CERES :: Browsing by Author "Gad-Briggs, Arnold"

Browsing by Author "Gad-Briggs, Arnold"

Now showing 1 - 20 of 21

Open Access
Addendum report: Detailed review of nuclear energy for generation IV nuclear power plants
(Cranfield University, 2017-10-25) Gad-Briggs, Arnold
The report is an addendum to the PhD thesis TERA of Gas Turbine High Temperature Reactor for Next Generation Nuclear Power Plants (Nov 2017). It provides a detailed review of current literature in the public domain, specifically relating to historic generations of plants as well as the technical factors concerned with operating cycles, working fluids, operational experience and plant control. The descriptions in this report supported the creation of a high fidelity conceptual tool to bridge the technical, economic and risk gaps in the Generation IV (Gen IV) framework in order to provide a method of evaluating Nuclear Power Plants (NPP).
Open Access
Analyses of a high pressure ratio intercooled direct Brayton helium gas turbine cycle for Generation IV reactor power plants
(ASME, 2016-12-20) Gad-Briggs, Arnold; Pilidis, Pericles; Nikolaidis, Theoklis
The intercooled cycle (IC) as an alternative to the simple cycle recuperated (SCR) and intercooled cycle recuperated (ICR) is yet to be fully analyzed for the purpose of assessing its viability for utilization within Generation IV nuclear power plants (NPPs). Although the benefits are not explicitly obvious, it offers the advantage of a very high overall pressure ratio (OPR) in the absence of a recuperator. Thus, the main objective of this study is to analyze various pressure ratio configurations, the effects of varying pressure ratio including sensitivity analyses of component efficiencies, ambient temperature, component losses and pressure losses on cycle efficiency, and specific work of the IC, including comparison with the SCR and ICR. Results of comparison between the IC and the SCR and ICR derived that the cycle efficiencies are greater than the IC by ∼4%∼4% (SCR) and ∼6%∼6% (ICR), respectively. However, the pressure losses for IC are lower when compared with the SCR and ICR. Nonetheless, heat from the turbine exit temperature of the IC can be used in a processing plant including the possibility of higher turbine entry temperatures (TETs) to significantly increase the cycle efficiency in a bid to justify the business case. The analyses intend to bring to attention an alternative to current cycle configurations for the gas-cooled fast reactors (GFRs) and very-high-temperature reactors (VHTRs), where helium is the coolant. The findings are summarized by evaluating the chosen pressure ratio configurations against critical parameters and detailed comparison with the SCR and ICR.
Open Access
Analyses of long term off-design performance strategy and operation of a high pressure ratio intercooled Brayton helium gas turbine cycle for generation IV nuclear power plants
(ASME, 2018-05-23) Gad-Briggs, Arnold; Pilidis, Pericles; Nikolaidis, Theoklis
The Intercooled Cycle (IC) is a simplified novel proposal for Generation IV Nuclear Power Plants (NPP) based on studies demonstrating efficiencies of over 45%. As an alternative to the Simple Cycle Recuperated (SCR) and the Intercooled Cycle Recuperated (ICR), the main difference in configuration is no recuperator, which reduces its size. It is expected that the components of the IC will not operate at optimum part power due to seasonal changes in ambient temperature and grid prioritisation for renewable sources. Thus the ability to demonstrate viable part load performance becomes an important requirement. The main objective of this study is to derive Off-Design Points (ODPs) for a temperature range of -35 to 50°C and COTs between 750 to 1000°C. The ODPs have been calculated using a tool designed for this study. Based on results, the intercooler changes the mass flow rate and compressor pressure ratio. However, a drop of ~9% in plant efficiency, in comparison to the ICR (6%) was observed for pressure losses of up to 5% . The reactor pressure losses for IC has the lowest effect on plant cycle efficiency in comparison to the SCR and ICR. Characteristic maps are created to support first order calculations. It is also proposed to consider the intercooler pressure loss as a handle for ODP performance. The analyses brings attention to the IC an alternative cycle and aids development of cycles for Generation IV Nuclear Power Plants specifically Gas Cooled Fast Reactors (GFRs) and Very High Temperature Reactors (VHTRs).
