Assessment of Current High-Temperature Design Methodology Based on Structural Failure Tests

1987 ◽  
Vol 109 (2) ◽  
pp. 160-168 ◽  
Author(s):  
J. M. Corum ◽  
W. K. Sartory
Keyword(s):  
High Temperature ◽  
Design Methodology ◽  
Service Failure ◽  
Failure Criteria ◽  
The United States ◽  
Department Of Energy ◽  
Structural Failure ◽  
Inelastic Analysis ◽  
Inelastic Responses ◽  
Asme Code

A mature design methodology, consisting of inelastic analysis methods provided in U.S. Department of Energy guidelines and failure criteria contained in ASME Code Case N-47, exists in the United States for high-temperature reactor components. The objective of this paper is to assess the adequacy of that overall methodology by comparing predicted inelastic deformations and lifetimes with observed results from structural failure tests and from an actual service failure. Comparisons are presented for three structural cases: 1) nozzle-to-spherical shell specimens, emphasizing stresses at structural discontinuities; 2) welded structures, emphasizing metallurgical discontinuities; and 3) thermally loaded cylinders and pipes, emphasizing thermal discontinuities. The comparisons between predicted and measured inelastic responses are generally reasonable; quantities are sometimes overpredicted somewhat and sometimes underpredicted. However, even seemingly small discrepancies in predicted stresses and strains can have a significant effect on life, which is thus not always as closely predicted. For a few cases, the lifetimes are substantially overpredicted, which raises questions regarding the methodology and/or the adequacy of the current design margins.

Failure Mode Effects Analysis for Section III, Division 5 Class A, High Temperature Service of a Printed Circuit Heat Exchanger

2020 ◽  
Author(s):  
Ian Jentz ◽  
Suzanne McKillop ◽  
Robert Keating
Keyword(s):  
High Temperature ◽  
Failure Mode ◽  
Heat Exchangers ◽  
Failure Modes ◽  
Department Of Energy ◽  
Compact Heat Exchangers ◽  
Printed Circuit ◽  
Mode Effects ◽  
Class A ◽  
Asme Code

Abstract The mission of the U.S. Department of Energy (DOE), Office of Nuclear Energy is to advance nuclear power in order to meet the nation’s energy, environmental, and energy security needs. Advanced high temperature reactor systems will require compact heat exchangers (CHX) for the next generation of nuclear reactor plant designs. A necessary step for achieving this objective is to ensure that the ASME Boiler and Pressure Vessel Code, Section III, Division 5 has rules for the construction of CHXs for nuclear service. Given their high thermal efficiency and compactness, expanding the use of Alloy 800H diffusion bonded Printed Circuit Heat Exchangers (PCHEs) beyond their current application in Section VIII, Division 1 to the high temperature nuclear applications is of interest. The research being completed under the Department of Energy project is focused on preparing a draft Code Case for consideration by the ASME Code Committees for high temperature nuclear components which must meet the requirements of Section III, Division 5, Subsection HB (Class A), Subpart B. Acceptance of a Code Case by the ASME Code Committees to use PCHEs in nuclear service requires a broad understanding of PCHE failure mechanisms. At the highest level, the ASME Code requirements prevent failures of structures and pressure boundaries. Historically, the approach is a process of understanding the known failure modes, such as overload failures, plastic collapse, progressive distortion (ratcheting) and fatigue, and then establishing rules for construction to preclude those failure modes in components. For Division 5 applications, attention to differential thermal expansion, creep life, and creep-fatigue must also be considered. Failure from these loadings is manifest within PCHEs both within the internal micro-channel geometry, and at substantially larger solid header and nozzle attachments. To address the adequacy of the PCHE, a Failure Mode Effects Analysis (FMEA) has been performed for standard etched channel PCHEs. This FMEA is linked to the proposed rules in the code case for compact heat exchangers in Section III, Division 5 Class A applications. The PCHE FMEA covers all design failures addressed by Section III.

