A High Reliability Straight Tube LMFBR Steam Generator Design

1980 ◽  
Vol 102 (3) ◽  
pp. 568-572 ◽  
Author(s):  
A. H. Spring ◽  
D. D. DeFur
Keyword(s):  
Thermal Expansion ◽  
Steam Generator ◽  
High Reliability ◽  
Straight Tube ◽  
Steam Generators ◽  
Geometric Size ◽  
Differential Thermal Expansion ◽  
Generator Design ◽  
Double Wall ◽  
Reliability And Availability

Straight-tube counterflow steam generators for LMFBR applications have been proposed, tested, fabricated and operated with varying degrees of success. A new embodiment of the straight-tube concept is described which incorporates a number of unique features which contribute to high reliability and availability. These features include a replaceable bellows for accommodation of differential thermal expansion between shell and tubes and a redundant, crevice-free tube-to-tubesheet joint design. The design can also easily incorporate single-wall or double-wall tubes. Single and double-wall tube versions are described whose thermal and geometric size are based on anticipated manufacturing limitations. The results of scoping tests of the tube-to-tubesheet welds are described which provide positive indications of the soundness of the weld design.

scholarly journals Russian and foreign steam generators for NPP power units with wet steam turbines

2020 ◽  
Vol 178 ◽  
pp. 01007
Author(s):  
Mikle Egorov ◽  
Ivan Kasatkin ◽  
Ivan Kovalenko ◽  
Irina Krectunova ◽  
Nataliya Lavrovskaya ◽  
...  
Keyword(s):  
Steam Generator ◽  
Nuclear Power ◽  
Temperature Drop ◽  
Heating Surface ◽  
Vessel Diameter ◽  
Absorption Efficiency ◽  
Steam Turbines ◽  
Steam Generators ◽  
Horizontal Type ◽  
Generator Design

The main aim of the current study is to analyze advantages and shortcomings of horizontal and vertical types of steam generator design. Design solutions and experience of operation of steam generators of horizontal type accepted in Russia and of vertical type applied by Westinghouse, Combustion Engineering, Siemens, Mitsubishi, Doosan were analyzed within the framework of the present study. It was established that steam generator equipment of horizontal type is characterized by disadvantages of design, technological and operational nature. Thus, horizontal steam generators with dimensions permissible for railroad transportation and, for VVER-1200 with reactor vessel diameter equal to 5 m, by water transport as well, have exhausted the possibilities for further significant increase of the per unit electric power. The demonstrated advantages of vertical-type steam generators are as follows: 1) absence of stagnant zones within the second cooling circuit; 2) uniformity of heat absorption efficiency of the heating surface that ensures improved conditions for moisture separation; 3) increased temperature drop with parameters of generated steam elevated by 0.3 – 0.4 MPa. Conclusion was made on the advisability of introduction of steam generators with vertical-type layout in the Russian nuclear power generation.

Characteristics of Transition Boiling in Sodium-Heated Steam Generator Tubes

1979 ◽  
Vol 101 (2) ◽  
pp. 270-275 ◽  
Author(s):  
D. M. France ◽  
R. D. Carlson ◽  
T. Chiang ◽  
R. Priemer
Keyword(s):  
Thermal Stress ◽  
Steam Generator ◽  
Tube Wall ◽  
Water Pressure ◽  
Thermal Fluctuations ◽  
Straight Tube ◽  
Steam Generators ◽  
Steam Generator Tubes ◽  
Heated Length ◽  
Boiling Zone

Thermal fluctuations were measured in the tube wall in the transition boiling zone of a full-scale LMFBR sodium-heated steam generator tube. The tube had an inside diameter = 10 mm, wall thickness = 2.90 mm, heated length = 13.1 m, and material = 2 1/4 Cr-1 Mo steel. Water flowed vertically upwards inside the straight tube, and sodium flowed counter-currently in a surrounding annulus. Results of thermal, spectral, and thermal stress analyses are presented for a test within the normal operating range of LMFBR steam generators. Results of other tests are presented that show the effects and sensitivity of sodium temperature and water pressure on the severity of the thermal fluctuations.

