ML20111B166
| ML20111B166 | |
| Person / Time | |
|---|---|
| Site: | Turkey Point  |
| Issue date: | 12/05/1984 |
| From: | Con V, Le A CALSPAN CORP. |
| To: | Nilesh Chokshi NRC |
| Shared Package | |
| ML17346A710 | List: |
| References | |
| CON-NRC-03-81-130, CON-NRC-3-81-130 IEB-80-11, TAC-42869, TAC-42870, TER-C5506-235, NUDOCS 8501080527 | |
| Download: ML20111B166 (32) | |
Text
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ATTACHMENT 1 i
TECHNICAL EVALUATION REPORT MASONRY WALL DESIGN FLORIDA POWER AND LIGHT COMPANY TURKEY POINT PLANT UNITS 3 AND 4 NRC DOCKET NO. 50-250, 50-251 FRC PROJECT C5606 NRC TAC NO. 42869, 42870 FRC ASSIGNMENT 8 NRC CONTRACT NO. NRCG41 130 FRC TASK 235 Preparedby Franklin Research Center Author: A. K. La -V. N. Con 20th and Race Street Philadelphia, PA 19103 FRC Group Leader:
V. N. Con Preparedfor Nuclear Regulatory Commission d
Washington, D.C. 20555 Land NRC Engineer: N. C. Chokshi December 5, 1984 This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Goyernment nor any agency thereof, or any of their employees, makes any warranty, expressed or impiled, or assumes any legsf ilability.or responsib!llty ior any third party's ute, or the results of such use, of any information, appa-retus, product or process disclosed in this report, or represents that its use by such third party would not infringe privately owned rights.
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FRANKUN RESEARCH CENTER DIVl540N OF AltVIN/CALSPAN OM9 2ots e.a a
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'T TECHNICAL EVALUATION REPORT MASONRY WALL DESIGN FLORIDA POWER AND LIGHT COMPANY TURKEY POINT PLANT UNITS 3 AND 4 NRC DOCKET NO. 50-250, 50-251 FRC PROJECT C5506 NRC TAC NO. 42869,'42870 FRC ASSIGNMENT 6
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NRC CONTRACT NO. NRC-03-81-130 FRC TASK 235 g
Preparedby Franklin Research Center Author: A. K. Le, V. N. Con 20th and Race Street Philadelphia, PA 19103 FRC Group Leader:
V. N. Con Prepared for Nuclear Regulatory Commission Washington, D.C. 20555 Lead NRC Engineer: N. C. Chokshi December 5, 1984 This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Goyernment nor any agency thereof, or any of their employees, makes any warranty, expressed or impiled, or assumes any legal liability.or responsibility for any third party's use, or the results of such use, of any information, appa-retus, product or process disclosed in this report, or represents that its use by r,uch third party would not infringe prlystely owned rights.
Prepared by:
Reviewed by:
Approved by:
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V Myc k Vu Pror W ( H Sa f Principal Author:
Group Leader Department Director Date: 47 05-14 Date:
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FRANKUN RESEARCH CENTER DIVISION OF AltVIN/CALSPAN 20th and Race Streets. Phila.. Pa. 19103 (215) 448-1000
'M TER-C5506-235 ColffENTS Section Title Page 1
INTRODUCTION 1
l.1 Purpose of Review.
1 1.2 Generic Issue Background 1
1.3 Plant-Specific Background.
1 2
EVALUATION CRITERIA.
4 3
TECHNICAL EVALUATION 5
3.1 Evaluation of Licensee's Criteria.
5 3.2 Evaluation of Licensee's Approach to Wall Modifications 16 3.3 Evaluation of In-place Material Tests.
17 4
CONCLUSIONS.
19 5
REFERENCES.
20 APPENDIX A - SGEB CRITERIA FOR SAFETY-RELATED MASONRY WALL EVALUATION (DEVELOPED BY THE STRUCTURAL AND GEOTECHNICAL ENGINEERING BRANCH [SGEB] OF THE NRC)
APPENDIX B - EVALUATION OF THE USE OF ARCHING THEORY IN THE ANALYSIS OF MASONRY WALLS UNDER DIFFERENTIAL PRESSURE - TURKEY POINT PLANT UNITS 3 AND 4 l
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TER-C5506-235 FORENORD This Technical Evaluation Report was prepared by Franklin Research Center under a contract with the U.S. Nuclear Regulatory Connaission (Office of Nuclear Reactor Regulation, Division of Operating Reactors) for technical assistance in support of NRC operating reactor licensing actions. The technical evaluation was conducted in accordance with criteria established by the NRC.
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S TER-C5506-235 1.
INTRODUCTION 1.1 PURPOSE OF REVIEW The purpose of this review is to provide technical evaluations of f
Licensee responses to IE Bulletin 80-11 (1)* with respect to compliance with the Nuclear Regulatory Commission (NRC) masonry wall criteria.
In addition, if a licensee has ple.nned repair work on masonry walls, the planned methods and procedures are to be reviewed for acceptability.
