ML20056F308

Forwards Proposed Ssar Markup Adopting NRC Position on App B to ACI349

ML20056F308
Person / Time
Site:	05200001
Issue date:	08/19/1993
From:	Fox J GENERAL ELECTRIC CO.
To:	Cheng T NRC
References
NUDOCS 9308260352
Download: ML20056F308 (7)

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23A6100 Rev. t Standard Safety Analysis Repon

. ABWR The support frame spacing is determined by allowable tray spans, which are governed by rigidity and sts ess. The frames may be ceiling-supported, or wall-supported, or a combination of both. Various types of frames form a support system with transverse and longitudinal bracing to the nearest wall or ceiling to take the seismic loads.

3.8.42 Applicable Codes, Standards, and Specifications 3.8.4.2.1 Reactor Building The major portion of the Reactor Building is not subjected to the abnormal and severe accident condmons associated with a contamment. A hsting of applicable documents follows: cas m4hed ay TaQ3, g-ro)

(1) ACl 349, Code Requirementifor Nuclear SafetyRelated Concrete J Stmc N

(2) ANS1/AlSG N690, Spenfication for, Design, Fabrication and Erection of Steel Safety. .

Rtlated Structuresfor Nuclear Faalitus (as modified by Table 5.8-9).

(3) AShfE Botler and Pressure vessel Code Section III. Subsection NE, Division 1 Class MC (for design of main steasn tunnel embedment piping anchorage in the R/B and C/B only).

(4) A HS Structural M*ciding Code, AWS D1.1 (5) AWS Structural Weldsng Code, AW5 D12.1.

(6) NRC publications TID 7024 (NuclearRecrtors andEanhquakes) and TID 25021 (Summar of Current Seismic Design Practicefor Nudear ReactorFaahties).

(7) The inservice inspection requirements for the fuel poolliners in the Reactor Building are in conformance with ASAfE Code Section Ill. DMsion 2.

(8) NRC Regulatorv Guides:

(a) Regulutory Guidc 1.10 - Mechanucci(Cadweld) Spizces in Reinforang Bars of Categon I Concrete Structures (b) Regulatorv Guide 1.15 - Testmg of Reinforcing Barsfor Category l Concrric S: uc:ure.:

ic) Regulatorv Guide 1.28 - Quahty Assurance Program Rcqui,ements (Desiga and Construcuon)

(d) Regulatorv Guide 1.29 - Sarmit Desrgn Classification (e) Regulatory Guide 1.31 - Control of 5tainless Steel Welding l I

(D Regulatory Guide 144 - Control of the Use of Sensiti:.ed Stuinicss Sted I

i 3 ft.34 Sersmk Categow1 Structures- Amendment 31 l

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23A6100 Rev. r ABWR standard safery Anatrsis neport Table 3,8-4 Codes, Standards, Specifications, and Hegulations Used in the Design and Construction of Soismic Category i Internal Structures of the Containment Specification Specification Reference or Standard Number Designation Title 2 ACI 307 Recommended Practice for Concrete Formwork 3 ACI 305 Recommended Practice for Hot Weather Concreting 4 ACI 211.1 Recommended Practice for Selecting Proportions for Normal Weight Concrete 5 ACI 315 Manual of Standard Practice for Detailing Reinforced

- Normal Weight Concrete .

6 ACI 306 Recommended Practice for Cold Weather Concreting 7 ACI 309 Recomme; ded Practice for Consolidation of Concrete .

8 ACl 308 Recommended rNetice for Curing Concrete 9 ACI 212 Guide for use of Admi.Mures in Concrete 10 ACI 214 Recommended Practice for C.'aluation of Compression Test results of Field Concrete 11 ACI 311 Recommended Practice for Concrete inspection 12 Act 304 Recommended Practice for Measuring, Mixing, Transporting, and Placing Concrete 13 ACI 349 Code Requirements for Nuclear Safety-Related 4~~~

- - Concrete Structures L CLS VicdifM by TOLE C 3.8-10) 14 ACI 359 ASME Boiler and Pressure Vessel Code, Section 111, Division 2, Concrete Reactor Vessets and Containments 15 AN$1/AISCNC90 Specification for the Design. Fabrication, and Erection of Steel Safety-Related Structures for Nuclear Fatihties (as modified by Table 3.8-9) 16 AWS D1.1 Structural Welding Code 17 NClG-02 Visual Wald Acceptance Criteria for Structural Welding at Nuclear Power Plants 18 ANSI /ASME Ouality Assurance Program Requirements for Nuclear N QA-1-1986 Facilities 19 (Deleted) 20 NRC Regulatory Quahty Assurance Requirements for installation, Guide 1.94 inspection, and Testing of Structural Concrete and Structura! Steel During the Construction Phase of Nuclear Power Plants 3.6 52 Seismic Co:egory I Structures - Amrnoment 31 l

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A M4N"W NW St%hjernew(ec( by W f$c Prov-cw e C) Section B.4.2 - Tension and Figs. B.4.1 and B.4.2 This section and the figures specify that the tensile strength of concrete for any anchorage can be calculated by a 45 degree failure cone theory. The staff has disseminated the German test data questioning the validity of the 45 degree failure cone theory to licensees, A/Es, bolt manufacturers, and the code committee members in its meetings with them.

