ML19341A989
| ML19341A989 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 01/15/1981 |
| From: | Clayton F ALABAMA POWER CO. |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| IEB-80-11, TAC-42861, TAC-43966, NUDOCS 8101290728 | |
| Download: ML19341A989 (18) | |
Text
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Alab:m2 Power Cornpany 1
600 North 18th Street 8
i Pc;t Offica Box 2641 Birmingham Alabama 35291
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Telephone 205 250-1000 m
F. L CLAYToN, JR.
senior Vice President Alabama Power d
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; } *dI the SOuttnyn ekictrC System January 15, 1981 7
Docket No /30-348
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U [ddi Lu Mr. James P. O'Reilly isl
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U. S. Nuclear Regulatory Commission Region II, Suite 3100 P
101 Marietta Street N. W.
4 Atlanta, Georgia 30303
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ALABAMA POWER COMPANY J. M. FARLEY NUCLEAR PLANT UNITS 1 & 2 CONCRETE MAS 0 M7 WALL DEFICIENCIES SUPPLEMENTAL REP 0kr TO I.E. BULLETIN 80-11
Dear Mr. O'Reilly:
In the course of preparing its response to I.E.Bulletin 80-11, Alabama Power Ccmpany perfonned sample test drilling on certain walls in Farley Unit 2 to detennine if reinforcing was in place.
In the Unit 2 walls tested a substantial portion of the vertical reinforcing required was not present.
Based on these tests and discussion with the designer, it has been concluded that a number of the Unit 2 walls are potentially deficient.
Subsequent to this, similar testing was performed on a sample of Unit I walls.
The results for the Unit 1 testing were similar to Unit 2 in that the walls do not meet current design criteria; however, 3
some amount of vertical reinforcing is present.
Based on these tests, it will be necessary to test or evaluate each Unit I wall to determine its specific status relative to current design criteria.
The evaluation and acceptance criteria being used by the designer is included as.
This criteria is intended to satisfy the requirements of I.E.Bulletin 80-11.
It should be noted that Farley Nuclear Plant has three (3) types of masonry wall designs which are as follows:
Type 1:
Hollow block walls with vertical reinforcing grouted in place in the vertical cells on 16 inch centers and which have horizontal reinforcing in every other course.
Type 2: Hollow block walls with no vertical reinforcing and which have horizontal reinforcing in every other course.
Type 3:
Solid block walls with no vertical reinforcing and which have horizontal reinforcing in every other course.
& b/DLMO9&B
Mr. James P. O'Reilly January 15, 1981 Hollow and solid block walls are constructed of standard masonry ur.its confonning to ASTM C90-70 and C145-71 respectively.
By original i
design, none of the concrete masonry walls were designed as seismic.
All the concrete masonry walls were specified by design as "non-Q" and were built by a subcontractor. All type 1 walls are considered deficient with respect to current design criteria. All type 2 and 3 walls are considered potentially deficient pending evaluation against current design criteria (e.g., Attachment 1).
As reported in our earlier responses to I.E.Bulletin 80-11, Alabama Power Company has walked down and identified (in Seismic Category I structures) concrete masonry walls and has determined whether or not i
there is safety-related equipment attached to or in the proximity'of the concrete masonry walls.
A " case" designation was assigned to each wall for I.E.Bulletin 80-11 evaluation purposes. These cases are based on whether or not safety-related equipment is attached or in the proximity of wall. The number of walls in each case in each unit is shown below.
Unit 1 Unit 2 Case I (safety-related equipment 27 14 attached to wall)
Case II (safety-related equipment in 18 16 proximity to wall)
Case III (all remaining walls) 44 15 TOTAL 89 45 Alabama Power Company is undertaki m to bring all Case I or Case II walls in both Units 1 and 2 into confon....:ce with current design requirements.
Prior to undertaking repair of any wall, the proposed repaired configuration will be evaluated and approved by the designer.
