• Journal of Radiation Protection and Research
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• v.18 no.1
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• pp.71-82
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• 1993

It is a fundamental element of the nuclear power plant operation to assess exactly the occupational radiation exposure. And, according to recently published ICRP 60 recommendation, it is needed to reduce individual radiaton exposure limit further. In this paper, an optimization techique was suggested for selection of alternatives for reducing occupational radiation exposure, and used in reviewing alternatives given by a plant utility. After the basic analysis, sensitivity analysis was performed to consider the variabilities of the economic variables. From the result, it was found that an option using steam generator nozzle dam and torquing machine was the best with respect to total benefits, and in case of multi-attribute utility analysis, an option using Co-No seal had the highest utility. Therefore, it was necessary to apply more than one technique togeter in optimization study and to consider qualitative factor, too.

• Journal of Radiation Protection and Research
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• v.9 no.2
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• pp.103-111
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• 1984

A convenient method of $^{99m}Tc$-methyl-ethyl-ketone (MEK) extraction technique was developed and a mobile $^{99m}Tc$-extraction generator was designed. The MEK extraction and the phase separation of $^{99m}TcO^-{_4}$ were carried out with a simple procedure in the same container. The shielding of $^{99}Mo$ radioactivity was made with one lead container. The system was simplified by shielding $^{99m}TcO_4{^-}({\gamma}_e=0.14\;MeV)$ separately. $^{99m}TcO^-{_4}\;in\;^{99m}Tc-MEK$ extract was recovered by adsorption and elution only, and therefore, the possibility of volatilization was reduced. The volume of $^{99m}TcO^{-}{_4}$-saline product was reduced to 1 ml by using a small alumina column and the column operation time was shortened. The separation time of $^{99m}Tc$ was reduced to 30 minutes, and the operation was carried out at the outside of the shielding. The system was designed to operate under the condition of bacteria-free.

• Korean Journal of Veterinary Research
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• v.54 no.3
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• pp.151-157
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• 2014

A nationwide survey on radiation safety management in Korean animal hospitals was conducted. By 2013, 53 radiation generators were registered as veterinary medical devices (41 X-ray generators and 12 computed tomography scanners). Additionally there were six approved laboratories for radiation equipment and protection facility, and five approved laboratories for radiation exposure of employees, respectively. By March 2013, 2,030 out of 3,829 animal hospitals operated radiation-generating devices. Among these devices, 389 (19.2%) out of 2,030 were not labeled with the model name and 746 (36.7%) were not labeled with production dates. Thus, most veterinary X-ray generators were outdated (42.6%) and needed replacements. When periodic inspections of 2,018 animal hospitals were performed after revision of the Veterinarians Act in 2011, the hospitals were found to be equipped with appropriate radiation generators and protection facilities. Among 2,545 employees exposed to radiation at the hospitals, 93.9% were veterinarians, 4.3% were animal nurse technicians, and 18% held other positions. Among 169 employees supervised by administrators, none of those had a weekly maximum operating load that exceeded $10mA{\cdot}min$. This study suggests that the radiation safety management system of animal hospitals was general good.

• Convergence Security Journal
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• v.13 no.2
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• pp.155-163
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• 2013

Connection hijacking attack using the vulnerability of the TCP protocol to redirect TCP stream goes through your machine actively (Active Attack). The SKEY such as one-time password protection mechanisms that are provided by a ticket-based authentication system such as Kerberos or redirection, the attacker can bypass.Someone TCP connection if you have access on TCP packet sniffer or packet generator is very vulnerable. Sniffer to defend against attacks such as one-time passwords and token-based authentication and user identification scheme has been used. Active protection, but these methods does not sign or encrypt the data stream from sniffing passwords over insecure networks, they are still vulnerable from attacks. For many people, an active attack is very difficult and so I think the threat is low, but here to help break the illusion successful intrusion on the UNIX host, a very aggressive attack is presented. The tools available on the Internet that attempt to exploit this vulnerability, known as the recent theoretical measures is required. In this paper, we propose analysis techniques on a wireless network intruder detection.

• Journal of Radiation Protection and Research
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• v.20 no.2
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• pp.85-95
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• 1995

Radiation measuring system using wireless communication method with single channel has been diveloped and tested. In this system, radiation signals from GM tube are transformed into digital pulses in pulse processing circuit and modulated in FSK (frequency shift keying) circuit for digital communication and then wirelessly transmitted to a receiving unit. The digital pulses received are then demodulated in FSK circuit and converted into radiation dose/dose rate in the data acquisition unit to display on the screen of a personal computer. The performance of this system was evaluated by using both a pulse generator and a standard radiation source(Cs-137). In both cases, digital pulses with 5V were observed in pulse processing circuit without distortion of their shape through wireless communication system. The experimental results of radiation measurement by this system after several test-irradiation of GM detector to a standard radiation source(Cs-137), showed good agreement with irradiation dose rate within 10% difference, and proved that this system could be effectively utillized as radiation measuring instrument. It is expected that this wireless radiation measuring system developed for the first time in Korea, can be used as a radiation monitor as well as a personal dosimeter if we can further improve this system to adopt wireless multichannel communication system.

