• 제목/요약/키워드: Criticality analysis

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Experimental analysis of whiplash injury with hybrid III 50 percentile test dummy

  • Gocmen, Ulas;Gokler, Mustafa Ilhan
    • Advances in Automotive Engineering
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    • 제1권1호
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    • pp.61-77
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    • 2018
  • In this study, the effects of sitting position of the driver on the whiplash neck injury have been analyzed experimentally by using hybrid III series 50 percentile male crash test dummy. A testing platform consisting of vehicle ground, driver foot rest, driver seat and a 3-point seatbelt has been prepared. This testing platform and the instrumented crash test dummy are prepared for tests according to the Euro NCAP whiplash testing protocol. The prepared test set-up has been exposed to 3 different acceleration-time loading curves defined in the Euro NCAP whiplash testing protocol by performing sled tests. 9 different sled tests have been performed with the combinations of 3 different seating positions of the crash test dummy and 3 different acceleration-time loading curves. The sensor data obtained from the crash test dummy and high-speed videos taken are analyzed according to the injury assessments criteria defined in the Euro NCAP whiplash testing protocol and the criticality of the whiplash injury is defined. It is seen that the backset distance of the driver head with the headrest and the height difference of the top of the head of the driver with the headrest have a great importance on whiplash injuries.

시스템 구성품의 위험 심각도를 반영한 안전중시 시스템의 설계 모듈화에 관한 연구 (On the Development of Modularized Structures for Safety-Critical Systems by Analyzing Components Failure)

  • 김영민;이재천
    • 대한안전경영과학회지
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    • 제16권4호
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    • pp.11-19
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    • 2014
  • Modern systems development becomes more and more complicated due to the need on the ever-increasing capability of the systems. In addition to the complexity issue, safety concern is also increasing since the malfunctions of the systems under development may result in the accidents in both the test and evaluation phase and the operation phase. Those accidents can cause disastrous damages if explosiveness gets involved therein such as in weapon systems development. The subject of this paper is on how to incorporate safety requirements in the design of safety-critical systems. As an approach, a useful system structure using the method of design structure matrix (DSM) is studied while reflecting the need on systems safety. Specifically, the effects of system components failure are analyzed and numerically modeled first. Also, the system components are identified and their interfaces are represented using a component DSM. Combining the results of the failure analysis and the component DSM leads to a modified DSM. By rearranging the resultant DSM, a modular structure is derived with safety requirements incorporated. As a case study, application of the approach is also discussed in the development of a military UAV plane.

Maintenance Priority Index of Overhead Transmission Lines for Reliability Centered Approach

  • Heo, Jae-Haeng;Kim, Mun-Kyeom;Kim, Dam;Lyu, Jae-Kun;Kang, Yong-Cheol;Park, Jong-Keun
    • Journal of Electrical Engineering and Technology
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    • 제9권4호
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    • pp.1248-1257
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    • 2014
  • Overhead transmission lines are crucial components in power transmission systems. Well-designed maintenance strategy for overhead lines is required for power utilities to minimize operating costs, while improving the reliability of the power system. This paper presents a maintenance priority index (MPI) of overhead lines for a reliability centered approach. Proposed maintenance strategy is composed of a state index and importance indices, taking into account a transmission condition and importance in system reliability, respectively. The state index is used to determine the condition of overhead lines. On the other hand, the proposed importance indices indicate their criticality analysis in transmission system, by using a load effect index (LEI) and failure effect index (FEI). The proposed maintenance method using the MPI has been tested on an IEEE 9-bus system, and a numerical result demonstrates that our strategy is more cost effective than traditional maintenance strategies.

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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    • 제46권1호
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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.