Concurrently with the repairs of deficient walls, the design re-evaluation as required by Bulletin 80-11 of all other Case I and II walls will be completed. All re-evaluations and all repairs of Case I and Case II walls will be completed for Unit 1 prior to the return to criti-cality upon completion of the current refueling outage, and for Unit 2 prior to initial criticality. The report on these activities required by Bulletin 80-11 will be submitted subsequently.
Yours very truly, i
M l
F.L.Claytpn,JrC.
CLB:rt Attachment cc:
See Page 3
Mr. James. P. O'Reilly January 15, 1981 cc: Mr. R. A. Thomas Mr. G. F. Trowbridge Mr. L. L. Kintner (w/ attachment)
Mr. W. H. Bradford (w/ attachment)
Office of I & E (w/ attachment)
Division of Reactor Operations Inspection Office of I & E (w/ attachment)
Division of Construction Inspection Mr. D. S. Price (w/ attachment)
I & E, Region II Mr. E. A. Reeves (w/ attachment)
ATTACHMENT 1 Sp:cificcticri-7597-C -
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k CRITERIA FOR THE RE-EVALUATION OF CONCRETE MASONRY WALLS IN RESPONSE TO NRC IE BULLETIN 80-11 FOR ALABAMA PoliER COMPANY JOSEPH H. FARLEY NUCLEAR PLANT UNITS 1 AND 2 M
APPENDIX B e
M O
me c..,
ATTACHMENT 1 Specific tica 7597-C _,
TABLE OF CONTENTS 1.0 General 2.0 Governing Code 3.0 Loads and Load Combinations 4.0 Materials 5.0 Design Allowables 6.0 Alternative Acceptance Criteria 7.0 Analysis and Design d
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ATTACHMENT 1
- SPicifiention 7597-C-
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CRITERIA FOR THE RE-EVALUATION OF CONCREIE MASONRY WALLS 1.0 GENERAL 1.1 Purpose This criteria is provided in order to establish design requirements and criteria for use in re-evaluating the structural adequacy of concrete block walls as required by NRC 'E Bulletin 80-11, Masonry I
Wall Design, dated May 8, 1980.
1.2 Scope 5
The re-evaluation shall determine whether the concrete masonry walls will perform their intended function under the loads and load com-binations prescribed herein. Verification of wall adequacy shall include a review of local transfer of load from block into wall, global response of wall', and transfer of wall reactions into support
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where response spectra are defined. Anchor bolts and embedments are not considered to be within the scope of the evaluation.
2.0 GOVERNING CODE The design of cone-masonry walls shall be based on the American Concrete Institute i ag Code Requirements for Concrete Masonry Structures (ACI 531-75 Supplemental allowables as specified herein shall be used for cases not directly covered in the governing code.
3.0 LOADS AND LOAD COMBINATIONS 3.1 Losd Definitions The following loads shall be used in analysis and design for the re-evaluation of concrete masonry walls:
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ATTACHMENT 1 Specification 7597-C- _
dead load of wall and attachments D
=
live load L
=
force or pressure on wall due to rupture of any one pipe R
=
To = thermal loads due to temperature under operating conditions Ho = force on wall due to thermal expansion of pipe under operating conditions TA = thermal loads due to temperature under accident conditions EA = force on wall due to thermal expansion of pipes under accident conditions maximum probable earthquake (OBE)
E
=
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E'=
maximum pcosible earthquake (SSE) wind load on wall W
=
We = tornado load on wall including differential pressure and missiles 3.2 Load Combinations 3.2.1 Service Load Combinations a.
D+L+E' b.
D + L + To + Ho + E (or W) 2
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ATTACHMENT 1 SP:cifientica-7597-C -
3.2.2 Load Combinations for Severe' Conditions a.
D + R + E (or W) b.
D + Ho + E (or W) c.
D+R+E' m
d.
D + R + HA + E '
e.