Proposed Code Case of Creep Fatigue Evaluation of 9Cr-1Mo-V Steels for High Pressure Vessels in ASME Section VIII Division 2

2015 ◽  
Author(s):  
Susumu Terada ◽  
Masato Yamada ◽  
Tomoaki Nakanishi
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Fatigue Curve ◽  
Pressure Vessels ◽  
Inelastic Analysis ◽  
Creep Fatigue ◽  
Asme Code ◽  
Section Viii ◽  
Fatigue Evaluation ◽  
Division 2

9Cr-1Mo-V steels (Gr. 91), which has an excellent performance at high temperature in mechanical properties and hydrogen resistance, has been used for tubing and piping materials in power industries and it can be a candidate material for high pressure vessels for high temperature processes in refining industries. The current Section VIII Division 2 of ASME code does not permit method A of paragraph 5.5.2.3 to be used for the exemption from fatigue analysis for Gr. 91 steels due to limitation of specified minimum tensile strength (585 MPa > 552 MPa). Method B of paragraph 5.5.2.4 also can’t be used because it requires the use of the fatigue curve which is limited to 371 °C lower than the needed temperature. Therefore new rules for fatigue evaluation of Gr. 91 steels at temperatures greater than 371 °C and less than 500 °C similar to CC 2605 for 2.25Cr-1Mo-0.25V(Gr. 22V) steels are necessary. This paper provides fatigue test results at 500 °C for Gr. 91 steels, the modification of CC 2605, sample inelastic analysis results for nozzles. Then, the new Code Case for Gr. 91 steels is proposed from these results.

The Introduction and Analysis of the World’s First High-Temperature Retrofit Project on a Subcritical Coal-Fired Power Unit

2021 ◽  
Author(s):  
Weizhong Feng ◽  
Li Li
Keyword(s):  
High Temperature ◽  
Power Plants ◽  
Energy Savings ◽  
High Efficiency ◽  
The United States ◽  
Department Of Energy ◽  
United States Department ◽  
Fossil Plants ◽  
Lower Efficiency ◽  
New Construction

Abstract Global warming concerns have pushed coal-fired power plants to develop innovative solutions which reduce CO2 emissions by increasing efficiency. While new ultra-supercritical units are built with extremely high efficiency, with Pingshan II approaching 50% LHV[1], subcritical units with much lower efficiency are a major source of installed capacity. The typical annual average net efficiency of subcritical units in China is about 37% LHV, and some are lower than 35% LHV. Since the total subcritical capacity in China is about 350GW and accounts for over one third of its total coal-fired power capacity, shutting all subcritical units down is not practical. Finding existing coal-fired plants a cost-effective solution which successfully combines advanced flexibility with high efficiency and low emissions, all while extending service lives, has challenged energy engineers worldwide. However, the (now proven) benefits a high temperature upgrade offers, compared to new construction options, made this an achievement worth pursuing. After many years of substantial incremental improvements to best-in-class technology, this first-of-its-kind subcritical high temperature retrofit successfully proves that a technically and economically feasible solution exists. It increases the main and reheat steam temperatures from 538°C (1000°F) to 600°C (1112°F), and the plant cycle and turbine internal efficiencies are greatly improved. This upgrade’s greatest efficiency gains occur at low loads, which is important as fossil plants respond to renewable energy’s increased grid contributions. These are combined with best-in-class flexibility, energy-savings, and technological advances, i.e., flue gas heat recovery technology and generalized regeneration technologies [4]. This project, the world’s first high-temperature subcritical coal-fired power plant retrofit, was initiated in April 2017 and finished in August 2019. Performance reports created by Siemens and GE record unit net efficiency at rated conditions improved from 38.6% to 43.5% LHV. The boiler’s lowest stable combustion load with operational SCR, without oil-firing support, was reduced from 55% to 19%. Substitution or upgrading of high-temperature components extended the lifetime of the unit by more than 30 years. At a third of the cost of new construction, this project set a high-water-mark for retrofitting subcritical units, and meets or supports the requisite attributes for Coal FIRST, Coal Plant of the Future, proposed by the United States Department of Energy (DOE) in 2019 [2].