Open Access
Analyses of simple and intercooled recuperated direct Brayton helium gas turbine cycles for Generation IV reactor power plants
(ASME, 2016-12-20) Gad-Briggs, Arnold; Pilidis, Pericles
As a nongreenhouse gas-emitting source, the benefits of nuclear as a main power-generation alternative are yet to be fully explored; part of the reason is due to the significant implementation costs. However, with cycle efficiencies of 45–50% in current studies, it can be argued that the long-term benefits outweigh the initial costs, if developed under the Generation-IV (Gen-IV) framework. The main objective of this study is to analyze the effects of pressure and temperature ratios (TRs) including sensitivity analyses of component efficiencies, ambient temperature, component losses and pressure losses on cycle efficiency and specific work. The results obtained indicate that pressure losses and recuperator effectiveness have the greatest impact on cycle efficiency and specific work. The analyses intend to aid development of the simple cycle recuperated (SCR) and intercooled cycle recuperated (ICR) cycles, applicable to gas-cooled fast reactors (GFRs) and very-high-temperature reactors (VHTRs), in which helium is the coolant.
Open Access
Analyses of the associated technical and economic risks of the simple and intercooled Brayton helium recuperated gas turbine cycles for Generation IV nuclear power plants
(ASME, 2018-11-30) Gad-Briggs, Arnold; Pilidis, Pericles; Nikolaidis, Theoklis
The Simple Cycle Recuperated (SCR) and Intercooled Cycle Recuperated (ICR) are highly efficient Brayton helium gas turbine cycles, designed for the Gas-cooled Fast Reactor (GFR) and Very-High-Temperature Reactor (VHTR) Generation IV (Gen IV) Nuclear Power Plants (NPPs). This paper documents risk analyses which considers technical and economic aspects of the NPP. The sensitivity analyses are presented that interrogate the plant design, performance and operational schedule and range from component efficiencies, system pressure losses, operating at varied power output due to short term load-following or long term reduced power operations to prioritise other sources such as renewables. The sensitivities of the economic and construction schedule are also considered in terms of the discount rates, capital and operational costs and increased costs in Decontamination and Decommissioning (D&D) activity due to changes in the discount rates. This was made possible by using a tool designed for this study to demonstrate the effect on the ‘non-contingency’ baseline Levelised Unit Electricity Cost (LUEC) of both cycles. The SCR with a cycle efficiency of 50%, has a cheaper baseline LUEC of $58.41/MWh in comparison to the ICR (53% cycle efficiency), which has a LUEC of $58.70 /MWh. However, the cost of the technical and economic risks is cheaper for the ICR resulting in a final LUEC of $70.45/MWh (ICR) in comparison to the SCR ($71.62/MWh) for the year 2020 prices.
Open Access
Analyses of the control system strategies and methodology for part power control of the simple and intercooled recuperated Brayton helium gas turbine cycles for generation IV nuclear power plants
(The American Society of Mechanical Engineers, 2017-05-15) Gad-Briggs, Arnold; Pilidis, Pericles; Nicolaidis, Theoklis
An important requirement for Generation IV Nuclear Power Plant (NPP) design is the control system, which enables part power operability. The choices of control system methods must ensure variation of load without severe drawbacks on cycle performance. The objective of this study is to assess the control of the NPP under part power operations. The cycles of interest are the Simple Cycle Recuperated (SCR) and the Intercooled Cycle Recuperated (ICR). Control strategies are proposed for NPPs but the focus is on the strategies that result in part power operation using the inventory control method. Firstly, results explaining the performance and load limiting factors of the inventory control method are documented; subsequently, the transient part power performances. The load versus efficiency curves were also derived from varying the load to understand the efficiency penalties. This is carried out using a modelling and performance simulation tool designed for this study. Results show that the ICR takes ~102% longer than the SCR to reduce the load to 50% in Design Point (DP) performance conditions for similar valve flows, which correlates to the volumetric increase for the ICR inventory tank. The efficiency penalties are comparable for both cycles at 50% part power, whereby a 22% drop in cycle efficiency was observed and indicates limiting time at very low part power. The analyses intend to aid the development of cycles for Generation IV NPPs specifically Gas Cooled Fast Reactors (GFRs) and Very High Temperature Reactors (VHTRs), where helium is the coolant.
