Risk Assessment of Nuclear Steam Turbine Destructive Overspeed

2003 ◽  
Author(s):  
Rolf Orsagh ◽  
Theodore Meyer ◽  
Stephen Hesler
Keyword(s):  
Power Generation ◽  
Steam Turbine ◽  
Nuclear Power ◽  
High Energy ◽  
Protection System ◽  
System Failure ◽  
Steady State Operation ◽  
Plant Maintenance ◽  
Maintenance Personnel ◽  
The Impact

In electric power generation facilities, steam turbine disk rupture due to overspeed can produce high-energy projectiles that may penetrate the turbine casing and damage other plant systems. While such projectiles could seriously damage a fossil fired plant, the risks are even greater for nuclear plants where a projectile could strike safety related systems. Plant maintenance personnel routinely test overspeed protection systems according to the manufacturer’s recommended schedule, but such tests require interruptions in normal steady state operation, and sometimes lead to undesirable events such as reactor SCRAMs. This risk evaluation of steam turbine destructive overspeed for nuclear power generation units reexamines the probability of an overspeed protection system failure, with the goal of optimizing maintenance practices and providing a basis for overspeed trip system testing intervals. Industry reliability databases and plant maintenance records are utilized to develop component and system failure probabilities and models that account for the impact of condition monitoring and periodic testing on overspeed protection system availability.

Thermal Model of a Thin Film Pulsed Pyroelectric Generator

2016 ◽  
Author(s):  
Nicholas R. Jankowski ◽  
Andrew N. Smith ◽  
Brendan M. Hanrahan
Keyword(s):  
Thin Film ◽  
Power Generation ◽  
Energy Conversion ◽  
High Speed ◽  
High Energy ◽  
High Energy Density ◽  
Working Fluid ◽  
Film Material ◽  
Thermodynamic Cycles ◽  
The Impact

Recent high energy density thin film material development has led to an increased interest in pyroelectric energy conversion. Using state-of-the-art lead-zirconate-titanate piezoelectric films capable of withstanding high electric fields we previously demonstrated single cycle energy conversion densities of 4.28 J/cm3. While material improvement is ongoing, an equally challenging task involves developing the thermal and thermodynamic process though which we can harness this thermal-to-electric energy conversion capability. By coupling high speed thermal transients from pulsed heating with rapid charge and discharge cycles, there is potential for achieving high energy conversion efficiency. We briefly present thermodynamic equivalent models for pyroelectric power generation based on the traditional Brayton and Ericsson cycles, where temperature-pressure states in a working fluid are replaced by temperature-field states in a solid pyroelectric material. Net electrical work is then determined by integrating the path taken along the temperature dependent polarization curves for the material. From the thermodynamic cycles we identify the necessary cyclical thermal conditions to realize net power generation, including a figure of merit, rEC, or the electrocaloric ratio, to aid in guiding generator design. Additionally, lumped transient analytical heat transfer models of the pyroelectric system with pulsed thermal input have been developed to evaluate the impact of reservoir temperatures, cycle frequency, and heating power on cycle output. These models are used to compare the two thermodynamic cycles. This comparison shows that as with traditional thermal cycles the Ericsson cycle provides the potential for higher cycle work while the Brayton cycle can produce a higher output power at higher thermal efficiency. Additionally, limitations to implementation of a high-speed Ericsson cycle were identified, primarily tied to conflicts between the available temperature margin and the requirement for isothermal electrical charging and discharging.

scholarly journals Does Combined Heat and Power Play the Role of a Bridge in Energy Transition? Evidence from a Cross-Country Analysis

2019 ◽  
Vol 11 (4) ◽  
pp. 1035 ◽  
Author(s):  
Hyo-Jin Kim ◽  
Jeong-Joon Yu ◽  
Seung-Hoon Yoo
Keyword(s):  
Power Generation ◽  
Renewable Energy ◽  
Electricity Generation ◽  
Nuclear Power ◽  
Energy Transition ◽  
Parameter Estimate ◽  
Combined Heat And Power ◽  
Cross Country ◽  
The Impact

In an era of energy transition involving an increase in renewable energy and a reduction in coal-fired power generation and nuclear power generation, the role of combined heat and power (CHP) as a bridging energy is highly emphasized. This article attempts to look empirically into the impact of increasing the share of renewable energy in total electricity generation on CHP share in total electricity generation in a cross-country context. Data from 35 countries during the period 2009–2015 were used, and the least absolute deviations estimator was applied to obtain a more robust parameter estimate. The results showed that a 1%p increase in the share of renewable energy significantly increased the CHP share by 0.87%p. Therefore, the hypothesis that CHP serves as bridge energy in the process of energy transition was established.

