Performance Comparison of VHTR Plants With Direct and Indirect Energy Conversion Cycles

2008 ◽  
Author(s):  
Mohamed S. El-Genk ◽  
Jean-Michel Tournier
Keyword(s):  
Pressure Ratio ◽  
Thermal Power ◽  
Performance Comparison ◽  
Working Fluid ◽  
Helium 4 ◽  
Very High Temperature Reactor ◽  
Exit Temperature ◽  
High Temperature Reactor ◽  
Very High ◽  
Reactor Pressure

This paper compared the performance of very high temperature reactor (VHTR) plants with direct and indirect closed Brayton Cycles (CBCs) and investigated the effect of the molecular weight of the CBC working fluid on the number of stages in and the size of the single shaft turbomachines. The CBC working fluids considered are helium (4 g/mole) and He-Xe and He-N2 binary mixtures (15 g/mole). Also investigated are the effects of using LPC and HPC with inter-cooling, cooling the reactor pressure vessel with He bled off at the exit of the compressor, and changing the reactor exit temperature from 700°C to 950°C on the plant thermal efficiency, CBC pressure ratio and the number of stages in and size of the turbo-machines. Analyses are performed for reactor thermal power of 600 MW, shaft rotation speed of 3000 rpm, and IHX temperature pinch of 50 °C.

On the Performance of Very High Temperature Reactor Plants With Direct and Indirect Closed Brayton Cycles

2009 ◽  
Vol 132 (3) ◽  
Author(s):  
Mohamed S. El-Genk ◽  
Jean-Michel Tournier
Keyword(s):  
High Temperature ◽  
Pressure Ratio ◽  
Thermal Power ◽  
Axial Flow ◽  
Working Fluid ◽  
Very High Temperature Reactor ◽  
Intermediate Heat Exchanger ◽  
Exit Temperature ◽  
High Temperature Reactor ◽  
Very High

The performance of very high temperature reactor plants with direct and indirect closed Brayton cycles (CBCs) is compared and the effects of the molecular weight of the CBC working fluid on the number of stages and sizes of the axial flow, single shaft compressor and turbine are investigated. The working fluids considered are helium (4 g/mole), He–Xe, and He–N2 binary mixtures (15 g/mole). Also investigated are the effects of using low and high pressure compressors with intercooling, instead of a single compressor, and changing the reactor exit temperature from 700°C to 950°C on the plant thermal efficiency, the CBC pressure ratio, and the number of stages in and size of the turbomachines. For plants with direct CBCs, the effect of cooling the reactor pressure vessel with He bled off at the exit of the compressor is also investigated. The present analyses are performed for a reactor thermal power of 600 MW, shaft rotation speed of 3000 rpm, and intermediate heat exchanger temperature pinch of 50°C.

scholarly journals Characterization of 2D-C/C Composite for Application of Very High Temperature Reactor(M & M 2009 Conference)

2010 ◽  
Vol 76 (764) ◽  
pp. 383-385 ◽  
Author(s):  
Taiju SHIBATA ◽  
Junya SUMITA ◽  
Taiyo MAKITA ◽  
Takashi TAKAGI ◽  
Eiji KUNIMOTO ◽  
...  
Keyword(s):  
High Temperature ◽  
Special Issue ◽  
Very High Temperature Reactor ◽  
High Temperature Reactor ◽  
Very High

Regulatory Viewpoint on Innovative VHTR Development in Korea

2008 ◽  
Author(s):  
Hun-Joo Lee ◽  
Sang-Kyu Ahn ◽  
Kju-Myeng Oh ◽  
Chang-Ju Lee
Keyword(s):  
Research Effort ◽  
Policy Statement ◽  
Light Water Reactors ◽  
Event Frequency ◽  
Very High Temperature Reactor ◽  
Regulatory Approach ◽  
High Temperature Reactor ◽  
Water Reactors ◽  
Gen Iv ◽  
Very High

This paper addresses that major changes in the safety approach, for instance the increased use of Probabilistic Risk Assessment (PRA), have been made. All commercial reactors in operation today belong to the Generations II and III. Generation IV International Forum (GIF) has launched several programs aimed at developing the next generation of nuclear energy systems. Part of the research effort is focused on new reactor concepts, such as the Very High Temperature Reactor (VHTR), currently developing in Korea. In parallel to the design process of VHTR currently underway, regulatory approach is moving forward to define new licensing rules. So, Korea Institute of Nuclear Safety (KINS) is defining, as a goal to risk-inform, the regulation and developing the regulatory framework and licensing process more efficient, predictable, and stable. However, the licensing of NPPs has focused until now on Light Water Reactors (LWRs) and has not incorporated systematically insights and benefits from PRA. In the meantime, USNRC and IAEA have recently drafted a risk-informed regulation and technology-neutral framework (TNF) for new plant licensing along with the innovative Gen-IV system design. KINS also expects that advanced NPPs will show enhanced margins of safety, and that advanced reactor designs will comply with the national safety goal policy statement. In order to meet these expectations, PRA tools are currently being considered by KINS; among them are frequency-consequence (F-C) curves, which plot the frequency of having Consequence. This paper discusses the role and the usefulness of such curves in risk-informing the licensing process in Korea, and shows that the use of F-C curve allows the implementation of both structural and rational Defence-In-Depth (DID). This paper focuses on F-C curves as means to assess the licensing basis events (LBEs) from the regulatory viewpoint on the innovative small and medium reactor (SMR) sized VHTR deployment in Korea. The principle underlying the F-C curve is that event frequency and dose are inversely related, i.e., the higher the dose consequences, the lower is the allowed event frequency.

A Techno-Economic Optimization of the Power Conversion System of a Very High Temperature Reactor

2006 ◽  
Author(s):  
Christine Mansilla ◽  
Michel Dumas ◽  
Franc¸ois Werkoff
Keyword(s):  
High Temperature ◽  
Power Conversion ◽  
Minimum Cost ◽  
Production Costs ◽  
Total Production ◽  
Economic Optimization ◽  
Very High Temperature Reactor ◽  
Conversion System ◽  
High Temperature Reactor ◽  
Very High

Generation IV nuclear reactors will not be implemented unless they enable lower production costs than with the current systems. In such a context a techno-economic optimization method was developed and then applied to the power conversion system of a very high temperature reactor. Techno-economic optimization consists in minimizing an objective function that depends on technical variables and economic ones. The advantage of the techno-economic optimization is that it can take into account both investment costs and operating costs. A techno-economic model was implemented in a specific optimization software named Vizir, which is based on genetic algorithms. The calculation of the thermodynamic cycle is performed by a software named Tugaz. The results are the values of the decision variables that lead to a minimum cost, according to the model. The total production cost is evaluated. The influence of the various variables and constraints is also pointed out.

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