Open Access
Analyses of the costs associated with very high turbine entry temperatures in helium recuperated gas turbine cycles for Generation IV nuclear power plants
(ASME, 2018-08-27) Gad-Briggs, Arnold; Pilidis, Pericles; Nikolaidis, Theoklis
Previous analyses of Generation IV (GEN IV) helium gas turbine cycles indicated the possibility for high Turbine Entry Temperatures (TETs) up to 1200°C in order to improve cycle efficiency, using improved turbine blade material and optimum turbine cooling fractions. The purpose of this paper is to understand the effect on the Levelised Unit Electricity Cost (LUEC) of the Nuclear Power Plant (NPP), when the TET is increased to 1200°C from an original TET of 950°C and when an improved turbine blade material is used to reduced the turbine cooling fraction. The analyses focus on the Simple Cycle Recuperated (SCR) and the Intercooled Cycle Recuperated (ICR). The baseline LUECs of the NPPs were calculated as $61.84/MWh (SCR) and $62.16/MWh for a TET of 950°C. The effect of changing the turbine blades improved the allowable blade metal temperature by 15% with a reduction in the LUEC by 0.6% (SCR) and 0.7% (ICR). Furthermore, increasing the TET to 1200°C has a significant effect on the power output but more importantly it reduces the LUECs by 22.7% (SCR) and 19.8% (ICR). The analyses intends to aid development of the SCR and ICR including improving the decision making process on choice of cycles applicable to the Gas-cooled Fast Reactors (GFRs) and Very High-Temperature Reactors (VHTRs), where helium is the coolant.
Open Access
Analyses of the effect of cycle inlet temperature on the precooler and plant efficiency of the simple and intercooled helium gas turbine cycles for generation IV nuclear power plants
(MDPI, 2017-03-24) Gad-Briggs, Arnold; Nikolaidis, Theoklis; Pilidis, Pericles
Nuclear Power Plant (NPP) precooler coolant temperature is critical to performance because it impacts the work required to increase the coolant pressure. Variation of the coolant temperature results in varied precooler hot gas temperatures, which are cooled before re-entry. For recirculation, the heat sink (usually sea water), could exit the precooler at unfavourable temperatures and impact the re-entering coolant, if not recirculated properly at the source. The study objective is to analyse the effects of coolant inlet temperature on the heat sink and cycle efficiency. The cycles are Simple Cycle Recuperated (SCR), Intercooler Cycle Recuperated (ICR), and Intercooled Cycle without Recuperation (IC). Results show that the co-current precooler provides favourable outlet heat sink temperatures but compromises compactness. For a similar technology level, the counter-current precooler yields excessive heat sink outlet temperatures due to a compact, robust, and efficient heat transfer design, but could be detrimental to precooler integrity due to corrosion, including the cycle performance, if not recirculated back into the sea effectively. For the counter-current, the ICR has the best heat sink average temperature ratio of 1.4; the SCR has 2.7 and IC has 3.3. The analyses aid the development of Gas Cooled Fast Reactors (GFRs) and Very High Temperature Reactors (VHTRs), where helium is used as the coolant.