1.2 GENERIC ISSUE BACKGROUND In the course of conducting inspections at the Trojan Nuclear Plant, Portland General Electric Company determined that some concrete masonry walls did not have adequate structural strength.
Further investigation indicated that the problem resulted from errors in engineering judgment, a lack of established procedures and procedural details, and inadequate design criteria.
Because of the implication of similar deficiencies at other operating plants, the NRC issued IE Bulletin 80-11 on May 8, 1980.
IE Bulletin 80-11 required licensees to identify plant masonry walls and their intended fdnctions.
Licensees were also required to present reevaluation I
criteria for the masonry walls with the analyses to justify those criteria.
If modifications were proposed, licensees were to state the methods and schedules for the modifications.
1.3 PLANT-SPECIFIC BACEGROUND In response to IE Bulletin 80-11, Florida Power and Light Company provided the NBC with letters and attachments describing the status of masont/ walls at Turkey Point Plant Units 3 and 4 [2, 3, 4, 5].
Based on the available informa-tion supplied by the Licensee, the Franklin Research Center (FRC) has conducted a review of the status of the masonry walls at this plant. As a result of this review, a list of questions was sent to the Licensee (6), to which the Licensee has responded [7]. As a result of the plant visit and design-
'* Numbers in brackets indicate references, which are cited in Section 5.
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TER-C5506-235 calculations review on August 15 and 16, 1983, a list of action items was sent to the Licensee (9), to which the Licensee responded [10].
In December 1983, the Licensee was requested to provide additional information regarding masonry l
i design; the Licensee also responded [11,12] to this request.
The total number of masonry walls at the plant is 99, of which 97 are attached to or near safety-related piping or equipment [5].
Masonry walls at Turkey Point Units 3 and 4 are used as partition walls, fire' barriers, water barriers, flood barriers, shield walls, or sound barriers.
l The walls are single-and multi-wythe (5 multi-wythe walls) and are constructed of hollow or grouted concrete blocks.
Materials used in construction are as follows:
Concrete Blocks ASTM C-90-66T Grade A l
Mortar ASTM C-270-64T using Type S for l
unreinforced masonry in contact l
with earth, type N elsewhere, and
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l type M for reinforced masonry i
Reinforcement ASTM A-15-66 bars
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Joint Reinforcement ASTM A-82-66 Dur-O-Wal l
The Licensee qualified 43 walls using the arching theory.
However, in a later response'[12], the Licensee decided to qualify all walls by elastic analyses as constructed or to repair them to meet elastic stress requirements (see Response 1 in Section 3.1 for further details), except for the steam generator feed pump (SGFP) enclosure walls which will be discussed in Section 3.2 of this report. The proposed approach for analyzing the SGFP enclosure walls (30 walls as shown in Figures 9 and 10 for Units 3 and 4 in Reference
- 11) is to meet the elastic criteria for all load combinations except for a postulated break in the feedwater pump discharge line, in which one-way arching action will be used.
The status of the walls at this plant can be summarized as follows:
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.c TER-C5506-235 Method of Analysis Number of Walls Elastic analysis 51 Arching theory 30 i
Walls to be removed M
97 Modification
' Number of walls to be modified 33 Number of walls to be removed 16 Number of walls to be removed and rebuilt 5
Number of walls to be determined for possible modification
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- A total of 13 walls originally qualified by arching action are reanalyzed using the working stress design method (see Section 3.2 for further details).
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s' TER-C5506-235 2.
EVALUATION CRITERIA The basic documents used for guidance in this review were the criteria developed by the Structural Geotechnical Engineering Branch (SGEB) of the NRC (attached as Appendix A to this report), the Uniform Building Code [13], and ACI 531-79 [14].
In general, the materials, testing, analysis, design, construction, and l
inspection of safety-related concrete masonry walls should conform to the SGEB criteria. For operating plants, the loads and load combinations for quali-fying the masonry walls should conform to the appropriate specifications in the Final Safety Analysis Report (F3AR) for the plant. Allowable stresses are specified in Reference 14 and the appropriate increase factors for abnormal
'and extreme environmental loads are given in the SGEB criteria (Appendix A).
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't TER-C5506-235 3.
TECHNICAL EVALUATION This technical evaluation is based on the Licensee's earlier submittals (2, 3, 4, 51, and subsequent responses (7, 10, 11, 12] to the NRC requests for additional information (6, 9].
The Licensee's criteria were evaluated with regard to design and analysis methods, loads and load combinations, allowable stresses, construction specifications, materials, and any relevant test data.
3.1 EVALUATION OF LICENSEE'S CRITERIA The Licensee evaluated the masonry walls using the following criteria:
o Allowable stresses were based on ACI 531-79 (14].
o The loads and load combinations considered are those of the Final Safety Analysis Report (FSAR) of the plant.
o The working stress design method, and arching theory and were used to qualify the walls.
o A test program is being conducted to verify the assumed values used for masonry and mortar strength, o A typical elastic analysis procedure is summarized below:
determine wall boundary conditions calculate the wall's fundamental frequency using one-way action assumption obtain inertial loading from the floor response spectra compc e computed stresses with the allowable values in ACI-531-79.
o Typical arching action procedure:
determine the stiffness characteristic using the secant modulus approach calculate the natural frequency of the sall obtain inertial loading from apprcpriate floor response spectra obtain mid-span deflection determine wall responses (deflection, stress) compare the resulted deflection and stress with the Licensee's allowables o Tne following damping values are used:
a.
