• 제목/요약/키워드: Energy criticality

검색결과 77건 처리시간 0.025초

Investigating Heavy Water Zero Power Reactors with a New Core Configuration Based on Experiment and Calculation Results

  • Nasrazadani, Zahra;Salimi, Raana;Askari, Afrooz;Khorsandi, Jamshid;Mirvakili, Mohammad;Mashayekh, Mohammad
    • Nuclear Engineering and Technology
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    • 제49권1호
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    • pp.1-5
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    • 2017
  • The heavy water zero power reactor (HWZPR), which is a critical assembly with a maximum power of 100 W, can be used in different lattice pitches. The last change of core configuration was from a lattice pitch of 18-20 cm. Based on regulations, prior to the first operation of the reactor, a new core was simulated with MCNP (Monte Carlo N-Particle)-4C and WIMS (Winfrith Improved Multigroup Scheme)-CITATON codes. To investigate the criticality of this core, the effective multiplication factor ($K_{eff}$) versus heavy water level, and the critical water level were calculated. Then, for safety considerations, the reactivity worth of $D_2O$, the reactivity worth of safety and control rods, and temperature reactivity coefficients for the fuel and the moderator, were calculated. The results show that the relevant criteria in the safety analysis report were satisfied in the new core. Therefore, with the permission of the reactor safety committee, the first criticality operation was conducted, and important physical parameters were measured experimentally. The results were compared with the corresponding values in the original core.

Evaluation of PNL30-35 Critical Experiments on ICSBEP

  • Joo, Hyung-Kook;Kim, Young-Jin;Sohn, Dong-Seong;J. Blair Briggs
    • 한국원자력학회:학술대회논문집
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    • 한국원자력학회 1997년도 춘계학술발표회논문집(1)
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    • pp.39-44
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    • 1997
  • The International Criticality Safety Benchmark Evaluation Project (ICSBEP) is under way for the purpose identifying, evaluating, and compiling benchmark critical experiment data into a standardized format that allows criticality analysts to easily use the data to validate calculational methods and cross sections. As part of this activity, PNL30-35 experiments, which had been adopted as benchmark problems by CSEWG in 1970s, were reevaluated, which results in some additions and modifications: changes in fuel number density, modification to the experimental keff, modifications to the soluble boron concentration for PNL-31, and addition of an uncertainty in the benchmark-model k$_{eff}$./.

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Monte Carlo simulations of criticality safety assessments of transuranic element storage in a pyroprocess facility

  • Kim, Jinhwan;Kim, Jisoo;Lim, Kyung Taek;Ahn, Seong Kyu;Park, Se Hwan;Cho, Gyuseong
    • Nuclear Engineering and Technology
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    • 제50권6호
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    • pp.815-819
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    • 2018
  • In this study, criticality safety assessments of the potential for storing transuranic element (TRU) ingots via a pyroprocess were evaluated to determine the appropriate TRU storage design parameters, in this case the ratio of the TRU ingot height to the radius and the number of TRU ingot canisters stacked within a container. Various accident situations were modeled over a modeling period of 5 years for a cumulative inventory of TRU ingots with various water densities in submerged containers and with various pitches between the containers in the facility. Under these combinations, we calculated the threshold of TRU height and radius ratio depending on the number of canisters in a container to keep the stored TRU in a subcritical state. The ratio of the TRU ingot height to radius should not exceed 4.5, 1.1, 0.5, 0.3, and 0.2 for two, three, four, five, and six levels of stacked canisters in a container, respectively.

An Energy Efficient Localized Topology Control Algorithm for Wireless Multihop Networks

  • Shang, Dezhong;Zhang, Baoxian;Yao, Zheng;Li, Cheng
    • Journal of Communications and Networks
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    • 제16권4호
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    • pp.371-377
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    • 2014
  • Localized topology control is attractive for obtaining reduced network graphs with desirable features such as sparser connectivity and reduced transmit powers. In this paper, we focus on studying how to prolong network lifetime in the context of localized topology control for wireless multi-hop networks. For this purpose, we propose an energy efficient localized topology control algorithm. In our algorithm, each node is required to maintain its one-hop neighborhood topology. In order to achieve long network lifetime, we introduce a new metric for characterizing the energy criticality status of each link in the network. Each node independently builds a local energy-efficient spanning tree for finding a reduced neighbor set while maximally avoiding using energy-critical links in its neighborhood for the local spanning tree construction. We present the detailed design description of our algorithm. The computational complexity of the proposed algorithm is deduced to be O(mlog n), where m and n represent the number of links and nodes in a node's one-hop neighborhood, respectively. Simulation results show that our algorithm significantly outperforms existing work in terms of network lifetime.

