View source for PNO-V-87-041, on 870602,engineer in Containment Noted Weepage from RHR Sys Line While RHR in Svc.Cause of Effect Undetermined.Licensee Preparing Work Orders to Isolate, Examine & Repair Weld

{{Adams
| number = ML20214W476
| issue date = 06/03/1987
| title = PNO-V-87-041:on 870602,engineer in Containment Noted Weepage from RHR Sys Line While RHR in Svc.Cause of Effect Undetermined.Licensee Preparing Work Orders to Isolate, Examine & Repair Weld
| author name = Mendonca M, Narbut P
| author affiliation = NRC OFFICE OF INSPECTION &amp; ENFORCEMENT (IE REGION V)
| addressee name = 
| addressee affiliation = 
| docket = 05000323
| license number = 
| contact person = 
| document report number = PNO-V-87-041, PNO-V-87-41, NUDOCS 8706160039
| document type = PRELIMINARY NOTIFICATION OF EVENT OR OCCURRENCE (PNO,, TEXT-INSPECTION &amp; AUDIT &amp; I&amp;E CIRCULARS
| page count = 1
}}
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PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-V-87-41          Date 06/03/87
.This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information presented is as initially received without verification or evaluation and is basically all that is known by Region V staff on this. date.
FACILITY:   PACIFIC GAS & ELECTRIC COMPANY                        Emergency Classification DIABLO CANYON UNIT 2                                      Notification of Unusual Event DOCKET NO. 50-323                                         Alert SAN LUIS OBISP0 COUNTY, CA                                Site Area Emergency General Emergency XX Not Applicable

==SUBJECT:==
RESIDUAL HEAT REMOVAL SYSTEM VENT LINE WELD CRACK On June 2,1987 at 11:00 pm (PDT) an engineer in containment noted weepage from a residual heat removal (RHR) system line while RHR was in service. The unit is in its first refueling outage, and drain down of the refueling cavity in preparation for head reinstallation was in progress. The licensee stopped drain down with the water level approximately five feet above the reactor vessel flange The licensee made a four hour reportable event to the NRC. This notification was based on the fact that the RHR system may have not been able to fulfill its safety function. The licensee is analyzing the affect on the system of the potential break.          Leakage from the vent line would slightly reduce RHR injection flow in the event the system were needed for a large break LOCA. However, the vent line is potentially isolable and the use of the RHR hot leg recirculation piping (about 19.5 hours after the initial break to preclude boric acid precipitation) is optional in the licensee's procedure.
The weepage noted was from a weld on a 3/4" vent line on the hot leg recirculation RHR piping in containment (high point vent 2-932 just prior to valve 8703). The weepage is located at a sockolet fitting in the hot leg recirculation piping where the 3/4" vent piping is attached. The configuration is understood to be similar to a socket weld.
The licensee is preparing work orders to isolate, examine, and repair the weld. The licensee intends to determine the cause of the defect. The licensee also intends to continue drain down and reinstall the reactor vessel head to reduce a growing airborne contamination problem and to reduce local radiation levels due to " shine" from the cavity.
The licensee public affairs personnel do not intend to issue a press release today, but will include a statement in tomorrow's normal plant status press release.
No media interest has been expressed.                                                                      .
This information is c rent as of 12 noon (PDT) June 3, 1987.
CONTACT:   M. Mendonca, RV                       P. Narbut FTS 463-3720                         805-595-2354    ~
8706160039 870603 DISTRIBUTION                               $ _yl 8 -041 PDR H St.                MNBB      Phillips      E/W     Willste ~
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