For uncracked walls, 24 damping for operating basis earthquake (OBE) and safe shutdown earthquake (SSE). --
t' TER-C5506-235 b.
For cracked reinforced walls, 4% damping for OBE and 7% damping 4
for SSE.
The Licensee's criteria [5] and response have been reviewed by"FRC and its consultants. In addition, an audit visit was conducted by NBC, FRC, and FRC's consultants on August 15 and 16, 1983 to gain first-hand knowledge about the conditions of the walls in the plant and how these conditions are reflected in the analysis. During these audits, each item of the Licensee's response dated May 27, 1982 [7] was reviewed. The applicability of the 4
arching theory was discussed. The licensee event report (LER) of June 20, 1983 [8] was also discussed. Drawings, general construction techniques, materials, etc. were reviewed. As a result of these audits, a list of action items was sent to the Licensee [9], and the Licensee has responded [10, 11,
~ 12].
Following is the review of the Licensee's responses [7, 10, 11, 12].
Request 1 Indicate whether the construction practice for the masonry structures at Turkey Point Plant Units 3 and 4 was in conformance with the provisions
-specified for the special inspection category in ACI 531-79 [14).
If not, explain and justify the use of allowable stresses.
i Response 1 The construction practice for the masonry walls at Turkey Point Plants Units 3 and 4 includes the following:
The masonry walls were constructed by personnel working from project drawings and specifications which specify the requirements for handling, storage, preparation of materials, and erection.
Field engineers were on the site during the construction of the masonry walls.
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However, the Licensee Event Report (LER) dated June 20, 1983 [8]
identified some masonry walls in the control building that do not comply with the original designs. During the construction activities related to the --- ---------------- --J
- 'l TER-C5506-235 control room modifications and computer room addition, some walls were found to have no internal grout and no reinforcing steel as called for by the design drawings. As a result of an overall inspection program, the Licensee decided to rely on the reinforcement (which was found in 5 walls as indicated in Response 10.2) in the analysis for only two walls (as opposed to a total of 87 walls identified by the design drawings).
In addition, a prism test program is planned to verify the material properties of the as-built conditions.
The Licensee?s response is considered adequate and satisfactory.
Request 2 With reference to Section II of Reference 5, justify the proposed 67%
increase in allowable stresses for masonry in tension and shear.
For factored loads, the SEB criteria [6] suggest the following factorst Shear reinforcement and/or bolts 1.5 Masonry tension parallel to bed joint 1.5 Shear carried by masonry 1.3 Masonry tension perpendicular to bed joint for reinforced masonry 0
for unreinforced masonry 1.3 Response 2 See Response 10.1.
Request 3 With reference to page 10 of Reference 5, explain how modes higher than-the fundamental mode were accounted for. Provide a sample calculation.
Resoonse 3 The Licensee indicated that the modal analysis. technique was used in conjunction with the response spectrum method to obtain the seismic response of the masonry walls. The total response was obtained by combining the first
'three modes of the beam model using-the SRSS method.
Therefore, the effect of higher modes has been accounted for.
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6 TER-C5506-235 It has been found, in many cases at other plants, that the first mode usually contributes 95% or more to the total responses. Therefore, it can be l
concluded that the Licensee's approach is adequate and in compliance with the SGEB criteria.
Request 4 I
i Explain how the openings and attachments from piping or equipment are accounted for in the beam analysis.
Request 10.9 IRequest 9, Reference 101 Perform a plate analysis of a wall with an opening, in order to justify the approach of transferring the loads above and below the opening to adjacent vertical strips, and provide the results for review.
Responses 4 and 10.9 With regard to wall openings, the Licensee stated that the block wall masses above the openings and/or penetrations are equally distributed to the vertical strips adjacent to the opening on both sides as additional mass for the purpose of analysis.
The concergtrated loads due to piping and/or attachments were considered as additional masses in the analysis. A plate computer model with a door opening has been analyzed for wall C-30-20.
The maximum bending stress using the plate analysis was found to be 22.48 psi which is smaller than the 26.10 psi bending stress using the approach of transferring the loads above the opening to adjacent vertical strip.- These results demonstrated that trans-fering the loads above the openings to the adjacent vertical strips is an adequate approach to account for openings in the walls.
In both cases, the stresses were less than the design allowable. Therefore, the Licensee's approach is considered adequate and in compliance with the SGEB criteria.
Request 5 Indicate how earthquake forces in three directions were considered in the analysis.
