Encoding a Model-Based Display with Dynamic Data

2000 ◽  
Vol 44 (22) ◽  
pp. 579-582 ◽  
Author(s):  
Leo Beltracchi
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Analytical Data ◽  
Heat Engine ◽  
Rankine Cycle ◽  
Direct Perception ◽  
Dynamic Data ◽  
Model Based ◽  
Heat Engine Cycle ◽  
Engine Cycle

A model-based display of the heat engine cycle for a nuclear power plant is defined and illustrated in terms of the thermodynamic first principles used to design the plant. The model-based display is a modified Rankine Cycle, the basic heat engine cycle for power plants. The display is made from measured process variables and the properties of water and presented on a CRT in iconic form, thereby providing a direct perception of the process. This structure of display design is an example of Rasmussen's means-ends hierarchy; starting with the abstract and ending with the specific display. Encoding the display with dynamic data aids operators in monitoring and interpreting the plant during transients and disturbances. Analytical data on the TMI-2 accident is used to illustrate the dynamic coding of the model-based display. The concepts discussed and illustrated are applicable to fossil and nuclear power plants and to other process industries.

Application of Supercritical Fluids in Thermal- and Nuclear-Power Engineering

2021 ◽  
pp. 601-658
Author(s):  
Igor L. Pioro
Keyword(s):  
Heat Transfer ◽  
Carbon Dioxide ◽  
Supercritical Fluids ◽  
Nuclear Power ◽  
Power Plants ◽  
Thermal Power ◽  
Rankine Cycle ◽  
Working Fluid ◽  
Thermal Power Plants ◽  
Power Cycles

Supercritical Fluids (SCFs) have unique thermophyscial properties and heat-transfer characteristics, which make them very attractive for use in power industry. In this chapter, specifics of thermophysical properties and heat transfer of SCFs such as water, carbon dioxide, and helium are considered and discussed. Also, particularities of heat transfer at Supercritical Pressures (SCPs) are presented, and the most accurate heat-transfer correlations are listed. Supercritical Water (SCW) is widely used as the working fluid in the SCP Rankine “steam”-turbine cycle in fossil-fuel thermal power plants. This increase in thermal efficiency is possible by application of high-temperature reactors and power cycles. Currently, six concepts of Generation-IV reactors are being developed, with coolant outlet temperatures of 500°C~1000°C. SCFs will be used as coolants (helium in GFRs and VHTRs, and SCW in SCWRs) and/or working fluids in power cycles (helium, mixture of nitrogen (80%) and helium (20%), nitrogen and carbon dioxide in Brayton gas-turbine cycles, and SCW/“steam” in Rankine cycle).

Mass Engine Cycle

2014 ◽  
Author(s):  
Mostafa H. Sharqawy
Keyword(s):  
Mass Concentration ◽  
Heat Engine ◽  
Thermodynamic Cycle ◽  
High Mass ◽  
Permeable Membrane ◽  
Thermal Reservoir ◽  
Thermodynamic Conditions ◽  
Heat Engine Cycle ◽  
Positive Work ◽  
Engine Cycle

A new thermodynamic cycle is proposed named mass engine cycle. In the proposed cycle, mass is transferred from a high mass concentration reservoir to the cycle, mass is rejected to a low mass concentration reservoir, and a net positive work is generated. This is similar to heat engine cycles where heat is transferred from a high temperature thermal reservoir (heat source) to the cycle; heat is rejected to a low temperature thermal reservoir (heat sink), and a net positive work is generated. The heat engine cycle uses heat exchangers to transfer heat between the cycle and the thermal reservoirs, while the mass engine cycle uses membrane mass exchangers which transfer mass between the cycle and the mass reservoir. These membrane mass exchangers transfer water through a semi-permeable membrane and reject other substances. The driving force for the mass transfer is the hydrostatic and osmotic pressure differences. Similar to Carnot limit of the thermal efficiency of the heat engine cycle, a theoretical limit is obtained for the proposed mass engine cycle under reversible thermodynamic conditions.

On the Use of Thermal Energy Storage for Flexible Baseload Power Plants: Thermodynamic Analysis of Options for a Nuclear Rankine Cycle

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Fletcher Carlson ◽  
Jane H. Davidson
Keyword(s):  
Energy Storage ◽  
Power Plant ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Nuclear Power ◽  
Power Plants ◽  
Dynamic Balance ◽  
Rankine Cycle ◽  
Capacity Factor ◽  
Primary Cycle

