Effect of Creep on the Residual Stresses in Tube-to-Tubesheet Joints

2010 ◽  
Author(s):  
Nor Eddine Laghzale ◽  
Abdel-Hakim Bouzid
Keyword(s):  
Contact Pressure ◽  
Analytical Model ◽  
Nuclear Power ◽  
Structural Integrity ◽  
Environmental Safety ◽  
Maintenance Cost ◽  
Joint Interface ◽  
Plant Safety ◽  
Material Creep ◽  
Nuclear Power Plant Safety

Steam generators are the subject of major concern in nuclear power plant safety. Within these generators, in addition to the structural integrity, the gross tightness barrier, which separates the primary and secondary circuits, is primarily ensured by the presence of a residual contact pressure at the tube-to-tubesheet joint interface. Any leakage is unacceptable, and its consequences are very heavy in terms of the human and environmental safety as well as maintenance cost. Some studies have been conducted to understand the main reasons for such a failure. However, no analytical model able to predict the attenuation of the residual contact pressure under the effect of material creep relaxation behavior. The development of a simple analytical model able to predict the change of the residual contact pressure as a function of time is laid out in this paper. The results from the analytical model are checked and compared with those of finite elements.

Effect of Creep on the Residual Stresses in Tube-to-Tubesheet Joints

2010 ◽  
Vol 132 (6) ◽  
Author(s):  
Nor Eddine Laghzale ◽  
Abdel-Hakim Bouzid
Keyword(s):  
Contact Pressure ◽  
Analytical Model ◽  
Nuclear Power ◽  
Environmental Safety ◽  
Maintenance Cost ◽  
Joint Interface ◽  
Plant Safety ◽  
Material Creep ◽  
Nuclear Power Plant Safety ◽  
The Subject

Steam generators are the subject of major concern in nuclear power plant safety. Within these generators, the tightness barrier, which separates the primary and secondary circuits, is ensured by the existence of a residual contact pressure at the tube-to-tubesheet joint interface. Any leakage is unacceptable, and its consequences are very heavy in terms of the human and environmental safety as well as maintenance cost. Some studies have been conducted to understand the main reasons for such failure. However, no analytical model able to predict the attenuation of the residual contact pressure under the effect of material creep relaxation behavior. The development of a simple analytical model able to predict the change in the residual contact pressure as a function of time is laid out in this paper. The results from the analytical model are checked and compared with those of finite elements. A simulation conducted on a high temperature tube-to-tubesheet joint has shown that relaxation of the contact stress due to creep can be significant and should be considered in the design.

An Advanced Method for Evaluating Risk From Seismically-Induced Internal Fires and Floods

2017 ◽  
Author(s):  
Paul J. Amico ◽  
Pierre Macheret ◽  
Robert P. Kassawara
Keyword(s):  
Nuclear Power ◽  
Tohoku Earthquake ◽  
Lessons Learned ◽  
Advanced Method ◽  
Plant Safety ◽  
Nuclear Plants ◽  
Significant Interest ◽  
Realistic Representation ◽  
Nuclear Power Plant Safety ◽  
Technical Guidance

It has been traditional in assessment of nuclear power plant safety that both deterministic safety analyses and probabilistic safety analyses treat the potential effects of various hazards individually. That is, the safety implications of internal events (e.g., randomly occurring transients and LOCAs), internal hazards (e.g., internal fire and flood), and external hazards (e.g., earthquakes, tornados) are treated as independent occurrences. With the occurrence of the Great Tohoku earthquake and the effects observed at nuclear plants in Japan, it was realized that this approach failed to provide a realistic representation of risk, and now there is a significant interest in correlated hazards. As a result, EPRI embarked on the development of an improved methodology focusing on seismically-induced internal fires and internal floods. All the technical work on the methodology has been completed and draft technical guidance developed. This guidance has been provided to some plants that are interested in piloting the methodology. As of the date of paper submittal, two pilots are underway and three more are under consideration. Upon completion of the pilots, the methodology will be updated to incorporate the lessons-learned and published.

Use of Nuclear Energy and Sustainable Development

2014 ◽  
Vol 1070-1072 ◽  
pp. 353-356
Author(s):  
Fang Chen ◽  
Qiang Yao
Keyword(s):  
Sustainable Development ◽  
Nuclear Power ◽  
Nuclear Energy ◽  
Energy Use ◽  
Clean Energy ◽  
Human Society ◽  
Plant Safety ◽  
The Status ◽  
Nuclear Power Plant Safety ◽  
Safety Operation

Nuclear energy as a clean energy, with the gradual depletion of traditional energy, is particularly important. In this paper, the status of the application of nuclear technology was reviewed. And problems during the use of nuclear energy were addressed, including environmental issue generated by radioactive mineral extraction, radwaste disposal, nuclear power plant safety operation. Although, there are still some problems in the process of nuclear energy use, undeniably nuclear energy is still the hope for the future of human society. Therefore, the technical and management improvement can achieve sustainable development of nuclear energy, in order to ensure the safety of human energy use and sustainability.

An Evaluation of Nuclear Power Plant Safety Parameter Display Systems

1981 ◽  
Vol 25 (1) ◽  
pp. 110-114 ◽  
Author(s):  
David D. Woods ◽  
John A. Wise ◽  
Lewis F. Hanes
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Evaluation Tool ◽  
Training Simulator ◽  
Plant Safety ◽  
Power Plant Control ◽  
Safety Parameter ◽  
Nuclear Power Plant Safety ◽  
Display Systems

Two proposed safety parameter display systems, of the type to be required in nuclear power plant control rooms, were evaluated using a training simulator and experienced crews undergoing refresher training. A decision analysis approach was used. The discussion addresses the effectiveness of the training situation as an evaluation tool and methodological issues.

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