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't TER-C5506-235 Response 5
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The Licensee stated that in-plane stresses due to seismic loads were insignificant and that out-of-plane horizontal loads were determined to be the governing horizontal loads. Therefore, the seismic load due to the horizontal out-of-plane earthquake component was combined with the vertical seismic load using the absolute 'ua method for the masonry walls. This is consistent with s
the plant's FSAR.
The Licensee's response is satisfactory and in compliance with the SGEB i
criteria.
Request 12.1 { Request 1, Reference 121 Provide the technical basis and justification for treating tornado differential pressure loads as an equivalent static load.*
i Response 12.1 The Licensee response indicated that the differential pressure is due to a postulated break in the feedwater pump discharge line and does not result from a postulated tornado (as previously mentioned in a conference conversation in 14cvember 1983).
The peak pipe break pressure is 1.14 psig, with a rise time of 1.33 seconds. The minimum natural frequency of the walls in question is 30.5 cys.
For a constant force with finite rise time (such as the subject pipe break),
the dynamic load factor is 1.0079.
This value is approximately 0.8% greater that the value corresponding to the static condition.
Based on the Licensee's calculation, consideration of the loads as an equivalent static load is justified.
l Request 12.2 (Request 2, Reference 121 1
j Identify test data which could be used to verify arching action and, based on these tests, discuss the following items:*
- In a conference conversation in November 1983, the Licensee stated that arching action was used for several walls subjected to tornado differential pecssure load. -.
s' TER-C5506-235 Applicability of blast loading (type, magnitude, rate, and duration) a.
to tornado differential pressure. Discuss the technical basis and justification for the assumption used.
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b.
Applicability of test data to actual walls in the plant with regard to boundary conditions, materials, geometry, openings, and attachments.
c.
The statistical significance of available test data (number of relevant tests, level of confidence) in view of the fact that masonry is a composite material with high variability.
d.
The correlation between the test data and the proposed analytical procedure with regard to ultimate load and maximum mid-height deflection.
Discuss the safety factors, if any, used in the analytical procedure e.
and how they are reflected from test data. Based on URS test data, I
determine the minimum factor of safety against collapse for walls in t
question.
i f.
Discuss the effect the joint cracking (particularly at top of walls),
if any, on the behavior and resistance of the walls under tornado loads.
g.
Calculation of the maximum deflection of a typical wall under tornado loads using the proposed technique and how it is compared to URS test data. Discuss the impact of maximum displacement on the functionality of the wall attachment.
Responses 6 and 12.2 a.
The Licensee indicated that the blast load used in the referenced test (15] is similar to the pipe break design load since both are relatively uniform pressure loads. The maximum reflected pressure from a surviving test wall is 7 psi compared with a pipe break pres-sure of 1.14 psi.
In addition, the rise time of the experimental load was 10 milliseconds or less, compared with a 1.33-second rise time for pipe break. The duration of the blast lead was about 100 milliseconds, which is much less than the duration of the design pressure. The minimum natural frequency of the walls in question is 30.5 cys. The rapid rise time of the blast load would imply a much more severe dynamic loading condition than the pipe break load.
b.
Test walls (walls 77 and 78 of Reference 15) are very much similar to actual steam generator feed pump (SGFP) enclosure walls. They are constructed of 8-in hollow block in running bond. The boundary conditions for both sets of walls allow rigid arching to take place.
The steam generator feed pump enclosure walls ate confined within the rigid supports (concrete walls). The SGEP walls are 8 ft high, and l
the test walls are 8.5 ft high. I-i l._-
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Even though two test results are available, the level of pressure of failure of test walls when compared to the design pressura provides a high level of confidence in the SGFP enclosure walls.
d.
The following table provides the calculated maximum load and mid-height deflection.
Calculated Test Maximum Allowable values Ultimate load 7-9 psi 3.33 psi 1.14 psi Mid-height 0.4 in 0.12 in 0.043 in deflection e.
The safety factor used in the analysis is a reduction in the calcu-lated maximum allowable arching force by a factor of (1/1.5). Based on test pressure, the factor of safety is 7 psi /1.14 poi = 6.14.
f.
Test wall 77 was cracked at different locations due to a pressure of 7 psi, but it could survive a second blast load of 4 psi. Based on these test results, it can be concluded that the effect of joint cracking (if any) will be minor when the design pressure is only 1.14 psi.
g.
The factor of safety based on the calculated mid-height deflection is 0.4/0.043 = 9.3.
Since the calculated maximum deflection is less than 1/16 in, it does not have any impact on the functionality of attachments to the walls.
It can be concluded from the above information that while the arching action is not acceptable for a dynamic, fully reversed cyclic load situation, it is recognized that the blast load tests [15] have certain similarities to the walls in question and therefore the analytical method can be used for this particular situation.
(See Appendix B for further comments on this subject.)
Request 10.1 [ Request 1, Reference 101 Justify the use of a 1.67 increase in allowable stresses for masonry in tension and shear for the walls which are qualified by the working stress method in the future.
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TER-C5506-235 Response 10.1 The Licensee referred to various test data to justify the increase factor of 1.67.