D + HA + Wt 4.0 MATERIALS Materials used in masonry construction are conforming to the requirements of the standard specifications listed below:
Masonry Units - ASDi C-90, Grade N-1 Horizontal Reinforcing - ASTM A-82 or approved equal (DUR-0-WAL, extra heavy, Ladur Type)
Vertical reinforcing - ASTM A-615, Grade 60 Grout or Mortar - ASTM C-476 4.1 Material Properties The material properties are as specified below:
f'm = the compressive strength of masonry, psi fy yield strength of reinforcing steel, psi
=
Em modulus of elasticity of masonry, psi
=
{
3
ATTACHMENT 1 Specification 7597-C,
Eg modulus of elasticity of grout, psi
=
modulus of elasticity of steel, psi Es
=
B' density of masonry units, pcf
=
minimum compressive strength of grout or mortar mo =
@ 28 days 4.1.1 Masonry Unit f'm = 1,000 psi 1,000 f'm Em
=
125 lbs./ft.3 Y
=
4.1.2 Grout or Mortar 6
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2,500 psi mo =
0 1.4 x 10 psi Eg
=
4.1.3 Vertical Reinforcing
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fy 60,000 psi
=
29,000,000 psi Es
=
4.1.4 - Horizontal Reinforcing (DUR-0-WAL) fy
- 70,000 psi
=
Es 29,000,000 psi
=
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ATTACHMENT 1 Spacification 7597-C- _
5.0 DESIGN ALLCMABLES 5.1 Allowable Stress for Service Load Conditions 5.1.1 The allowable stresses for masonry units are specified below:
Allowable stresses, psi E "
Related to f/
Maximum See ACI 531-79 Compressiv, sections 10.13 A nal F.
and 10.1.4 1000 Flaxural F.
0.33 f.*
1200 Bearing On full ares F.
0.25 fJ 900 On one-third area or less F.
0.375 fJ 1200 Shear No shear reinforcement Mexural members v.
1.1Y f.*
50 Shearwalls MND. h 1 w.
0.9Y f.*
34
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MNd. < 1 '
v.
2.0Y f.*
40
, L85 - MNd.)
(
Reinforcement taking entire shcar
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Flexural members s
3.0y f.*
150 Shearwalls M N d. h 1 e
1.5V f.*
75 MNd. <1 e
2.0Y f.*
45 (2.67 - MNd.)
Tension No tension reinforce-ment Tension normal to bed joints Hollow units F.
0.5Y m.
25 Solid and/or F.
1.0Y m.
40
)
grouted units Tension parallel to bed joints in running i
bond i
Hollow units F,
1.0yX
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80 50
.i Solid and/or 7,
1.5Y m.
i grouted units l
Modulus of elasticity E.
1000 ft 2,500,000 l
Modulus of rigidity E.
400 ft 1,000.000 5
ATTACHMENT 1 Specifice. tion 7597-C.
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5.1.2 Core concrete or cell Grout The allowable tension stresses shall be 2.5 Yf'c or 0.33 times the modulus of rupture as determined by test.
5.1.3 Reinforcing Steel Stresses in steel reinforcement shall not exceed the following limit:
I 24,000 psi Grade 60 Bars 0.5 f7 but limited to 30,000 psi DUR-0-WAL 5.1.4 Secondary Effects Design allowable stresses may be increased by 307. when considering thermal effects or displacement limited loads.
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In-plane effects due-to interstory drift may be determined by analysis or in-plane strains ( 6 /H) shall be limited to 0.00012, where A is the relative displacement between the top and bottom of ahe wall and H is the height of the wall.
A wall confined on all four sides may be limited to a strain of 0.0008 provided the structural shear resisting elements bounding each vertical side of the wall have a shear resist-4 ing capability larger than the wall and the wall width to height ratio is at least 0.5.
