Regulatory Guide 1.142

Safety-Related Concrete Structures for Nuclear Power Plants (Other than Reactor Vessels and Containments)

ML13064A115
Person / Time
Issue date:	04/30/1978
From:	Office of Nuclear Regulatory Research
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RG-1.142
Download: ML13064A115 (3)

U.S. NUCLEAR REGULATORY COMMISSIONApril 1!978REGU "LATORnkYk GUIDEOFFICE OF STANDARDS DEVELOPMENTREGULATORY GUIDE 1.142SAFETY-RELATED CONCRETE STRUCTURES FOR NUCLEAR POWER PLANTS(OTHER THAN REACTOR VESSELS AND CONTAINMENTS)

A. INTRODUCTION

ACI Standard 349-76 delineates requirements forthe sizing of concrete structural systems and ele-General Design Criteria 1, "Quality Standards and ments, requirements for construction ,etails, andRecords," 2, "Design Bases for Protection Against specifications and tests for materials, regulatoryNatural Phenomenal" and 4, "Environmental and positions below relate only to Cha through 19Missile Design Bases," of Appendix A, "General of that standard. Committee 3 of th mericanDesign Criteria for Nuclear Power Plants," to 10 Concrete Institute has in p at man itory ap-CFR Part 50, "Licensing of Production and Utiliza- pendices to ACI Standar 3 g thermal ef-tion Facilities," require, in part, that structures, sys- fects, steel embedme , and eci provisions fortems, and components important to safety be de- impulsive and impact cts. gulatory positionssigned, fabricated, erected, and tested to quality on these appen s eveloped after theirstandards commensurate with the importance of the adoption by the ca ncrete Institute.safety functions to be performed and that they be de-signed to withstand the effects of postulated accidents L TORY POSITIONand environmental conditions as well as those effects T ce s and requirements described in ACIassociated with normal operating conditions. This 9-76, "Code Requirements for Nuclearguide describes a method acceptable to the NRC staff d ed Concrete Structures," are generally*Concree Structuf n res,"e aregeeruallyfor complying with the Commission's regulation a p e to the NRC staff and provide an adequatewith regard to safety-related concrete structu a for complying with the Commission's regula-(other than reactor vessels and containments) for -ions with regard to the design of safety-related con-clear power plants. crete structures other than reactor vessels and con-