연소를 고려한 사용후핵연료저장조 핵임계 안전성분석에서 계산체제간의 편차결정 (A Determination of Bias between Calculational Methods for the Criticality Safety Analysis of Spent Fuel Storage Pool with Burnup Credit)

  • Byung Jin Jun;Chang-Kun Lee;Hee-Chun No
    • Nuclear Engineering and Technology
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    • 제18권1호
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    • pp.17-26
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    • 1986
  • 연소를 고려하는 사용후핵연료저장조의 핵임계 안전성 분석에서 검증용 계산 체제와 rack계산 체제 사이의 편차를 신뢰성 있게 결정하는 방법을 시험하였다. 이를 위하여 고리 1호기의 사용후핵연료저장조를 연소를 고려하는 가장 조밀한 rack으로 개념설계하고, 핵연료의 농축도 및 연소도에 따라 증배계수를 계산하였다. 표준값 생산용 Monte Carlo 코드로는 KENO-IV를 그리고 실제 rack 설계용으로는 2차원 충돌화률 코드인 FATAC을 사용하였다. 이 두 계산의 결과를 상호 비교하여 계산 체제 사이의 편차와 이의 경향성 및 신뢰도를 평가하였다. 이 방법을 사용하면 확실한 신뢰도 근거를 마련할 수 있을 뿐만 아니라 반응도 여유면에서 기존의 방법보다 불리하지 않음이 입증되었다.

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사용후 핵연료의 핵임계도 분석에 필요한 핵분열생성물의 핵군단면적 생산 (Generation of Group Constant of Fission Product for Criticality Analysis of Spent Fuel)

  • 신희성;최병일;박종묵;노성기
    • Journal of Radiation Protection and Research
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    • 제14권2호
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    • pp.30-36
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    • 1989
  • 고리 1호기의 사용후 핵연료에 함유된 핵종중 핵임계도에 미치는 영향이 큰 22개 핵종에 대한 핵단면적 자료를 XLACS-II에 의해서 ENDF/B-IV로 부터 취해서 FISSLIB(51군 핵단면적 자료)를 만들었다. 그리고 AMPX 조직에 의해서 DLC-43/CSRL 자료로 부터 생산된 51군 핵단면적 자료와 함께 사용할 수 있도록 하였다. 한편 BNL-325와 FISSLIB을 비교하여 후자의 유용성을 확인하였다. 그리고 FISSLIB에 수록된 핵분열 생성물 핵종에 대한 핵군단면적을 기본 입력자료로 하여 무한 배열된 고리 1호기 사용후 핵연료봉에 대한 핵임계도 계산을 수행하였다. 그 결과 냉각기간에 따라 핵분열 생성물 핵종을 고려할 때의 핵임계도는 그것을 무시할 때보다 9-14%의 감소효과를 나타냈다.

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KSC-4 수송용기의 핵임계도 분석 (Criticality Analysis of KSC-4 Spent Fuel Shipping Cask)

  • 최병일;신희성;박종묵;노성기
    • Journal of Radiation Protection and Research
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    • 제14권1호
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    • pp.56-65
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    • 1989
  • 가압 경수로형 사용후 핵연료 4개를 수송할 수 있는 KSC-4 수송 용기에 대한 핵임계도 분석을 KENO-IV 전산 코드와 AMPX 전산 코드계로 부터 생산한 19군 핵단면적 자료를 써서 수행하였다. 핵임계도 계산은 10CFR71에서 제시한 기준에 따라 보수적인 계산을 위해 수송 용기내에 사용후 핵연료 대신 신핵연료로 가정하여 정상 수송 조건 및 가상 사고 조건에 대해 수행하였다. 그 결과, 핵임계도는 정상 수송 조건 및 가상 사고 조건시에 각각 0.85289 및 0.94185이었다. 따라서 KSC-4 수송 용기의 핵임계도는 10CFR71에서 규정하고 있는 미임계 요건을 만족하고 있다.

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