ML18100A835

LER 93-019-00:on 931203,TS Action Statement Entered Due to Waste Gas Holdup Sys Oxygen Concentration Being Greater than 2% for More than 48 H.Oxygen Concentration within Waste Gas Sys Reduced to Less than 2% on 931212.W/940104 Ltr

ML18100A835
Person / Time
Site:	Salem
Issue date:	01/04/1994
From:	PASTVA M J, VONDRA C A Public Service Enterprise Group
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-93-019, LER-93-19, NUDOCS 9401310028
Download: ML18100A835 (5)

Text

.. . e PStiG *Public Service Electric arid 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-70 DOCKET NO. 50-272 UNIT NO. 1 LICENSEE EVENT REPORT*93-019-0b.

January 4, 199'} t./ This Licensee Event Report is being submitted pursuant to the . requirements of Code of Federal Regulation lOCFR50.73(a)

(2) (i)(B). This report is required to be issued within thirty (30) days of event discovery.

MJPJ:pc Distribution 9401310028 940104 PDR ADOCK 05000272 S PDR TherxJ'i\'cr is 11; your hands. l Sincerely yours, i ' I . 95*2189 REV 7-92 l NRC FORM-366 (6-891 U.S. NUCLEAR REGULATORY COMMISSION APPROVED OMB NO. 3150-0104

.. LICENSEE EVENT REPORT (LERI EXPIRES: 4/30/92 .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-530). U.S. NUCLEAR REGULATORY COMMISSION.

WASHINGTON.

DC 20555. AND TO THE PAPERWORK REDUCTION PROJECT 13150-01041, OFFICE OF MANAGEMENT AND BUDGET. WASHINGTON, DC :20503. FACILITY NAME (11 I DOCKET NUMBER 121 I PAGE 131 Salem Generating Station--Unit 1 o 15IoIoIo12 I 712 1 loF 0 14 TITLE (41 Waste Gas Holdup System Oxygen Concentration Greater Than :z% For More Than 48 Hours. EVENT DATE (51 MONTH DAY ii 2 ol 5 OPERATING MODE (91 YEAR 9 3 5 0 0 LER NUMBER 161 REPORT DATE (71 OTHER FACILITIES INVOLVED (Bl YEAR \?? SEQUENTIAL it\ REVlSION MONTH DAY YEAR FACILITY NAMES DOCKET NUMBERISI NUMBER NUMBER o1s1010101 I 913 -ol 1 19 -o lo 0I1 ol4 9[ 4 0 1 5 IO J.O I O I I THIS REPORT IS SUBMITTED PURSUANT TO THE OF 10 CFR §: (Ch*_ck ono or moro of th* fo/low;ngJ 1111 20.402(bl 20.405lcl 60.73l*ll2Hivl 73.71lbl -,_ ,___ 20.405(o)(1llil

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,* .... *' '...... ,* :* ,* .* ,* ,*: .. ' ;* ;* LICENSEE CONTACT FOR THIS LER (121 NAME TELEPHONE NUMBER AREA CODE M. J. Pastva, Jr. -LER.Coordinator COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN *THIS REPORT 1131 :*:* :*:-:**:*::*:*:.;

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-:*::::::::::;:.,., *:*:* I I I I SUPPLEMENTAL REPORT EXPECTED 1141 (If v*s. comp/*<* EXPECTED SUBMISSION DATE! ABSTRACT (Umii to 1400 spaces, i.ll., approximately fifrsen single-space rvpewrirren lines) (16) TURER I I I I I I EXPECTED SUBMISSION DATE 1151 MONTH DAY YEAR I I I oxygen (0 2) concentration within the waste Gas Holdup System was > 2% for > 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />. On 12/3/93, at 0910 hours0.0105 days <br />0.253 hours <br />0.0015 weeks <br />3.46255e-4 months <br />, Technical Specification (TS) Action Statement 3.11.2.5.a.

was entered due to o 2 concentration of

• 2.17% by volume in 13 Waste Gas Decay Tank (WGDT). Efforts to reduce the concentration to < 2% were implemented

.. -o 2 concentrations above were subsequently measured in other WGDTs; 3.04% in 11 WGDT on 12/8/93, .3.11% in 14 WGDT on 12/8/93, and 3.29% in 12 WGDT on 12/9/93. _The maximum o 2 concentration was 4.25% in 13 WGDT on 12/4/93. The root cause is attributed to "Design, Manufacturing, Construction/

Installation", as per NUREG-1022.

The source of the o is attributed to routine refueling/

maintenance outage fn addition, extensive modifications to the Waste Gas Analyzer and Waste Gas System were performed requiring these systems be opened. Prior to closure, steps were performed to purge these systems with nitrogen *. However, the design of these systems does not lend itself to effective purging. Furthermore, the calibration of the Waste Gas Analyzer introduced additional o 2 into the system. This was further due to the fact that the online o 2 analyzer was out of service for replacement.

o 2 concentration within the Waste Gas System was reduced to < 2% on 12/12/93, at 0408 hours0.00472 days <br />0.113 hours <br />6.746032e-4 weeks <br />1.55244e-4 months <br />, at which time the TS Action Statement was exited. Lessons learned from this event will be incorporated into future planning regarding Waste Gas System modifications.

