• Title/Summary/Keyword: nuclear organization

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PROTECTION SEQUENCE OF AC/DC CONVERTERS FOR ITER PF MAGNET COILS

  • Oh, Byung-Hoon;Hwang, Churl-Kew;Lee, Kwang-Wang;Jin, Jeong-Tae;Chang, Dae-Sik;Oh, Jong-Seok;Choi, Jung-Wan;Suh, Jae-Hak;Tao, Jun;Song, In-Ho
    • Nuclear Engineering and Technology
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    • v.42 no.3
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    • pp.305-312
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    • 2010
  • The protection sequence of an AC/DC converter for an ITER PF coil system is developed in this study. Possible faults in the coil system are simulated and the results reflected in the design of a sequence to protect the coil and converter. The inductances of the current sharing reactors and thyristor numbers in parallel with the bridge arms are optimized with the designed protection sequence.

Lamin A/C and Polymeric Actin in Genome Organization

  • Ondrej, Vladan;Lukasova, Emilie;Krejci, Jana;Matula, Pavel;Kozubek, Stanislav
    • Molecules and Cells
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    • v.26 no.4
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    • pp.356-361
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    • 2008
  • In this work, we have studied the structural and functional linkage between lamin A/C, nuclear actin, and organization of chromosome territories (CTs) in mammary carcinoma MCF-7 cells. Selective down-regulation of lamin A/C expression led to disruption of the lamin A/C perinuclear layer and disorganization of lamin-bound emerin complexes at the inner nuclear membrane. The silencing of lamin A/C expression resulted in a decrease in the volume and surface area of chromosome territories, especially in chromosomes with high heterochromatin content. Inhibition of actin polymerization led to relaxation of the structure of chromosome territories, and an increase in the volumes and surface areas of the chromosome territories of human chromosomes 1, 2 and 13. The results show an important role of polymeric actin in the organization of the nuclei and the chromosome territories.

Neutronic analysis of control rod effect on safety parameters in Tehran Research Reactor

  • Torabi, Mina;Lashkari, A.;Masoudi, Seyed Farhad;Bagheri, Somayeh
    • Nuclear Engineering and Technology
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    • v.50 no.7
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    • pp.1017-1023
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    • 2018
  • The measurement and calculation of neutronic parameters in nuclear research reactors has an important influence on control and safety of the nuclear reactor. The power peaking factors, reactivity coefficients and kinetic parameters are the most important neutronic parameter for determining the state of the reactor. The position of the control shim safety rods in the core configuration affects these parameters. The main purpose of this work is to use the MTR_PC package to evaluate the effect of the partially insertion of the control rod on the neutronic parameters at the operating core of the Tehran Research Reactor. The simulation results show that by increasing the insertion of control rods (bank) in the core, the absolute values of power peaking factor, reactivity coefficients and effective delayed neutron fraction increased and only prompt neutron life time decreased. In addition, the results show that the changes of moderator temperature coefficients value versus the control rods positions are very significant. The average value of moderator temperature coefficients increase about 98% in the range of 0-70% insertion of control rods.

CURRENT STATUS AND IMPORTANT ISSUES ON SEISMIC HAZARD EVALUATION METHODOLOGY IN JAPAN

  • Ebisawa, Katsumi
    • Nuclear Engineering and Technology
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    • v.41 no.10
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    • pp.1223-1234
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    • 2009
  • The outlines of seismic PSA implementation standards and seismic hazard evaluation procedure were shown. An overview of the cause investigation of seismic motion amplification on the Niigata-ken Chuetsu-oki (NCO) earthquake was also shown. Then, the contents for improving the seismic hazard evaluation methodology based on the lessons learned from the NCO earthquake were described. (1) It is very important to recognize the effectiveness of a fault model on the detail seismic hazard evaluation for the near seismic source through the cause investigation of the NCO earthquake. (2) In order to perform and proceed with a seismic hazard evaluation, the Japan Nuclear Energy Safety Organization has proposed the framework of the open deliberation rule regarding the treatment of uncertainty which was made so as to be able to utilize a logic tree. (3) The b-value evaluation on the "Stress concentrating zone," which is a high seismic activity around the NCO hypocenter area, should be modified based on the Gutenberg-Richter equation.

Effectiveness of the neutron-shield nanocomposites for a dual-purpose cask of Bushehr's Water-Water Energetic Reactor (VVER) 1000 nuclear-power-plant spent fuels

  • Rezaeian, Mahdi;Kamali, Jamshid;Ahmadi, Seyed Javad;Kiani, Mohammad Amin
    • Nuclear Engineering and Technology
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    • v.49 no.7
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    • pp.1563-1570
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    • 2017
  • In order to perform dry interim storage and transportation of the spent-fuel assemblies of the Bushehr Nuclear Power Plant, dual-purpose casks can be utilized. The effectiveness of different neutron-shield materials for the dual-purpose cask was analyzed through a set of calculations carried out using the Monte Carlo N-Particle (MCNP) code. The dose rate for the dual-purpose cask utilizing the recently developed materials of $epoxy/clay/B_4C$ and $epoxy/clay/B_4C/carbon$ fiber was less than the allowable radiation level of 2 mSv/h at any point and 0.1 mSv/h at 2 m from the external surface of the cask. By utilization of $epoxy/clay/B_4C$ instead of an ethylene glycol/water mixture, the dose rates on the side surface of the cask due to neutron sources and consequent secondary gamma rays will be reduced by 17.5% and 10%, respectively. The overall dose rate in this case will be reduced by 11%.

