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ASME NTB-2-2019 pdf download

ASME NTB-2-2019 pdf download.Background Information for Addressing Adequacy or Optimization of ASME BPVC Section III, Division 5 Rules for Metallic Components.
Some of the critical features of elevated temperature material behavior and how they differ from material response below the creep regime are discussed in Section 17.4.4.3.2, Elevated Temperature Material Behavior. These critical features apply to both load-controlled and displacement-controlled loading. How the limits on loading and material response at elevated temperature were separated into load-controlled and displacement-controlled quantities is discussed in Section 17.4.4.3.4, Stress and Strain Categories and Controlled Quantities. The load-controlled quantities are covered in HBB-3000 and the displacement- controlled quantities in HBB Appendix T.
Also shown is the flow diagram for elevated temperature analysis, Figure HBB-3221-1, that replaces the hopper diagrams used to illustrate the sequential application of the design rules below the creep regime. The various regimes of creep behavior are described.Representations of creep data are also illustrated, including the effect of hold times at constant strain on cyclic life. This is a broad-brush treatment that sets the stage for further detailed discussions. HBB-3214.2 Inelastic Analysis Inelastic analysis may be required to satisfy strain limits and creep-fatigue damage evaluation; however, only general guidance is presented in HBB-3214.2, however, specific guidance was provided for early liquid metal fast breeder reactor (“LMFBR”) programs. Section 17.4.4.3.9.4, Inelastic Analysis Methods, provides an overview of that guidance. More details on the early guidance are provided in Welding Research Council, Inc. (“WRC”) Bulletin 365, Volume III- Inelastic Analysis, July 1991, as discussed in Section 3.3 of this background document. HBB-3220 Design Rules for Load Controlled Stresses in Structures Other than Bolts HBB-3221 General Requirements Allowable stress criteria for Design Limits are discussed in Section 17.4.4.3.5.1 and criteria for Service Limits in Section 17.4.4.3.5.2. As discussed above, how the limits on loading and material response at elevated temperature are classified into load-controlled and displacement-controlled quantities is discussed in Section 17.4.4.3.4, Stress and Strain Categories and Controlled Quantities. Also shown in Section 17.4.4.3.4 is the flow diagram for elevated-temperature analysis, Figure HBB-3221-1, that replaces the hopper diagrams used to illustrate the sequential application of the design rules below the creep regime. Weld metal rupture strength factors are discussed as well in Section 17.4.4.3.5.2. HBB-3222.1 Design Limits Section 17.4.4.3.5.1 describes the limits for Design Loadings, which are analogous to the allowable stress values in BPVC Section I and BPVC Section VIII, Division 1.The limits for the primary membrane portion of the combined membrane and bending loading in HBB-3223, HBB-3224, and HBB-3225 are described in Section 17.4.4.3.5.3. The limits for the primary bending portion of the combined membrane and bending loading in HBB-3223, HBB-3224, and HBB-3225 are described in Section 17.4.4.3.5.4. This also includes the rationale for the bending stress load factors that address the reduced load carrying capacity in bending with creep as compared to the ideal elastic-plastic distribution applicable below the creep regime. Section 17.4.4.3.5.5 discusses the use fraction approach to account for a component not operating at a single temperature and/or primary load level throughout its operating history. The applicable code paragraph for use-fraction is HBB-3224(b). HBB-3227.8 Cladding Although cladding is not addressed in Chapter 17 of the Companion Guide, it is included here as an item of interest for proposed molten salt reactors. The current rules provide limited requirements on primary stress limits (i.e., no credit for cladding strength) and similarly limited requirements for deformation- controlled limits (i.e., cladding shall be considered for deformation-controlled limits) but no specific requirements are defined. No additional cladding requirements are provided in Division 5 for fabrication, inspection, or testing. There is a recent technical paper by Messner et al, The Mechanical Interaction of Clad and Base Metal for Molten Salt Reactors, PVP2018-84101 [4], that addresses design issues with the goal of improved code provisions for cladding. HBB-3230 Stress Limits for Load Controlled Stress on Bolts Section 17.4.4.3.9.2 provides the background for the primary stress Design Limits for bolts in HBB-3232, Service Level A and B limits in HBB-3233, Service Level C in HBB-3234, and Service Level D in HBB-3235. Also discussed are the rules for deformation-controlled stress and the special provisions in HBB-T-1721 and HBB-T-1722 for creep-fatigue damage evaluation.

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