An advanced core design for a soluble-boron-free small modular reactor ATOM with centrally-shielded burnable absorber

  • Nguyen, Xuan Ha;Kim, ChiHyung;Kim, Yonghee
    • Nuclear Engineering and Technology
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    • 제51권2호
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    • pp.369-376
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    • 2019
  • A complete solution for a soluble-boron-free (SBF) small modular reactor (SMR) is pursued with a new burnable absorber concept, namely centrally-shielded burnable absorber (CSBA). Neutronic flexibility of the CSBA design has been discussed with fuel assembly (FA) analyses. Major design parameters and goals of the SBF SMR are discussed in view of the reactor core design and three CSBA designs are introduced to achieve both a very low burnup reactivity swing (BRS) and minimal residual reactivity of the CSBA. It is demonstrated that the core achieves a long cycle length (~37 months) and high burnup (~30 GWd/tU), while the BRS is only about 1100 pcm and the radial power distribution is rather flat. This research also introduces a supplementary reactivity control mechanism using stainless steel as mechanical shim (MS) rod to obtain the criticality during normal operation. A further analysis is performed to investigate the local power peaking of the CSBA-loaded FA at MS-rodded condition. Moreover, a simple $B_4C$-based control rod arrangement is proposed to assure a sufficient shutdown margin even at the cold-zero-power condition. All calculations in this neutronic-thermal hydraulic coupled investigation of the 3D SBF SMR core are completed by a two-step Monte Carlo-diffusion hybrid methodology.

Influence of nuclear data library on neutronics benchmark of China experimental fast reactor start-up tests

  • Guo, Hui;Jin, Xin;Huo, Xingkai;Gu, Hanyang;Wu, Haicheng
    • Nuclear Engineering and Technology
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    • 제54권10호
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    • pp.3888-3896
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    • 2022
  • Nuclear data is the basis of reactor physics analysis. This paper aim at studying the influence of major evaluated nuclear data libraries, CENDL-3.2, ENDF/B-VIII.0, JEFF-3.3, and JENDL-4.0u, on the neutronics modelling of CEFR start-up tests. Results show these four libraries have a good performance and consistency in the modelling CEFR start-up tests. The JEFF-3.3 results exhibit only an 8 pcm keff difference with the measurement. The difference in criticality is decomposed by nuclide, which shows the large overestimation of CENDL-3.2 is mainly from the cross-section of 52Cr. Except for few cases, the calculation results are within 1σ of measurement uncertainty in control rod worth, sodium void reactivity, temperature reactivity, and subassembly swap reactivity. In the evaluation of axial and radial reaction distribution, there are about 65% of relative errors that are less than 5% and 82% of relative errors that are less than 10%.

Verification of OpenMC for fast reactor physics analysis with China experimental fast reactor start-up tests

  • Guo, Hui;Huo, Xingkai;Feng, Kuaiyuan;Gu, Hanyang
    • Nuclear Engineering and Technology
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    • 제54권10호
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    • pp.3897-3908
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    • 2022
  • High-fidelity nuclear data libraries and neutronics simulation tools are essential for the development of fast reactors. The IAEA coordinated research project on "Neutronics Benchmark of CEFR Start-Up Tests" offers valuable data for the qualification of nuclear data libraries and neutronics codes. This paper focuses on the verification and validation of the CEFR start-up modelling using OpenMC Monte-Carlo code against the experimental measurements. The OpenMC simulation results agree well with the measurements in criticality, control rod worth, sodium void reactivity, temperature reactivity, subassembly swap reactivity, and reaction distribution. In feedback coefficient evaluations, an additional state method shows high consistency with lower uncertainty. Among 122 relative errors in the benchmark of the distribution of nuclear reaction, 104 errors are less than 10% and 84 errors are less than 5%. The results demonstrate the high reliability of OpenMC for its application in fast reactor simulations. In the companion paper, the influence of cross-section libraries is investigated using neutronics modelling in this paper.

