ML20040C090

Safety Evaluation Supporting Amend 25 to License DPR-13, Evaluation Incomplete

ML20040C090
Person / Time
Site:	San Onofre
Issue date:	04/01/1977
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML13319A635	List: L-79-421, Forwards Steam Generator Insp Results Re Cracking of Small Bend Radius Steam Generator Tubes at Turkey Point Unit 3. Concurrence Requested Re Proposed Corrective Actions ML13319A634 ML20040B988 ML20040B995 ML20040B998 ML20040C002 ML20040C010 ML20040C040 ML20040C045 ML20040C050 ML20040C055 ML20040C060 ML20040C061 ML20040C065 ML20040C071 ML20040C073 ML20040C075 ML20040C078 ML20040C081 ML20040C086 ML20040C090 ML20040C093 ML20040C097 ML20040C102 ML20040C105 ML20040C113 ML20040C116 ML20040C121
References
FOIA-81-313 NUDOCS 8201270254
Download: ML20040C090 (2)

Text

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SAFETY EVALUATION EY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPP0PTING AMENDMEi;T NC. 2: TO OROVISIONAL OPERATItiG LICENSE TC. DPR-13 50tTTHERN CALIFORNI A EDISON COMPANY SAN DIEGO GAS AND ELECTRIC COMPANY SAN ONOFRE NUCLEAR GENERATING STATION, tilt NO.1 DOCKET N0. 50-206 QATE: April 1, 1977 8201270254 810925 PDR FOIA UDELL81-313 PDR Document 10

2.4-i5 s

pr:Jectile in;act tests at velocities simulating a aors case air

.36:

. 9 o re a r. USLE} acticent,ndicate that the tuces cil'

"'t fail u::- f raprent it:act.

The eddy current tests ;ECT) demonstrated that tuce denting in the 50-1 steam gererators has been minimal.

Steam generator "E" had no denting at any of the tube / tube suoport plate interfaces.

The denting in steam generators "A" and "C", is confined to the bottom un support plates with no denting at the upper two support plates.

The present severity of the OD/ID indentations is nominally 0.001 inch on the diarreter, and the rate of denting' has been no more than 0.5% per year.

The S0-1 steam generators have exoerienced no leaks associated with dented tubes, since the first observation of dent 4ng in April 1975.,

Results of the hand hole entry, upper bundle entry, and the 3-inch hole (at the top support plate in the "C" steam generator) inspections at flow slots in the top support plates confirm the tube denting observations.

There has been minor. tube support plate deformation and flow slot hourglassing only in steam generators "A" and "C" and confined to the bottom two support plates.

There was no evidence of either of these phenomena in steam generator "B".

Physical measurements of the nearest three flow slot widths in the upper support plate of generator "C" indicated no deviations from the manufactured condition.

SCEC measured a width of 2-3/8 1 0.0625 inches (manufactured width was 2-3/8 1 0.0120 iaches).

Measurements of the hourglassed flow slots in the lower two support plates in generators "A"

& "C" were not made.

O