Status of Design Code Work in Germany Concerning Materials and Structural Aspects for the Heat Exchanger Components of Advanced HTR’s

1983 ◽  
Vol 105 (4) ◽  
pp. 713-718 ◽  
Author(s):  
F. Schubert ◽  
H. J. Seehafer ◽  
E. Bodmann
Keyword(s):  
Critical Discussion ◽  
Time Dependent ◽  
Status Report ◽  
Design Codes ◽  
Design Code ◽  
Design Data ◽  
Creep Buckling ◽  
Asme Code ◽  
Design Analyses ◽  
Structural Aspects

A brief status report on the work concerning design codes for HTR components with service temperatures above 800°C is given. The evaluation of experimental test work and preliminary time-dependent design data are reviewed and some design analyses for an IHX concerning fatigue, creep buckling, and creep ratcheting are described as a basis for critical discussion of some features of ASME Code Case N 47.

A Single Technically Consistent Design Formula for the Thickness of Cylindrical Sections Under Internal Pressure

2006 ◽  
Vol 129 (1) ◽  
pp. 211-215 ◽  
Author(s):  
John D. Fishburn
Keyword(s):  
Experimental Data ◽  
Internal Pressure ◽  
State Of The Art ◽  
Original Data ◽  
Pressure Vessels ◽  
Time Dependent ◽  
Design Codes ◽  
Recent Developments ◽  
Current Design ◽  
Single Formula

Within the current design codes for boilers, piping, and pressure vessels, there are many different equations for the thickness of a cylindrical section under internal pressure. A reassessment of these various formulations, using the original data, is described together with more recent developments in the state of the art. A single formula, which can be demonstrated to retain the same design margin in both the time-dependent and time-independent regimes, is shown to give the best correlation with the experimental data and is proposed for consideration for inclusion in the design codes.

Dose- and Time-Dependent Effects of Ethanol on Functional and Structural Aspects of the Liver Sinusoid in the Mouse

1997 ◽  
Vol 21 (6) ◽  
pp. 1128-1136 ◽  
Author(s):  
G. Sarphie ◽  
N. B. D'Souza ◽  
D. H. Thiel ◽  
D. Hill ◽  
C. J. McClain ◽  
...  
Keyword(s):  
Time Dependent ◽  
Liver Sinusoid ◽  
Structural Aspects

A Life-Cycle Risk-Informed Systems Structured Nuclear Code

2002 ◽  
Author(s):  
Ralph S. Hill
Keyword(s):  
Life Cycle ◽  
American Concrete Institute ◽  
Design Code ◽  
Replacement Decisions ◽  
Plant Operations ◽  
Operations And Maintenance ◽  
Asme Code ◽  
American Society ◽  
Construction Operation ◽  
Design Construction

Current American Society of Mechanical Engineers (ASME) nuclear codes and standards rely primarily on deterministic and mechanistic approaches to design. The design code is a separate volume from the code for inservice inspections and both are separate from the standards for operations and maintenance. The ASME code for inservice inspections and code for nuclear plant operations and maintenance have adopted risk-informed methodologies for inservice inspection, preventive maintenance, and repair and replacement decisions. The American Institute of Steel Construction and the American Concrete Institute have incorporated risk-informed probabilistic methodologies into their design codes. It is proposed that the ASME nuclear code should undergo a planned evolution that integrates the various nuclear codes and standards and adopts a risk-informed approach across a facility life-cycle — encompassing design, construction, operation, maintenance and closure.

A Historical Overview of Design Analyses and Experimental Observations of Ratcheting Phenomenon

2020 ◽  
Author(s):  
Jean Macedo ◽  
Stéphane Chapuliot ◽  
Jean-Michel Bergheau ◽  
Eric Feulvarch ◽  
Olivier Ancelet ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
State Of The Art ◽  
Constitutive Models ◽  
Experimental Tests ◽  
Design Codes ◽  
Historical Overview ◽  
Design Rules ◽  
Current Article ◽  
The Difference ◽  
Design Analyses

Abstract In order to investigate the ratcheting behavior and to determine new design rules, some experimental tests were conducted in many countries in the last decades. In France, some tests were carried out under mechanical or thermal cyclic loading to examine this risk. The first section of the current article is addressed to the state of the art concerning the ratcheting effects. The difference between Local and Global Ratcheting is clarified. The second section is dedicated to the experimental observations of ratcheting. The following section describes the constitutive models which are able to simulate material/structural ratcheting responses. The models presented are Linear Kinematic, Armstrong-Frederick, Chaboche, Ohno-Wang and Chen-Jiao-Kim. Finally, the ratcheting rules in design codes are exposed. Both simple and complex rules are presented.

