ML18093A428

Special Rept 87-8:on 870928,svc Water Leaking from Containment Fan Coil Unit 11.Caused by Corrosion of Spool Weld.Corroded Weld Cut Out & Flange Replaced and Rewelded. Fifty Similar Welds Will Be Ultrasonically Tested

ML18093A428
Person / Time
Site:	Salem
Issue date:	10/07/1987
From:	Zupko J Public Service Enterprise Group
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
87-8, IEB-80-24, NUDOCS 8710140040
Download: ML18093A428 (3)

Text

e PS~G Public Service Electi"ic and Gas Cori-1panv P.O. Box E Hr.ncocks 8:1cige, l\Je'"* Jersev 08035 Salem Generating Station October 07, 1987 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 SPECIAL REPORT 87-8 This Special Report addresses the circumstances surrounding a Service Water leak inside containment. This report is being submitted within fourteen days of the occurrence in accordance with the reporting requirements of I.E. Bulletin 80-24.

Sincerely yours, Vw~9 J. M. Zupko, Jr.

General Manager-Salem Operations MJP:pc Distribution 8710140040 871007 PDR ADOCK 05000272 S PDR

., SPECIAL REPORT NUMBER 8.8 PLANT IDENTIFICATION:

• Salem Generating Station - Unit 1 Public Service Electric & Gas Company Hancock's Bridge, New Jersey 0803-8 IDENTIFICATION OF OCCURRENCE:

SERVICE WATER LEAK INSIDE CONTAINMENT - SERVICE WATER LEAK FROM NO.

11 CONTAINMENT FAN COIL UNIT DUE TO CORROSION OF SPOOL WELD Event Date(s): 09/28/87 Report Date: 10/07/87 This report was initiated by Incident Report No.87-365 CONDITIONS PRIOR TO OCCURRENCE:

Mode 1 - Rx Power 74% - Unit Load 820 MWe DESCRIPTION OF OCCURRENCE:

On September 28, 1987 at 1424 hours0.0165 days <br />0.396 hours <br />0.00235 weeks <br />5.41832e-4 months <br />, during routine power operation a Service Water (SW) leak from No. 11 Containment Fan Coil Unit (CFCU) was discovered as part of the piping walkdown required by test procedure M9-IHP-SW17, "11 CFCU Hydro". This procedure is part of hydrostatic testing, of the Service Water System piping which enters Containment, in accordance with the ten year hydrostatic testing requirements of ASME Code Section XI.

Technical Specification Action 3.6.2.3.a was already in effect due .to the inoperability of No. 11 CFCU for the. performance of the hydrostatic test.

In accordance with I. E. Bulletin No. 80-24 the Commission was notified of the event involving *No. 11. CFCU at *1435 hours on 9/28/87. Notification was in accordance with the requirements of the Code of Federal Regulations, 10CFR 50.72.

APPARENT CAUSE OF OCCURRENCE:

The root cause of the leak was an equipment failure. Investigation revealed the leak to come from a hole of approximately 0.125" diameter. This hole is located on a spool flange neck weld which had apparently corroded. When the hydrostatic test was initiated and the SW piping was pressurized the weakened corroded weld gave *way resulting in the leak. No other similarly corroded welds were discovered.

ANALYSIS OF OCCURRENCE:

The presence of the No. 11 CFCU SW leak was identified by Inservice Inspection personnel during the performance of a ten year hydrostatic test of the SW piping entering Containment. The leak apparently started when the hydrostatic test was initiated and SW system pressure was increased. Pressure was to be increased to 256 psig,

UNIT 1 SPECIAL REPORT *-8

• ANALYSIS OF OCCURRENCE: (cont'd) however, the leak was observed when pressure reached 100 psig. The test was terminated upon discovery of the leak and the SW piping spool weld isolated.

Had the leak occurred independent of the test, the leak would have been identified by operations as a result of an increase in sump level. The unavailability of one CFCU does not signif1cantly affect the accident cooling capability for the containment since the CFCU's are' redundant to the Containment Spray System (which was operable at the time of this event}.

PSE&G performed a study in July 1985 (reference Engineering Safety Evaluation S-C-M600-NSE-228 Rev. 2, "Safety Considerations of a Containment Fan Coil Unit Tube Severence"} which addresses concerns associated with service water leakage from the CFCU's during LOCA conditions. The study concluded that the present detection systems (e.g. , mismatch *detection betwee-n service water inlet and outlet flow and the containment water level monitoring system) are adequate for detecting major service water leakage from the CFCU's. Also, minor leakage can be detected through sampling and administrative controls. The study also addresses concerns associated with exceeding the design flood level, potential boron dilution, chloride contamination and pH effects; these concerns are adequately addressed by the current plant design and .administrative controls in effect.

Based upon the above analysis of the events, the events involved no undue risk to the health or safety of the public, and no equipment damage resulted from the service water leak (other than the corroded weld). However, all service water leaks inside containment are reportable in accordance with I.E. Bulletin No. 80-24.

CORRECTIVE ACTION:

The corroded weld was cut out and the flange was replaced and rewelded. During the current Unit 1 refueling outage, fifty (50) similar welds (approximately ten welds per CFCU) will be ultrasonically tested. Appropriate corrective action will be taken for welds found to be questionable.

Corrective Actions for the generic Service Water System concerns will be addressed by the "Service Water System Improvement Program" which was addressed at the PSE&G/NRC Region I conference held on September 29, 1987.

Ge<}:; t:!:9-Salem Operations MJP:pc SORC Mtg.87-080