• The data indicated that the actual failure cone was about 35 degree and the use of the 45 degree cone theory could be unconservative for anchorage design, especially for anchorage of groups of bolts. The Code '

Committee, having gone through some research of its own, recently agreed with the staff's position. Changes to this section are in the making by the Code Committee. In the meantime, the staff position on issues related to this Section is to ensure adoption of design approaches I

(,2) 8.5.1.1 - Tension This section states a criterion for ductile anchors. The criterion is i that the design pullout strength (force) of the concrete as determined in Section B.4.2 exceeds the minimum specified tensile strength (force) i of the steel anchor. Any anchor that meets this criterion is qualified as a ductile anctor and, thus, a low safety factor can be used. The staff believes that the criterion is deficient in two areas. One is

- that the design pullout strength of the concrete so calculated is usually higher than the actual strength, which has been stated in Section B.4.2 above. The other is that anchor steel characteristics are not taken into consideration. For example, the Drillco Maxi-Bolt Devices, Ltd. claims that its anchors are ductile anchors and, thus, can use a low safety factor. The strength of the Maxi-Bolt is based on the yield strength of the anchor steel, which is 105 ksi. The embedment length of the anchor, which is used to determine the pullout strength of the concrete, is based on the minimum specified tensile strength of the anchor steel of 125 ksi. The staff believes that the 19% margin (125/105) for the embedment length calculation is insufficient considering the variability of parameters affecting the concrete cone strength. The staff also questions the energy absorption capability (deformation capability after yield) of such a high strength anchor steel. Therefore, in addition to the position taken with regard to Section B.4.2 above, the staff will review vendor or manufacturer specific anchor bolt behaviors to determine the acceptable design margins between anchor bolt strengths and their corresponding pullout strengths based on concrete cones.

4E 19 '93 10:2241 G E t M LEAP BLDG .T P.5 5

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B.5.1.1(a) - Lateral bursting concrete strength This section states that the lateral bursting concrete strength is determined by the 45 degree concrete failure cone assumption. Since this assumption is wrong and likely to be replaced as stated before, the staff believes that the lateral bursting concrete strength determination ,

is also wrong and needs to be replaced. The staff will review the  :

lateral bursting concrete strength provided by the concrete cover around  ;

anchor bolts and lateral bursting force created by the pulling of anchor bolts against test data to determine if adequate reinforcement against lateral bursting force needs to be provided on a case by case basis. l (3) B.5.1.2.1 - Anchor, Studs, or Bars This section states that the concrete resistance for shear can be ,

determined by a 45 degree half-cone to the concrete free surface from I the centerline of the anchor at the shearing surface. Since the 45  ;

degree concrete failure cone for tension has been found to be incorrec' the staff believes that the use of the 45 degree half-cene for shear '

should be re'-examined, In the meantime, the staff will review the  :

adequacy of shear espacity calculation of concrete cones on a case by #

case basis with emphasis on methodology verification through vendor specific test data.

(4) B.5.1.2.2(c) - Shear Lugs

• This section states that the concrete resistance for each shear lug in  !

the direction of a free edge shall be determined based on the 45 degree  !

half-cone assumption to the concrete free surface from the bearing edge of the shear lug. This is the same assumption as used in Section  ;

8.5.J.2.1 and the staff has the same comment as stated in that section.

Therefore, the staff position related to the design of shear lugs is to perform case-by-case reviews. The staff review will emphasize rethodology verification through' specific test data.

(5) B.7.2 - Alternative design requirements for expansion anchors This section states that the design strength of expansion anchors shall '

be 0.33 times the average tension and shear test failure loads, which provides a safety factor of 3 against anchor failure. The staff position on safety factor for design against anchor failure is 4 for wedge anchors and 5 for shell anchors unless a lower safety factor can be supported by vendor specific test data.

(6) Anchors in tension :ene of supporting concrete When anchors are located within a tensile zone of suoporting concrete, the anchor capacity reduction due to concrete cracking shall be accounted for in the anchor design.

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