Parametric Study of External Pressure on Steam Generator Tube Bends

2012 ◽  
Author(s):  
Mitch Hokazono ◽  
Clayton T. Smith
Keyword(s):  
Steam Generator ◽  
Parametric Study ◽  
External Pressure ◽  
Light Water Reactor ◽  
Material Strength ◽  
Steam Generators ◽  
Elliptical Cross ◽  
Light Water ◽  
Water Reactor ◽  
Steam Generator Tubes

Integral light-water reactor designs propose the use of steam generators located within the reactor vessel. Steam generator tubes in these designs must withstand external pressure loadings to prevent buckling, which is affected by material strength, fabrication techniques, chemical environment and tube geometry. Experience with fired tube boilers has shown that buckling in boiler tubes is greatly alleviated by controlling ovality in bends when the tubes are fabricated. Light water reactor steam generator pressures will not cause a buckling problem in steam generators with reasonable fabrication limits on tube ovality and wall thinning. Utilizing existing Code rules, there is a significant design margin, even for the maximum differential pressure case. With reasonable bend design and fabrication limits the helical steam generator thermodynamic advantages can be realized without a buckling concern. This paper describes a theoretical methodology for determining allowable external pressure for steam generator tubes subject to tube ovality based on ASME Section III Code Case N-759-2 rules. A parametric study of the results of this methodology applied to an elliptical cross section with varying wall thicknesses, tube diameters, and ovality values is also presented.

scholarly journals Gas Turbine Heat Recovery Steam Generators for Combined Cycles Natural or Forced Circulation Considerations

1988 ◽  
Author(s):  
Akber Pasha
Keyword(s):  
Gas Turbine ◽  
Steam Generator ◽  
Heat Recovery ◽  
Power Plants ◽  
Natural Circulation ◽  
Combined Cycle ◽  
Heat Recovery Steam Generator ◽  
Steam Generators ◽  
Forced Circulation ◽  
Gas Turbine Exhaust

In recent years the combined cycle has become a very attractive power plant arrangement because of its high cycle efficiency, short order-to-on-line time and flexibility in the sizing when compared to conventional steam power plants. However, optimization of the cycle and selection of combined cycle equipment has become more complex because the three major components, Gas Turbine, Heat Recovery Steam Generator and Steam Turbine, are often designed and built by different manufacturers. Heat Recovery Steam Generators are classified into two major categories — 1) Natural Circulation and 2) Forced Circulation. Both circulation designs have certain advantages, disadvantages and limitations. This paper analyzes various factors including; availability, start-up, gas turbine exhaust conditions, reliability, space requirements, etc., which are affected by the type of circulation and which in turn affect the design, price and performance of the Heat Recovery Steam Generator. Modern trends around the world are discussed and conclusions are drawn as to the best type of circulation for a Heat Recovery Steam Generator for combined cycle application.

scholarly journals Reliability, Availability, and Maintainability Usage in the Development of the 501F Combustion Turbine and Auxiliaries

1991 ◽  
Author(s):  
R. J. Engel ◽  
P. J. Tyler ◽  
L. R. Wood ◽  
D. T. Entenmann
Keyword(s):  
Life Cycle ◽  
Product Design ◽  
Conceptual Design ◽  
High Reliability ◽  
Full Range ◽  
Design Phase ◽  
Conceptual Design Phase ◽  
Critical Components ◽  
Tools And Techniques ◽  
Reliability And Availability

Westinghouse has been a strong supporter of Reliability, Availability, and Maintainability (RAM) principles during product design and development. This is exemplified by the actions taken during the design of the 501F engine to ensure that high reliability and availability was achieved. By building upon past designs, utilizing those features most beneficial, and improving other areas, a highly reliable product was developed. A full range of RAM tools and techniques were utilized to achieve this result, including reliability allocations, modelling, and effective redesign of critical components. These activities began during the conceptual design phase and will continue throughout the life cycle of these engines until they are decommissioned.

scholarly journals Fabry–Perot Cavity Sensing Probe with High Thermal Stability for an Acoustic Sensor by Structure Compensation