Open Access
Analyses of the load following capabilities of Brayton Helium gas turbine cycles for generation IV nuclear power plants
(ASME, 2017-06-09) Gad-Briggs, Arnold; Pilidis, Pericles; Nikolaidis, Theoklis
The control system for Generation IV Nuclear Power Plant (NPP) design must ensure load variation when changes to critical parameters affect grid demand, plant efficiency and component integrity. The objective of this study is to assess the load following capabilities of cycles when inventory pressure control is utilised. Cycles of interest are Simple Cycle Recuperated (SCR), Intercooled Cycle Recuperated (ICR) and Intercooled Cycle without recuperation (IC). Firstly, part power performance of the IC is compared to results of the SCR and ICR. Subsequently, the load following capabilities are assessed when the cycle inlet temperature is varied. This was carried out using a tool designed for this study. Results show that the IC takes ~2.7% longer than the ICR to reduce the power output to 50% when operating in Design Point (DP) for similar valve flows, which correlates to the volumetric increase for the IC inventory storage tank. However, the ability of the IC to match the ICR’s load following capabilities is severely hindered because the IC is most susceptible to temperature variation. Furthermore, the IC takes longer than the SCR and ICR to regulate the reactor power by a factor of 51 but this is severely reduced, when regulating NPP power output. However, the IC is the only cycle that does not compromise reactor integrity and cycle efficiency when regulating the power. The analyses intend to aid the development of cycles specifically Gas Cooled Fast Reactors (GFRs) and Very High Temperature Reactors (VHTRs), where helium is the coolant.
Open Access
Analysis of control-system strategy and design of a small modular reactor with different working fluids for electricity and hydrogen production as part of a decentralised mini grid
(MDPI, 2022-03-18) Gad-Briggs, Arnold; Osigwe, Emmanuel O.; Jafari, Soheil; Nikolaidis, Theoklis
Hydrogen is increasingly being viewed as a significant fuel for future industrial processes as it offers pathways to zero emission. The UK sees hydrogen as one of a handful of low-carbon solutions for transition to net zero. Currently, most hydrogen production is from steam reforming of natural gas or coal gasification, both of which involve the release of carbon dioxide. Hydrogen production from mini decentralised grids via a thermochemical process, coupled with electricity production, could offer favourable economics for small modular reactors (SMRs), whereby demand or grid management as a solution would include redirecting the power for hydrogen production when electricity demand is low. It also offers a clean-energy alternative to the aforementioned means. SMRs could offer favourable economics due to their flexible power system as part of the dual-output function. This study objective is to investigate the critical performance parameters associated with the nuclear power plant (NPP), the cycle working fluids, and control-system design for switching between electricity and hydrogen demand to support delivery as part of a mini grid system for a reactor power delivering up to approximately 600 MWth power. The novelty of the work is in the holistic parametric analysis undertaken using a novel in-house tool, which analyses the NPP using different working fluids, with a control function bolt-on at the offtake for hydrogen production. The results indicate that the flow conditions at the offtake can be maintained. The choice of working fluids affects the pressure component. However, the recuperator and heat-exchanger effectiveness are considered as efficiency-limiting factors for hydrogen production and electricity generation. As such, the benefit of high-technology heat exchangers cannot be underestimated. This is also true when deciding on the thermochemical process to bolt onto the plant. The temperature of the gas at the end of the pipeline should also be considered to ensure that the minimum temperature-requirement status for hydrogen production is met.
Open Access
Benefits, drawbacks, and future trends of Brayton helium gas turbine cycles for gas-cooled fast reactor and very-high temperature reactor Generation IV nuclear power plants
(American Society of Mechanical Engineers, 2020-10-02) Gad-Briggs, Arnold; Osigwe, Emmanuel O.; Pilidis, Pericles; Nikolaidis, Theoklis; Sampath, Suresh; Teixeira, Joao Amaral
Numerous studies are on-going on to understand the performance of generation IV (Gen IV) nuclear power plants (NPPs). The objective is to determine optimum operating conditions for efficiency and economic reasons in line with the goals of Gen IV. For Gen IV concepts such as the gas-cooled fast reactors (GFRs) and very-high temperature reactors (VHTRs), the choice of cycle configuration is influenced by component choices, the component configuration and the choice of coolant. The purpose of this paper to present and review current cycles being considered—the simple cycle recuperated (SCR) and the intercooled cycle recuperated (ICR). For both cycles, helium is considered as the coolant in a closed Brayton gas turbine configuration. Comparisons are made for design point (DP) and off-design point (ODP) analyses to emphasize the pros and cons of each cycle. This paper also discusses potential future trends, include higher reactor core outlet temperatures (COT) in excess of 1000 °C and the simplified cycle configurations.
