• Title/Summary/Keyword: nuclear structure

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Development of a structure analytic hierarchy approach for the evaluation of the physical protection system effectiveness

  • Zou, Bowen;Wang, Wenlin;Liu, Jian;Yan, Zhenyu;Liu, Gaojun;Wang, Jun;Wei, Guanxiang
    • Nuclear Engineering and Technology
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    • v.52 no.8
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    • pp.1661-1668
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    • 2020
  • A physical protection system (PPS) is used for the protection of critical facilities. This paper proposes a structure analytic hierarchy approach (SAHA) for the hierarchical evaluation of the PPS effectiveness in critical infrastructure. SAHA is based on the traditional analysis methods "estimate of adversary sequence interruption, EASI". A community algorithm is used in the building of the SAHA model. SAHA is applied to cluster the associated protection elements for the topological design of complicated PPS with graphical vertexes equivalent to protection elements.

Research on the structure design of the LBE reactor coolant pump in the lead base heap

  • Lu, Yonggang;Zhu, Rongsheng;Fu, Qiang;Wang, Xiuli;An, Ce;Chen, Jing
    • Nuclear Engineering and Technology
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    • v.51 no.2
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    • pp.546-555
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    • 2019
  • Since the first nuclear reactor first critical, nuclear systems has gone through four generations of history, and the fourth generation nuclear system will be truly realized in the near future. The notions of SVBR and lead-bismuth eutectic alloy coolant put forward by Russia were well received by the international nuclear science community. Lead-bismuth eutectic alloy with the ability of the better neutron economy, the low melting point, the high boiling point, the chemical inertness to water and air and other features, which was considered the most promising coolant for the 4th generation nuclear reactors. This study mainly focuses on the structural design optimization of the 4th-generation reactor coolant pump, including analysis of external characteristics, inner flow, and transient characteristic. It was found that: the reactor coolant pump with a central symmetrical dual-outlet volute structure has better radial-direction balance, the pump without guide vane has better hydraulic performance, and the pump with guide vanes has worse torsional vibration and pressure pulsation. This study serves as experience accumulation and technical support for the development of the 4th generation nuclear energy system.

Beyond design basis seismic evaluation of underground liquid storage tanks in existing nuclear power plants using simple method

  • Wang, Shen
    • Nuclear Engineering and Technology
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    • v.54 no.6
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    • pp.2147-2155
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    • 2022
  • Nuclear safety-related underground liquid storage tanks, such as those used to store fuel for emergency diesel generators, are critical components for safety of hundreds of existing nuclear power plants (NPP) worldwide. Since most of those NPP will continue to operate for decades, a beyond design base (BDB) seismic screening of safety-related underground tanks in those NPP is beneficial and essential to public safety. The analytical methodology for buried tank subjected to seismic effect, including a BDB seismic evaluation, needs to consider both soil-structure and fluid-structure interaction effects. Comprehensive analysis of such a soil-structure-fluid system is costly and time consuming, often subjected to availability of state-of-art finite element tools. Simple, but practically and reasonably accurate techniques for seismic evaluation of underground liquid storage tanks have not been established. In this study, a mechanics based solution is proposed for the evaluation of a cylindrical underground liquid storage tank using hand calculation methods. For validation, a practical example of two underground diesel fuel tanks in an existing nuclear power plant is presented and application of the proposed method is confirmed by using published results of the computer-aided System for Analysis of Soil Structural Interaction (SASSI). The proposed approach provides an easy to use tool for BDB seismic assessment prior to making decision of applying more costly technique by owner of the nuclear facility.

Adaptive energy group division in the few-group cross-section generation for full spectrum reactor modeling with deterministic method

  • Yichen Yang;Youqi Zheng;Xianan Du;Hongchun Wu
    • Nuclear Engineering and Technology
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    • v.56 no.6
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    • pp.2019-2028
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    • 2024
  • Advanced nuclear reactors, especially the newly developed small and micro-reactors have complex neutron spectrum, which makes the deterministic reactor core calculations sensitive to the energy group structure of few-group cross-sections. To avoid significantly increasing the cost of energy discretization in the core calculation, two energy group structures with 31 groups and 33 groups were adopted for typical thermal and fast reactor cores, respectively. Then, an adaptive scheme of group division for reactor cores with a medium neutron spectrum was proposed. The works were based on the full spectrum nuclear reactor analysis code SARAX/TULIP. An equivalent one-dimensional model of the core was proposed to capture the key neutron spectrum features of the reactor core. Such features were used to adaptively determine a few-group structure for the following reactor core calculations. Then, the neutron spectrum in different zones with more details was calculated. With this spectrum, the cross-sections were condensed into the determined energy groups. Three tests based on different neutron spectrum were calculated to verify the schemes. The results show that using the adaptive energy group division scheme, the following core calculation can meet the accuracy requirement of different reactors with different neutron spectra.

Design of a Reliable Network for DCS in Nuclear Power Plant (원자력 발전소 분산 제어 시스템을 위한 고신뢰 통신망의 설계)

  • Lee, Sung-Woo;Im, Han-Suck
    • Proceedings of the KIEE Conference
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    • 1997.11a
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    • pp.588-590
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    • 1997
  • In this paper, a highly reliable communication network for DCS in nuclear power plant is designed. The structure and characteristics of DCS in nuclear power plant is briefly explained. The features needed for a communication network for DCS in nuclear power plant is described. According to the abovo features, the layer structure of the communication network is determined and each layer is designed in detail.

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IMPACT ANALYSIS OF A WATER STORAGE TANK

  • Jhung, Myung-Jo;Jo, Jong-Chull;Jeong, Sang-Jin
    • Nuclear Engineering and Technology
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    • v.38 no.7
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    • pp.681-688
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    • 2006
  • This study investigates the dynamic response characteristics of a structure impacted by a high speed projectile. The impact of a 300 kg projectile on a water storage tank is simulated by the general purpose computer codes ANSYS and LS-DYNA. Several methods to simulate the impact are considered and their results are compared. Based upon this, an alternative impact analysis method that is equivalent to an explicit dynamic analysis is proposed. The effect of fluid on the responses of the tank is also addressed.

In-structure Response Evaluation of Shear Wall Structure via Shaking Table Tests (진동대 실험을 통한 전단벽 구조물의 층응답 특성 평가)

  • Jung, Jae-Wook;Ha, Jeong-Gon;Hahm, Daegi;Kim, Min Kyu
    • Journal of the Earthquake Engineering Society of Korea
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    • v.25 no.3
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    • pp.129-135
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    • 2021
  • After the manual shutdown of the Wolseong nuclear power plant due to an earthquake in Gyeongju in 2016, anxiety about the earthquake safety of nuclear power plants has become a major social issue. The shear wall structure used as a major structural element in nuclear power plants is widely used as a major structural member because of its high resistance to horizontal loads such as earthquakes. However, due to the complexity of the structure, it is challenging to predict the dynamic characteristics of the structure. In this study, a three-story shear wall structure is fabricated, and the in-structure response characteristics of the shear wall structure are evaluated through shaking table tests. The test is performed using the Gyeongju earthquake that occurred in 2016, and the response characteristics due to the domestic earthquake are evaluated.