It should be noted that the Licensee used conservative values of damping (24 for OBE and SSE for uncracked walls). In addition, whenever the natural frequency of the wall was on the lower side of the peak response spectra curve, the peak value was used in the analysis as shown in Figure 1.
Even though the increase factor is higher than the SGEB allowable, these conservative measures should constitute an acceptable basis. Therefore, the Licensee's approach is considered adequate and meets the intent of the SGEB criteria.
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TER-C5506-235 Request 10.2 [ Request 2, Reference 10]
Address the effect of horizontal wall reinforcement in reinforced. walls.
Response 10.2 1
The Licensee stated that joint reinforcement was used to aid in reducing shrinkage cracks and to preserve the integrity of the wall after the formation of vertical flexural cracks and concluded that joint reinforcement has a negligible effect in reinforced walls at Turkey Point Units 3 and 4.
' There are five walls at Turkey Point Units 3 and 4 which will be analyzed as reinforced walls. However, three of these are walls that have been demolished and rebuilt. For the remaining two walls, recent inspections have shown that horizontal reinforcing is present in the middle portion of their spans.
The Licensee 's response is adequate and in compliance with the SGEB criteria.
Request 10.3 [ Request 3, Reference 101 Provide justification for assuming one-way action (vertical) is valid.
Response 10.3 l
The Licensee stated that beam models (one-way spans) typically overpredict bending stresses when compared with plate models and that natural frequencies calculated assuming one-way action result in lower frequencies and higher wall accelerations than would be predicted by a two-way analysis. The Licensee presented the analysis results of three plate models with respect ratios of 1.0, 1.5, and 2.0 and compared the analysis results with the results obtained from beam analysis. For calculated stresses, the Licensee indicated that the beam models overpredicted the plate model results by a minimum of more than 2.5 times. Also, the beam model frequencies were at most one-half of those resulting from a plate analysis..
TER-C5506-235 The Licensee's analysis is judged to be reasonably adequate and acceptable.
Request 10.4 [ Request 4, Reference 101 Indicate the disposition for the cracks found on walls C-18-43, C-30-2, C-30-3, and A-42-3.
Response 10.4 The Licensee provided a summary of the location of cracking, possible causes, and the proposed disposition for the cracks for the subject walls. A review of the summary shown in the table indicated that the Licensee approach 4
to fixing these cracks is. adequate and satisfactory (see Table 1).
Request 10.5 {Recuest 5, Reference 10]
The calculation"for Wall C-42-15 indicates the compression allowable for OBE loading was exceeded by 114; however, the wall was accepted based on engineering judgment. Provide a summary of the walls where the calcu-lated stresses exceed the allowables, and justify the variations.
itesponse 10.5 The Licensee indicated that a review of wall calculations has shown that for three walls out of 95, compression allgrables for OBE loadings were exceeded. Howeve, the Licensee indicated that these three walls have been i
reevaluated and redesigned and were found to be qualified.
The Licensee's response is satisfactory and in compliance with the SGEB criteria.
Request 9.8 The calculations for wall C-42-16 (reinforced, fully grouted) indicated apparent differences between the results obtained from the computer program CE-917 (in conjunction with the CE-918 program) and the "BLOCRWALL" program. Provide a detailed comparison of the results of these two programs for wall C-42-16.
Explain the differences and discuss their impact in determining wall adequacy.
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Modification of Walls' Cracks
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CRact WALL CCWDIT138 RgASON OF CRACE FIIING MEDED RDWUCS Crack e Interface Shrinkage Drypack C-13-43 between original well (After clearing and repaired portion esisting nortar) a) Around botton Due to the Clear Appros.
Repair of well takse flasse of transfer of con-3'-3" x 3'-0" sin. bearing load from str. been 8 top contrated load area around str.
above into account free been above been and replace bearing eves C-30-2 and ORI.
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b) At top of us11 Block was possibly Drypack No load transfer free (borisontal) cracked during (after clearing above because of 1/2" installation of pipe saisting nortsr) compressible material penetrations and,
Protruding steel sembers a) Atisset sortar Poor wortmooship As required during joints above grosting of colla E1. of cable C-30-3 trav osenina b) Arsund bottom Due to the transfer' Provide finished No load transfer free flange of str.
of concentrated opening w/1" ama, above because of beam 9. top load from beam and 1/2" sin.
provided clearance above clearance around girder 6 channel At bottaa of the Possible Shrinkage Clost esisting Well is being analyzed A-41-3 us11 five courses vertical sortar.
a$ vertical span.
of vertical joints Use sintaus 1/2" Vertical joint cracks assisim 3/8" deep do not have any effect drypack on the wall's strength.
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Response 9.8
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l The Licensee indicated that the reason for the apparent differences between the results of analysis using the "BLOCKNALL" program and the CE-917/
CE-918 programs is that the "BLOCKWALL" program evaluates the wall as a simplified stick model with masses lumped at different locations on the wall and one-half of the mass of the batteries and the battery racks was lumped directly on the masonry wall model. On the other hand, for the CE-917/CE-918 programs, the computer model incorporates the wall and the battery racks.