Abstract The intermittency of wind and solar energy can disrupt the dynamic balance utilities must maintain to meet fluctuating demand. This work examines the use of thermal energy storage (TES) to increase the operational flexibility of a baseload power plant and thus incentivize renewable energy and decarbonize the grid. A first and second law thermodynamic model of a nuclear power plant establishes the impacts of TES on the capacity factor and thermal efficiency of the plant. Four storage options, which are distinguished by the location within the cycle where steam is diverted for charging and whether discharge of the TES is via the primary or a secondary Rankine cycle, are considered. TES is compared to steam bypass, which is an alternative to provide baseload flexibility. TES is significantly better than steam bypass. The storage option with the greatest thermodynamic benefit is charged by diverting superheated steam at the outlet of the moisture separator/reheater (MSR) to the TES. The TES is discharged for peaking power through an optimized secondary cycle. TES increases the capacity factor as much as 15% compared to steam bypass at representative charging mass flowrates. The storage option that diverts steam from the steam generator to charge the TES and discharges the TES to the primary cycle extends the discharge power to a lower range and does not require a secondary cycle. In this case, the capacity factor and efficiency are as much as 8% greater than that of steam bypass.

scholarly journals Analysis of Factors Affecting Thermodynamic Efficiency in Generation III+ PWR Nuclear Power Plants.

2017 ◽  
Vol 4 ◽  
pp. 141-154
Author(s):  
Marcus Vitlin ◽  
Miroshan Naicker ◽  
Augustine Frederick Gardner
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Rankine Cycle ◽  
Steam Temperature ◽  
Factors Affecting ◽  
Electrical Efficiency ◽  
Balance Of Plant ◽  
The Impact ◽  
The Relationship

Generation III+ reactors are the latest generation of Nuclear Power Plants to enter the market. The key evolution in these reactors is the introduction of stringent safety standards. This is done through thorough incident scenario analysis and preparation, resulting in the addition of novel active and passive auxiliary safety systems, affecting the power consumption in the balance of plant. This paper analyses the parameters of PWR power plants of similar design, to determine the parameters for optimal efficiency, regarding gross and net electrical output, determining the impact the balance of plant has on this efficiency. While two of the three main factors affecting the Rankine cycle – boiler pressure and steam temperature – behaved as theoretically expected, there was a notable point of departure with the third parameter – condenser pressure. The relationship between steam temperature and gross electrical efficiency was linear across all reactors but the relation between the steam temperature and the net electrical efficiency ceased to be linear for secondary loop steam temperatures above 290°C. The relationship between boiler pressure and both gross and net electrical efficiency was linear, proving the Rankine cycle. A relationship was not observed between the condenser pressure and either the gross or net electrical efficiency

scholarly journals An Enhanced Preventive Maintenance Optimization Model Based on a Three-Stage Failure Process

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Ruifeng Yang ◽  
Jianshe Kang ◽  
Zhenya Quan
Keyword(s):  
Optimization Model ◽  
Preventive Maintenance ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Failure Process ◽  
Maintenance Optimization ◽  
Maintenance Policy ◽  
Model Based ◽  
Inspection Interval

Nuclear power plants are highly complex systems and the issues related to their safety are of primary importance. Probabilistic safety assessment is regarded as the most widespread methodology for studying the safety of nuclear power plants. As maintenance is one of the most important factors for affecting the reliability and safety, an enhanced preventive maintenance optimization model based on a three-stage failure process is proposed. Preventive maintenance is still a dominant maintenance policy due to its easy implementation. In order to correspond to the three-color scheme commonly used in practice, the lifetime of system before failure is divided into three stages, namely, normal, minor defective, and severe defective stages. When the minor defective stage is identified, two measures are considered for comparison: one is that halving the inspection interval only when the minor defective stage is identified at the first time; the other one is that if only identifying the minor defective stage, the subsequent inspection interval is halved. Maintenance is implemented immediately once the severe defective stage is identified. Minimizing the expected cost per unit time is our objective function to optimize the inspection interval. Finally, a numerical example is presented to illustrate the effectiveness of the proposed models.

A Novel Absorption Regeneration-Thermodynamic Heat Engine Cycle

1978 ◽  
Vol 100 (4) ◽  
pp. 566-570 ◽  
Author(s):  
B. Nimmo ◽  
R. Evans
Keyword(s):  
Electrical Power ◽  
Research Work ◽  
Heat Engine ◽  
Rankine Cycle ◽  
Design Parameters ◽  
Plant Design ◽  
Power Cycle ◽  
First Order ◽  
Important Design ◽  
Heat Engine Cycle

This paper introduces and provides a first order thermal cycle analysis of a new power plant design, the absorption-regeneration power cycle. Preliminary analysis indicates that this new cycle may have potential for increased operating efficiencies compared to the modified Rankine cycle presently in use for most stationary electrical power production. Graphs are presented to illustrate calculated efficiencies as well as some important design parameters of the cycle. Research work on extending presently available thermo-chemical data required to improve the model analysis is suggested.

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