Bulletin 79-02: Revision 1, (Supplement No. 1), Pipe Support Base Plate Designs Using Concrete Expansion Anchor Bolts

                                                            SSINS: 6820 
                                                            Accession No:  
                                                            7908150164 

                               UNITED STATES 
                       NUCLEAR REGULATORY COMMISSION 
                    OFFICE OF INSPECTION AND ENFORCEMENT 
                           WASHINGTON, D.C. 20555 

                              August 20, 1979 

                                                  IE Bulletin No. 79-02  
                                                  Revision No. 1  
                                                  (Supplement No. 1) 

PIPE SUPPORT BASE PLATE DESIGNS USING CONCRETE EXPANSION ANCHOR BOLTS 

Description of Circumstances: 

The supplement to IE Bulletin No. 79-02 is intended to establish criteria 
for the evaluation of interim acceptability of plant operation with less 
than the design factors of safety for piping supports due to as-built 
problems, under design, base plate flexibility, or anchor bolt deficiencies.

In the reviews for system operability of the Duane Arnold and Crystal River 
facilities, criteria have been developed by the NRC staff that defines pipe 
support operability. The criteria has been applied in lieu of other analysis
or evaluation. Specifically, the licensees identified problems with pipe 
supports in which the original design factors of safety were not met but 
some lesser margin was available. The design margins of four or five are 
intended to be final design and installation objectives but systems may be 
classed as operable on an interim basis with some lesser margin providing a 
program of restoration to at least the Bulletin factors of safety has been 
developed. Facilities which fall outside the operability criteria are 
considered to probably require a Technical Specification exception and will 
require review on a case by case basis. 

Action to be Taken by Licensees: 

For the following two cases, plant operation may continue or may begin: 

     a. For the support as a unit, the factor of safety compared to ultimate
     strengths is less than the original design but equal to or greater than
     two. 

     b. For the anchor bolts the factor of safety is equal to or greater 
     than two and for the support steel the original design factor of safety 
     compared to ultimate strengths is met. 

The above criteria may be applied provided that the affected systems are 
upgraded to design margins of safety expeditiously for normally accessible 
supports and by the next refueling for nonaccessible supports. Accessibility
is as defined in Bulletin No. 79-14 where "normally accessible" refers to 
those areas of plant which can be entered during reactor operation. 
.

IE Bulletin No. 79-02, Revision No. 1                       Page 2 of 2 
Supplement No. 1                                            August 20, 1979 

1.   Any support not satisfying the criteria should be classed as inoperable
     and the Technical Specification action statement met unless it can be 
     shown that the system can function in a design basis seismic event 
     without the support.  

2.   Repairs to supports should result in return to the design factor of 
     safety. 

3.   Operations may be continued while repairs to upgrade the system from a 
     factor of safety equal to or greater than two with respect to design 
     loads are performed. Consideration must be given to the effect of the 
     repair process on support function and system operability. In other 
     words the time the support is not functional should be limited to T.S. 
     action statement times or the support must be determined not to cause 
     the system to be unable to perform its function in a seismic event. The
     licensee should also exercise care not to take several supports on a 
     given system out of service at the same time or cause both trains of 
     one safeguards system to be made inoperable at the same time. Control 
     over workmen on safety related systems during plant operation requires 
     a high degree of control by the licensee. 

4.   There are no special reporting requirements for this supplement to the 
     Bulletin; however, the reporting requirements as set forth in the 
     regulations and licenses must be met.