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Becht Engineering Blog

In this section of the site contributing authors submit interesting articles relating to the various services, industries and research & development efforts of Becht Engineering.

Elevated Temperature Reactor Component Design and Qualification

Elevated Temperature Reactor Component Design and Qualification
 Becht Engineering, Nuclear Services Division, has completed a finite-element numerical study of two proposed Code Cases for ASME III Division 1 Subsection NH, Class 1 Components in Elevated Temperature Service.  They are:“Satisfaction of Strain limits for Class 1 Components at Elevated Temperature Service Using Elastic-Perfectly Plastic Analysis” and “Calculation of Creep-Fatigue for Class 1 Components at Elevated Temperature Service Using Elastic-Perfectly Plastic Analysis.” Proposed Code CasesThese two proposed ASME III Code Cases provide methods and criteria for the prediction of the accumulated strain and creep-fatigue life evaluations for a nuclear component operating in the creep range, using elastic-perfectly plastic (EPP) models. Creep regime as considered in Subsection NH corresponds to components at temperatures above 700oF or 800oF depending on material.  EPP-Strain and EPP-Creep-Fatigue are the abbreviated terms used for these two Code Cases in the following discussion.  Subsection NH currently provides elastic, simplified elastic-plastic and inelastic methods for the evaluation of strain...
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Lift Director - Are You In Compliance With The Current Standards?

Lift Director - Are You In Compliance With The Current Standards?
 Are You In Compliance???In construction today, it seems like the rules and regulations are changing everyday. There is good reason for this. As an industry we are getting smarter about addressing safety in the work place.Recently, I searched the OSHA website looking for information regarding the requirements for a “Lift Director.” Upon entering the terms in the search window, I was immediately directed to a news release titled:"US Labor Department's OSHA cites two Wisconsin companies following worker's death on US Route 41 bridge construction site near Oshkosh."The  incident occurred on July 5 when a crane collapsed at a bridge construction site on U.S. Route 41.  A truck driver died when he was struck by the boom of a crane that overturned while bridge girders were being erected with a multiple crane lift.Penalties for “XYZ” Construction totaled $105,000 and penalties for “ABC” Construction totaled $13,220.  OSHA has placed “XYZ” Construction in its Severe...
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NonMetallic Composite Wrap Pipe Repair

NonMetallic Composite Wrap Pipe Repair
Nonmetallic composite wrap repairs are wraps comprising two constituents:A fabric woven from a fiber such as graphite or glassA thermoset polymer such as a two-component mix epoxy resin.This material is also referred to as fiber-reinforced polymer (FRP). These repairs can be liners wrapped inside, or jackets wrapped over a corroded pipe.There are three main considerations in a nonmetallic composite wrap repair project:Selecting and designing the wrap systemInstalling the wrap correctlyPeriodically inspecting the adequacy of the repairIn this article we will address these three main considerations for the repair of a corroded metallic host pipe, but similar considerations apply for the repair of a tank.1 - Selection and Design of the Wrap SystemDesign Code: These types or repair materials are not addressed in ASME III. Some guidance is provided in ASME B31.1 non-mandatory Appendix III “Rules for Nonmetallic Piping and Piping Lined with Nonmetals”. A useful reference, as a starting point for...
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Designing Elevated Temperature Equipment with Internal Pressure

If the behavior of discontinuity stresses due to pressure is not properly understood in elevated temperature design, unconservative designs can result. One particular issue with pressure stresses is the behavior of the discontinuity bending stresses.An example of discontinuity stresses would be with a pipe welded to a flange. When pressured, the pipe will radially displace (balloon) Pr2/Et (neglecting longitudinal stress effects) and the radial displacement of the flange will be very much less than the pipe (considering the massive flange ring). Since they are welded together, the radial displacements must be the same where they are joined, that is, the pipe must be pulled in by the flange to mate. Looking at it as two steps, the pipe expands due to internal pressure, and is pulled back by the constraint of the flange which prevents the expansion where they are joined. This results in through-wall, discontinuity bending stresses in the pipe.  Historically,...
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