REPORT (LERI COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS AND REPORTS MANAGEMENT BRANCH IP-530), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO THE PAPEf!WORK REDUCTION PROJECT 13150-0104), OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.

FACILITY NAME (1) DOCKET NUMBER (2) PAGE 13

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SUPPLEMENTAL REPORT EXPECTED 1141 MONTH DAY YEAR EXPECTED n YES (If yos, comp/010 EXPECTED SUBMISSION DATE)

SUBMISSION DATE (151 I I I ABSTRACT (Limit to 1400 spacss, i.e., approximately f~fteen single-spsce typewritten lines} (161 On 2/18/93, at 0835 hours0.00966 days <br />0.232 hours <br />0.00138 weeks <br />3.177175e-4 months <br />, Unit 1 experienced a Reactor Protection System Reactor Trip/Turbine Trip signal, when 12 Steam Generator (S.G)'

level decreased to 25%. This level satisfied the reactor trip signal for SG low level coincident with steam flow/feed flow mismatch. The mismatch signal was satisfied by ongoing 12 SG steam flow channel I circuit troubleshooting, which manually tripped the channel bistables. 12 SG level1 which was reduced to between 24 and 25%, was restored within approximateiy 7 minutes. Reactor Coolant System (RCS)

Tave was *being maintained via the Auxiliary Feedwater System (AFW) in *conjunction with the respective MSlO atmospheric relief valves.

The root cause of this event is personnel error due to misjudgment by the secondary console Operator. He chose to increase Taye by reducing AFW flow to 12 SG level to support completion or an in-progress RCS leak rate surveillance. This event has been reviewed by. Operations Department management and disciplinary action has been taken. This event will be reviewed with applicable Operations Department personnel. This event will be reviewed by the Nuclear Training Center for incorporation in applicable training programs.

NRC Form 366 (6-891

~ , I

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION

.. Salem Generating Station DOCKET NUMBER LER NUMBER PAGE Unit 1 5000272 *93-005-00 2*of 4 PLANT AND SYSTEM IDENTIFICATION:

Westinghouse - Pressurized Water Reactor Energy Industry Identification System (EIIS) codes* are identified in the text as {xx}

IDENTIFICATION OF OCCURRENCE:

Reactor Protection system actuation: Reactor Trip/Turbine Trip Signal Due To Personnel Error Event Date: 2/18/93 Report Date: 3/22/93

- _-This repo'rt _was initiated by Incident Report No.93-144. _

CONDITIONS PRIOR TO OCCURRENCE:

The Unit was in Mode 3 (Hot Standby) following an automatic Reactor trip on February 16, 1993, due to an overtemperature Delta Temperature (OTDT) Trip signal (reference LER 272/93-004-00): In

_preparation for subsequent startup, procedure Sl.IC-ST.SSP-0006(Q),

nTRAIN A REACTOR TRIP BREAKER AND-P-4 PERMISSIVE PRIOR TO STARTUP"

-was in progress. This procedure closed the reactor trip breakers and latched the main turbine. -

Troubleshootirig, in accordance with procedure Sl~IC-CC.RCP-0038(Q) I 11

1. 12 STEAM GENERATOR STEAM FLOW PROTECTION - CHANNEL I", was in progress to investigate actuation of the Loop 12 high steam flow channel I and failure of the channel alarm annunciation to clear following the February 16, 1993 reactor trip. Per this. procedure, the channel I bistab],es were manually tripped enabling one half of a Steam Generator (SG) steam flow/feed flow mismatch with low level Reactor -trip signal.

Reactor Coolant System (RCS) {AB} Tav~ was being maintained via the Auxiliary Feedwater System {BA} in conjunction with the respective MSlO atmospheric valve (main steam and turbine by-pass steam generator air-operated automatic/manual adjustable setpoint relief valves)

• The 11 and 14MS10s were in automatic setpoint control, .

12MS10 was i-p manual setpoint control, and 13MS10 was cleared and tagged in support of maintenance.

RCS leak rate surveillance procedure SP(0)4.4.6.2d, "REACTOR COOLANT SYSTEM:... .WATER INVENTORY BALANCE", was in progress.

