United States Nuclear Regulatory Commission - Protecting People and the Environment

Information Request on Category I Masonry Walls Employed by Plants Under CP and OL Review (Generic Letter 80-32)

BOX TITLE


GL80032 

                               APR 21  1980 

TO ALL CONSTRUCTION PERMIT AND OPERATING LICENSE APPLICANTS 

SUBJECT:  INFORMATION REQUEST ON CATEGORY I MASONRY WALLS EMPLOYED BY PLANTS
          UNDER CP AND OL REVIEW 

In Licensee Event Report 79-15, dated November 4, 1979, Portland General 
Electric Company stated that some piping supports and restraints at the 
Trojan Nuclear Plant were supported off masonry walls not designed to carry 
these loads. Subsequently, these conditions were corrected. 

A meeting between the NRR staff and the staff of Portland General Electric 
Company and Bechtel Corporation including their consultants, was held on 
December 11, 1979. In the meeting the philosophy of the analysis and design 
of masonry walls, in general, was examined and the structural safety of the 
masonry walls at the Trojan Plant was discussed. Subsequent to the meeting 
Bechtel Power Corporation, the Architect/Engineer for the Trojan Plant, 
conducted a survey of another thirteen plants whose project spans overlapped
that of the Trojan Plant. This survey revealed that six of the thirteen 
plants had some Category I large pipe (2-1/2* and larger) supports attached 
to reinforced masonry walls. This was reported in a letter from Bechtel to 
NRC, dated November 15, 1979. Based on this finding, we believe that masonry
walls are probably being used or are intended to be used in other unsurveyed
plants to support Category I piping and components. 

Since present standard review plans do not explicitly provide acceptance 
criteria for analysis, design, construction and quality control applicable 
to Category I masonry walls, there is a need to determine the extent of 
usage of such walls in plants under construction, to ascertain what criteria 
are actually being used, to establish the acceptance criteria for concrete 
and reinforcing steel used in these walls and to be informed on the 
procedures used for the analysis and design of such walls. In order to 
develop the aforementioned information and to assure the design adequacy of 
masonry walls and the support anchors for piping equipment hung from such 
walls, we have prepared a list of questions to which it is requested that 
all applicants whose dockets are tinder CP and OL review respond. 

This request for generic information was approved by GAO under blanket 
clearance number B180225 (R0072). This clearance expires July 31, 1980. 

                                 Sincerely, 


                                 Steven A. Varga, Acting Assistant Director 
                                      for Light Water Reactors 
                                 Division of Project Management 

Enclosure:
As stated

8007280306 
.

                               ENCLOSURE 
      REQUEST FOR INFORMATION ON THE USE OF CATEGORY I MASONRY WALLS 

1.   Are there any concrete masonry walls being used in any of the Category 
     I structures of your plant? If the answer is "No" to this question 
     there is no need to answer the following questions. 

2.   Indicate the loads and load combinations to which the walls were 
     designed to resist. If load factors other than one(1) have been 
     employed, please indicate their magnitudes. 

3.   In addition to complying with the applicable requirements of the SRP 
     Sections 3.5, 3.7 and 3.8, is there any other code, such as the 
     "Uniform Building Code" or the "Building Code Requirements for Concrete 
     Masonry Structures" (proposed by the American Concrete Institute) which 
     was or is being used to guide the design of these walls? Please 
     identify and discuss any exceptions or deviations from the SRP 
     requirements or the aforementioned codes. 
     
4.   Indicate the method that you used to calculate the dynamic forces in 
     masonry walls due to earthquake, i.e., whether it is a code's method 
     such as Uniform Building Code, or a dynamic analysis. Identify the code
     and its effective date if the code's method has been used. Indicate the
     input motion if a dynamic analysis has been performed. 

5.   How were the masonry walls and the piping/equipment supports attached 
     to them designed? Provide enough numerical examples including details 
     of reinforcement and attachments to illustrate the methods and 
     procedures used to analyze and design the walls and the anchors needed 
     for supporting piping/equipment (as applicable). 

6.   Provide plan and elevation views of the plant structures showing the 
     location of all masonry walls for your facility. 

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