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3393 ◽  
Author(s):  
Jin Cheng ◽  
Yu Zhou ◽  
Xiaoping Zou
Keyword(s):  
Thermal Stability ◽  
Thermal Expansion ◽  
Cavity Length ◽  
High Reliability ◽  
Simple Approach ◽  
High Thermal Stability ◽  
Acoustic Sensor ◽  
Practical Applications ◽  
Fabry Perot ◽  
Expansion Model

Fiber Fabry–Perot cavity sensing probes with high thermal stability for dynamic signal detection which are based on a new method of structure compensation by a proposed thermal expansion model, are presented here. The model reveals that the change of static cavity length with temperature only depends on the thermal expansion coefficient of the materials and the structure parameters. So, fiber Fabry–Perot cavity sensing probes with inherent temperature insensitivity can be obtained by structure compensation. To verify the method, detailed experiments were carried out. The experimental results reveal that the static cavity length of the fiber Fabry–Perot cavity sensing probe with structure compensation hardly changes in the temperature range of −20 to 60 °C and that the method is highly reproducible. Such a method provides a simple approach that allows the as-fabricated fiber Fabry–Perot cavity acoustic sensor to be used for practical applications, exhibiting the great advantages of its simple architecture and high reliability.

Crack Growth Prediction and Leakage Potential of Steam Generator Tubes Subjected to Flow Induced Vibrations

2014 ◽  
Author(s):  
Salim El Bouzidi ◽  
Marwan Hassan ◽  
Jovica Riznic
Keyword(s):  
Crack Growth ◽  
Steam Generator ◽  
Power Plants ◽  
Mechanical Energy ◽  
Steam Generators ◽  
Two Phase ◽  
Element Analysis ◽  
Wide Range ◽  
Flow Induced Vibrations ◽  
Crack Growth Model

Nuclear steam generators are critical components of nuclear power plants. Flow-Induced Vibrations (FIV) are a major threat to the operation of nuclear steam generators. The two main manifestations of FIV in heat exchangers are turbulence and fluidelastic instability, which would add mechanical energy to the system resulting in great levels of vibrations. The consequences on the operation of steam generators are premature wear of the tubes, as well as development of cracks that may leak radioactive heavy water. This paper investigates the effect of tube support clearance on crack propagation. A crack growth model is used to simulate the growth of Surface Flaws and Through-Wall Cracks of various initial sizes due to a wide range of support clearances. Leakage rates are predicted using a two-phase flow leakage model. Non-linear finite element analysis is used to simulate a full U-bend subjected to fluidelastic and turbulence forces. Monte Carlo Simulations are then used to conduct a probabilistic assessment of steam generator life due to crack development.

Thermally Induced Synchronous Instability of a Radial Inflow Overhung Turbine: Part I

1997 ◽  
Author(s):  
H. B. Faulkner ◽  
W. F. Strong ◽  
R. G. Kirk
Keyword(s):  
Thermal Expansion ◽  
Operating Speed ◽  
Lateral Motion ◽  
Turbine Wheel ◽  
Thermally Induced ◽  
Lateral Dynamics ◽  
Morton Effect ◽  
Speed Range ◽  
Differential Thermal Expansion ◽  
Rotor Dynamic

Abstract This paper is in two parts, and concerns the lateral dynamics of a large turbocharger rotor with overhung wheels. Initial rotor dynamic analysis indicated no excessive motion in the operating speed range. However, testing showed excessive motion, which was initially traced to the radial-inflow turbine wheel becoming loose on the shaft, due to transient differential thermal expansion in the wheel on startup. The attachment of the wheel was modified to eliminate this problem. The discussion up to this point is in Part I of the paper, and the remainder is in Part II. The wheel attachment modification extended the range of satisfactory operation upward considerably, but excessive lateral motion was again encountered near the upper end of the operating speed range. This behavior was traced to thermal bowing of the shaft at the turbine end, known as the Morton Effect. The turbine end bearing was modified to eliminate this problem, and satisfactory operation was then achieved throughout the operating speed range.

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