1、ACI 349.3R-02 supersedes ACI 349.3R-96 and became effective June 17, 2002.Copyright 2002, American Concrete Institute.All rights reserved including rights of reproduction and use in any form or by anymeans, including the making of copies by any photo process, or by electronic ormechanical device, pr
2、inted, written, or oral, or recording for sound or visual reproduc-tion or for use in any knowledge or retrieval system or device, unless permission inwriting is obtained from the copyright proprietors.1ACI Committee Reports, Guides, Manuals, and Commentariesare intended for guidance in planning, de
3、signing, executing,and inspecting construction. This document is intended for theuse of individuals who are competent to evaluate thesignificance and limitations of its content and recommendationsand who will accept responsibility for the application of thematerial it contains. The American Concrete
4、 Institute disclaimsany and all responsibility for the stated principles. The Instituteshall not be liable for any loss or damage arising therefrom.Reference to this document shall not be made in contractdocuments. If items found in this document are desired by theArchitect/Engineer to be a part of
5、the contract documents, theyshall be restated in mandatory language for incorporation bythe Architect/Engineer.Evaluation of Existing Nuclear Safety-Related Concrete StructuresReported by ACI Committee 349ACI 349.3R-02(Reapproved 2010)This report recommends guidelines for the evaluation of existing
6、nuclearsafety-related concrete structures. The purpose of this report is to providethe plant owner and engineering staff with an appropriate procedure andbackground for examining the performance of facility structures and takingappropriate actions based on observed conditions. Methods of examination
7、,including visual inspection and testing techniques, and their recommendedapplications are cited. Guidance related to acceptance criteria for variousforms of degradation is provided.Keywords: corrosion; cracking; degradation; inspection; load test; nuclearpower plant; reinforced concrete; reinforcem
8、ent; reinforcing steels; safety;serviceability; structural design; test.CONTENTSChapter 1Introduction, p. 2Chapter 2General methodology, p. 2Chapter 3Evaluation procedure, p. 33.1Scope3.2Selective evaluation3.3Periodic evaluation3.4Evaluation procedure development3.5Evaluation techniquesChapter 4Deg
9、radation mechanisms, p. 74.1General4.2Concrete degradation4.3Steel reinforcement and structural steel degradation4.4Prestressing steel degradationChapter 5Evaluation criteria, p. 135.1Acceptance without further evaluation5.2Acceptance after review5.3Conditions requiring further evaluationChapter 6Ev
10、aluation frequency, p. 16Chapter 7Qualifications of evaluation team,p. 16Chapter 8Repair, p. 17Chapter 9References, p. 189.1Referenced standards and reports9.2Cited referencesRonald J. Janowiak*ChairHans G. Ashar*Gunnar A. Harstead Richard E. Klingner Barendra K. TalukdarRanjit L. Bandyopadhyay Chri
11、stopher Heinz Daniel J. Naus Donald T. WardRonald A. Cook Charles J. Hookham*Dragos A. Nuta Albert Y. C. WongBranko Galunic Jagadish R. Joshi Richard S. Orr Charles A. Zalesiak*Herman L. Graves, III*Members of subcommittee authoring this report.2 EVALUATION OF EXISTING NUCLEAR SAFETY-RELATED CONCRET
12、E STRUCTURES (ACI 349.3R-02)American Concrete Institute Copyrighted Materialwww.concrete.orgCHAPTER 1INTRODUCTIONThis report supplements the ACI 349 code by recommendingan evaluation procedure for nuclear safety-related concretestructures. Before initiating this report, the scope of ACICommittee 349
13、 was self-limited to the design and inspectionof newly constructed concrete nuclear structures. As thenuclear facilities in the United States grow older and becomesusceptible to the adverse effects of aging, periodic inspectionand proper evaluation have become important issues. RecentU.S. Nuclear Re
14、gulatory Commission programs such as 10CFR 50.65, Maintenance Rule,1and 10 CFR 54, TheLicense Renewal Rule,2require licensees to inspect andevaluate the condition of concrete nuclear structures thatmay have experienced age-related degradation. Effectivemaintenance, modification, and repair of any co
15、ncrete structurebegins with a comprehensive program of inspection andevaluation. For this report, evaluation is defined as anengineering review of an existing concrete nuclear structurewith the purpose of determining physical condition andfunctionality of the structure. This evaluation may include a
16、review of previously accomplished repairs or maintenance,and performing condition surveys, testing, maintenance, andstructural analysis. This report does not address the evaluationrequirements for concrete containment vessels (ACI 359,ASME Section III, Division 2, Boiler the term “nuclearsafety-rela
17、ted concrete structure” refers to a specific qualityclassification and is a subset of “concrete nuclear structures.”Nuclear safety-related concrete structures are designed toresist the loads associated with plant operating conditions,postulated accidents, and environmental conditions. Thesestructure