Open Access
Effect of change in role of an aircraft on engine life
(2017-05-03) Gad-Briggs, Arnold; Halsam, Anthony; Laskaridis, Panagiotis
New aircraft require years of development from concept to realisation and can be prone to delays. Consequently, military operators take existing fleets and operate them in a different role. The objective of this study is to examine the effect of operating a typical low bypass military fast jet engine, originally designed for a European theatre, in a hot and harsh climate. The specific purpose is to determine the effect on the high-pressure turbine blade life and the life- cycle cost of the engine. A mission profile and respective performance conditions were analysed and modelled using an in-house performance tool. The flow conditions were simulated using ANSYS® FLUENT. A conjugated heat transfer solution was adopted to determine the blade metal temperature. The blade was modelled physically in 3D using SIMULIA® ABAQUS FEA software. The stresses were derived and used to calculate the temperature coupled low cycle fatigue and creep life. A deterioration case was also studied to evaluate the effect of sand and dust ingestion. There was a significant life reduction of approximately 50% due to creep. The reduction in life was inversely proportional to the life cycle cost of the engine depending on the operating conditions. The results were compared with similar engines and summarised in the context of airworthiness regulations and component integrity.
Open Access
Effect of working fluid on selection of gas turbine cycle configuration for Gen-IV nuclear power plant system
(JSME, 2019-05-31) Osigwe, Emmanuel O.; Gad-Briggs, Arnold; Pilidis, Pericles; Nikolaidis, Theoklis; Sampath, Suresh
The cycle configuration of the energy conversion system in a nuclear power plant tends to have a governing effect on the overall performance and acquisition cost. Interestingly, one factor that could greatly affect the design choice of the cycle configuration which may not have been explored extensively in many literatures reviewed is the choice of the working fluid. This paper presents a technical analysis on the effect of working fluid on selection of the cycle arrangement for a Generation IV nuclear power plant. It provides insight on potential performance gains that justifies the benefit for an additional cost of a complex cycle, and how the working fluid can influence this choice. The study identifies candidate working fluid that may be suitable for simple, inter-cooled-recuperated, recuperated and other complex cycles. The results obtained shows that for fluid like carbon dioxide, its optimal performance is achieved above it critical points which will require pressurizing the system or operating at high pressure ratio, hence, it would be suitable for a re-compressed inter-cooled cycle configuration. Similar, for fluid like helium with low molecular weight and high gas properties, the simple cycle configuration seem more realistic for its highest cycle efficiency of 41% and turbomachinery design.
Open Access
Feasibility of a helium closed-cycle gas turbine for UAV propulsion
(MDPI, 2020-12-22) Osigwe, Emmanuel O.; Gad-Briggs, Arnold; Nikolaidis, Theoklis
When selecting a design for an unmanned aerial vehicle, the choice of the propulsion system is vital in terms of mission requirements, sustainability, usability, noise, controllability, reliability and technology readiness level (TRL). This study analyses the various propulsion systems used in unmanned aerial vehicles (UAVs), paying particular focus on the closed-cycle propulsion systems. The study also investigates the feasibility of using helium closed-cycle gas turbines for UAV propulsion, highlighting the merits and demerits of helium closed-cycle gas turbines. Some of the advantages mentioned include high payload, low noise and high altitude mission ability; while the major drawbacks include a heat sink, nuclear hazard radiation and the shield weight. A preliminary assessment of the cycle showed that a pressure ratio of 4, turbine entry temperature (TET) of 800 °C and mass flow of 50 kg/s could be used to achieve a lightweight helium closed-cycle gas turbine design for UAV mission considering component design constraints.