Much of the load from the batteries thus is transferred through the wall and the racks into the floor slab, with only a relatively small amount being carried by the wall. This modeling approach results in lower bending stresses in the masonry wall and acceptable interaction values.
However, the Licensee stated that these batteries and racks will be replaced in the near future. The new racks will be freestanding and will not interact with block walls.
The Licensee's response is adequate and in compliance with the SGEB criteria.
3.2 EVALUATION OF LICENSEE'S APPROACH TO WALL MODIFICATIONS During te meeting on August 15 and 16, 1983, the Licensee provided a listing of walls to be modified. According to this list, the modifications consist of the following:
o Number of walls to be modified 33 l
o Number of walls to be removed 16 o
Number of walls to be removed and rebuilt 5
According to this list, 43 walls were qualified by arching action.
However, as indicated earlier, only the steam generator feed pump enclosure walls, which consist of 30 walls in both units, are qualified by arching action. The remaining 13 walls are reanalyzed relying on the working stress design method, and if the calculated stresses exceed the required allowables they will be repaired. As of this writing, the number of walls requiring modification in this category is not yet known. l
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D TER-C5506-235 The modifications of masonry walls at Turkey Point Units 3 and 4 include adding grout, rebar, and supports so that the walls can be qualified relying
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on the working stress design method.
The procedures used to add grout and rebar to the walls have been j
reviewed and judged to be adequate.
3.3 EVALUATION OF IN-PLACE MATERIAL TESTS In order to verify the assumed values for material properties used in the ana' lysis, the Licensee plans to conduct tests of in-place materials in existing masonry walls [11]. The tests can be summarized as follows:
a.
Selection of Walls 4
Samples are taken from different buildings in the plant.,
Six-in, 8-in, and 12-An thick ungrouted and unreinforced walls are selected for prism tests and masonry unit tests.
i Eight-in grouted unreinforced walls are selected for testing grout specimens.
b.
Number of Samples Masonry prism tests: minimum of three samples from each type of wall (6-in, 8-in, and 12-in tweell and 8-in three-cell hollow units)
Concrete masonry unit tests: minimum of six unit samples from each type of wall (6-in, 8-in, and 12-in two-cell and 8-in three-cell hollow units)
GrJut tests: minimum of three samples from 8-in grouted walls, c.
Testing Methods Masonry prism tests:
the compression test is in accordance with Section 6 of ASTM E447-80.
l Concrete masonry unit-tests:
the tests are in accordance with i
Sections 8 and 9 of ASTM C 140-80.
l Grout tests:
the tests are in accordance with ASTM C42-77.
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i TER-C5506-235 In addition, the plan also provides techniques for removing the specimen and for preparing and controlling specimens before tests.
The test plan as summarized above has been reviewed and found to be acceptable.
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CONCLUSIONS e
A detailed study was performed to provide a technical evaluation of the masonry walls at the Turkey Point Plant Units 3 and 4.
Review of the
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Licensee's criteria and additional information provided by the Licensee led to
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the conclusions given below.
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The criteria used for reevaluation of the masonry walls, along with the y
additional information provided by the Licensee, indicate that the Licensee's criteria are in compliance with the SGEB criteria except for the following a
Ir areas:
h o Higher increase factor for strsss calculation. However, as discussed
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in Response 10.1 of Seccion Q, the Licensee used conservative damping i
values (2h for OBE and SSE for uncracked walls as opposed to 44 for OBE and 74 for SSE). In addition, whenever the natural frequency of the wall was on the lower side of the peak response spectra, the peak value was used in the analysis. These conservative measures should be i
adequate to compensate for a higher increase factor; hence, the Licensee's approach is considered to meet the intent of the SGEB
{
criteria.
Although the arching theory is not acceptable for a dynamic, fully E
o E
reversed cyclic load, it is recognized that the blast load tests [15]
i have certain similarities to the SGFP walls in question (as discussed in Response 12.2).
Based on test data, it is observed that a signifi-cant margin of safety exists when the calculated ultimate' loads and maximum deflections are obtained.
It is therefore concluded that the analytical method can be used in this particular case.
T 5
h b
7 r
E E
E. '
E _...
i-s TER-C5506-235 5.
REFERENCES
=
1.
IE Bulletin 80-11 Masonry Wall Design NRC, 08-May-80 2.
R. E. Uhrig Letter to J. P. O'Reilly, NRC.
Subject:
Response to IE Bulletin 80-11 Florida Power & Light Co., 24-Jul-80 L-80-234 3.
Letter to J. P. O'Reilly, NRC.
Subject:
IE Bulletin 80 Delay of Re-evaluation and Final Report Florida Power & Light Co., 04-Nov-80 L-80-373 4.
R. E. Uhrig -
Letter to J. P. O'Reilly, NRC.
Subject:
Response to IE Bulletin 80-11 Florida Power & Light Co., ll-Feb-81 L-81-47 5.
