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
OFFICE OF NUCLEAR REACTOR REGULATION
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
Addressees:
All holders of operating licenses or construction permits for nuclear power
reactors.
Purpose:
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.
8712300091
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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.
Discussion
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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December 31, 1987
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
office.
Charles E. Rossi, Director
Division of Operational Events Assessment
Office of Nuclear Reactor Regulation
Technical Contact: A. A. Varela
(215) 337-5346
Attachments:
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
EXAMPLES OF IE BULLETIN 80-11 INSPECTION FINDINGS
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
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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
assumed.
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
work.
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
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December 31, 1987
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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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