R5 Procedure Based Damage Estimation in a Steam Turbine Valve Under In-Service Conditions

The fatigue behavior in steam turbine valve is generally considered to be associated with thermal transients during start and stop phase. However, the recent analysis has shown that steam parameter fluctuations under in-service steady state operation could induce significant increase in the damage. In this paper, the effect of in-service steam parameter fluctuations on stress-strain behavior in the valve was analyzed based on FE analysis under in-service data. The rain-flow cycle counting method was applied to get effective stress-strain cycle numbers and cycle amplitudes to classify the types of fatigue cycle based on in-service data. The creep-fatigue damage during steady state operation of the valve was estimated by using R5 (Volume 2/3) high temperature assessment procedure together with the FE results. Frequent steam pressure fluctuations at steady state operation were identified as the most influential factor for the fatigue life of the steam turbine valve.

THE EFFECTS OF MANIPULATING THE SYSTEM OPERATING PARAMETERS ON THE FUEL CONSUMPTION IN CO-GENERATION PLANT MODEL

Co-generation can be classified as a clean technology in producing electricity now days, however it still produces carbon dioxides and carbon monoxides which directly related with the fuel consumption. Therefore, it is important to study the effect of changing the High Pressure Steam parameter in order to fully utilize fuel supplied while maintaining the power production of the plant. This research is based on data gathered from the actual Co-Generation Plant in Malaysia. The data gathered was used to develop the base case using HYSIS simulation and all the analysis is done using the result from the simulations. From the analysis it was found by manipulating the temperature of the High Pressure Steam will give appositive linear relation with a significant effect on the fuel consumption and power generated. However, by manipulating the pressure of the High Pressure Steam will not give a significant effect on the fuel consumption and power generated. As a conclusion, based on this study it can be said that by manipulating the High Pressure Steam temperature it will give a significant effect on the fuel consumption and power generated.

Investigation on Modeling Thermal-Hydraulic System of CPR1000 NPP Based on RELAP5

Based on the best-estimate program RELAP5/MOD4.0, a full-scope thermal-hydraulic model with reference to CPR1000 nuclear power plant is established in this paper, which includes the thermal-hydraulic systems of conventional island as well as the primary nuclear island which has already been researched in traditional safety analysis. Therefore, this paper mainly details the numerical model of the turbine and other parts of the conventional island thermodynamic system. A comparison between the calculated results in steady-state and the actual data of reactor demonstrates a fine consistency, thus verifying the accuracy and reliability of the model. In addition, the steam parameter changes are numerically simulated during the steam turbine’s off-design operating condition such as back pressure variation and the variation trends are the same as the actual situation of nuclear power plants.

Research on the Water Wall Material Selections of USC Boiler With 700°C Steam Parameter

This paper discusses the materials properties of candidate water wall materials for USC boiler with 700°C steam parameter, and analyzes the serviceability of water wall panels made of different tubes, such as T12, 12Cr1MoVG, T23, T24, T91, T92, T122(HCM12A), VM12, 617 and 617 mod. In addition, some suggestions and optimization measures on the material selection have been proposed. Paper published with permission.

A Method and Analysis for Improving Thermal Efficiency of Nuclear Power Plant

In order to improve thermal efficiency of nuclear power plant with a pressurized water reactor, this paper analyzed the reason why nuclear power plant runs with a low thermal efficiency, and then pointed out that the conventional operation mode results in a low thermal efficiency for middle and high load regions. A new method was proposed to improve its thermal efficiency by operating nuclear power plant under the condition with a high and constant steam parameter. Two problems encountered by the proposed method were investigated, and the results indicate that it is preferential way to increase flow rate of primary side coolant to boost steam parameter of the rated condition, and it is feasible to maintain steam parameter constant by regulating flow rate of primary side coolant continuously.

The PFBC-CC Generation Power System Used Natural Gas Supplementary Combustion

Based on the first generation PFBC-CC, the natural gas was supplied as a fuel to increase gas turbine inlet temperature, so as to increase net efficiency of power generation. In this paper the analyses of technical, thermal and economic performance for system were carried out under different parameters, including reasonable dust remover inlet temperature, alkali metal concentration in gas before it entering gas turbine and cooling condition in gas turbine combustor. The thermal performance and power-production cost were also studied within the range of reasonable parameters. The results show that the flue gas temperature ≤ 973K at the inlet of hot filter can satisfy the conventional industry-use gas turbine requirement on the alkali metal content and dust content in flue gas. The net efficiency of this system can reach 43.3∼44.6% with sub-critical steam parameter condition and 45∼46.1% with supercritical steam parameter condition. With the increasing of steam parameters, the net efficiency of this system can be increased more. And the consumption of natural gas needs to be controlled in a reasonable level for obtaining the system preferable net efficiency and economics.