United States Nuclear Regulatory Commission - Protecting People and the Environment

Information Notice No. 87-67: Lessons Learned from Regional Inspections of Licensee Actions in Response to IE Bulletin 80-11

                                                        IN 87-67

                                  UNITED STATES
                          NUCLEAR REGULATORY COMMISSION
                             WASHINGTON, D.C.  20555

                                December 31, 1987

Information Notice No. 87-67:  LESSONS LEARNED FROM REGIONAL 
                                   INSPECTIONS OF LICENSEE ACTIONS IN 
                                   RESPONSE TO IE BULLETIN 80-11 


All holders of operating licenses or construction permits for nuclear power 


This information notice is being provided to inform addressees of lessons 
learned from Nuclear Regulatory Commission (NRC) inspections of certain 
activities related to the reevaluation work conducted and plant modifications 
made in response to Bulletin 80-11, Masonry Wall Design, issued on May 8, 
1980.  It is expected that recipients will review the information for 
applicability to their facilities and consider actions, as appropriate, to 
avoid similar problems.  However, suggestions contained in this information 
notice do not constitute NRC requirements; therefore, no specific action or 
written response is required.  

Description of Circumstances:

IE Bulletin 80-11, Masonry Wall Design, addressed the potential for problems 
with the structural adequacy of concrete masonry walls in proximity to or with 
attachments to safety-related piping or equipment.  In brief, all licensees 
for operating nuclear power reactor facilities were required to:

1.   identify all masonry walls in each facility that are located in proximity 
     to or have attachments to safety-related piping or equipment

2.   provide a reevaluation of the design adequacy of the subject walls

3.   provide written reports of the activities required by the bulletin  

While performing inspections to follow up on IE Bulletin 80-11 activities at 
several plants, NRC inspectors and consultant personnel noted several defi-
ciencies having the potential for affecting plant safety.  Some of the types 
of deficiencies discovered are described below; specific examples are 
discussed in Attachment 1.  

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                                                            December 31, 1987
                                                            Page 2 of 3

Unanalyzed Conditions

Unreinforced masonry walls were discovered to contain cracks that were not 
accounted for in the structural analyses of the walls.  This situation was 
found at several plants and ranged from mortar joint cracks to through-wall 
cracks in block and mortar.  These conditions required remedial action by 
licensees after the cracks were discovered.  

Improper Assumptions

Several instances were found in different facilities where assumptions made 
during the reevaluation analyses for individual walls were either in error or 
had not been verified.  Items in question included unsubstantiated mortar 
properties, faulty assumptions for wall boundary conditions, and assumed 
reinforcement that had not been verified.  In each case, remedial action was 
required by the licensee.  

Improper Classification

Classification of masonry walls as safety-related and not safety-related was 
also found to be a problem.  At one site, it was discovered that five walls 
that were not safety-related had been reclassified as safety-related after the 
initial IE Bulletin 80-11 work had been completed.  However, the reclassified 
walls were not reevaluated to verify that the bulletin requirements were met.  

Lack of Procedural Controls

Several cases were identified at different facilities where activities were 
performed on safety-related components or equipment without proper controls.  
These activities included the performance of walkdown surveys, record keeping, 
and the control of modification activities.  


The deficiencies regarding unanalyzed conditions and faulty assumptions high-
light the need for careful field verification of all critical parameters used 
in the qualification by analysis of masonry walls.  Use of carefully written 
and approved procedures would have helped to prevent overlooking walls subject 
to bulletin action during the original surveys.  Written procedures governing 
reclassification of or modification to the subject walls would have helped to 
prevent the failure to evaluate the reclassified or newly installed walls to 
the bulletin requirements.  

NRC inspectors observed that mechanisms did not exist at certain facilities to 
ensure that the physical conditions of masonry walls remained as previously 
analyzed.  Some licensees have developed programs with procedural controls 
requiring engineering notification, reevaluation, and periodic inspections to 
ensure that the structural integrity of these walls is maintained.  These 
programs ensure that the physical condition of the walls, such as lack of 
mortar cracking and boundary conditions, remain as analyzed.  
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                                                            Page 3 of 3

No specific action or written response is required by this information notice.
If you have any questions about this matter, please contact the technical 
contact listed below or the Regional Administrator of the appropriate regional 

                              Charles E. Rossi, Director
                              Division of Operational Events Assessment
                              Office of Nuclear Reactor Regulation

Technical Contact:  A. A. Varela
                    (215) 337-5346

1.  Examples of IE Bulletin 80-11 Inspection
      Findings with Potential Safety Impact
2.  List of Recently Issued NRC Information Notices
.                                                            Attachment 1
                                                            IN 87-67
                                                            December 31, 1987
                                                            Page 1 of 3

                          WITH POTENTIAL SAFETY IMPACT

Specific examples of some of the deficiencies discovered during the 
inspections performed to follow up on IE Bulletin 80-11 activities and 
licensee actions to correct the problems are discussed below.  

