ML19316A523
| ML19316A523 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 03/16/1977 |
| From: | Shao L Office of Nuclear Reactor Regulation |
| To: | Eisenhut D Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7912300065 | |
| Download: ML19316A523 (3) | |
Text
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MAR 16197T MEMOPANDUM FOR:
D. Eisenhut. Assistant Director for Operational Technology, Division of Operating Reactors FRDH:
L. Shao, Ch6ef. Engineering Branch, Division of 407 Operating Reactors P
SUBJECT:
B&W STEAM GENERATOR TUBING INTEGRITY In accordance with your verbal request, the Engineering Branch. Division of Operating Reactors, has summarized concerns raised during the recent meeting with B&W and Duke Power Company concerning steam generator tube failures at Oconee Units 1, 2 & 3.
These questions are listed in the attachr.ent.
We previously provided a preliminary list of questions, essenthily j
identical to the attached list, to the ORP!i.
Wessuggest that this new list be included in the letter that you plan to write to K.E. Suhrke, B&W licensing manager.
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L Shao,1 Chief t
Engineering Branch Division of Operating Reactors t
Enclosure:
As stated DISTRIBUTION:
Contact:
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B. D. Liaw EB-Rdg 28060 EB-FileNumberd.o7Aq Those on Concurrence cc:
V. Stello, Jr.
J. Reece J. Vaight R. Stuart W. Hazelton L. Frank D. Neighbors F. Almeter R. Gamble B. D. Liaw h
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MAR 161977 MEMORANDUM FOR:
D. Eisenhut, Assistant Director for Operational j
Technology, Division of Operating Reactors FROM:
L. Shao, Chief, Engineering Branch, Division of Operating Reactors
SUBJECT:
B&W STEAM GENERATOR TUBING INTEGRITV In accordance with your verbal request, the Engineering Branch, Division of Operating Reactors,'has summarized concerns raised during the recent meeting with B&W and Duke Power Company concerning steam generator tube
' failures at Oconee Units 1, 2 & 3.
These questions are listed in the attachment.
We previously provided a preliminary list of questions, essentially identical to the attached list, to the ORPM.
We suggest that this new
+
list be incleided in the letter that you plan to write to K.E. Suhrke, u&W licensing manager.
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L Sha, Chief
- Engineering Branch Division of Operating Reactors
Enclosure:
As stated
Contact:
B. D. Liaw 28060 cc:
V. Stello, Jr.
J. Reece J. Knight R. Stuart W. Hazelton L. Frank D. Neighbors F. Almeter R. Gamble B. D. Liaw I
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t REQUEST FOR INFORMATION RELATED TO OCONEE O
STEAM GENERATORS ENGINEERING BRANCH DlVISION OF OPERATING REACTORS It was stated.that defective and plugged tubes, were stabilized 1.
down to the top support plate if the deffect was found near the top tube sheet. Assess the consequence of possible failures of these defective tubes at 1cwer or un-stablized sections.
2.
Provide a re-evaluation of past ECT records to show whether or not there were tube defects that might have led *to initiation of tube cracking.
3.
Due to failure in all units at nearly the same point in time, indicate any change in operating procedures or other possibl' e incidents that might have led to tube failures in Oconee steam generators.
4.
Indicate any plan to perform ECT examinations of periphery tubes.
5.
Provide analytical calculations and/or tests to justify that the crack length, in the circumferential directions, associated with the proposed leakage rate will not increase in an unstable fashion under normal operating and accident conditions.
6.
During the recent meeting with the NRC staff, it was indicated that J
there is 0.4% sulphur content in the sediment deposits.
Provide an assessment on the ef fect of the high sulphur content to the tubes in terms of L
possible chemical reactions.
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7.
Provide the micro-hardness test results of both virgin and cracked tubes to determina any evidence of plastic cyclic straining that may-initiate the cracks.
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Provide accident consequence analyses assuming:
(a) A certain number of tube failures,that can be tolerated, concurrent with a LOCA.
(b) The equivalent number of tubes failures that can be tolerated during a MSLB in terms of off site dosage.
9.
Provide analytical and/or test data to assure tube integrity by demonstrating the capability of degraded tubes (circumferential1y partial cracked tubes) to withstand accident induced loads. NRC's positions on this matter were delineated in Regulatory Guide 1.121 which was published for comment in August, 1976.
1 10.
Indicate B&W's on-going and planned future programs associated with tube failure, i.e.,
tests on mechanical strengths and fatigue strengths of degraded tubes.
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