5.1.5 Seismic and Wind Loading The 337. increase in allowable stresses for masonry and reinforcing steel due to seismic or wind loadings is not
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permitted except as permitted in the SAR.
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ATTACHMENT 1 SPecificction 7597-C-5.2 Allowables for Savora Lo* ding Combinations Design allowables for severe load conditions which contain dead, live, operating basis earthquake or wind loads, or accident pressure, accident thermal, tornado or safe shutdown (design basis) earth-quake loads shall be as follows:
5.2.1 Masonry The allowable masonry stresses shall be 1.67 times the values given in Paragraphs 5.1.1 through 5.1.3.
5.2.2 Reinforcing Steel The allowable steel stresses shall be 90% of minimum ASTM specified yield strength provided lap splice lengths and embedment (anchorage) can develop this stress level.
Allowable bond stresses may be increased by a factor of 1.67 in determining' splice and anchorage lengths.
5.2.3 Impact and Suddently Applied (Step Pulse) Loads Load combinations which contain loads due to missile impact, jet impingement or pipe whip may exceed' the allowables provided there will be no loss of function of any safety
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related system. The alternate acceptance criteria as des-cribed in Section 6.0 shall be used.
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5.2.4 Secondary Effects In lieu of a more rigorous analysis, in-plant strains due to interstory drift may be limited to 1.67 times the values in Paragraph 5.1.5.
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ATTACHMENT 1 Sp:cificctien 7597-C-5.3 Damping 5.3.1 The damping values to be used shall be as follows:
a.
For uncracked sections use 4% for both OBE and SSE b.
For cracked sections use 7% for OBE and 7% for SSE 5.4 Modulus of Rupture 5.4.1 The extreme tensile fiber stress for use in determining the lower bound uncracked moment capacity is 6 Y f'c or 0.8 times the modulus of rupture as determined by test for the core concrete or cell grout and 2.4 times the allowable flexural tensile stress for masonry.
5.5 Non-Category I Masonry Walls 5.5.1 Concrete masonry' walls not supporting safety systems but whose collapse could result in the loss of required function of safety related equipment or systems shall be evaluated the same as walls that support safety systems. Alternatively, the walls may be analytically checked to verify that they will not collapse when subjected to accident, tornado or safe shutdown (design basis) earthquake loads.
5.6 Inspection 5.6.1 It shall be determined if adequate inspection was performed during masonry construction. Performance of inspection shall dictate which design allowable stresses of the govern-ing code are to be used.
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ATTACHMENT 1 Spsc1ricacion east-G-
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_l 6.0 ALIERNATIVE ACCEPTANCE CRITERIA Where the bending due to out-of-plane inertial loading causes
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flexural stresses in the wall to exceed the design allowables given in Section 5.0, the wall can be evaluated by the " energy balance technique." If the deflection exceeds three times the yield deflection, the resulting displacement shall be multiplied by a
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factor of 2 and a determination made as to whether such factored i
displacements would adversely impact the function of safety related systems attached and/or adjacent to the wall.
In any event, the midspan displacement shall be limited to five times the yield displacement, and the masonry compression stresses shall be limited to 0.85 f'm based on a rectangular stress distri-bution. Values in excess of these may be used if justified on a wall-by-wall basis.
7.0 ANALYSIS AND DESIGN
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7.1 Structural Response of Masonry Walls 7.1.1 Equivalent Moment of Inertia (I,)
To determine the out-of-plane frequencies of masonry walls, the uncracked behavior and capacities of the walls (Step 1) and, if applicable, the cracked behavior and capacities of the walls (Step 2) shall be considered, l
Step 1 - Uncracked Condition The equivalent moment of inertia of an uncracked wall (I ) shall be obtained from a transformed section con-sisting of the block,, mortar, cell grout and core concrete. Alternatively the cell grout an,d core concrete, neglecting block and mortar on the tension side, may be used.