Missile Safety Analysis of Nuclear Steam Turbine

2012 ◽  
Author(s):  
Rong Chen ◽  
Feng Liang ◽  
Wen Xiang Hua ◽  
Pu Ning Jiang ◽  
Xiao Zhong He
Keyword(s):  
Steam Turbine ◽  
Nuclear Power ◽  
Turbine Unit ◽  
Safety Analysis ◽  
Low Pressure ◽  
Turbine Rotor ◽  
High Energy ◽  
Fracture Mechanisms ◽  
Low Pressure Turbine ◽  
Plant Safety

This paper introduced the basic turbine missile safety analysis process for the Shanghai Turbine Plant’s nuclear power station. The turbine-generator unit is not considered as part of a nuclear power plant’s safety related equipment, but there is still the possibility that a high-energy missile created by failure of the low-pressure turbine disks could penetrate the stationary barriers of the turbine (especially the last stage of the low-pressure turbine), and damage plant safety-related equipment. The failure mechanisms of the turbine failure that could hypothetically generate missiles were described. Rotor damage due to stress corrosion cracking with brittle fracture and ductile fracture and destructive over-speed protection control system failure were discussed as the main elements to evaluate the safety of the turbine unit. Rotor stress analysis using FEA was used to evaluate the strength of the turbine rotor. Key factors that influence fracture mechanisms were discussed. Crack initiation and growth to the critical size was estimated. The strike probability of the turbine missile was accessed to assure the safety of the nuclear safety related equipment from a steam turbine unit generated missile.

Developing Predictive Maintenance Expertise to Improve Plant Equipment Reliability

2002 ◽  
Author(s):  
Richard N. Wurzbach
Keyword(s):  
Power Generation ◽  
Data Management ◽  
Value Added ◽  
Predictive Maintenance ◽  
Quality Data ◽  
Nuclear Facilities ◽  
Management Tools ◽  
Nuclear Operators ◽  
Maintenance Personnel ◽  
The Impact

On-line equipment condition monitoring is a critical component of the world-class production and safety histories of many successful nuclear plant operators. From addressing availability and operability concerns of nuclear safety-related equipment to increasing profitability through support system reliability and reduced maintenance costs, Predictive Maintenance programs have increasingly become a vital contribution to the maintenance and operation decisions of nuclear facilities. In recent years, significant advancements have been made in the quality and portability of many of the instruments being used, and software improvements have been made as well. However, the single most influential component of the success of these programs is the impact of a trained and experienced team of personnel putting this technology to work. Changes in the nature of the power generation industry brought on by competition, mergers, and acquisitions, has taken the historically stable personnel environment of power generation and created a very dynamic situation. As a result, many facilities have seen a significant turnover in personnel in key positions, including predictive maintenance personnel. It has become the challenge for many nuclear operators to maintain the consistent contribution of quality data and information from predictive maintenance that has become important in the overall equipment decision process. These challenges can be met through the implementation of quality training to predictive maintenance personnel and regular updating and re-certification of key technology holders. The use of data management tools and services aid in the sharing of information across sites within an operating company, and with experts who can contribute value-added data management and analysis. The overall effectiveness of predictive maintenance programs can be improved through the incorporation of newly developed comprehensive technology training courses. These courses address the use of key technologies such as vibration analysis, infrared thermography, and oil analysis not as singular entities, but as a toolbox resource from which to address overall equipment and plant reliability in a structured program and decision environment.

scholarly journals An economic analysis on Taiwanese wind power and regional development