R. E. Uhrig Letter to J. P. O'Reilly, NRC.
Subject:
Turkey Point Units 3 and 4
- Final Report in Response to IE Bulletin 80-11 Florida Power & Light Co., 03-Apr-81
..f, L-81-153 6.
S. A. varga Letter to R. E. Uhrig, FPL
Subject:
Requesc for Additional Information Regarding Masonry Wall Design (IE Bulletin 80-11)
March 29, 1982
- 7. R. E. Uhrig Letter to S. A. Varga, NRC
Subject:
Turkey Point Units 3 & 4 Decket No. 50-250, 50-251, IE Bulletin 80-11 f
May 27, 1983
- 8. Licensee Event Report
= J-Reportable Occurrence 250-83-06.
Turkey Point.
Date of Occurrence: April 5, 1983.
Control Building Masonry Halls e s
- 9. S. A. Varga
=- L" Letter to J. W. Williams, FPL
~
~ -- -
Subject:
Request for Additional Information Regarding Masonry Wall Design (IE Bulletin 80-11)-
~
l September 2, 1983
i--
\\
s.
TER-C5506-235
- 10. J. W. Williams a
Letter to S. A Varga, NRC
Subject:
Turkey Point Units 3 and 4 IE Bulletin 80-11 Masonry Wall Design Request for Additional Information November 7, 1983
- 11. J. W. Williams Letter to S. A Varga, NRC
Subject:
Turkey Point Units 3 and 4 IE Bulletin 80-11 Masonry Wall Design Request for Additional Information January 24, 1984
- 12. J. W. Williams Letter to S. A Varga, NRC
Subject:
Turkey Point Units 3 and 4 IE Bulletin 80-11 Masonry Wall Design Request for Additional Information l
February 1, 1984
- 13. Uniform Building Code International Conference of Building Officials, 1979
- 14. Building Code Requirements for Concrete Masonry Structures Detroit: American Concrete Institute, 1979 ACI 531-79 and ACI 531-R-79 f
j
- 15. URS Research Co.
Shock Tunnel Tests of Preloaded and Arched Wall Panels June 1973
- 16. H. G. Harris and A. A. Hamid
" Applicability of Arching Theroy to Unreinforced Block Masonry Walls Under Earthquake Loading" Department of Civil Engineering, Drexel University L
August 1982
- 17. A. A. Hamid, H. G. Harris, and V. Con
" Evaluation of Arching Theory in Unreinforced Masonry Walls in Nuclear Power Plant" Franklin Research Center June 1983 l -,
';s APPENDIX A SGEB CRITERIA FOR SAFETY-RELATED MASONRY WALL EVALUATION (DEVELOPED BY THE STRUCTURAL AND GEOTECHNICAL ENGINEERING BRANCH l
[SGEB} OF THE NBC) l l
FRANKUN RESEARCH CENTER DtVtSION OF ARVIN/CALSPAN 20th and Race Streets. Phda.. Pa.19103 (215) 448-1000
- b s
=L TER-C5506-235 CONTENTS Section Title Page A-1 1
GENERAL REQUIREMDrrS 2
LOADS AND LOAD COMBINATIONS.
A-1 a.
Service Load Combinations A-1 b.
Extreme Environmental, Abnormal, Abnormal / Severe Environmental, and Abnormal / Extreme Environmental Conditions.
A-2 A-2 3
ALLONABLE STRESSES.
4 DESIGN AND ANALYSIS CONSIDERATIONS.
A-3 A-4 5
REFERENCES.
iii
?
TER-C5506-235 1.
General Requirements The materials, testing, analysis, design, construction, and inspection related to the design and construction of safety-related concrete masonry walls should conform to the applicable requirements contained in Uniform Building. Code - 1979, unless specified otherwise, by the provisions in this criteria.
The use of other standards or codes, such as ACI-531, ATC-3, or NCMA, is also acceptable. However, when the provisions of these codes are less conservative than the corresponding provisions of the criteria, their use should be justified on a case-by-case basis.
- In new construction, no unreinforced masonry walls will be permitted.
For operating plants, existing unreinforced walls will be evaluated by the provisions of these criteria. Plants which are applying for an operating license and which have already built unreinforced masonry walls will be evaluated on a case-by-case basis.
2.
Loads and Load Combinations The loads and load combinations shall include consideration of normal loads, severe environmental loads, extreme environmental loads, and abnormal loads.
Specifically, for operating plants, the load combinations provided in the plant's FSAR shall govern. For operating license applications, the following load combinations shall apply (for definition of load terms, see SRP Section 3.8.4II-3).
(a)
Service Load Conditions (1) D+L t
(2) D + L + E f
(3) D+L+W i
If thermal stresses due to To and Ro are present, they should be included in the above combinations as follows:
(la) D + L + To + Ro
-(2a) D + L + To + Ro + E (3a) D + L + To + Ro + W Check load combination for controlling condition for maximum 'L' and for no
'L'.
A-1
~
, f.