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ATTACHMENT 1 SPecificcti n 7597-C-Step 2 - Cracked Condition If the applied moment (M,) due to all loads in a load combination exceeds the uncracked moment capacity (M
),
the wall shall be considered to be cracked. In this event, the equivalent moment of inertia (I,) shall be computed as follows:
I, 9 E,
I
+
1M M
er I
g er k a) a I
f t
M
=
er rl I
N)
- where, M
= uncracked moment capacity M,
applied maximum moment on the wall
=
moment of inertia of transformed section-I
=
g moment of inertia of the cracked section I
=
modulus of rupture (as defined in Paragraph f
=
5.4.1) y distance of neutral plane from tension face
=
l If the use of I, results in an applied moment, M,,
which'is less than Mer, then the wall shall be verified for H er i
i For walls in which two-way spans are considered, consult.
with the. Chief Civil Engineer for analytical approaches.
I 1
10 l
ATTACHMENT 1 Sp:cific tica 7597-C,
7 1.2 Modes of Vibration The effect of modes of vibration higher than the fundamental mode shall be considered. For this purpose, a modal analysis may be performed. Alternatively, the inertia load on the wall due to its own veight for the fundamental mode may be considered as a uniform load in lieu of deter =ining an effective mass. The corresponding bending moment and reac-tion will account for the higher mode effects.
7.1.3 Frequency Variations Uncertainties in structural frequencies of the masonry wall due to variations in structural properties and mass shall be taken into account. Significant variables include mass, boundary conditions, modulus of elasticity, extent of cracking, vertical load, in-plane and out-of-plane loads, two-way action and composite action of multi-wythe walls.
To account for the effect of frequency variations, it is considered conservative to use the lower bound frequency if it is on the higher frequency side of the peak response spectrum. If the lower bound frequency is on the lower frequency side of the peak, the peak acceleration shall be used unless a more detailed analysis is performed.
7.1.4 Accelerations For a wall spanning between two floors, the effective accelerations shall be the average of the accelerations as given by the floor response spectra corresponding to the wall's natural frequency.
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ATTACHMENT 1 Spacification.7597-C-
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7.2 Structural Strength of Masonry Walls a
7.2.1 Boundary Conditions Boundary conditions shall be determined considering one-way or two-way spans with hinged, fixed or free edges as appro-priate. Conservative assumptions may be used to simplify the analysis as long as due consideration is given to frequency variations.
7.2.2 Distribution of Concentrated Out-of-Plane Loads
- Two-Way Action Where two-way bending is present in the wall, the localized moments per unit width under a concentrated load can be determined using appropriate analytical procedures for plates. Standard solutions and tabular values based on elastic theory contained in textbooks or other published documents can be used if applicable for the case under investigation (considering load location and boundary conditions).
A conservative estimate of the localized moment per unit length for plates supported on all edges can be taken as:
g = 0.4P where: g = localized moaent per unit length (in.-lbs./in.)
concentrated load perpendicular to wall P
=
(1bs.)
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For loads close to an unsupported edge, the upper limit moment per unit length can be taken as:
Q -= -1.2P
ATTACHMENT 1 Sp cific-tien 7597-C-7.2.3 Interstory Drift Effects Interstory drift effects shall be derived from the original dynamic analysis.
7.2.4 In-Plane and Out-of-Plane Effects The combined effects of in-place (e.g., seismic) and out-of-plane (e.g., piping) loads shall be considered.
7.2.5 Stress calculations All stress calculations shall be performed by conventional methods prescribed by the Working Stress Design method.
The collar joint shear stress shall be determined by the relationship VQ/IB for uncracksd sections in the compression zone of cracked sections. The relationship V/bjd shall be used for collar joints in cracked sections between the neutral axis and the tension steel.
7.2.6 Analytical Techniques In general, classical design tedhniques shall be used in the evaluation. Simplified conservative analytical assump-tions may be used. However, more refined methods utilizing computer analyses or dynamic analyses may be used on a case-by-case basis.
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