Open Access
Inventory control systems for nuclear powered closed-cycle gas turbine: technical studies on effect of working fluid options
(Unknown, 2019-05-24) Osigwe, Emmanuel O.; Gad-Briggs, Arnold; Pilidis, Pericles; Nikolaidis, Theoklis; Sampath, Suresh
The Inventory Control System (ICS) offer unique characteristics when modulating the gas turbine output power to match the required load demand. The unique opportunities it offers have made it to be widely used in most nuclear powered closed-cycle gas turbine plant design and operations. This paper presents a technical study on how the different working fluid options affect the design and performance characteristics of the inventory control system. The results from this study shows that using helium as cycle working fluid offers an advantage in terms of Reynolds effect on cycle efficiency and also enable the design for compact inventory tank size and weight which could have a direct effect on the capital cost, due to its thermodynamic characteristics. However, the long term operational cost of helium compared with other working fluid utilized in this study provides a reasonable argument to justify any investment decision.
Open Access
Performance analyses and evaluation of CO2 and N2 as coolants in a recuperated Brayton gas turbine cycle for a Generation IV nuclear reactor power plant
(ASME, 2019-04-24) Osigwe, Emmanuel O.; Gad-Briggs, Arnold; Nikolaidis, Theoklis; Pilidis, Pericles; Sampath, Suresh
As demands for clean and sustainable energy renew interests in nuclear power to meet future energy demands, Generation IV nuclear reactors are seen as having the potential to provide the improvements required for nuclear power generation. However, for their benefits to be fully realised, it is important to explore the performance of the reactors when coupled to different configurations of closed-cycle gas turbine power conversion systems. The configurations provide variation in performance due to different working fluids over a range of operating pressures and temperatures. The objective of this paper is to undertake analyses at the design and off-design conditions in combination with a recuperated closed-cycle gas turbine and comparing the influence of carbon dioxide and nitrogen as the working fluid in the cycle. The analysis is demonstrated using an in-house tool, which was developed by the authors. The results show that the choice of working fluid controls the range of cycle operating pressures, temperatures and overall performance of the power plant due to the thermodynamic and heat properties of the fluids. The performance results favored the nitrogen working fluid over CO2 due to the behavior CO2 below its critical conditions. The analyses intend to aid the development of cycles for Generation IV NPPs specifically Gas-cooled Fast Reactors (GFRs) and Very High-Temperature Reactors (VHTRs).
Open Access
Performance modeling and analysis of a single-shaft closed-cycle gas turbine using different operational control strategy
(ASME, 2019-07-18) Osigwe, Emmanuel O.; Gad-Briggs, Arnold; Igbong, Dodeye; Nikolaidis, Theoklis; Pilidis, Pericles
In the last few years, one considerable factor for the viability and interest in closed-cycle gas turbine systems for nuclear or conventional power plant application is its potential to maintain high cycle performance at varying operating conditions. However, for this potential to be realised, more competitive analysis and understanding of its control strategy is importantly required. In this paper, the iterative procedure for three independent control strategies of a 40 MW single-shaft intercooled-recuperated closed-cycle gas turbine incorporated to a Generation IV nuclear reactor is been analysed and their performance at various operating conditions compared. The rationale behind this analysis was to explore the different control strategy and to identify potential limitations using each independent control. The inventory control strategy offered a more viable option for high efficiency at changes in ambient and part-load operations, however, operational limitations in terms of size and pressure of inventory tank, rotational speed for which the centrifugal forces acting on the blade tips could become too high, hence would affect the mechanical integrity and compressor performance. The bypass control responds rapidly to load rejection in event of loss of grid power. And more interestingly the results showed the need for a mixed or combined control instead of a single independent technique, which is limited in practice due to operational limits.