18、s provide protection for safety-related componentsfrom hazards internal and external to the structure, such aspostulated missile impacts, impulsive loads, flooding, fire,earthquakes, and other severe environmental conditions.Additionally, the design for some of these structures may becontrolled by t
19、he required thickness of concrete intended forshielding against radiation produced during the nuclearfission process. All nuclear safety-related structures share acommon function: they are integrally designed with thevarious systems and components they support and protect torestrict the spread of ra
20、diation and radioactive contaminationto the general public. An effective evaluation procedureshould provide the rational methodology to maintain theserviceability of nuclear safety-related structures. Each eval-uation should consider the original design basis for theaffected structure(s) in the disp
21、osition of findings andresults. This includes qualification of any damage or degra-dation found, or suitability of various repair options.Concrete nuclear structures, while unique in application,share many physical characteristics with other concretestructures. The four basic constituents of a concr
22、ete mixtureare the same for nuclear or non-nuclear concrete structures:cement, fine aggregate, coarse aggregate, and water.Admixtures that enhance the constructibility and durability ofconcrete are also permitted in nuclear structures, with certainlimitations as defined in ACI 349. Nuclear safety-re
23、latedstructures may be similarly reinforced with normal reinforcingsteel or prestressing steel, and may contain various structuralsteel embedments. Over time, operational and environmentalconditions and loads can result in degradation of theseconstituents and could affect the expected behavior of th
24、estructure. Whether the structure is considered nuclear safety-related or not, prudent engineering practices during material(concrete mixture) design and specification, structural design,and construction are necessary to minimize the potential fordegradation during service. Sound inspection programs
25、, inwhich the performance and condition of plant structures areperiodically evaluated and monitored, can be used to ensurethat the structures continue to serve their intended function.Because of the many similarities between nuclear and non-nuclear concrete structures, practices and procedures used
26、fortheir inspection and maintenance are also similar.The purpose and final scope of an evaluation procedure isdefined by the plant owner, utility, holding company,governmental agency, or other organization. Developmentand implementation of an evaluation procedure for nuclearsafety-related structures
27、 can serve many purposes:Provide documented evidence of continued performanceand function by periodic evaluation;Identify and mitigate age-related degradation at earlystages;Provide guidance for the development of an effectiveplant-maintenance program;Support the application for an extended operatin
28、g license;Provide baseline condition data for comparison followingan earthquake, a short-term environmental load, or aplant accident; andProvide configuration and material property informationfor structural reanalysis, physical modification, orsimilar activity.This report identifies a procedure for
29、the determination ofcritical structures, defines and characterizes the primarydegradation mechanisms, provides insight on inspectiontechniques and frequencies, and provides guidance on theevaluation of inspection results.CHAPTER 2GENERAL METHODOLOGYThis report focuses on industry-accepted evaluation
30、practices and recommends the application of those practicesto the unique situations typically encountered in nuclearsafety-related concrete structures. The objective is to develop aprogram of inspection and evaluation that recommends themost effective practices for inspection and evaluation ofsafety
31、-related concrete structures. Through proper inspectionand evaluation, the most likely locations for degradation andits causes within the plants safety-related structures can beidentified. A thorough survey of these critical locations willprovide data to describe the current physical condition of th
32、econcrete, evaluate past structural performance, and form abasis for comparison during future inspections. The responsibleengineer, the individual responsible for administering theevaluation procedure, can then review the information toevaluate the severity of the condition. The condition may beacce
33、ptable as is or may require further in-depth examinationEVALUATION OF EXISTING NUCLEAR SAFETY-RELATED CONCRETE STRUCTURES (ACI 349.3R-02) 3American Concrete Institute Copyrighted Materialwww.concrete.organd evaluation. The plant owner may opt to monitor thecondition over a period of time to obtain m
