ML18096B020

LER 92-015-00:on 920831,2A Control Air Header Inlet Air Operated Globe Valve Failed Closed.Caused by Test Voltage Intermittently Causing Solenoid Valve to pick-up.Corrective Actions Will Be Taken After investigation.W/920930 Ltr

ML18096B020
Person / Time
Site:	Salem
Issue date:	09/30/1992
From:	Pollack M, Vondra C Public Service Enterprise Group
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-92-015-01, LER-92-15-1, NUDOCS 9210060051
Download: ML18096B020 (5)

Text

Public Service Electric and Gas Company P.O. Box 236 Hancocks Bridge. New Jersey 08038 Salem Generating Station September 30, 1992 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 92-015-00 This Licensee Event Report is being submi tte_d pursuant to the requirements of the Code of Federal Regulations 10CFR 50.73(a) (2) (iv). This report is required to be issued within thirty (30) days of event discovery.

Sincerely yours,

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c. A. Vondra General Manager -

Salem Operations MJP:pc Distribution I ,-* L'. l r'

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. NRC FORM 366 (6-89)

U.S. NUCLEAR REGULATORY COMMISSION APPROVED OMB NO. 3150*0104 EXPIR.ES:.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 (P*530). U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON. DC 20555. AND TO THE PAPERWORK REDUCTION PROJECT (3150-0104), OFFICE I

OF MANAGEMENT AND BU_DGET, WASHINGTON, DC 20503.

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

Salem Generating Station - Unit 2 015101010131 11 1 1 OF 0 14 TITLE (4)

Eng. Safety Feature: Containment Isolation Valve Failed Closed EVENT DATE (5) LER NUMBER (6) REPORT DATE 171 OTHER FACILITIES INVOLVED (8)

MONTH DAY YEAR YEAR ){ SEQUENTIAL NUMBER HY REVISION NUMBER MONTH DAY YEAR FACILITY NAMES DOCKET NUMBERISI 0151010101 I I ols 311 9 2 9 12

- ol 1 ls - olo 019 3 1 o 912 0151010101 I I THIS REPORT IS SUBMITTED PURSUANT TO THE R~QUIREMENTS OF 10 CFR §; (Ch*ck on* or more of th* following) 111)

OpERATING x

1 MO_DE (9) 20.402(b) 20.405(c) 50.73(o)(2)(iv) 73.71(b)

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I I I I I I I I I SUPPLEMENTAL REPORT EXPECTED (14) MONTH DAY YEAR EXPECTED ITT YES (If v*s. compl*t* EXPECTED SUBMISSION DATE!

ABSTRACT (Limit to 1400 spBces, i.e .. approximately fiftetm sing/e-spsce typewritten Jines} (16) h NO SUBMISSION DATE 1151 111 310 9 12 On 8/31/92, during normal power operation, the 2A Control Air Header inlet air operated globe valve (21CA330) failed closed. At the time of the event, Solid State Protection System (SSPS) Train A slave relay testing was in progress. 'The 21CA330 valve is a Masoneillan International air operated globe valve (model number 38-20561). The 21CA330 valve is a Containment Isolation Valve. Investigation of the causal factors associated with this event is continuing. As stated above SSPS Train A slave relay testing was in progress. When Test Switch 612 was placed in the operate output position the 21CA330 valve closed. The slave rela,y testing involved a continuity check of the CA330 solenoid valve circuit using low current circuit input~ Normally, the test voltage is low enough to prevent the solenoid valve from picking up.

However, investigation revealed that during this testing, the test voltage may intermittently cause the solenoid valve to pick-up resulting in CA330 valve closure. This was reproducible, although not after each test. In March 1992, the Unit 2 CA330 solenoid valves were replaced with equivalent components (ASCO Model NP8342B23E replaced with ASCO Model NPK8342B23E) . CA330 valve inadvertent closure, during SSPS slave relay testing, was not expected since the valves were equivalent. Closure, as shown from testing, is intermittent. Prior to this component replacement, Unit 2 CA330 valves had not experienced inadvertent closure during SSPS slave relay testing. Appropriate corrective actions will be taken upon completion of the causal factor investigation.

NRC Form 366 (6-B91

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating station DOCKET NUMBER LER NUMBER PAGE Unit 2 . 5000311 92-015-00 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:

Engineered Safety Feature: Containment Isolation Valve Faileq Close Event Date: 8/31/92 Report Date: 9/30/92 This report was initiated by Incident Report No. 553.