Open Access
Performance simulation to understand the effects of multi-fluid scaling of gas turbine components for Generation IV nuclear power plants
(ASME, 2019-08-05) Osigwe, Emmanuel O.; Gad-Briggs, Arnold; Nikolaidis, Theoklis; Pilidis, Pericles; Sampath, Suresh
A significant hurdle in the development of performance simulation tools to analyse and evaluate nuclear power plants (NPP) is finding data relating to component performance maps. As a result, Engineers often rely on an estimation approach using various scaling techniques. The purpose of this study is to determine the component characteristics of a closed-cycle gas turbine NPP using existing component maps with corresponding design data. The design data is applied for different working fluids using a multi-fluid scaling approach to adapt data from one component map into another. The multi-fluid scaling technique described herein was developed as an in-house computer simulation tool. This approach makes it easy to theoretically scale existing maps using similar or different working fluids without carrying out a full experimental test or repeating the whole design and development process. The results of selected case studies show a reasonable agreement with available data. The analyses intend to aid the development of cycles for Generation IV NPPs specifically Gas-cooled Fast Reactors (GFRs) and Very High-Temperature Reactors (VHTRs).
Open Access
A review of the turbine cooling fraction for very high turbine entry temperature helium gas turbine cycles for Generation IV reactor power plants
(ASME, 2016-12-05) Gad-Briggs, Arnold; Pilidis, Pericles; Nikolaidis, Theoklis
The potential for high Turbine Entry Temperatures (TET) turbines for Nuclear Power Plants (NPPs) require improved materials and sophisticated cooling. Cooling is critical to maintaining mechanical integrity of the turbine for temperatures >1000°C. Increasing TET is one of the solutions for improving efficiency after cycle optimum pressure ratios have been achieved but cooling as a percentage of mass flow will have to increase, resulting in cycle efficiency penalties. To limit this effect, it is necessary to know the maximum allowable blade metal temperature to ensure the minimum cooling fraction is used. The main objective of this study is to analyse the thermal efficiencies of four cycles in the 300 – 700 MW class for Generation IV NPPs, using two different turbines with optimum cooling for TETs between 950°C - 1200°C. The cycles analysed are Simple Cycle (SC), Simple Cycle Recuperated (SCR), Intercooled Cycle (IC) and Intercooled Cycle Recuperated (ICR). Although results showed that deterioration of cycle performance is lower when using improved turbine material, the justification to use optimum cooling improves the cycle significantly when a recuperator is used. Furthermore, optimised cooling flow and the introduction of an intercooler improves cycle efficiency by >3%, which is >1% more than previous studies. Finally, the study highlights the potential of cycle performance beyond 1200°C for IC. This is based on the IC showing the least performance deterioration. The analyses intend to aid development of cycles for deployment in Gas Cooled Fast Reactors (GFRs) and Very High Temperature Reactors (VHTRs).
Open Access
Techno-economic study on implementation of inventory control requirements for a nuclear powered closed-cycle gas turbine power plant
(ASME, 2020-10-23) Osigwe, Emmanuel O.; Gad-Briggs, Arnold; Obhuo, Mafel; Pilidis, Pericles
The use of an inventory control system offers a unique benefit of stable cycle thermal efficiency during part-load operation. This article focuses on the influence of initial inventory tank pressure on the control level using pressure differential as a driving force of the inventory control system. The study also considered the effects of using multiple tanks to increase the overall size of the inventory control tank and the use of insulation to reduce the impact of temperature variation between the compressor discharge temperature and the inventory tank temperature. The second part of this analysis is a cost comparison between the use of multiple tanks and the use of a transfer compressor to achieve high cycle efficiency at continuous part-load operation. The discussions in this paper accentuate the optimum benefit for utilizing an inventory control system for a single-shaft intercooled-recuperated closed-cycle gas turbine plant