High-Temperature Structural Analysis of a Lab-Scale Alloy 800HT PCHE

2016 ◽  
Vol 713 ◽  
pp. 280-283 ◽  
Author(s):  
Kee Nam Song ◽  
Eung Seon Kim ◽  
S.Y. Jang

The IHX (Intermediate Heat Exchanger) of a VHTR (Very High Temperature Reactor) transfers 950°C heat generated from the VHTR to a hydrogen production plant. The Korea Atomic Energy Research Institute has manufactured a lab-scale Alloy 800HT PCHE (Printed Circuit Heat Exchanger) prototype under consideration as a candidate of the IHX (Intermediate Heat Exchanger). In this study, as a part of a structural integrity evaluation of the PCHE prototype, an elasto-plastic structural analysis including a thermal analysis was carried out under the designed test conditions of the PCHE prototype in a helium experimental loop (HELP). The analysis results were reflected to re-design the pipeline layout of HELP and to determine the actual test conditions of the PCHE prototype in the re-designed HELP in view of experimental safety.

2013 ◽  
Vol 577-578 ◽  
pp. 333-336
Author(s):  
Kee Nam Song ◽  
S.D. Hong

The IHX (Intermediate Heat Exchanger) of a VHTR (Very High Temperature Reactor) transfers 950°C heat generated from the VHTR to a hydrogen production plant. The Korea Atomic Energy Research Institute (KAERI) has manufactured a 70 kW class lab-scale PCHE (Printed Circuit Heat Exchanger) prototype made of SUS316L under consideration as a candidate. In this study, as a part of a structural integrity evaluation of the lab-scale PCHE prototype, an elastic structural analysis including structural analysis modeling and a thermal/elastic structural analysis was carried out under the test conditions of a helium experimental loop (HELP). In addition, a structural integrity evaluation considering the weld material properties was conducted.


Author(s):  
Mohamed S. El-Genk ◽  
Jean-Michel Tournier

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.


2010 ◽  
Vol 76 (764) ◽  
pp. 383-385 ◽  
Author(s):  
Taiju SHIBATA ◽  
Junya SUMITA ◽  
Taiyo MAKITA ◽  
Takashi TAKAGI ◽  
Eiji KUNIMOTO ◽  
...  

Author(s):  
Nariaki Sakaba ◽  
Shimpei Hamamoto ◽  
Yoichi Takeda

Lifetime extension of high-temperature equipment such as the intermediate heat exchanger of high-temperature gas-cooled reactors (HTGRs) is important from the economical point of view. Since the replacing cost will cause the increasing of the running cost, it is important to reduce replacing times of the high-cost primary equipment during assumed reactor lifetime. In the past, helium chemistry has been controlled by the passive chemistry control technology in which chemical impurity in the coolant helium is removed as low concentration as possible, as does Japan’s HTTR. Although the lifetime of high-temperature equipment almost depends upon the chemistry conditions in the coolant helium, it is necessary to establish an active chemistry control technology to maintain adequate chemical conditions. In this study, carbon deposition which could occur at the surface of the heat transfer tubes of the intermediate heat exchanger and decarburization of the high-temperature material of Hastelloy XR used at the heat transfer tubes were evaluated by referring the actual chemistry data obtained by the HTTR. The chemical equilibrium study contributed to clarify the algorism of the chemistry behaviours to be controlled. The created algorism is planned to be added to the instrumentation system of the helium purification systems. In addition, the chemical composition to be maintained during the reactor operation was proposed by evaluating not only core graphite oxidation but also carbon deposition and decarburization. It was identified when the chemical composition could not keep adequately, injection of 10 ppm carbon monoxide could effectively control the chemical composition to the designated stable area where the high-temperature materials could keep their structural integrity beyond the assumed duration. The proposed active chemistry control technology is expected to contribute economically to the purification systems of the future very high-temperature reactors.


Author(s):  
Christine Mansilla ◽  
Michel Dumas ◽  
Franc¸ois Werkoff

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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