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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.

Mentoring Nuclear Power Plant Engineers

Mentoring-Nuclear-Engineers
As the Nuclear Power Plant workforce continues to age, it is imperative that nuclear plant supervisors and managers use as many tools as possible to mentor younger engineers. This article discusses several ways proven to be successful in mentoring younger engineers as a means of filling the voids created by the retirements of senior workforce individuals. These tools are also be effective in retaining younger engineers. The Aging Workforce It is well known that one of the nuclear power industry’s challenges is addressing its aging workforce. In a 2015 Article [Ref. 1], Power Engineering Magazine cites the following statistics: “The Nuclear Energy Institute estimates that 39 percent of the nuclear workforce will be eligible for retirement by 2018, which means the industry must hire 20,000 new workers over the next four years to replace those retiring workers.” “About 40 percent of the work force at America's electric and natural gas utilities...
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The Meaning of the Class 1 Nuclear Piping Equations in NB-3650

piping_systems
Below we review the meaning of the six Class 1 piping stress equations in ASME III NB-3650, Class 1. The nomenclature is found in NB-3650. Two things must be kept in mind when applying these Class 1 piping equations: All the stresses are elastically calculated, i.e. the calculation model considers the material to be such that s = E e, even when the stress exceeds yield. All the stress terms are stress intensities, i.e. twice the maximum shear stress. Using the Tresca criterion for elastic behavior, the stress intensities can be compared directly to yield. EQUATION (9) B 1 (P D o )/(2 t) + B 2   D o /(2 I)  M i  ≤ k S m     Eq.(9) Equation (9) is a primary stress intensity amplitude equation. It is meant to prevent failure by structural instability of the joint or fitting (elbow, tee, reducer, etc.). For example, for...
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Evolution of Pipe Stress Equations in the ASME Nuclear Codes (and where we are today)

piping_systems
The Pre-1955 Era Until 1955, the ASME Boiler and Pressure Vessel Codes, and the ASME B31 Pressure Piping code provided rules of good design practice with quantitative criteria for pressure design.  For example, quoting from ASME VIII Rules for the Construction of Unfired Pressure Vessels Section VIII A. S. M. E. Boiler Construction Code, 1927: U-20. For Internal Pressure. The maximum allowable working pressure on the shell of a pressure vessel shall be determined by the strength of the weakest course, computed from the thickness of the plate, the efficiency of the longitudinal joint, the inside diameter of the course, and the maximum allowable unit working stress.  (S×t×E)/R = maximum allowable working pressure Where S = maximum allowable unit working stress in lb. per sq. in. = 11,000 lb. per sq. in. for steel plate stamped 55,000 lb. per sq. in., 10,000 lb. per sq. in. for steel plate stamped less...
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Evaluation of Corroded Pipe in Accordance with ASME B&PV Code Section XI - A Comparison of the Three Code Cases

Evaluation of Corroded Pipe in Accordance with ASME B&PV Code Section XI -
A Comparison of the Three Code Cases
The evaluation of wall thinning corrosion in steel pipes is addressed in three ASME XI code cases: N-513, N-597, and N-806. I have no ambition here other than to summarize in a table the differences between these three code cases. A brief commentary follows the table. The brief commentary... Line A – While these are Section XI Code Cases applicable to ASME III Class 2 and 3, technically, nothing would prevent from applying these Code Cases for B31.1 piping. Line B – There is no technical basis for limiting N-513 to moderate energy lines, i.e. pressure at or below 275 psi and (“or”, depending on the plant vintage) temperature at or below 200oF, other than the understandable reluctance to operate with hot water flashing to steam through a pinhole leak. Line D – It can be confusing that N-513 includes fracture mechanics consideration because it attempts to address cracks (so-called “planar...
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