B. DISCUSSION

tainments, subject to the following:ACI Standard 349-76,1 "Code Require for 1. The applicability of strength design methods toNuclear Safety Related StrucSJes," was prepared by structures whose principal function is to provide aCommittee 349 of the Concrete Institute barrier to contain or retain pressure such as the di-(ACI) and was publish ACI in October vider barrier of the ice-condenser of the PWR con-1976. The standar .s n I Standard 318- tainment or the drywell of the Mark III BWR con-711 (ANSI A89.197 '" Iding Code -Require- tainment is questionable. Therefore, for those struc-ments for Re o d Co ete," with modifications tures, mere conformance with the requirements* ofto accom at t ings and performance -re- ACI 349-76. is unacceptable to the staff, who willquirements iar to nuclear power plants. ACI continue to review the design of these structures on aStandard 318 long been the basis for the design of case-by-case basis.concrete buildi s in the United States and has beenused by the NRC staff as a starting point in evaluat- 2. When concrete structures are used to provideing the adequacy of concrete structures. radiation shielding, the provisions of Sections 5.1and 10 of ANSI Standard N101.6-1972 2 "ConcreteCopies may be obtained from the American Concrete Institute, 2 Copies may be obtained from the American Nuclear Society,P.O. Box 4754, Redford Station, Detroit, Michigan 48219. 555 North Kensington Avenue, La Grange Park, Illinois 60525.USNRC REGULATORY GUIDES Comments should be sent to the Secretary of the Commisson, US. Nuclear Rtgu-Regulatory Guides are isued to deIrribe and make available to the public methods latory Commission, Washington, D.C. 20555. Attention: Docketing and Serviceacceptable to the NRC staff of imnplementing specific parts of the Commission's Branch.regulations, to delineate techniques used by the staff in evaluating pecific problems The guides are issued in the following ten broad divisions:or postulated aecidents, or to Provide guidance to applicants. Regulatory Guidesare not iubesitutes for regulations, and compliance with them is not required. 1. Power Reactors 6. ProductsNMrthods and solutions different from those sat out in the guides will be accept- 2. Research arid Test Reactors 7. Transportationasle if they provide a basis for the findings requisite to the issuance or continuance 3. Fuels and Materials Facilities 8. Occupational Healthof a permit or Ic by the Commission. 4. Environmental and Siting 9. Antitrust Review5. Materials and Plant Protection 10. GeneralComments and su.ggetions for improvements in these guides ae encouraged at alltimes, and guides will be revised, as appropriate, to accommodate comments and Requests for single copies of issued guides 1which may be reproduced) or for place.to reflect new information or experience. However, comments on this guide,if ment on an automatic distribution list for single copies of fulture guides in specificreceived within about two months after its iseuance, will be particularly useful in divisions should be made in writing to the US. Nuclear Regulatory Commission.evaluating the need for an early revision. Washington. D.C. 20555. Attention: Directo,. Division of Document Contro Radiation Shields," and those of ANSI StandardN101.4-1972,3 as by Regulatory Guide1.54, "Quality Assurance Requirements for Protec-tive Coatings Applied to Water-Cooled NuclearPower Plants," are applicable.3. ACI Standard 349-76 lacks specific require-ments to ensure ductility of framed structures.Adherence to the requirements of Appendix A to ACIStandard 318-71 is acceptabie.4. Section 5.1.2 permits depositing concrete with-out the prior removal of water from the place of de-posit at the discretioni of the owner. Since the pres-ence of water in the place of deposit may seriouslyaffect the strength properties of concrete, it is impor-tant that water be removed before concrete is depos-ited unless a trernie is used.5. Section 5.4.1 allows concrete that has partiallyhardened or has been contaminated with .foreign ma-terials or remixed after initial set to be reused at thediscretion of the engineer. Such a material would bedefective and therefore should not be used.6. in addition to the requirements of Section 1.3.1of ACI Standard 349-76, the inspectors should havesufficient experience in reinforced and prestressedconcrete practice to interpret plans and specifica-tions. The inspectors should be thoroughly familiarwith the applicable ACI and ASTM standards. ACIStandard 311-74,1 "Recommended Practice for Con-crete Inspection," should be followed except wherethe requirements of Section 1.5 of ACI Standard349-76 control.7. The frequency of cylinder testing required bySection 4.3.1 of ACI Standard 349-76 is not consist-ent with generally accepted practice. A test frequencyinconformance with ANSI Standard N45.2.5-1974,4as endorsed by Regulatory Guide 1.94, '"'Quality As-surance Requirements for Installation, Inspection.and Testing of Structural Concrete and StructuralSteel During the Construction Phase of NuclearPower Plants," is acceptable.8. The minimum pressure-testing requirements forembedded piping of ACI Standard 318-71 .have beendeleted from ACI Standard 349-76. In order to en-sure that minimum pressure-testing requirements are3 ANSI N101.4-1972, "Quality Assurance for Proteztive Coat-ings Applied to Nuclear Facilities. " Copies may be obtained fromthe American Society of Mechanical Engineers, 345 East 47thStreet, New York, N.Y. 10017.4 ANSI N45.2.5-1974, "Supplementary Quality Assurance Re-quirements for Installation, Inspection, and Testing of StructuralConcrete and Structural Steel During the Construction Phase ofNuclear Power Plants." Copies may be obtained from the Ameri-can Society of Mechanical Engineers. 345 East 47th Street, NewYork, N.Y.. 10017.met, the pressure tests of embedded pipes in Section6.3.2.4 of ACI 349-76 should also satisfy the re-quirements of Section 6.3.2.4 of ACI 318-71.9. More- conservative load factors are appropriatein accounting for the effects of normal or shutdownthermal loads, postulated pipe break accidents, andan operating basis earthquake (OBE) in combinationwith a postulated pipe break. The load factors used inSection 9.3.1 of ACI Standard 349-76 are acceptable-to the staff except for the following:a. In load combinations (9), (10), and (11), 1.7T. should be used in place of 1.4 T,.b. In load combination (6), 1.5 Pa should beused in place of 1.25 Pa.c. In load combination (7), 1.25 P5 and 1.25 E0should be tised in place of 1.15 Pa and 1.15E0, respectively.d. In load combinations (2) and (10), 1.9 E,,should be used in place of 1.7 E,.10. Structures must be able to withstand the effectsof differential settlement under environmental loadsas well as under abnormal loads. Thus, in Section9.3.2 of ACI 349-76, consideration of the effects ofdifferential settlement should be included in loadcombinations (I) (11).11. The provisions of Section 9.3.3 of ACI Stand-ard 349-76 to account for the effects of transitoryloads are not sufficiently general. Thus, in Section9.3.3 of ACI Standard 349-76, when any load re-duces the effects of other loads, the correspondingcoefficient for that load should be taken as 0.9 if itcan be demonstrated that the load is always present oroccurs simultaneously with the other- loads. Other-wise, the coefficient for that load should be taken aszero.12. The provision in Section 9.3.6 of ACI Stand-ard.,349-76 permitting local exceedance of sectionstrength under concentrated dynamic loads does notensure that the section can withstand the associateddistributed loadings. Thus, if the provision of Section9.3.6 of ACI 349-76 permitting exceedance of localsection strengths is invoked, it should be demon-strated that secion strengths are adequate to accom-modate load combinations (7) and (8) without thedynamic loads Yj, Yn', and Yr.13. The NRC staff would accept the local excee-dance of section strength for concentrated tornado-generated-missile loading under load combination(5). However, an analysis should be performed to.demonstrate that section strengths are adequate to ac-commodate load combination (5) without thedynamic load effect of tornado-generated missiles.1.142-2 14. ACI Standard 349-76 does not address the sub-ject of openings in slabs and footings. -Provisions ofSection 11. 12 of ACI 318-71 are acceptable for thispurpose.

D. IMPLEMENTATION

The purpose of this section is to provide informa-tion to applicants regarding the NRC staff's plans forusing this regulatory guide.Except in those cases in which the applicant pro-poses an acceptable alternative method for complyingwith specified portions of the Commission's regula.-tions, the method described herein will be used in theevaluation of submittals in connection with construc-tion permit applications docketed after December 15,1978, unless this guide is revised as a result ofsuggestions from the public or additional staff re.-view.If an applicant wishes to use this regulatory guidein developing submittals for applications docketed onor before December 15, 1978, the pertinent portionsof the application will be evaluated on the basis ofthis guide.1.142-3/ ,5;/~ A~