scholarly journals About leak detection systems in the framework of LBB concept application at Russian NPPs

Author(s):  
Alexander Arzhaev ◽  
Alexey Arzhaev ◽  
Valentin Makhanev ◽  
Mikhail Antonov ◽  
Anton Emelianov ◽  
...  

Application of "leak before break" concept to reactor coolant circuit is obligatory for RF NPPs and the success depends also on fulfilment of requirements to the leak detection systems specified in RF national standard. During 1999-2020 requirements to the leak detection systems were permanently improved in regulatory documents. The most important changes in requirements have been done according to the Federal law on ensuring the uniformity of measurements. Paper gives comparative analyses of these evolutionary changes of requirements as well as details of their implementation during design and manufacturing of leak detection systems to supply NPP Units with VVER-440/1000/1200 and RBMK-1000 reactor facilities. Recently approved in the Russian Federation, the Federal norms and rules (FNR) in the field of atomic energy use ensure the continuity of the general requirements for reactor coolant leak monitoring (detection) systems (LDS) at nuclear power plants (NPPs) in relation to the previously valid regulatory documents.

2005 ◽  
Vol 19 (11) ◽  
pp. 1988-1997 ◽  
Author(s):  
June-soo Park ◽  
Ha-cheol Song ◽  
Ki-seok Yoon ◽  
Taek-sang Choi ◽  
Jai-hak Park

2006 ◽  
Vol 985 ◽  
Author(s):  
James Bresee

AbstractIn the January 2006 State of the Union address, President Bush announced a new Advanced Energy Initiative, a significant part of which is the Global Nuclear Energy Initiative. Its details were described on February 6, 2006 by the U.S. Secretary of Energy. In summary, it has three parts: (1) a program to expand nuclear energy use domestically and in foreign countries to support economic growth while reducing the release of greenhouse gases such as carbon dioxide. (2) an expansion of the U.S. nuclear infrastructure that will lead to the recycling of spent fuel and a closed fuel cycle and, through transmutation, a reduction in the quantity and radiotoxicity of nuclear waste and its proliferation concerns, and (3) a partnership with other fuel cycle nations to support nuclear power in additional nations by providing small nuclear power plants and leased fuel with the provision that the resulting spent fuel would be returned by the lessee to the lessor. The final part would have the effect of stabilizing the number of fuel cycle countries with attendant non-proliferation value. Details will be given later in the paper.


Author(s):  
Takahisa Nose ◽  
Takao Nakamura ◽  
Takanori Kitada

In order to conduct effective and rational maintenance activity of components in nuclear power plants, it is proposed to manage fatigue degradation based on crack size corresponding to an extent of cumulative fatigue damage. The purpose of this study focuses on the influence of strain rate in simulated reactor coolant environment for fatigue crack initiation and growth. 3-dimensional replica observations were conducted for environmental fatigue test specimens in different strain rates. Crack initiation and growth were observed in the experiments. It is clarified that low strain rate influences crack propagation and coalescence and increases crack growth rate that finally decrease fatigue life.


Author(s):  
S. Herstead ◽  
M. de Vos ◽  
S. Cook

The success of any new build project is reliant upon all stakeholders — applicants, vendors, contractors and regulatory agencies — being ready to do their part. Over the past several years, the Canadian Nuclear Safety Commission (CNSC) has been working to ensure that it has the appropriate regulatory framework and internal processes in place for the timely and efficient licensing of all types of reactor, regardless of size. This effort has resulted in several new regulatory documents and internal processes including pre-project vendor design reviews. The CNSC’s general nuclear safety objective requires that nuclear facilities be designed and operated in a manner that will protect the health, safety and security of persons and the environment from unreasonable risk, and to implement Canada’s international commitments on the peaceful use of nuclear energy. To achieve this objective, the regulatory approach strikes a balance between pure performance-based regulation and prescriptive-based regulation. By utilizing this approach, CNSC seeks to ensure a regulatory environment exists that encourages innovation within the nuclear industry without compromising the high standards necessary for safety. The CNSC is applying a technology neutral approach as part of its continuing work to update its regulatory framework and achieve clarity of its requirements. A reactor power threshold of approximately 200 MW(th) has been chosen to distinguish between large and small reactors. It is recognized that some Small Modular Reactors (SMRs) will be larger than 200 MW(th), so a graded approach to achieving safety is still possible even though Nuclear Power Plant design and safety requirements will apply. Design requirements for large reactors are established through two main regulatory documents. These are RD-337 Design for New Nuclear Power Plants, and RD-310 Safety Analysis for Nuclear Power Plants. For reactors below 200 MW(th), the CNSC allows additional flexibility in the use of a graded approach to achieving safety in two new regulatory documents: RD-367 Design of Small Reactors and RD-308 Deterministic Safety Analysis for Small Reactors. The CNSC offers a pre-licensing vendor design review as an optional service for reactor facility designs. This review process is intended to provide early identification and resolution of potential regulatory or technical issues in the design process, particularly those that could result in significant changes to the design or analysis. The process aims to increase regulatory certainty and ultimately contribute to public safety. This paper outlines the CNSC’s expectations for applicant and vendor readiness and discusses the process for pre-licensing reviews which allows vendors and applicants to understand their readiness for licensing.


2018 ◽  
pp. 66-70
Author(s):  
O. V. Taran ◽  
O. G. Sandul

The nuclear energy use progressively becomes part of the life of every modern person, who more and more faces radioactive materials in medical institutions, in industry. Half of all electricity generated in Ukraine is generated by nuclear power plants. The peculiarities of the nuclear energy use generate appropriate rules for people dealing with radioactive materials. The article analyzes the standards of the Criminal Code of Ukraine, which provides for liability for acts related to the illegal handling of radioactive materials, for violation of the nuclear and radiation safety rules, violation of radiation safety requirements, the threat of theft of radioactive materials, the illicit manufacturing of a nuclear explosive device, abduction or capture of radioactive materials, attack on radioactive materials transportation means. The grounds and peculiarities for bringing to criminal liability have been reviewed, the range of persons who can be prosecuted has been defined. Conditions and grounds for exemption from criminal liability in the absence of a person's criminal intent to use radioactive material are considered. It has been demonstrated that the Criminal Code of Ukraine, by prohibiting certain actions on the illegal radioactive materials handling, ensures protection of the most important social relations and social benefits.


Author(s):  
Hag-Ki Youm ◽  
Kwang-Chu Kim ◽  
Man-Heung Park ◽  
Tea-Eun Jin ◽  
Sun-Ki Lee ◽  
...  

Recent events reported at a number of nuclear power plants worldwide have shown that thermal stratification, cycling, and striping in piping can cause excessive thermal stress and fatigue on the piping material. These phenomena are diverse and complicated because of the wide variety of geometry and thermal hydraulic conditions encountered in reactor coolant system. Thermal stratification effect of re-branched lines is not yet considered in the fatigue evaluation. To evaluate the thermal load due to turbulent penetration, this paper presents a fatigue evaluation methodology for a branch line of reactor coolant system with the re-branch line. The locations of fatigue monitoring and supplemented inspections are discussed as a result of fatigue evaluations by Interim Fatigue Management Guideline (ITFMG) and detail finite element analysis. Although the revised CUF was increased less than 50 %, the CUF values for some locations was greater than the ASME Code limits.


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