ML18100A328

LER 92-015-01:on 920831,2A Control Air Header Inlet Air Operated Globe Valve Failed Closed,During Normal Power Operation.Caused by Design,Mfg,Const/Installation of Ssps Circuit.Design Change implemented.W/930422 Ltr

ML18100A328
Person / Time
Site:	Salem
Issue date:	04/22/1993
From:	Pollack M, Vondra C Public Service Enterprise Group
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-92-015, LER-92-15, NUDOCS 9305030237
Download: ML18100A328 (5)

Text

Public Service Electric and Gas Company P.O. Box 236 Hancocks Bridge, New Jersey 08038 Salem Generating Station 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 April 22, 1993 SUPPLEMENTAL LICENSEE EVENT REPORT 92-015-01 This supplemental Licensee Event Report is being submitted pursuant to Code of Federal Regulations 10CFR50.73.

The Apparent Cause of Occurrence and Action sections have been modified based upon completed investigations.

MJP:pc Distribution Tl,,,

ic in 4 8 9305030237 930422 ADOCK 05000272 PDR Sincerely yours, C. A. Vondra General Manager -Salem Operations 95*2189 REV 7-92

• NRC FORM 366 16-89) U.S. NUCLEAR REGULATORY COMMISSION APPROVED OMB NO. 3150-0104 LICENSEE EVENT REPORT (LERI FACILITY .NAME 111 Salem Generating Station -Unit 2 EXPIRES: 4/30/92 ESTIMATED BURDEN PEA RESPONSE TO COMPLY WTH THIS INFORMATION COLLECTION REQUEST: 50.0 HAS. FORWARD 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 13150-0104).

OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503. PAGE I'S! l OOCKET NUMBER (2)

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• 1 5 I o Io I o I 31 111 I TITLE (41 Engineered Safetv Feature: Containment Isolation Valve Failed Closed. EVENT DATE 151 LER NUMBER.161 REPORT DATE (7) OTHER FACILITIES INVOLVED (81 MONTH DAY YEAR YEAR 1:::::::::

SEQUENTIAL t::::::::::

REVISION MONTH . DAY 1::::::::::

NUMBER YEAR FACI NAMES OOCKET NU.MBEAISI Salem Unit.l o I 5 Io I o I o I 2 17 I 2 ol s 3 I 1 9 2 9 I 2 -o I 1 b -ol 1 o I 4 2 I 2 913 OPERATING MODE (9) THIS REPORT IS SUBMITTED PURSUANT TO THE OF 10 CFR §: (Check one or more of tho following)

(11) 1 20.402(bl 20.405(c) . 60.73(1)(2)(ivl .._ 1--20.406(1)(1

)(i) 60.311(c)(1) 50.7311H21M

,_ ._... ,___ 73.71(b) 73.71(c).

POWER LEVEL (10) 1 0 0 20.405(1)(1

)(ii) 50.38(c)(2) 50.7311H2Hvii)

OTHER (S1>ocify in Absrract ._... -f---bolow and in Toxt. NRC Form '{ {<;:;::::;::::

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........ ,*.'.' . """"""* ... """ LICENSEE CONTACT FOR THIS LER (12) NAME TELEPHONE NUMBER AREA CODE M J. Pollack -LER Coordinator 6 I 0 I 9 3 13 I 9 1-12 I 0 12 I 2 CAUSE SYSTEM COMPONENT I I I I I I I I COMPLETE ONE LINE FOR EACH FAILURE DESCRIBED IN THIS REPORT (131 MANUFAC-*

TUR ER I I I I I I REPORTABLE'::::::::;:,.;:;:;:::::::::::::::r>>>?