CONDITIONS PRIOR TO OCCURRENCE:

Mode 1 Reactor Power 100% - Unit Load 1130 MWe DESCRIPTION OF OCCURRENCE:

On August 31, 1992, at 0345 hours0.00399 days <br />0.0958 hours <br />5.704365e-4 weeks <br />1.312725e-4 months <br />, during normal power operation, the 2A Control Air Header inlet air operated globe valve (21CA330) failed closed. At the time of the event, Solid state Protection system (SSPS) {JC} Train A slave rel~y testing was in progress.

The 21CA330 valve is a Masoneillan International air operated globe valve (model number 38-20561). It takes. air*to open and is spring loaded to fail* close.

• The 21CA330 valve is a* Containment Isolation Valve {JM}. Containment isolation is an Erigineered Safety Feature (ESF). *Therefore, on August 31, 1992, at 0436 hours0.00505 days <br />0.121 hours <br />7.208995e-4 weeks <br />1.65898e-4 months <br />, the Nuclear Regulatory Commission (NRC) was notified of the valve closure, in accordance with Code of Federal Regulations 10CFR 50.72(b) (2) (ii).

APPARENT CAUSE OF OCCURRENCE:

~nvestigation of the causal factors associated with this event is continuing.

As stated above SSPS Train A slave relay testing was in progress.

When Test Switch 612 was placed in the operate output position the 21CA330 valve closed. The slave relay testing involved a contin~ity check of the CA330 solenoid valve circuit using low current circuit input. Normally, the test voltage is low enough to prevent the solenoid valve from picking up. However, investigation revealed that during this testing, the test voltage may intermittently cause the.

LICENSEE EVENT.REPORT (LER) TEXT CONTINUATION Salem Generating Station DOCKET NUMBER LER NUMBER PAGE Unit 2 5000311 92-015-00 3 of 4 APPARENT CAUSE OF OCCURRENCE: (cont'd) solenoid valve to pick-up resulting in CA330 valve closure. This was reproducible, although not after each test.

In March 1992, the Unit 2 CA330 solenoid valves were replaced with equivalent components (ASCO Model NP8342B23E replaced with ASCO Model NPK8342B23E). CA330 valve inadvertent closure, during SSPS slave relay testing, was not expected since the valves were equivalent.

Closure, as shown from testing, is intermittent. Prior to this component replacement, Unit 2 CA330 valves had not experienced inadvertent closure during SSPS slave relay testing. The difference between the two ASCO models is that the older model uses leaded terminal connectors and the newer model uses screwed terminal connectors.

Investigation is continuing t.o determine if this event is a direct result of the March 1992 solenoid valve replacement or if other factors are involved.

ANALYSIS OF OCCURRENCE:

Though the 21CA330 valve is the Control Air Header 2A inlet valve, it also functions as a containment isolation valve. The operability of the containment isolation valves ensures that the containment atmosphere will be isolated from the outside environment in the event of a release of radioactive material to the containment atmosphere or pressurization of the containment.

In this event, the 21CA330 valve failed to the safe configuration, as per design. Therefore, there was no affect on the health or safety of the public. However, since. containment isolation is an ESF function, the 21CA330 valve inadvertent closure is reportable in accordance with Code of Federal Regulations 10CFR 50.73(a) (2) (iv).

In 1986, the Salem Unit 1 CA330 valves failed closed during SSPS testing. The Unit 1 CA330 solenoid valves had been replaced with a model of_ lower wattage (not an equivalent replacement). Following that installation a series of inadvertent valve .closures occurred. A design change, to add test circuit potentiometers, was completed

• eliminating further Unit 1 .CA330 valve inadvertent closures.

Installation of test circuit potentiometers was considered for Unit 2; however, it was determined to not be warranted since its solenoid valves were different from Uriit l's (and had not been .replaced).

On June 19, 1989 (reference LER.272/89-027-00), a similar event occurred.* In that event a main steam isolation valve (MSIV) failed closed during SSPS surveillance testing. The MSIV Closure resulted in a reactor trip. The cause of that event was attributed to the continuity check circuit design.

I '

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station DOCKET NUMBER LER NUMBER PAGE Unit 2 5000311 92-015-00 4 of 4 CORRECTIVE ACTION:

Investigation to determine the causal factors of this event is continuing. Additional corrective actions will be taken, as appropriate, upon completion of the ~igation.

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Salem Operations

.MJP:pc SORC Mtg.92-106