DESCRIPTION OF OCCURRENCE:

On February 18, 1993, at approximately 0816 hours0.00944 days <br />0.227 hours <br />0.00135 weeks <br />3.10488e-4 months <br />, Auxiliary

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station DOCKET NUMBER LER NUMBER PAGE Unit 1 5000272 93-005-00 3 of 4 DESCRIPTION OF OCCURRENCE: (cont'd)

Feedwater System flow to 12 SG was reduced to incr~ase Ta e to

• support completion of surveillance procedure SP(0)4.4.6.2X. A:t* 0835 hours0.00966 days <br />0.232 hours <br />0.00138 weeks <br />3.177175e-4 months <br /> (same day), the Unit experienced a Reactor Protection. System (RPS) {JC} Reactor Trip/Turbine Trip signal, opening the reactor trip breakers, when 12 SG level decreased to 25%. Reaching this level satisfied the reactor trip signal for SG low level coincident with a steam flow/feed flow mismatch signal. The mismatch signal was satisfied by the ongoing 12 SG steam flow channel I circuit troubleshooting.

Following the RPS signal actuation, Auxiliary Feedwater flow to 12 SG was increased restoring SG level within approximately seven (7) minutes. Level had reduced to between 24 and 25% prior to being restored. The Reactor trip* breakers were reclosed and the Main Turbine was relatched. *

.The Nuclear Regulatory Commission was notified of the automatic actuation of'the RPS at 0859 hours0.00994 days <br />0.239 hours <br />0.00142 weeks <br />3.268495e-4 months <br /> (same day) in accordance with

. 10 CFR 5 0 . 7 2 ( b) ( 2 ) ( ii) .

APPARENT CAUSE OF OCCURRENCE:

The.root cause of this event is personnel error. This occurred due to misjudgment by the secondary console operator when he chose to increase Tave by reducing Auxiliary Feedwater flow (AFW) to 12 SG.

Reducing AFW flow to 12 SG in turn reduced SG mass inventory ~nd resulted in the 12 SG low level ~5% setpoint being reached. A more appropriate method wo~ld have been to manipulate the MSlri of a different SG (i.e., one without the steam flow/feed flow mismatch

. bistables tripped) to achieve the desired increase in Tave' while

• maintaining a steady or incre::asing mass inventory.

ANALYSIS OF OCCURRENCE:

This event did not affect the health and safety of the public. It is reportable to the Nucle.ar Regulatory Commission in accordance with 10CFR 50 *. 73(a) (2) (iv) due to the RPS actuation.

The consequences of this event were minimal. The Unit was in Mode 3 (Control Rods inserted) and the lowest SG level reached was 24-25%.

As such, SG heat sink capability was not challenged. Systems and components functioned per design following signal actuation.

The Reactor trip on Steam Flow/Feed Flow mismatch coincident with Low SG level at 25% is an anticipato~y function, to the Low-Low Level reactor trip. It is designed for at power conditions to prevent possible Reactor core damage due to a loss of heat sink capability by sensing conditions which would eventually result in a dry steam generator.

. ~

.. LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station DOCKET NUMBER LER NUMBER PAGE Unit 1* 5000272 93-005-00 4 of 4 ANALYSIS OF OCCURRENCE: (cont'd)

A prlor similar *occurrence, involving an RPS actuation due to Low-Low SG level, was reported in LER 272/90-010-00. The root cause of that event was personnel error involving the operator's use of poor methodology when transferring Tave control from 11 SG to 12 SG while in Mode 3. The corrective actions taken in response to the 1~90 event were appropriate .. The current event *(i.e., 1993) involved different specific.causal factors and circumstances.

• CORRECTIVE ACTION:

• This event has been reviewed -by Operations man,ageme,nt and appropriate

• corrective disciplinary action has been taken.

This event will be reviewed with applicable o'perations Department personnel.

This event will be reviewed by the Nuclear Training Center for incorporation in applicable training programs .

.J/<%?~er~

~"4s-eneral Manager -

Salem Operations .

MJPJ:pc SORC Mtg.93-024