Ratchet Boundary for Superimposed Biaxial Membrane Stress States

2018 ◽  
Author(s):  
Wolf Reinhardt
Keyword(s):  
Thermal Expansion ◽  
Thermal Stress ◽  
Analytical Solution ◽  
Pressure Vessels ◽  
Stress Fields ◽  
Design Codes ◽  
Bending Stress ◽  
Membrane Stress ◽  
Asme Code ◽  
Stress States

Thermal membrane and bending stress fields exist where the thermal expansion of pressure vessel components is constrained. When such stress fields interact with pressure stresses in a shell, ratcheting can occur below the ratchet boundary indicated by the Bree diagram that is implemented in the design Codes. The interaction of primary and thermal membrane stress fields with arbitrary biaxiality is not implemented presently in the thermal stress ratchet rules of the ASME Code, and is examined in this paper. An analytical solution for the ratchet boundary is derived based on a non-cyclic method that uses a generalized static shakedown theorem. The solutions for specific applications in pressure vessels are discussed, and a comparison with the interaction diagrams for specific cases that can be found in the literature is performed.

Design Limits for Buckling in the Creep Range

2010 ◽  
Author(s):  
Maan Jawad ◽  
Donald Griffin
Keyword(s):  
Cylindrical Shells ◽  
Time Dependent ◽  
Design Approach ◽  
Stress Strain ◽  
Buckling Stress ◽  
Creep Buckling ◽  
Practical Design ◽  
Slender Columns

A methodology is introduced for calculating the allowable buckling stress in equipment operating in the time-dependent (creep) range. Norton’s equation coupled with various procedures such as the stationary stress method, classical creep buckling equations, and the isochronous stress-strain diagrams are utilized to obtain a practical design approach for equipment operating in the time-dependent range. Various components are investigated such as slender columns, cylindrical shells, spherical components, and conical transition sections.

Design Limits for Buckling in the Creep Range

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Maan Jawad ◽  
Donald Griffin
Keyword(s):  
Cylindrical Shells ◽  
Time Dependent ◽  
Design Approach ◽  
Stress Strain ◽  
Buckling Stress ◽  
Creep Buckling ◽  
Practical Design ◽  
Slender Columns

A methodology is introduced for calculating the allowable buckling stress in equipment operating in the time-dependent (creep) range. Norton's equation coupled with various procedures such as the stationary stress method, classical creep buckling equations, and the isochronous stress–strain diagrams are utilized to obtain a practical design approach for equipment operating in the time-dependent range. Various components are investigated such as slender columns, cylindrical shells, spherical components, and conical transition sections.

Applications of Code Case 2605 for Fatigue Evaluation of Vessels Made in 2.25Cr-1Mo-0.25V Steels Slightly Into Creep Range

2010 ◽  
Author(s):  
Susumu Terada
Keyword(s):  
Fatigue Curve ◽  
Time Dependent ◽  
Inelastic Analysis ◽  
Asme Code ◽  
Section Viii ◽  
Preliminary Study ◽  
Number Of Cycles ◽  
Fatigue Evaluation ◽  
Division 2 ◽  
Made In

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 when the design allowable stress is taken in the time dependent temperature range. Method B of paragraph 5.5.2.4 also cannot be used because it requires the use of the fatigue curve which is limited to 371 ° C and below the needed temperature. Code Case 2605 is a rule for fatigue evaluation of 2.25Cr-1Mo-0.25V steels at temperatures greater than 371 ° C and less than 454 ° C. An inelastic analysis including the effect of creep shall be performed for all pressure parts according to Code Case 2605. Especially, a full inelastic analysis shall be performed using the actual time-dependent thermal and mechanical loading histograms for the lateral nozzle based on preliminary study. It takes much time to perform this inelastic analysis for all full histograms and obtain the fatigue evaluation results when large number of cycles of full pressure is specified in user’s design specification. This paper provides sample analysis results for nozzles and clarifies issue of implementation of Code Case 2605. Then, the proposal of simplification and modification of Code Case 2605 from these results are proposed.

Evaluation Technique With MCNP for Temperature Dependent Problems

2010 ◽  
Author(s):  
Hiroyuki Fujime ◽  
Shinji Abe ◽  
Kazuya Yamaji ◽  
Daisuke Sato ◽  
Hideki Matsumoto
Keyword(s):  
Monte Carlo ◽  
Cross Sections ◽  
Monte Carlo Calculation ◽  
Design Codes ◽  
Design Code ◽  
Temperature Dependent ◽  
Validation And Verification ◽  
The World ◽  
Profile Changes ◽  
Complex Temperature

Monte Carlo calculation has come to be used as reference solutions instead of experiments in nuclear design code validation and verification (V&V), although comparisons with measurements are still indispensable for V&V in nuclear design. MCNP [1] is one of the most famous Monte Carlo codes widely used in the world. Many reference results are given for the analyses of critical experiments. When using the use MCNP calculations for validations of commercial design codes, we will face to a problem of lacking temperature dependent cross-sections. The cross-sections can be generated by the NJOY code [2]. However, if the model has complex temperature distribution, many NJOY calculations are necessary. Besides, if the temperature profile changes with fuel power and so on, many NJOY calculations have to be performed again and again. These back and forth procedures make us give up using MCNP for commercial LWR calculations. In order to solve this problem, we propose an easy approximation to solve the temperature problems using MCNP. Note that our technique does not require any code modifications.

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