• Journal of Radiation Protection and Research
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• v.42 no.1
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• pp.1-8
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• 2017

Background: The use of radiation and radioisotopes in Korea has been increasing each year, and its impact on economy and industry is expected to be increasing progressively following the development of industrial technology and the expansion of their usage. To establish and supporting policies for industries using radiation and radioisotopes, it is necessary to check the status of related industries accurately, as well as to gather data required to establish plans for industrial development by studying both revenues and economic scale (contributing to revenue). Materials and Methods: To analyze the status of utilization, surveys were carried out on 6,621 organizations engaged in nuclear operations handling radiation and radioisotopes pursuant to the Nuclear Safety Act as of end 2014, on 33,471 medical institutions using radiation generators for medical and diagnostic purposes pursuant to the Medical Service Act, and on 2,218 organizations using radiation generators for animal diagnostics pursuant to the Veterinary License Act. Results and discussion: The overall status of the domestic radiation market including the number of user organizations, that of employees, and the size of distributions (imports, productions, and exports) with which the scale of domestic radiation market can be judged showed a growth trend compared to the previous year, though the number of employees for radiation operation in industrial sector, research sector, education sector, military sector, and power plants (nuclear power plants) and the size of imports was reduced somewhat. Conclusion: It is expected that data acquired through periodic surveys on the status of utilization would be utilized practically in establishing governmental policies related to the promotion of usage of radiation and radioisotopes, and also be utilized widely in cultivating and developing the industry efficiently to invigorate the related industries.

• Journal of Radiation Protection and Research
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• v.23 no.1
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• pp.17-23
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• 1998

Dose response relationships for one of biological end-points (gene mutation) in somatic cells of Tradescantia 4430 clones were studied using neutrons coming out of a californium-252 isotopic source. And the relative biological effectiveness (RBE) of neutrons in relation to X-rays in the induction of TSH pink mutations was assessed. Inflorescences were irradiated with X-ray from X-ray generator and neutrons from $^{252}Cf$ source. Irradiated cuttings were incubated with aeration in neutrient solution under the controlled condition. For more than 4 weeks after irradiation cell mutations were scored. Pink mutation frequencies were calculated from the pooled data for the peak interval (days 6 to 13 post-irradiation). Somatic cell mutations in TSH showed linear dose response relationships in the range of neutron doses available for the experiment. The RBE values estimated for neutrons in relation to X-rays were in the range 3.1 to 6.8, which were much lower than normally recognized value.

• Journal of Radiation Protection and Research
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• v.47 no.2
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• pp.93-98
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• 2022

Background: This study aims to derive the characteristics of each work type for industrial radiography based on empirical evidence through expert advice and a survey of radiation workers of various types of industrial radiography. Materials and Methods: According to a Korean report, work types of industrial radiography are classified into indoor tests, underground pipe tests, tests in a shielded room (radiographic testing [RT] room test), outdoor field tests, and outdoor large structure tests. For each work type, exposure geometry and radiation sources were mainly identified through the expert advice and workers' survey as reliable empirical evidence. Results and Discussion: The expert advice and survey results were consistent as the proportion of the work types were high in the order of RT room test, outdoor large structure test, underground pipe test, outdoor field test, and indoor test. The outdoor large structure test is the highest exposure risk work type in the industrial radiography. In most types of industrial radiography, radiation workers generally used ¹⁹²Ir as the main source. In the results of the survey, the portion of sources was high in the order of ¹⁹²Ir, X-ray generator, ⁶⁰Co, and ⁷⁵Se. As the exposure geometry, the antero-posterior geometry is dominant, and the rotational and isotropic geometry should be also considered with the work type. Conclusion: In this study, through expert advice and a survey, the external exposure characteristics for each work type of industrial radiography workers were derived. This information will be used in the reconstruction of organ dose for health effects assessment of Korean radiation workers.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.1
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• pp.23-29
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• 2005

This paper presents the characteristics of leakage currents flowing through ZinC Oxide(ZnO) surge arrester blocks under mixed direct and 60 Hz alternating voltages. A mixed voltage, in which an alternating voltage is superimposed upon a direct voltage, appears on the HVDC system network. The mixed direct and alternating voltage generator with a peak open-circuit of 10 kV was designed and fabricated. The leakage currents and V-I curves for the fine and used ZnO surge arrester blocks were measured as a function of the voltage ratio k, where the voltage ratio k is defined as the ratio of the peak of alternating voltage to the peak of the mixed voltages. The resistive component in the leakage current in the low conduction region is significantly increased with increasing the voltage ratio k. The V-I characteristic curves for the mixed voltages lies between the direct and alternating characteristics, and the cross-over phenomenon in the high conduction region was appeared.

• Nuclear Engineering and Technology
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• v.39 no.2
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• pp.133-142
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• 2007

The Electric Power Research Institute (EPRI) demonstrated a method for monitoring the performance of instrument channels in Topical Report (TR) 104965, 'On-Line Monitoring of Instrument Channel Performance.' This paper presents the results of several models originally developed by EPRI to monitor three nuclear plant sensor sets: Pressurizer Level, Reactor Protection System (RPS) Loop A, and Reactor Coolant System (RCS) Loop A Steam Generator (SG) Level. The sensor sets investigated include one redundant sensor model and two non-redundant sensor models. Each model employs an Auto-Associative Kernel Regression (AAKR) model architecture to predict correct sensor behavior. Performance of each of the developed models is evaluated using four metrics: accuracy, auto-sensitivity, cross-sensitivity, and newly developed Error Uncertainty Limit Monitoring (EULM) detectability. The uncertainty estimate for each model is also calculated through two methods: analytic formulas and Monte Carlo estimation. The uncertainty estimates are verified by calculating confidence interval coverages to assure that 95% of the measured data fall within the confidence intervals. The model performance evaluation identified the Pressurizer Level model as acceptable for on-line monitoring (OLM) implementation. The other two models, RPS Loop A and RCS Loop A SG Level, highlight two common problems that occur in model development and evaluation, namely faulty data and poor signal selection