INFRASTRUCTURE RISK MANAGEMENT IN PREPAREDNESS OF EXTREME EVENTS

  • Eun Ho Oh;Abhijeet Deshmukh;Makarand Hastak
    • 국제학술발표논문집
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    • The 3th International Conference on Construction Engineering and Project Management
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    • pp.83-90
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    • 2009
  • Natural disasters, such as the recent floods in the Midwest, Hurricane Ike in the Gulf coast region (U.S.), and the earthquake in Sichuan (China), cause severe damage to the infrastructure as well as the associated industries and communities that rely on the infrastructure. The estimated damages due to Hurricane Ike in 2008 were a staggering $27 billion, the third worst in U.S. history. In addition, the worst earthquake in three decades in Sichuan resulted in about 90,000 people dead or missing and $20 billion of the estimated loss. A common observation in the analyses of these natural disaster events is the inadequacy of critical infrastructure to withstand the forces of natural calamities and the lack of mitigation strategies when they occur on the part of emergency-related organizations, industries, and communities. If the emergency-related agencies could identify and fortify the vulnerable critical infrastructure in the preparedness stage, the damage and impacts can be significantly reduced. Therefore, it is important to develop a decision support system (DSS) for identifying region-specific mitigation strategies based on the inter-relationships between the infrastructure and associated industries and communities in the affected region. To establish effective mitigation strategies, relevant data were collected from the affected areas with respect to the technical, social, and economic impact levels. The data analysis facilitated identifying the major factors, such as vulnerability, criticality, and severity, for developing a DSS. Customized mitigation strategies that will help agencies prepare, respond, and recover according to the disaster response were suggested.

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Application of two different similarity laws for the RVACS design

  • Min Ho Lee;Ji Hwan Hwang;Ki Hyun Choi;Dong Wook Jerng;In Cheol Bang
    • Nuclear Engineering and Technology
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    • 제54권12호
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    • pp.4759-4775
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    • 2022
  • The RVACS is a versatile and robust safety system driven by two natural circulations: in-vessel coolant and ex-vessel air. To observe interaction between the two natural circulations, SINCRO-IT facility was designed with two different similarity laws simultaneously. Bo' based similarity law was employed for the in-vessel, while Ishii's similarity law for the ex-vessel excluding the radiation. Compared to the prototype, the sodium and air system, SINCRO-IT was designed with Wood's metal and air, having 1:4 of the length reduction, and 1.68:1 of the time scale ratio. For the steady state, RV temperature limit was violated at 0.8% of the decay heat, while the sodium boiling was predicted at 1.3%. It showed good accordance with the system code, TRACE. For an arbitrary re-criticality scenario with RVACS solitary operation, sodium boiling was predicted at 25,100 s after power increase from 1.0 to 2.0%, while the system code showed 30,300. Maximum temperature discrepancy between the experiments and system code was 4.2%. The design and methodology were validated by the system code TRACE in terms of the convection, and simultaneously, the system code was validated against the simulating experiments SINCRO-IT. The validated RVACS model could be imported to further accident analysis.

Development of multigroup cross section library generation system TPAMS

  • Lili Wen;Haicheng Wu;Ying Chen;Xiaoming Chai;Xiaofei Wu;Xiaolan Tu;Yuan Liu
    • Nuclear Engineering and Technology
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    • 제56권6호
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    • pp.2208-2219
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    • 2024
  • Kylin-2 is an advanced neutronics lattice code, developed by Nuclear Power Institute of China. High-precision multigroup cross section library is need for KYLIN-2 to carry out simulation of current pressurized water reactor (PWR) and advanced reactor. In this paper a multigroup cross section library generation system named TPAMS was developed, the methods in TPAMS dealing with resonance data such as subgroup parameters, lambda factor, resonance integral were discussed. Moreover, the depletion chain simplification method was studied. TPAMS can produce multigroup library in binary and ASIIC formats, including detailed data contents for resonance, transport and depletion calculations. A multigroup cross section library has been generated for KYLIN-2 based on TPAMS system. The multigroup cross section library was verified through the analysis of various criticality and burnup benchmarks, the values of multiplication factor and isotope density were compared with the experiment data. Numerical results demonstrate the accuracy of the multigroup cross section library and the reliability of the multigroup cross section library generation system TPAMS.