New Requirements of Defence in Depth and Extension of its Application

Author(s):  
Wang Chengcheng

Abstract As states in the IAEA SSR-2/1 (Rev.1) and IAEA TECDOC-1791, the defence in depth concept is not to be understood as merely limited to the request for the implementation of a number of consecutive barriers and protection levels, but is to be understood as the main general principle that leads to the formulation of safety requirements including requirements necessary to achieve the quality and reliability expected for the barriers and for systems ensuring their integrity. Thus, the application of defence in depth concept is not only limited in the reactor core design, but also can extend to a wider range in nuclear power plant design. In this paper, the application of defence in depth concept, which is defined in IAEA latest requirements, in the irradiated fuel water pool storage, electrical system, internal hazards and external hazards of the nuclear power plant design are reviewed. Base on the study of the newest standard and codes, the design requirements of each level of defence in depth in the above systems are confirmed. The analysis of defence in depth design features of an advanced nuclear power plant in China are also show the application value of defence in depth in these extended regions.

2022 ◽  
Vol 9 ◽  
Author(s):  
Zhiyi Yang ◽  
Fengchen Li ◽  
Guohan Chai

The significant impact brought by a severe nuclear accident at the Fukushima Daiichi Nuclear Power Plant (NPP) in Japan in March 2011 has made global regulators to review the requirements against severe accidents. In China, comprehensive safety inspection and external hazard safety margin assessment on NPPs were carried out, regulatory requirements on improvement measures for NPPs based on the inspection were given, the nuclear safety 5-year plan was made and executed, and the safety requirements on the new NPP design were drafted. The Nuclear Safety Law came into effect in 2018. The “Code on the Safety of Nuclear Power Plant Design” (HAF102) was revised in 2016, and relevant safety guides were developed. In this article, improvement actions and requirements about NPP safety in China over the past 10 years were reviewed, and the nuclear safety philosophy and requirements including practical elimination, classification of accident conditions, and defense in depth portable equipment were elaborated. In summary, some suggestions of NPP safety in China in the future were provided.


2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Hongyun Xie ◽  
Haixia Gu ◽  
Chao Lu ◽  
Jialin Ping

Real-time Simulation (RTS) has long been used in the nuclear power industry for operator training and engineering purposes. And, online simulation (OLS) is based on RTS and with connection to the plant information system to acquire the measurement data in real time for calibrating the simulation models and following plant operation, for the purpose of analyzing plant events and providing indicative signs of malfunctioning. OLS has been applied in certain industries to improve safety and efficiency. However, it is new to the nuclear power industry. A research project was initiated to implement OLS to assist operators in certain critical nuclear power plant (NPP) operations to avoid faulty conditions. OLS models were developed to simulate the reactor core physics and reactor/steam generator thermal hydraulics in real time, with boundary conditions acquired from plant information system, synchronized in real time. The OLS models then were running in parallel with recorded plant events to validate the models, and the results are presented.


Author(s):  
Xiaomeng Dong ◽  
Zhijian Zhang ◽  
Zhaofei Tian ◽  
Lei Li ◽  
Guangliang Chen

Multi-physics coupling analysis is one of the most important fields among the analysis of nuclear power plant. The basis of multi-physics coupling is the coupling between neutronics and thermal-hydraulic because it plays a decisive role in the computation of reactor power, outlet temperature of the reactor core and pressure of vessel, which determines the economy and security of the nuclear power plant. This paper develops a coupling method which uses OPENFOAM and the REMARK code. OPENFOAM is a 3-dimension CFD open-source code for thermal-hydraulic, and the REMARK code (produced by GSE Systems) is a real-time simulation multi-group core model for neutronics while it solves diffusion equations. Additionally, a coupled computation using these two codes is new and has not been done. The method is tested and verified using data of the QINSHAN Phase II typical nuclear reactor which will have 16 × 121 elements. The coupled code has been modified to adapt unlimited CPUs after parallelization. With the further development and additional testing, this coupling method has the potential to extend to a more large-scale and accurate computation.


Author(s):  
Xiaohu Yang ◽  
Jiao Deng ◽  
Hong Jiang ◽  
Lifei Yang ◽  
Wen Chen

1969 ◽  
Vol 7 (2) ◽  
pp. 181-181
Author(s):  
T. V. Sheehan

2014 ◽  
Vol 989-994 ◽  
pp. 2097-2100
Author(s):  
Zheng Zhang ◽  
Hai Bo He ◽  
Hao Liang Lu

In order to satisfy the calculation requirements of nuclear power plant operating in different conditions, the integration and combination of reactor core computation modules have been proposed. By writing logical language instructions, and then read by interpreter, the engineering designers can make grammatical analysis, lexical analysis, semantic analysis and information extraction. In Linux system environment, the interpreter can fulfill computational tasks based on the actual operating parameters of nuclear power plant. The comparison results indicate that the calculated results obtained by the interpreter language are correct. Therefore, it also demonstrates that the interpreter language is valid.


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