4 TER-C5506-235 1
(b)
Extreme Environmental, Abnormal, Abnormal / Severe Environmental, and Abnormal / Extreme Environmental Conditions (4) D + L + To + Ro + E (5) D + L + To + Ro + Wt (6) D + L + Ta + Ra + 1.5 Pa (7) D + L + Ta + Ra + 1.25 Pa + 1.0 (Yr + Yj + Ym) + 1.25 E (8) D + L + Ta + Ra + 1.0 Pa + 1.0 (Yr + Yj + Ym) + 1.0 E' In combinations (6), (7), and (8) the maximum values of P, T '
a a
R, Yj, Yr, and 'In, including an appropriate dynamic load a
factor, should be used unless a time-history analysis is performed to justify otherwise. Combinations (5), (7)', and (8) and the corresponding structural acceptance criteria should be satisfied first without the tornado missile load in (5) and without Yr, Yj, and Yu in (7) and (8). When considering these loads, local section strength capacities may be exceeded under these concentrated loads, provided there will be no loss of function of any safety-related t
system.
Both cases of L having its full value or being completely absent should be checked.
t 3..
Allowable Stresses Allowable stressas provided in ACI-531-79, as supplemented by the i
following modifications / exceptions, shall apply.
(a)
When wind or seismic loads (OBE) are considered in the loading combinations, no increase in the allowable stresses is permitted.
(b)
Use of allowable stresses corresponding to special inspection category shall be substantiated by demonstration of compliance with the inspection requirements of the SEB criteria.
(c) When tension perpendicular to bed joints is used in qualifying the unreinforced masonry walls, the allowable value will be justified by test program or other means pertinent to the plant and loading conditions.
For reinforced masonry walls, all the tensile stresses j
will be resisted by reinforcement.
t j
(d)
For load conditions which represent extreme environmental, abnormal, abnormal / severe environmental, and abnormal / extreme environmental conditions, the allowable working stress may be multiplied by the factors shown in the following table:
A-2
r
-c TER-C5506-235 Type of Stress Factor
~
Axial or Flexural Compression 2.5 Bearing 2.5 Reinforcement stress except shear 2.0 but not to exceed 0.9 fy Shear reinforcement and/or bolts 1.5 Masonry tension parallel to bed joint 1.5 Shear carried by masonry 1.3 Masonry tension perpendicular to bed joint for reinforced masonry 0
2 1.3 for unreinforced masonry Notes (1)
When anchor bolts are used, design should prevent facial spalling of masonry ' unit.
(2)
See 3(c).
4.
Design and Analysis Considerations (a)
The analysis should follow established principles of engineering mechanics and take into account sound engineering practices.
(b)
Assumptions and modeling techniques used shall give proper considerations to boundary conditions, cracking of sections, if any, and the dynamic behavior of masonry walls.
(c)
Damping values to be used for dynamic analysis shall be those for reinforced concrete given in Regulatory Guide 1.61.
(d)
In general, for operating plants, the seismic analysis and Category I structural requirements of FSAR shall apply. For other plants, corresponding SRP requirements shall apply. The seismic analysis shall account for the variations and uncertainties in mass, materials, and other pertinent parameters used.
(e)- The analysis should consider both in-plane and out-of-plane loads.
(f)
Interstory drift effects.should be considered.
A-3 i
TER-C5506-235 (g)
In new construction, grout in concrete masonry walls, whenever used, shall be compacted by vibration.
(h) For masonry shear walls, the minimum reinforcement requirements of ACI-531 shall apply.
(i)
Special constructions (e.g., multiwythe, composite) or other items not covered by the code shall be reviewed on a case-by-case basis for their acceptance.
(j)
Licensees or applicants shall submit QA/QC information, if available, for staff's review.
In the event QA/QC information is not available, a field survey and a test program reviewed and approved by the staff shall be implemented to ascertain the conformance of masonry construction to design drawings and specifications (e.g., rebar and grouting).
(k)
For masonry walls requiring protection from spalling and scabbing due to accident pipe reaction (Yr), jet impingement (Y ), and missile 3
impact (Y,), the requirements similar to those of SRP 3.5.3 shall apply. However, actual review will be conducted on a case-by-case basis.
5.
References (a)
Uniform Building Code - 1979 Ed. tion.
(b)
Building Code Requirements for Concrete Masonry Structures ACI-531-79 and Commentary ACI-531R-79.
(c)
Tentative Provisions for the Development of Seismic Regulations for Euildings - Applied Technology Council ATC 3-06.
(d)
Specification for the Design and Construction of Load-Bearing Concrete Masonry - NCMA August, 1979.
(e)
Trojan Nuclear Plant Concrete Masonry Design Criteria Safety Evaluation Report Supplement - November, 1980.
s A-4
s' APPENDIX B EVALUATION OF THE USE OF ARCHING THEORY IN THE ANALYSIS OF MASONRY NALLS UNDER DIFFERENTIAL PRESSURE - TURKEY POINT PLANT UNITS 3 AND 4 PRANKUN RESEARCH CENTER DIV1510N OF ARVIN/CALSPAN 20th and Race Streets. Phda.. Pa.19103 (215) 448-1000
.