TO NPRDS :::::::::::::::::::::::::::::::

• • • • • -:*:*

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!*1 .. *:1:1:::::::::i*:::l*::*:'l*.**:1.:*1.:::.*::1:1 CAUSE SYSTEM I I COMPONENT MANUFAC* TUR ER I I I I I I I . I I I I l SUPPLEMENTAL REPORT EXPECTED (14) MONTH DAY YEAR I EXPECTED SUBMISSION DATE .1151 I l YES (If .yes, com1>fete EXPECTED SUBMISSION DATE! ABSTRACT (limit to 1400 spacfls, i.t1., approximotely fifteen single-space lines} (16) 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. The root cause of this event is the "Design, Manufacturing, Construction/Installation" of the SSPS circuit. When Test switch 612 was placed in the operate output position, during SSPS Train A slave relay*continuity check, the 21CA330 valve closed. Investigation revealed that during testing, the test voltage is significant enough to cause solenoid valve pick-up resulting in CA330 valve closure. 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 was not expected since the valves were equivalent.

Testing has shown that the same solenoid valves can have as much as a 30 volt difference in pick-up. A design change is being implemented during the current Unit 2 refueling outage. It adds a test circuit potentiometer to reduce the voltage seen by the CA33'0 solenoid valve during slave relay testing and the solenoid valve model is being replaced with the model used in Unit 1. Also, the slave relay circuit continuity test light bulb is being replaced (both Salem Units) with a higher resistance bulb, further reducing the voltage seen by the CA330 solenoid valve. NRC Form 366 (6-89) I LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station Unit 2 DOCKET NUMBER. 5000311 PLANT AND SYSTEM IDENTIFICATION:

Westinghouse

-Pressurized Water Reactor LER NUMBER 92-015-01 PAGE 2 of 4 Energy Industry Identification System (EIIS) codes are identified in the text as {xx} IDENTIFICATION OF OCCURRENCE:

Engineered Safety Feature: Containment Isolation Valve Failed Close Event Date: 8/31/92 Report Date: 4/22/93 This report is a supplement to LER 311/92-015-00 whi'.ch was initiated by Incident Report l'Jo.92-553. The Apparent Cause of Occurrence section has been revised to address the results of subsequent investigation (committed to in the original LER). 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 relay 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 Engineered 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 lOCFR 50.72(b)(i) (ii). APPARENT CAUSE OF OCCURRENCE:

The root cause of this event is "Design Manufacturing, Construction/

Installation" 6f the SSPS circuit. As stated above, SSPS Train A slave relay testing was iri progress.

When Test Switch 612 was placed in the operate output position the 21CA330 .valve closed. The slave relay testing involved a continuity check of the CA330 solenoid valve circuit using low current circuit input. Investigation revealed that the test voltage is sufficient to cause solenoid valve resulting in CA330 valve closure. This LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station Unit 2 APPARENT CAUSE OF OCCURRENCE:

was reproducible.

DOCKET NUMBER 5000311 (cont'd} LER NUMBER 92-015-01 PAGE 3 of 4 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.

Prior to this component replacement, Unit 2 CA330 valves had not experienced inadvertent.closure during SSPS slave relay 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 revealed that this replacement was not a direct contributing factor to CA330 valve inadvertent closure. Subsequent testing has shown that the same solenoid valves can have as much as a 30 volt difference in pick-up. 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 lOCFR 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 Unit 1 CA330 valve inadvertent closures (until recently).

In 1986, test circuit potentiometer installation was considered for Unit 2; however, it was determined to* not be warranted since its solenoid valves were different from Unit l's (and had not been replaced) . Recently, Unit 1 CA330 valves have experienced inadvertent closure during SSPS slave relay testing. This is aiso attributed to design of the SSPS circuit. 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 Unit 2 CORRECTIVE ACTION: DOCKET NUMBER LER NUMBER 92-015-01 PAGE. 4 of 4 A design change is being implemented during the current Unit 2 refueling outage. It adds a test circuit potentiometer (similar to Unit l's design) to reduce the voltage seen by the CA330 solenoid valve during slave relay testing and the solenoid valve model is being replaced with the model used in Unit 1. The slave relay circuit continuity test light bulb is being replaced (both Salem Units) with a higher resistance bulb, further reducing the voltage seen by the CA330 solenoid va we. MJP:pc SORC Mtg.93-036 General Manager -Salem Operations