2020 ◽  
Vol 38 (4) ◽  
pp. 1228-1247
Author(s):  
Li-Jiun Chen ◽  
Liguo Zhang ◽  
Chih-Chun Kung
Keyword(s):  
Power Generation ◽  
Wind Power ◽  
Alternative Energy ◽  
Nuclear Power ◽  
Wind Farm ◽  
Renewable Energy Sources ◽  
Policy Implications ◽  
Maintenance Cost ◽  
Energy Structure ◽  
The Impact

Due to environmental concern, Taiwan aims to remove nuclear power from its energy structure. Since an increase in fossil fuel-based generation is foreboded by law, the lost nuclear power can only be replaced by renewable energy sources. The maritime climate and constant monsoons make wind power a feasible alternative energy source to Taiwan. With more than 300 potential wind farm sites under consideration, the government does not have enough information to determine the best sites in terms of power generation and capital investments. To explore such information, this study employs a lifecycle analysis to identify the economic components of these sites under the estimates of wind speed data and potential wind power generation obtained in our previous study. We also use a sensitivity analysis to examine the impact of construction cost, maintenance cost, energy sale, and emission trade on the site selection decision. We show that variations in construction costs and energy prices have larger impacts than greenhouse gases prices. In addition, the results point out that most sites pass the cost-benefit examination, but site rankings may alter in the face of capital rationing and climate change. Some policy implications derived from the results are discussed in detail.

Simplified Approach to Design of Crushable Material due to Dynamic Load

2012 ◽  
Author(s):  
Sivadol Vongmongkol ◽  
Asgar Faal-Amiri ◽  
Hari M. Srivastava
Keyword(s):  
Closed Form ◽  
Energy Absorption ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Closed Form Solution ◽  
High Energy ◽  
Form Solution ◽  
Piping System ◽  
The Impact

Crushable material has widely been used as an engineering solution for energy absorption devices among many industries. Abnormal and severe accident loads in the design of nuclear power plants are required to be addressed in order to comply with Nuclear Regulatory Commission (NRC) requirements which makes the crushable material more suitable in its highly dynamic application. One of the severe loads is from a postulated high energy piping system rupture. Its effects are required to be mitigated so that the proper operation of safety related systems, structures and components (SSC) of these facilities is assured. The postulated pipe rupture loads are among the highest loads that need to be addressed in the design process of nuclear power plants. The impact forces produced by the postulated pipe rupture are typically being absorbed by energy absorption devices called “Pipe Whip Restraints” in which the restraints can minimize the loads affecting the SSCs to within an acceptable limit. This paper provides a simplified closed-form solution to determine the energy absorbing characteristic that will help to design these devices. This paper will also provide a comparison between results of the proposed simplified closed-form solution equations to the experimental test results and the calculated results using finite element analysis.

Condition-Based Maintenance—A Tool for Improving Productivity in Shipyards

2002 ◽  
Vol 18 (03) ◽  
pp. 175-184
Author(s):  
Jonathan M. Ross
Keyword(s):  
Nuclear Power ◽  
Cost Savings ◽  
Condition Based Maintenance ◽  
Open Pit ◽  
Clear Trend ◽  
Strategic Investment ◽  
Important Means ◽  
Maintenance Personnel ◽  
The Impact ◽  
Nuclear Power Production

The National Shipbuilding Research Program's 2001 Strategic Investment Plan cites "reduce overhead costs associated with maintenance" as a key issue in responding to difficult Facilities and Tooling challenges. The Plan goes on to state that balancing the proper amount of preventative maintenance with reducing overhead costs is a constant struggle and recommends that studies be performed to help determine the impact of equipment downtime. However, a clear trend is already emerging that points to condition-based maintenance (CBM) as an important means to help reduce shipyard maintenance costs. In fact, CBM is being successfully applied in industries ranging from open pit coal mining to nuclear power production, as well as on board naval and commercial ships and oil production facilities. In some instances, CBM has been providing substantial equipment and facilities cost savings for over twenty years. U.S. shipyards are already implementing important aspects of CBM and have the opportunity to further this systems-oriented trend as a way to continue to trim costs through enhanced technology, improved processes, and cross boundary interactions between management, maintenance personnel, and production staff.

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