ML20196F847
| ML20196F847 | |
| Person / Time | |
|---|---|
| Issue date: | 07/27/1977 |
| From: | Gluckman A NRC |
| To: | Bagchi G, Shao L, Stuart R NRC |
| Shared Package | |
| ML20196F442 | List:
|
| References | |
| FOIA-87-854, TASK-03-07.A, TASK-03-07.C, TASK-03-07.D, TASK-3-7.A, TASK-3-7.C, TASK-3-7.D, TASK-RR NUDOCS 8803040214 | |
| Download: ML20196F847 (4) | |
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, ( c JUL 2 7 577 NOTE T0: .L. C. Shao R. J. Stuart G. Bagchi C. Hofmayer FROM: A. Gluckmann
SUBJECT:
SYSTEMATIC EVALUATION PROGRAM (SEP) CO M NTS ON L. C. SHA0 NOTE DATED 7/14/77 AND D. G. EISENHUT MEMORANDUM DATED 7/13/77 I was requested by G. Bagchi to provide some comments on documents listed above. They are presented in the enclosure.
A. L. Gluckmann, Consultant Engineering Branch Division of Operating Reactors
Enclosure:
As stated S '
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- 8803040214 080229
.. , C . C ENCLOSURE SYSTEMATIC EVALUATION PROGRAM (SEP)
COMMENTS ON L. C. SHA0 NOTE DATED 7/14/1977 AND D. G. EISENHUT MEMORANDUM DATED 7/13/77 Conynents were requested on three topics listed below:
1 TOPICS: 111-7.0 Containment Structural Integrity Tests ;
III-7.C Delamination of Prestressed Concrete Containment Structures III-7.A Inservice Inspection Including Prestressed i Concrete Containments With Either Grouted or i Ungrouted Tendons l
Coments: Ill.7.D Containment Structural Integrity Tests g It can be safely stated that all' containment structures have been g
tested. However, since the 10 CFR 50 Appendix A has been published relatively late it cannot be assumed that tests on all operating plants comply in all particulars with this regulation. it is however felt that tests for steel containments fully satisfy the spirit of 10 CFR 50 Appendix A, since they have all been successfully tested in accordance with the ASME pressure vessel code applicable at the date E of the test. For conventional concrete and' prestressed concrete con-tainment the same considerations do not apply, since pertinent codes, standards and regulations were not in existence when the tests have bee l made, it should be noted, however, that tests have been successful, that visuci inspection has been performed on all containments during pressurization, that no excessive cracking has been discovered and that a series of measurements has been performed without showing any excessive deformation. Therefore, it can be concluded, that although not always in complete agreement with all the details of 10 CFR 60 Appendix A, the tests satisfy its spirit and that the plants, at the time of the tests were fully capable to function without endangering the public safety.
The conclusion from the discussion above would be that it does not appear to be useful to review the structural integrity tests performed
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C 2-by the licensees on all operating plants. This conclusion, however, should not preclude the necessity of futurs inspection and in some cases re-pressurization to check on the capacity of the containtnent structures to perform their function in a satisfactory anner, Comments: III-7.C Delamination of Prestressed Concrete Containment Structures There is no doubt that in all prestressed containments there is potential risk of delamination, especially where no radial ties have been provided. Even with radial ties this risk exists, but to a much smaller degree. It does not however appear that a useful work could be performed by reviewing the operating plants to assess the degree of risk involved: this is due mostly to our imperfect under-standing of the phenomenon of delamination. It should be much more useful and productive to stress future special inspection procedures to try to uncover delaimination occurrences. It is recomended that a serious effort of research (theoretical and experimental) be directed to this phenomenon.
Coments: Il-7.A Inservice Inspection Including Prestressed Concrete E Containments With Either Grouted or Ungrouted Tendons Inservice inspection of all containment structures is of extreme importance. It should be noted that ASME Pressure Vessel Code,Section XI will cover this subject in detail. If interim suggestions are required, a memorandum by A. L. Gluckmann to L. C. Shao and R. J.
Stuart dated 6/30/77 covers this topic in detail. In general no back-fitting would be required, only modifications of pertinent Technical Specifications, it can be stated, without further review that the licensees inspection programs in general are:
For steel containments and conventional reinforced concrete containments - i not satisfactory. l For prestressed concrete containments - only partially satisfactory. l i
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It is felt that the best way of handling this item would be by considering it as a generic problem and enforce the new Section XI of the pressure vessel code, or impose typical modifications to existing Technical Specifications.
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