ML13331A864
| ML13331A864 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 03/28/1986 |
| From: | SOUTHERN CALIFORNIA EDISON CO. |
| To: | |
| Shared Package | |
| ML13331A862 | List: |
| References | |
| TAC-61130, NUDOCS 8604010206 | |
| Download: ML13331A864 (2) | |
Text
-5 4.10 AUGMENTED INSERVICE INSPECTION OF HIGH ENERGY LINES OUTSIDE CONTAINMENT APPLICABILITY:
Applies to welds in piping systems or portions of systems located outside containment where protection from the consequences of postulated pipe breaks is not provided by a system of pipe whip restraints, protective enclosures, or other measures specifically designed to cope with such breaks.
OBJECTIVE:
To provide assurance of the continued integrity of the piping systems over their service lifetime.
SPECIFICATION:
A.
For the welds in the main steam, main feedwater, and first point extraction lines identified in Reference 1, Table 1 and Table IA, Column:
"Break Point Location",
for which inservice inspection is specified in Column:
"Solution":
(1) At refueling outage No. 4, a baseline inspection consisting of a volumetric examination of all specified welds shall be performed in accordance with the requirements of ASME Section XI Code, "Inservice Inspection of Nuclear Reactor Coolant Systems" 1971, up to and including 1972 addenda.
(2) Subsequent to the baseline examination, the inservice inspection of each weld shall be performed in accordance with the requirements of the Edition and Addenda of the ASME Boiler and Pressure Vessel Code,Section XI, "Rules for Inservice Inspection of Nuclear Power Plant Components" as required by Technical Specification 4.7, with the following schedule:
(a) During the first 3-1/3 years (or nearest refueling outage), volumetric examination of 100% all welds.
(b) Every 10 years thereafter (or nearest refueling outage), volumetric examination of 33-1/3% of the welds at the expiration of each 1/3 of the inspection interval with a cumulative 100% coverage of all welds every 10 years.
1604010206 860328 PDR ADOCK 05000206
-6 NOTE:
The welds selected during each inspection period shall be distributed among the total number to be examined to provide a representative sampling of the conditions of all specified welds.
(3) Any evidence revealed by the examinations specified in (1) or (2) that indications have developed or grown shall be investigated, including evaluation of comparable areas of the applicable system. It may be determined that the condition can be tolerated or that repair is necessary. In the event that repair is required, restoration shall be governed by the original acceptance standards.
(4) In the event repair of any weld is required following an examination, the inspection schedule for the repaired weld will be changed to provide for its inspection at the following inspection.
B.
For all welds in the main steam lines, main feedwater lines, and first point extraction lines located outside containment:
(1) A visual inspection of the surface at the insulation joints nearest to all weld locations shall be performed on a monthly basis for detection of leaks.
Any detected leaks shall be investigated and evaluated. If the leakage is caused by a through-wall flaw, either the plant shall be shut down or the leaking piping isolated. Repairs shall be performed prior to return of this line to service.
BASIS:
Under normal plant operating conditions, the piping materials operate under ductile conditions and within stress limits considerably below the ultimate strength properties of the materials. Flaws which could grow under such conditions are generally associated with cyclic loads which fatigue the metal and lead to cracks. The inservice examination and the frequency of inspection will provide a means for timely detection before the flaw penetrates the wall of the piping.
Reference:
(1) Report on the Effects of a Piping System Break Outside the Containment, December 1973, including November 1974 Addendum 1, and May 1975 Addendum 2.
MJT:6126F