• Title/Summary/Keyword: Safety-net

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Development of easy-to-use interface for nuclear transmutation computing, VCINDER code

  • Kum, Oyeon
    • Nuclear Engineering and Technology
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    • v.50 no.1
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    • pp.25-34
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    • 2018
  • The CINDER code has about 60 years of development history, and is thus one of the world's best transmutation computing codes to date. Unfortunately, it is complex and cumbersome to use. Preparing auxiliary input files for activation computation from MCNPX output and executing them using Perl script (activation script) is the first difficulty, and separation of gamma source computing script (gamma script), which analyzes the spectra files produced by CINDER code and creates source definition format for MCNPX code, is the second difficulty. In addition, for highly nonlinear problems, multiple human interventions may increase the possibility of errors. Postprocessing such as making plots with large text outputs is also time consuming. One way to improve these limitations is to make a graphical user interface wrapper that includes all codes, such as MCNPX and CINDER, and all scripts with a visual C#.NET tool. The graphical user interface merges all the codes and provides easy postprocessing of graphics data and Microsoft office tools, such as Excel sheets, which make the CINDER code easy to use. This study describes the VCINDER code (with visual C#.NET) and gives a typical application example.

A refinement and abstraction method of the SPZN formal model for intelligent networked vehicles systems

  • Yang Liu;Yingqi Fan;Ling Zhao;Bo Mi
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.18 no.1
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    • pp.64-88
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    • 2024
  • Security and reliability are the utmost importance facts in intelligent networked vehicles. Stochastic Petri Net and Z (SPZN) as an excellent formal verification tool for modeling concurrent systems, can effectively handles concurrent operations within a system, establishes relationships among components, and conducts verification and reasoning to ensure the system's safety and reliability in practical applications. However, the application of a system with numerous nodes to Petri Net often leads to the issue of state explosion. To tackle these challenges, a refinement and abstraction method based on SPZN is proposed in this paper. This approach can not only refine and abstract the Stochastic Petri Net but also establish a corresponding relationship with the Z language. In determining the implementation rate of transitions in Stochastic Petri Net, we employ the interval average and weighted average method, which significantly reduces the time and space complexity compared to alternative techniques and is suitable for expert systems at various levels. This reduction facilitates subsequent comprehensive system analysis and module analysis. Furthermore, by analyzing the properties of Markov Chain isomorphism in the case study, recommendations for minimizing system risks in the application of intelligent parking within the intelligent networked vehicle system can be put forward.

OVERVIEW OF RECENT EFFORTS THROUGH ROSA/LSTF EXPERIMENTS

  • Nakamura, Hideo;Watanabe, Tadashi;Takeda, Takeshi;Maruyama, Yu;Suzuki, Mitsuhiro
    • Nuclear Engineering and Technology
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    • v.41 no.6
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    • pp.753-764
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    • 2009
  • JAEA started the LSTF experiments in 1985 for the fourth stage of the ROSA Program (ROSA-IV) for the LWR thermal-hydraulic safety research to identify and investigate the thermal-hydraulic phenomena and to confirm the effectiveness of ECCS during small-break LOCAs and operational transients. The LSTF experiments are underway for the ROSA-V Program and the OECD/NEA ROSA Project that intends to resolve issues in thermal-hydraulic analyses relevant to LWR safety. Six types of the LSTF experiments have been done for both the system integral and separate-effect experiments among international members from 14 countries. Results of four experiments for the ROSA Project are briefly presented with analysis by a best-estimate (BE) code and a computational fluid dynamics (CFD) code to illustrate the capability of the LSTF and codes to simulate the thermal-hydraulic phenomena that may appear during SBLOCAs and transients. The thermal-hydraulic phenomena dealt with are coolant mixing and temperature stratification, water hammer up to high system pressure, natural circulation under high core power condition, and non-condensable gas effect during asymmetric SG depressurization as an AM action.

PRELIMINARY SAFETY STUDY OF ENGINEERING-SCALE PYROPROCESS FACILITY

  • Moon, Seong-In;Chong, Won-Myung;You, Gil-Sung;Ku, Jeong-Hoe;Kim, Ho-Dong;Lim, Yong-Kyu;Chang, Hyeon-Sik
    • Nuclear Engineering and Technology
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    • v.46 no.1
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    • pp.63-72
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    • 2014
  • Pyroprocess technology has been considered as a fuel cycle option to solve the spent fuel accumulation problems in Korea. The Korea Atomic Energy Research Institute has been studying pyroprocess technology, and the conceptual design of an engineering-scale pyroprocess facility, called the Advanced Fuel Cycle (AFC) facility, has been performed on the basis of a 10tHM throughput per year. In this paper, the concept of the AFC facility was introduced, and its safety evaluations were performed. For the safety evaluations, anticipated accident events were selected, and environmental safety analyses were conducted for the safety of the public and workers. In addition, basic radiation shielding safety analyses and criticality safety analyses were conducted. These preliminary safety studies will be used to specify the concept of safety systems for pyroprocess facilities, and to establish safety design policies and advance more definite safety designs.