A.   During an inspection conducted at Indian Point, Unit 2, on 
     September 16-20, 1985, the NRC inspectors observed mortar joint cracking 
     in the west and south walls of the fan house.  The licensee proposed an 
     appropriate repair procedure to fix these cracks.  This approach was 
     accepted by the NRC as part of the licensee's proposed modifications.  
     Inspectors observed evidence of repair activities during the onsite field 
     walkdown conducted as part of the followup inspection.  However, they 
     also observed the presence of numerous mortar joint cracks, some of which 
     were in joints that appeared to have been previously repaired.  
     The NRC reevaluation acceptance criteria includes a provision for 
     allowing tension in masonry walls that are not reinforced if the 
     reanalysis considers assumptions and modeling techniques for boundary 
     conditions, cracking of sections, and other conditions that would affect 
     the dynamic behavior of these walls.  A periodic surveillance program to 
     monitor any special conditions, such as the growth of existing cracks, 
     was not specifically required.  The recurring nature of some of the 
     observed cracks may justify a periodic surveillance by licensees to 
     ascertain that the level of structural adequacy to which licensees 
     committed is maintained.  
B.   During the field walkdown portion of the followup inspection conducted at 
     Calvert Cliffs, Units 1 and 2, on January 13-17, 1986, the inspectors 
     determined that two of the masonry walls included in the sample group had 
     boundary conditions deviating from those assumed in the reevaluation 
     analyses.  There was relative motion between one wall (wall T) and the 
     ceiling beam and the mortar joint between the wall and the ceiling beam 
     appeared cracked for its entire length.  At some points, this joint 
     contained voids that allowed probing of the interior of the wall.  The 
     second wall (wall U) also showed evidence of cracking at the wall to 
     ceiling beam mortar joint.  

     The reanalysis assumed a simple support at the wall-to-ceiling beam 
     location for wall T and assumed a fixed support at this location for 
     wall U.  However, the inspection team concluded that the actual boundary 
     conditions deviated from those assumed in the reanalyses for walls T 
     and U.  The assumption of a positive connection between the wall and the 
     ceiling beam had been an important factor in the reevaluation 
     calculations for these two walls.  
.                                                            Attachment 1
                                                            IN 87-67
                                                            December 31, 1987
                                                            Page 2 of 3

     The licensee conducted a followup testing program and found that 5 of the 
     11 walls included in the test sample did not contain rebar as previously 

C.   In preparation for an NRC followup inspection to IE Bulletin 80-11 
     scheduled at Maine Yankee on March 10-14, 1986, the licensee conducted a 
     new survey of masonry block walls.  The survey identified 10 masonry 
     walls that were classified as safety-related by the bulletin definitions 
     but had not been included in bulletin actions.  Of the 10 walls, 5 had 
     been in existence at the time of the licensee's original survey (1980) 
     and the remaining 5 walls had been added or reclassified after the 
     original survey.  The inspectors determined that surveys were not 
     performed by controlled procedures and instructions and that this 
     omission contributed to the lack of complete coverage of the original 

D.   During the followup inspection conducted at Oyster Creek on May 5-9, 
     1986, the licensee stated that approximately 200 masonry walls exist 
     throughout the plant and that 45 of these walls had been addressed by 
     bulletin responses.  The licensee identified the walls that needed to be 
     addressed in response to the bulletin presumably by reviewing existing 
     plant drawings and conducting an in-plant walkdown.  However, the 
     licensee could not provide records to verify the adequacy of these 
     activities.  This lack of documentation made it impossible for the 
     inspectors to verify that the licensee had correctly identified all the 
     masonry walls specified by the bulletin.  

     For the analysis, the licensee assumed that type M mortar had been used 
     in accordance with the original construction specification.  However, no 
     documentation showed that type M mortar was used during construction.  
     The licensee had not developed a test program to demonstrate the strength 
     values of the mortar used, nor had the licensee considered lower strength 
     properties in the reanalysis.  

     The licensee is planning to resurvey the 200 masonry walls to reestablish 
     baseline data (e.g., physical dimensions, boundary conditions, and 
     attached equipment) that will be used for any future plant modifications 
     that might affect safety-related masonry walls.  This data also will be 
     used to determine which masonry walls are categorized as safety-related.  
     The licensee is developing a procedure to control future modifications to 
     safety-related masonry walls.  This procedure is intended to prevent the 
     alteration of any masonry wall such that the structural analysis would be 
     invalidated or, as an alternative, to provide for proper notification so 
     an engineering evaluation can be completed.  The licensee will perform 
     periodic surveillance of masonry walls to ensure that the physical condi-
     tions assumed during the reanalysis effort remain valid.  

.                                                            Attachment 1
                                                            IN 87-67
                                                            December 31, 1987
                                                            Page 3 of 3

     During the NRC walkdown portion of the inspection, inspectors noted that 
     wall 22 had incurred a through-wall crack and that wall 23 had incurred a 
     similar crack.  In addition, because of the location of equipment it 
     could not be determined whether the crack in wall 23 extended through the 
     wall. There were several other, less extensive cracks noted in these two 
     walls.  Licensee actions to correct this problem include:

     1.   an analysis of the probable cause of the cracks 

     2.   documentation of the repair efforts for these cracks or a demonstra-
          tion of the structural adequacy of the walls, including the effects 
          of the cracked block and mortar

     3.   a description of the measures to be taken to prevent recurrence of 
          similar cracking in these and other safety-related masonry walls 
          that are not reinforced

E.   Similar deficiencies to those specified above were also identified during 
     the followup inspections to Bulletin 80-11 conducted at Yankee Rowe, 
     Salem, Units 1 and 2, and Peach Bottom, Units 2 and 3.  These NRC inspec-
     tions were conducted on January 26-30, 1987, April 7-10, 1987, and 
     June 15-19, 1987, respectively.  
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