34、ore data. In moresevere cases, the observed condition can require repair,rehabilitation, or replacement of the affected structure. Ineach case, the evaluation and ultimate corrective actions arebased upon interpretation of both qualitative and quantitativeinformation regarding the structure in quest
35、ion.The recommendations in this report use many establishedACI reports developed for general concrete structures (seeChapter 9). By implementing established recommendationsin typical nuclear power plant (NPP) applications, an effectiveevaluation procedure can be developed for nuclear safety-related
36、concrete structures. Emphasis on the use of generalcondition survey (visual inspection) practices in the evaluation,supplemented by additional testing or analysis as required, isa recommended approach and common theme.CHAPTER 3EVALUATION PROCEDURE3.1ScopeEvaluation of existing nuclear safety-related
37、 concretestructures may be required as a result of identified degradationor abnormal performance, in support of physical modifications,or for periodical validation of structural integrity. Comprehen-sive evaluation of all safety-related plant structures at periodicintervals is also desirable to moni
38、tor operational effects andpossible degradation due to environmental conditions.Economics and scheduling concerns, however, can prohibitthis level of evaluation. This chapter describes the proceduralsteps that can be used to effectively monitor and maintain thesafety-related concrete structures via
39、prioritized evaluation.3An evaluation procedure document should be developedby the plant owner (Section 3.4). This document should becomprehensive and include provisions for addressing thevariety of potential uses such as those cited in Chapter 1. Thetwo procedural methods of evaluation that can be
40、performedare “selective” and “periodic” evaluations (Sections 3.2 and3.3, respectively). These two methods use similar evaluationtools, such as visual inspections, but are quite different interms of scope. The primary components of an evaluationprocedure and guidelines for preparing the evaluationpr
41、ocedure document are further discussed in Section 3.4.3.2Selective evaluationThe selective evaluation method is used when an evaluationof a specific structure or structural component is needed toprovide information such as structural condition data orother input for structural re-analysis or modific
42、ation design.When the selective evaluation method is used, the structurein question and the desired outcome of the evaluation, suchas in-place compressive strength and physical condition, aregenerally known and predefined. The appropriate evaluationtechniquessuch as visual inspection and testingused
43、 tosupport the selective evaluation may be selected from theevaluation procedure document. Selective evaluations aretypically performed once for a specific purpose, and aregenerally not repeated unless the initial evaluation indicatesa need to monitor certain degradation mechanisms or structuralperf
44、ormance over a defined period of operation.3.3Periodic evaluationThe periodic evaluation method can be used to demonstratesatisfactory performance of concrete safety-related structures,identify the presence and activity of age-related degradation,or for other reasons as noted in Chapter 1. It is dif
45、ferent fromselective evaluation in that specific structure and desiredoutcomes are generally not defined initially. Periodicevaluations are often repeated at a certain frequency using astandardized procedure. This form of evaluation shouldprovide an effective method for addressing the U.S. NuclearRe
46、gulatory Commission (NRC) mandated MaintenanceRule or for technical justification in a license renewalapplication for the plant. Periodic evaluation can be scheduledby prioritizing the structures in terms of safety significance,environmental exposure, and anticipated tolerance todegradation.3This se
47、ction discusses the basic criteria forprioritizing and selecting structures for periodic evaluation.The intent of this prioritization process is to inspect arepresentative sample of the areas most likely to havedegraded, and inspect those areas where degradation is crit-ical to the structural integr
48、ity of safety-related structures. Toverify that the selected sample areas are, in fact, representativeof worst-case conditions, complementary sample area inspec-tions should be made in areas where little or no degradationis expected. For example, structures primarily located belowgrade may not be re
49、adily accessible for evaluation, but maybe exposed to an aggressive environment. Measures can beimplemented that establish the condition of these structuresthrough determination of soil and groundwater chemistryand local inspection during opportune soil excavations, suchas during new equipment installation. While such efforts areindirect and not comprehensive, they can be used to characterizeenvironmental exposure conditions and their effects to assistin prioritizing further evaluation efforts.Three primary factors pertinent to each plant structure arecommon
