Electrochemical decontamination of irradiated nuclear graphite from corrosion and fission products using molten salt

Author(s):  
Tatiana Grebennikova ◽  
Abbie N Jones ◽  
Clint Alan Sharrad

Irradiated graphite waste management is one of the major challenges of nuclear power-plant decommissioning throughout the world and significantly in the UK, France and Russia where over 85 reactors employed...

2018 ◽  
Vol 17 (1) ◽  
pp. 1-36 ◽  
Author(s):  
Iain J. Tromans ◽  
Guillermo Aldama-Bustos ◽  
John Douglas ◽  
Angeliki Lessi-Cheimariou ◽  
Simon Hunt ◽  
...  

Author(s):  
Yasuyoshi Taruta ◽  
Satoshi Yanagihara ◽  
Takashi Hashimoto ◽  
Shigeto Kobayashi ◽  
Yukihiro Iguchi ◽  
...  

Abstract Decommissioning of Nuclear Power Plant is a long-term project during which generations are expected to change. Therefore, it is necessary to appropriately transfer knowledge, technology and skills to the next generation. In recent years, in the world of decommissioning, attempts have been made to apply advanced technologies such as utilization of knowledge management and digital technology. This study describes adaptation in decommissioning from viewpoint of utilizing IT technology called digital twin and aspect of knowledge management.


Author(s):  
Shihong Ma

Sanmen Nuclear Power Plant is constructing the first AP1000 unit in the world, and DCS system is adopted as the non-safety control system. This paper reviews the experience of Sanmen project, and analyzes the necessity of nuclear power plant Owner’s management for developing the DCS system, as well as how to manage the development effectively.


Author(s):  
T. Jelfs ◽  
M. Hayashi ◽  
A. Toft

Gross failure of certain components in nuclear power plant has the potential to lead to intolerable radiological consequences. For these components, UK regulatory expectations require that the probability of gross failure must be shown to be so low that it can be discounted, i.e. that it is incredible. For prospective vendors of nuclear power plant in the UK, with established designs, the demonstration of “incredibility of failure” can be an onerous requirement carrying a high burden of proof. Requesting parties may need to commit to supplementary manufacturing inspection, augmented material testing requirements, enhanced defect tolerance assessment, enhanced material specifications or even changes to design and manufacturing processes. A key part of this demonstration is the presentation of the structural integrity safety case argument. UK practice is to develop a safety case that incorporates the notion of ‘conceptual defence-in-depth’ to demonstrate the highest structural reliability. In support of recent Generic Design Assessment (GDA) submissions, significant experience has been gained in the development of so called “incredibility of failure” arguments. This paper presents an overview of some of the lessons learned relating to the identification of the highest reliability components, the development of the structural integrity safety arguments in the context of current GDA projects, and considers how the UK Technical Advisory Group on Structural Integrity (TAGSI) recommendations continue to be applied almost 15 years after their work was first published. The paper also reports the approach adopted by Horizon Nuclear Power and their partners to develop the structural integrity safety case in support of the GDA process to build the UK’s first commercial Boiling Water Reactor design.


Author(s):  
Guang Jun Chen ◽  
Yu Lin Cui ◽  
Guo Guo Zhang ◽  
Hong Jun Yao

With an increased population and an increasing demand for power, nuclear power has attracted an increasing attention and mass nuclear power plant have been built in different countries in the past several decades. At present, about ten thousands ton spent fuels are discharged from nuclear power plant every year and the estimated capacity will approximately add up to 5×105 ton. Therefore, spent fuel reprocessing, by which the co-extraction and separation as well as purification of Uranium and Plutonium could be realized and ensure the recycle of uranium resources and the management of nuclear waste, is a vital step in nuclear fuel cycle including two major strategies, i.e. once-through cycle and closed fuel cycle. It is worth noting that the utilization of MOX fuel made by plutonium mixed with uranium has been successfully achieved in thermal reactor. Fortunately, the middle experiment plant of china spent fuel reprocessing has been being debugged and will be operated completely in future two years. Various reprocessing schemes have been proposed for the extraction of actinides from fission products and other elements presented in spent nuclear fuel. However, after numerous studies of alternate reprocessing methods and intensive searches for better solvents, the PUREX process remains the prime reprocessing method for spent nuclear fuels throughout the world. High burning and strong radioactive spent fuel resulting from the evolution of various reactors drive the development of the advanced PUREX technology, which emphasizes the separation of neptunium and technetium besides the separation of the Uranium and Plutonium from the majority of highly active fission products. In addition, through Partitioning and Transmutation method, some benefits such as segregating the actinides and long life fission products from the high level waste can be obtained. The GANEX process exploited by CEA, which roots in COEX process belonged to advanced PUREX process, considers the separation of the actinides and long life fission products. The study on the pyro-chemical processing such as the method of electro-deposition from molten salts has still not replaced the traditional PUREX process due to various reasons. In conclusion, the future PUREX process will focus on the modified process including predigesting the technical flowsheets and reducing reprocessing costs and using salt-less reagent in order to minimize the waste production.


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