United States Nuclear Regulatory Commission - Protecting People and the Environment

Bulletin 74-01A: Southern California Edison Company



                                 UNITED STATES
                           ATOMIC ENERGY COMMISSION
                     DIRECTORATE OF REGULATORY OPERATIONS
                                   REGION V
                                 P.O. BOX 1515
                          BERKELEY, CALIFORNIA 94701

                                            January 10, 1974

Southern California Edison Company                       Docket No. 050-0206
P. O. Box 800
2244 Walnut Grove Avenue
Rosemead, California 91770

Attention:  Mr. Rollin E. Woodbury
            Vice President and General Counsel

Gentlemen:

The enclosed Directorate of Regulatory Operations' Information Request 
No. 74-1 is sent to you for response.  Please submit your reply within thirty
(30) days of the date of this letter to this office with a copy to the
Assistant Director for Construction and Operation, Directorate of Regulatory
Operations, U. S. Atomic Energy Commission, Washington, D. C. 20545.

                                       Sincerely,



                                       R. H. Engelken
                                       Director

Enclosure:
RO Information Request No. 74-1








8302220104

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                                       Directorate of Regulatory Operations
                                       Information Request No. 74-1


ABNORMAL OCCURRENCES IN PIPING SYSTEMS

The AEC has received notification of recent occurrences at the Indian Point 2
and San Onofre reactors which have resulted in damage to piping or piping
hanger systems inside containment.  Previously, reports of events resulting in
unanticipated movement or damage to piping and hanger systems both inside and
outside containment involving reactors of both PWR and BWR types have been
received from licensees.  These occurrences suggest that a pattern of events
may be occurring which at individual facilities appear to be isolated events,
but which in fact may have a common cause or causes and be generic in nature.

It is possible that licensees have experienced other occurrences which may not
have been of sufficient severity to have caused system damage, and may not
have been considered reportable to the AEC under existing reporting
requirements.  To permit evaluation of these events for generic implications
and the identification of possible common causes, information is requested
regarding any event, condition, or malfunction or operating error which has
been observed or experienced at your facility since plant startup relating to
the following:

1.  Anomalous and excessive vibrations of piping and/or components in Quality
    Group A and B systems as defined in Regulatory Guide No. 1.26.

2.  Unanticipated pipe, component, or structural displacements, plastic
    deformations, or damage to Quality Group A or B pipe or component support
    systems.

3.  Malfunctions of control systems or components which resulted in the
    imposition of unanticipated dynamic forces upon Quality Group A or B 
    piping systems or components.

With respect to each event identified above, the following information is
requested:

1.  The causes and operational sequences relevant to the condition or event.

2.  The corrective actions taken, such as replacement or modification of
    malfunctioning components, or the addition or modification of piping
    system restraints, to prevent the recerrence of the event.


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Information Request No. 74-1-          2 -


In addition to the above items of interest there is another matter which may
be related to events of the type under consideration.  The AEC has learned of
the existance at several PWR facilities of bulges in containment liners at
locations adjacent to containment piping penetrations.  To our knowledge these
bulges have not affected containment integrity but their cause and
significance are still being evaluated.  To assist in further evaluation of
this problem, please include in your responses to this request information on
any containment liner bulges observed at your facility that exceed the limits
accepted following construction.

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