Neutronics analysis of JSI TRIGA Mark II reactor benchmark experiments with SuperMC3.3

  • Tan, Wanbin;Long, Pengcheng;Sun, Guangyao;Zou, Jun;Hao, Lijuan
    • Nuclear Engineering and Technology
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    • v.51 no.7
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    • pp.1715-1720
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    • 2019
  • Jozef Stefan Institute (JSI), TRIGA Mark II reactor employs the homogeneous mixture of uranium and zirconium hydride fuel type. Since its upgrade, a series of fresh fuel steady state experimental benchmarks have been conducted. The benchmark results have provided data for testing computational neutronics codes which are important for reactor design and safety analysis. In this work, we investigated the JSI TRIGA Mark II reactor neutronics characteristics: the effective multiplication factor and two safety parameters, namely the control rod worth and the fuel temperature reactivity coefficient using SuperMC. The modeling and real-time cross section generation methods of SuperMC were evaluated in the investigation. The calculation analysis indicated the following: the effective multiplication factor was influenced by the different cross section data libraries; the control rod worth evaluation was better with Monte Carlo codes; the experimental fuel temperature reactivity coefficient was smaller than calculated results due to change in water temperature. All the results were in good agreement with the experimental values. Hence, SuperMC could be used for the designing and benchmarking of other TRIGA Mark II reactors.

A new method for safety classification of structures, systems and components by reflecting nuclear reactor operating history into importance measures

  • Cheng, Jie;Liu, Jie;Chen, Shanqi;Li, Yazhou;Wang, Jin;Wang, Fang
    • Nuclear Engineering and Technology
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    • v.54 no.4
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    • pp.1336-1342
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    • 2022
  • Risk-informed safety classification of structures, systems and components (SSCs) is very important for ensuring the safety and economic efficiency of nuclear power plants (NPPs). However, previous methods for safety classification of SSCs do not take the plant operating modes or the operational process of SSCs into consideration, thus cannot concentrate on the safety and economic efficiency accurately. In this contribution, a new method for safety classification of SSCs based on the categorization of plant operating modes is proposed, which considers the NPPs operating history to improve the economic efficiencies while maintaining the safety. According to the time duration of plant configurations in plant operating modes, average importances of SSCs are accessed for an NPP considering the operational process, and then safety classification of SSCs is performed for plant operating modes. The correctness and effectiveness of the proposed method is demonstrated by application in an NPP's safety classification of SSCs.

Identification of Fire Modeling Issues Based on an Analysis of Real Events from the OECD FIRE Database

  • Hermann, Dominik
    • Nuclear Engineering and Technology
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    • v.49 no.2
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    • pp.342-348
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    • 2017
  • Precursor analysis is widely used in the nuclear industry to judge the significance of events relevant to safety. However, in case of events that may damage equipment through effects that are not ordinary functional dependencies, the analysis may not always fully appreciate the potential for further evolution of the event. For fires, which are one class of such events, this paper discusses modelling challenges that need to be overcome when performing a probabilistic precursor analysis. The events used to analyze are selected from the Organisation for Economic Cooperation and Development (OECD) Fire Incidents Records Exchange (FIRE) Database.

TECHNICAL RATIONALE FOR METAL FUEL IN FAST REACTORS

  • Chang, Yoon-Il
    • Nuclear Engineering and Technology
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    • v.39 no.3
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    • pp.161-170
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    • 2007
  • Metal fuel, which was abandoned in the 1960's in favor of oxide fuel, has since then proven to be a viable fast reactor fuel. Key discoveries allowed high burnup capability and excellent steady-state as well as off-normal performance characteristics. Metal fuel is a key to achieving inherent passive safety characteristics and compact and economic fuel cycle closure based on electrorefining and injection-casting refabrication.

Experimental technique for efficiency transfer along different geometries and volumes

  • Haddad, Kh;AL-Homyed, A.
    • Nuclear Engineering and Technology
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    • v.53 no.2
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    • pp.695-698
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    • 2021
  • Efficiency calibration is a fundamental procedure in gamma spectrometric measurement. Experimental technique for efficiency calibration transfer in gamma spectrometer along different geometries and volumes has been developed and validated in this work. The developed technique offers simple and easy procedures to overcome several problems encountered in efficiency calibration of gamma spectrometer such as rate-related correction and different sample volumes. The validation shows that application of the developed technique has a precision of 95%.

POSSIBILITIES AND LIMITATIONS OF APPLYING SOFTWARE RELIABILITY GROWTH MODELS TO SAFETY-CRITICAL SOFTWARE

  • Kim, Man-Cheol;Jang, Seung-Cheol;Ha, Jae-Joo
    • Nuclear Engineering and Technology
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    • v.39 no.2
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    • pp.129-132
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    • 2007
  • It is generally known that software reliability growth models such as the Jelinski-Moranda model and the Goel-Okumoto's non-homogeneous Poisson process (NHPP) model cannot be applied to safety-critical software due to a lack of software failure data. In this paper, by applying two of the most widely known software reliability growth models to sample software failure data, we demonstrate the possibility of using the software reliability growth models to prove the high reliability of safety-critical software. The high sensitivity of a piece of software's reliability to software failure data, as well as a lack of sufficient software failure data, is also identified as a possible limitation when applying the software reliability growth models to safety-critical software.