Suggestions for More Reliable Measurement of Korean Nuclear Power Industry Safety Culture

  • Lee, Dhong Ha
    • Journal of the Ergonomics Society of Korea
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    • v.35 no.2
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    • pp.75-84
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    • 2016
  • Objective: The aim of this study is to suggest some improvement ideas based on the validity and the reliability analyses of the current safety culture measurement method applied to the Korean nuclear power industry. Background: Wrong safety culture is known as one of the major causes of the disasters such as the space shuttle Columbia disaster or the Fukushima Nuclear Power Plant accident. Assessment of safety culture of an organization is important to build a safer organizational environment as well as to identify the risks hidden in the organization. Method: A face validity of the current safety culture measurement method was analyzed by comparison of the key factors of safety culture in the Korean nuclear power industry with those factors reviewed in the previous studies. The current interview method was analyzed to identify the problems which degrade the consistency of evaluation. Results: Most safety culture factors reviewed in the literatures are covered in the list of the Korean nuclear power industry safety culture factors. However the unstructured questions used in the interview may result in inconsistency of safety culture evaluation among interviewers. Conclusion: This study suggests some examples which might improve the consistency of interviewers' evaluation on safety culture such as a post interview evaluation form. Application: An extended post interview evaluation form might help to increase the accuracy of the interviewing method for Korean nuclear industry safety culture evaluation.

Evaluation of neutronics parameters during RSG-GAS commissioning by using Monte Carlo code

  • Surian Pinem;Wahid Luthfi;Peng Hong Liem;Donny Hartanto
    • Nuclear Engineering and Technology
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    • v.55 no.5
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    • pp.1775-1782
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    • 2023
  • Several reactor physics commissioning experiments were conducted to obtain the neutronic parameters at the beginning of the G.A. Siwabessy Multi-purpose Reactor (RSG-GAS) operation. These parameters are essential for the reactor to safety operate. Leveraging the experimental data, this study evaluated the calculated core reactivity, control rod reactivity worth, integral control rod reactivity curve, and fuel reactivity. Calculations were carried out with Serpent 2 code using the latest neutron cross-section data ENDF/B-VIII.0. The criticality calculations were carried out for the RSG-GAS first core up to the third core configuration, which has been done experimentally during these commissioning periods. The excess reactivity for the second and third cores showed a difference of 510.97 pcm and 253.23 pcm to the experiment data. The calculated integral reactivity of the control rod has an error of less than 1.0% compared to the experimental data. The calculated fuel reactivity value is consistent with the measured data, with a maximum error of 2.12%. Therefore, it can be concluded that the RSG-GAS reactor core model is in good agreement to reproduce excess reactivity, control rod worth, and fuel element reactivity.

Challenges of implementing the policy and strategy for management of radioactive waste and nuclear spent fuel in Indonesia

  • Wisnubroto, D.S.;Zamroni, H.;Sumarbagiono, R.;Nurliati, G.
    • Nuclear Engineering and Technology
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    • v.53 no.2
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    • pp.549-561
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    • 2021
  • Indonesia has policies and strategies for the management of radioactive waste and spent nuclear fuel that arises from the use of nuclear research and development facilities, including three research reactors, and the use of radioisotopes in medicine and industries. The Indonesian government has provided extensive facilities such as an independent regulatory organization (BAPETEN) and a centralized radioactive waste management organization (CRWT-BATAN). Further, the presence of regulations and several international conventions guarantee the protection of the public from all risks due to handling radioactive waste and spent nuclear fuel. However, the sustainability of radioactive waste management in the future faces various challenges, such as disposal issues related to not only to site selection but also financing of radioactive waste management. Likewise, the problem of transportation persists; as an archipelago country, Indonesia still struggles to manage the infrastructure required for the transport of radioactive materials. The waste from the production of the radioisotopes, especially from the production of 99Mo, requires special attention because BATAN has never handled it. Indonesia should also resolve the management of NORM from various activities. In Indonesia, the definition of radioactive waste does not include NORM. Therefore, the management of this waste needs revision and improvement on the regulations, infrastructure, and technology.

Organizational Personality Types, Employer-Organization Fit and Job Satisfaction/Involvement of the Nuclear Power Plants (원자력발전소 조직의 성향과 종사자의 조직적합도 및 직무만족/몰입)

  • Kim, Dae-Ho;Lee, Yong-Hee
    • Journal of the Korean Society of Safety
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    • v.21 no.5 s.77
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    • pp.77-83
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    • 2006
  • The purpose of this study is to assess the organizational personality types, employee-organization fits and the job satisfaction/involvement in a Korea standard nuclear power plant(NPP), which is a representative safety work place. First we chose 427 procedures that are related to safety out of 777 officially managed procedures referenced by 13.5 of FSAR(final safety analysis report). Next, we finally chose 70 procedures of 8 divisions for 44 employees regarding the duties for NPPs' division, experiences of operations, an operational know-how, and the indication of operational weakness. This study used OPTI(organizational personality type indicators) and the combination of 4 preference types for determining the organizational personality to produce personality types of organizations for NPPs' division. To assess the job satisfaction and involvement, we used a questionnaire and an interview, for 300 employees(83.5%) of the Korea standard NPP.