Pathway to Evaluate Printed Circuit Heat Exchanger Based on Simplified Elastic-Perfectly Plastic Analysis Methodology for High Temperature Nuclear Service

2019 ◽  
Author(s):  
Urmi Devi ◽  
Machel Morrison ◽  
Tasnim Hassan
Keyword(s):  
High Temperature ◽  
Fatigue Damage ◽  
Analysis Method ◽  
Printed Circuit ◽  
Perfectly Plastic ◽  
Analysis Methodology ◽  
Inelastic Analysis ◽  
Creep Fatigue ◽  
Asme Code ◽  
Elastic Perfectly Plastic

Abstract Printed Circuit Heat Exchangers (PCHEs) are well-suited for Very High Temperature Reactors (VHTRs) due to high compactness and efficiency for heat transfer. The design of PCHE must be robust enough to withstand possible failure caused by cyclic loading during high temperature operation. The current rules in ASME Code Section III Division 5 to evaluate strain limits and creep-fatigue damage based on elastic analysis method have been deemed infeasible at temperatures above 650°C. Hence, these rules are inapplicable for temperatures ranging from 760–950°C for VHTRs. A full inelastic analysis method with complex constitutive material description as an alternative, on the other hand, is time consuming; hence impracticable. Therefore, the simplified Elastic-Perfectly Plastic (EPP) analysis methodology is used as a solution in ASME Code Section III Division 5. The current literature, however, lacks any study on the performance evaluation of PCHE through EPP analysis. To address these issues, this study initiates the pathway of EPP evaluation of an actual size PCHE starting with elastic orthotropic analysis in the global scale. Subsequently, preliminary planning for analyzing intermediate and local submodels are provided to determine channel level responses to evaluate PCHE performance against strain limits and creep-fatigue damage using Code Case-N861 and N862 respectively.

Assessment of Moderate- and High-Temperature Geothermal Resources of the United States

Fact Sheet ◽  
2008 ◽  
Author(s):  
Colin F. Williams ◽  
Marshall J. Reed ◽  
Robert H. Mariner ◽  
Jacob DeAngelo ◽  
S. Peter Galanis
Keyword(s):  
United States ◽  
High Temperature ◽  
The United States ◽  
Geothermal Resources

NCSS notable trade book lesson plan: the girl who buried her dreams in a can

2020 ◽  
Vol 15 (2) ◽  
pp. 121-126
Author(s):  
Takisha Durm
Keyword(s):  
United States ◽  
Research Design ◽  
Design Methodology ◽  
Lesson Plan ◽  
The United States ◽  
Elementary Grades ◽  
Effect Change ◽  
Content Type ◽  
Similarities And Differences ◽  
Future Date

PurposeThe Girl Who Buried Her Dreams in a Can, written by Dr Tererai, profiles a cultural, yet global experience of the power of believing in one's dream. Through this study of the similarities and differences of how children in the United States and abroad live and dream of a better life, this lesson seeks to enhance students' understandings of the power and authority they possess to effect change not only within their own lives but also in the lives of countless others in world. After reading the text, students will work to create vision boards illustrating their plans to effect change within their homes, schools, communities, states or countries. They will present their plans to their peers. To culminate the lesson, the students will bury their dreams in can and collectively decide on a future date to revisit the can to determine how far they have progressed in accomplishing their goals.Design/methodology/approachThis is an elementary grades 3–6 lesson plan. There was no research design/methodology/approach included.FindingsAs this is a lesson plan and no actual research was represented, there are no findings.Originality/valueThis is an original lesson plan completed by the first author Takisha Durm.

An Overview of the Direct Energy Conversion Proof of Principle Power Production Program

2004 ◽  
Author(s):  
D. King ◽  
G. Rochau ◽  
D. Oscar ◽  
C. Morrow ◽  
P. Tsvetkov ◽  
...  
Keyword(s):  
Energy Conversion ◽  
The United States ◽  
Department Of Energy ◽  
Future Research ◽  
United States Department ◽  
Commercial Development ◽  
Direct Energy Conversion ◽  
Project Description ◽  
Direct Energy ◽  
Proof Of Principle

The United States Department of Energy, Nuclear Energy Research Initiative (NERI) Direct Energy Conversion Proof of Principle (DECPOP) project has as its goal the development of a direct energy conversion process suitable for commercial development. We define direct energy conversion as any fission process that returns usable energy without an intermediate thermal process. A prior Direct Energy Conversion (DEC) project [1] has been completed and indicates that a viable direct energy device is possible if several technological issues can be overcome. The DECPOP program is focusing on two of the issues: charged particle steering and high voltage hold-off. This paper reports on the progress of the DECPOP project. Two prototype concepts are under development: a Fission Electric Cell using magnetic insulation and a Fission Fragment Magnetic Collimator using magnetic fields to direct fission fragments to collectors. Included in this paper are a short project description, an abbreviated summary of the work completed to date, a description of ongoing and future project activities, and a discussion of the potential for future research and development.

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