NRC Form 366 (6-891 LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station Unit 1. DOCKET NUMBER 5000272 PLANT AND SYSTEM IDENTIFICATION:

Westinghouse

-Pressurized Water Reactor LER NUMBER 93-019..:00 PAGE 2 of 4 Energy Industry Identification System (EIIS) codes are identified in the text as {xx} IDENTIFICATION OF OCCURRENCE:

Waste Gas Holdup System Oxygen Concentration Greater Than 2% For More Than 48 Hours

• Event Date: 12/5/93 Report Date: 1/4/94 This report was initiated by Incident Report No.93-494. CONDITIONS PRIOR TO OCCURRENCE:

Mode 5; 11th refueling/maintenance outage in progress; Reactor core reload complete DESCRIPTION OF OCCURRENCE:

Oxygen concentration within the Waste Gas Holdup System {WE} was greater than 2% for more than 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />, which exceeded Technical Specification (TS) Action Statement 3.11.2.5.a.

On December 3, 1993, at 0910 hours0.0105 days <br />0.253 hours <br />0.0015 weeks <br />3.46255e-4 months <br />,' TS .Action Statement 3-.11.2.5.a.

was entered due to oxygen concentration of 2.17% by volume as measured in 13 Waste* Gas Decay Tank (WGDT). Efforts to reduce the oxygen concentrat:ion to< 2% were implementtad.

oxygen concentrations above* 2% were subsequently measured in other WGDTs; 3.04% in 11 WGDT on December 8, 3.11% in 14 WGDT on December 8, and 3.29% in 12 WGDT on December 9. The maximum measured concentration was 4.25% in 13 WGDT on December 4. Oxygen.concentration within the Waste Gas Holdup System was reduced to less than 2% on December 12, 1993 at 0408 hours0.00472 days <br />0.113 hours <br />6.746032e-4 weeks <br />1.55244e-4 months <br />, at which time the TS -Action Statement was exited. ANALYSIS OF OCCURRENCE:

There is an increased probability of oxygen concentration greater than 2% within the Waste Gas Holdup System after a refueling/maintenance outage. oxygen may enter the Waste Gas Holdup System via the eves Holdup Tanks, the Reactor Coolant Drain Tank, the Pressurizer Relief Tank, and the Volume Control Tank (VCT). The valves which provide direct flow to the Waste Gas Header when these tanks are opened to the LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating station Unit 1 DOCKET NUMBER 5000272 ANALYSIS OF OCCURRENCE: (cont'd) LER NUMBER 93-019-00 PAGE 3 of 4 ambient atmosphere are required to be closed. In addition, extensive modifications to the Waste Gas Analyzer and the Waste Gas System were performed.*

APPARENT CAUSE OF OCCURRENCE:

The root cause is attributed to "Design, Manufacturing, Construction/Installation", as per NUREG-1022.

The source of the oxygen is attributed to routine refueling/

maintenance outage . activities.

In addition, extensive modifications to the Waste Gas Analyzer and Waste Gas System were* performed requiring th*ese systems be Prior to closure, steps were performed to purge the_se systems with nitrogen.

However, the design of these systems does not lend itself to effective purging. Furthermore, the of the Waste Gas Analyzer introduced additional oxygen into the system. This situation was further complicated due to the fact that the online oxygen analyzer was out of service for replacement.

PREVIOUS SIMILAR OCCURRENCES:

LER 272/87-019-00 reported a similar event in the Waste Gas System. Corrective actions to the 1987 event have been effective for normal . refueling/maintenance outage activities.

SAFETY SIGNIFICANCE This event is reportable in accordance with lOCFR 50.73(a) (2) (i) (B), since TS Action statement 3.11.2.5.a was not met. This event did not affect the health or safety of the public. The concern for oxygen within the Waste Gas Holdup System is due to the presence of hydrogen gas within the system*. In sufficient quantities, hydrogen in the presence of oxygen can be explosive.

The TS level of not greater than 2% oxygen is conservatively low, ensuring that this explosive hazard is not present. Monitoring of the oxygen concentration in accordance with TS ensures that if the concentration increases above the 2% limitation, expeditious corrective action can* be taken to lower the level to below 2%. During this event the highest-measured hydrogen concentration was 1.51%, therefore potential for an explosive mixture of hydrogen and oxygen in the Waste Gas Holdup system did not exist. CORRECTIVE ACTION: oxygen concentration within the Waste Gas system was reduced to less than 2% on December 12, 1993 at 0408 hours0.00472 days <br />0.113 hours <br />6.746032e-4 weeks <br />1.55244e-4 months <br />, at.which time the TS Action Statement was exited.

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station Unit 1 CORRECTIVE ACTION: (cont'd) DOCKET NUMBER 5000272 LER NUMBER 93-019-00 PAGE 4 of 4 Lessons learned from this event will be incorporated into future planning regarding Waste Gas System MJPJ:pc SORC Mtg.94-001 eneral Manager -Salem Operations