ML19322C081
| ML19322C081 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 03/17/1977 |
| From: | Eisenhut D Office of Nuclear Reactor Regulation |
| To: | Goller K Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7912300070 | |
| Download: ML19322C081 (3) | |
Text
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v MAR 171977 MDiORANDUM FOR:
K. R. Coller, Assistant Director for Operating Reactors, Division of Operating Ranctors p9 W
FROM:
D. C. Eisenhut, Assistant Director for Operational Technology, Division of Operating Reactors
SUBJECT:
OCONEE UNIT NOS.1, 2 & 3 STEAM CENERATOR TULE 1hTEGRITY As an outcome of the meeting between NRC staff and Duke Power and their IISSS, B&W, on February 15, 1977 the Engineering Branch, Division of Operating Reactors, has identified several issues related to tha i
integrity of Oconee Steam Generators. These issues are listed in the
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attach =ent.
We previously provided a preliminary list of questions, I
essentially identical to the attached list, to J. D. Neighbors, ORPM for the Oconee Station. An informal partial response was recently submitted by the licensee.
We suggest that the new list be formally transmit,ted to the, licensee.,iut
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any change in operating procedures or otuur i" t..
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D. G. Eisenhut, Assistant Director for Operational Technology Division of Operating Reactors
Contact:
D. D Liaw DISTRIBUTION:
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V. Stello, Jr., DOR EB-File Number Oconee L. Shao, Or Those on Concurrence A. Schwencer. OR R. Stuart, OT J. D. Neighbors, OR F. M. Almeter, OT
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REQUEST FOR INFORMATION RELATED TO OCONEE STEAM GENERATORS ENGINEERING BRANCH DIVISION OF OPERATING REACTORS It was stated.that defective' and plugged tubes, were stcbilized 1.
down to the top support plate if the deffect was found near the Assess the consequence of possible failures of top tube sheet.
these defective tubes at lower or un-stablized sections.
Provide a re-evaluation of past ECT records to show whether or not 2.
there were tube defects that might have led
.to initiation of tube cracking.
Due to failure in all units at nearly the same point in time, indicate 3.
any change in operating procedures or other possible incidents that might have led to tube failures in Oconee steam generators.
Indicate any plan to perform ECT examinations of periphery tubes.
4.
Provide analytical calculations and/or tests to justify that the 5
crack length, in the circumferential directions, associated with the proposed leakage rate will not increase in an unstable f ashion under normal operating and accident conditions.
During the recent meeting with the NRC staff, it was indicated that 6.
Provide an assessment there is 0.4% sulphur content in the sediment deposits.
on the effect of the high sulphur content to the tubes in terms of possible chemical reactions.
Provide the micro-hardness test results of both virgin and cracked 7.
tubes to determine any evidence of plastic cyclic straining that may initiate the cracks.
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Provide accident consequence analyses assuming:
8.
A certain number of tube failures,that can be tolerated, (a) concurrent with a LOCA.
The equivalent number of tubes failures that can be tolerated (b) during a MSLB in terms of off site dosage.
Provide analytical and/or test data to assure tube integrity by 9.
demonstrating the capability of degraded tubes (circumferential1y NRC's partial cracked tubes) to withstand accident induced loads.
positiens on this matter were delineated in Regulatory Guide 1.121 which was published for comment in August, 1976.
Indicate B&W's on-going and planned future programs associa ed with 10.
tube failure, i.e., tests on mechanical strengths and fatigue strengths of degraded tubes.
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