• Proceedings of the KSR Conference
• /
• 2007.05a
• /
• pp.968-973
• /
• 2007

The systems such as the railway control system, satellite control system and nuclear power plant control system are the safety critical systems because the failure of them could lead to risk significant events. These softwares of digital systems must follow the life cycle process from the beginning of software development to guarantee their safety and reliability. The NRC(Nuclear Regulatory Commission) Reg Guide of nuclear fields, the RTCA/DO-178B standard which is used to acquire the certification for software in industrial aero field in European Union and United State, the DEF STAN 00-55 standard for the safety of electronic weapon in England, the IEC 601-1-4 for medical equipment and the IEC 62279 for railway system recommended the development life cycle. This paper introduces the development process and compares each other. Also it indicates applicable development criteria for the software of systems related to railway fields and describes the detailed procedure of development criteria. We describe the procedure to make the software development criteria in nuclear filed. For the software development related to railways, the process from plan phase to maintenance phase must be satisfied. The safety and reliability is guaranteed through these standards.

• Applied Chemistry for Engineering
• /
• v.33 no.4
• /
• pp.352-366
• /
• 2022

Nuclear power plant operations for electricity generation, rare-earth mining, nuclear medical research, and nuclear weapons reprocessing considerably increase radioactive waste, necessitating massive efforts to eradicate radioactive waste from aquatic environments. Cobalt (⁵⁸Co) and strontium (⁹⁰Sr) radioactive elements have been extensively employed in energy generation, nuclear weapon testing, and the manufacture of healthcare products. The erroneous discharge of these elements as pollutants into the aquatic system, radiation emissions, and long-term disposal is extremely detrimental to humans and aquatic biota. Numerous methods for treating radioactive waste-contaminated water have emerged, among which the adsorption process has been promoted for its efficacy in eliminating radioactive waste from aquatic habitats. The current review discusses the adsorptive removal of radioactive waste from aqueous solutions using low-cost adsorbents, such as graphene oxide, metal-organic frameworks, and inorganic metal oxides, as well as their composites. The chemical modification of adsorbents to increase their removal efficiency is also discussed. Finally, the current state of ⁵⁸Co and ⁹⁰Sr removal performances is summarized and the efficiencies of various adsorbents are compared.

• Journal of Radiation Protection and Research
• /
• v.40 no.3
• /
• pp.181-186
• /
• 2015

Measurement of xenon radioisotopes from nuclear fission is a key element for monitoring underground nuclear weapon tests. $^{131m}Xe$, $^{133}Xe$, $^{133}mXe$ and $^{135}Xe$ in the air can be detected via low background systems such as a beta-gamma coincidence counting system. Radioxenon monitoring is performed through air sampling, xenon extraction, measurement and spectrum analysis. The minimum detectable concentration of $^{135}Xe$ can be significantly variable depending on the sampling time, extraction time and data acquisition time due to its short half-life. In order to optimize the acquisition time with respect to certain experimental parameters such as sampling and xenon extraction, theoretical approach and experiment using SAUNA system were performed to determine the time to minimize the minimum detectable concentration, which the results were discussed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2013.05a
• /
• pp.791-794
• /
• 2013

Electronic systems may be cause of various serious failures due to an ionizing radiation effect when exposed to a prompt gamma-ray pulse. This transient electrical malfunction can, in some cases, results in a failure of the electronic system of which the circuits are a part. Transient radiation measurement and evaluation system is required to development for enhanced radiation-resistance against the initial nuclear radiation produced by the detonation of a nuclear weapon of semiconductor devices. In these studies, we performed the following work. In the first part of the work, we carried out a SPICE simulation applied to nuclear radiation condition for PN diode and we also investigated the photocurrent by a pulsed gamma-ray on a PN diode using a TCAD simulation.

• Economic and Environmental Geology
• /
• v.33 no.3
• /
• pp.195-204
• /
• 2000

order to investigate physical characteristics and element concentrations of sediments, coastal bottom sediments were collected at 20 stations in the vicinity of Youngkwang Nuclear Power Plant. After air drying of samples in the laboratory. article size distribution was examined by Master sizer (X-350F), radio-activity by HPGe ${\gamma}$-spectrphotometer, and element concentrations by ICP-AES and AAS. According to particle size analysis , sediments are mainly composed of silt fraction weith 23% of sand, 65% of silt and 12% of clay on average. Most sediments are derived from muddy environment that silt dominates with the characteristics of 5.3${\varsigma}$ mean particle size, poorly sorted, very fine skewed and lepto-kurtic. Only two sediments are well sorted with sandy silt owing to wind, winnowing action, tide and current andits complex reactions. Element concentrations in the coastal bottom sediments are relatively high at finer sediment and show significant relationship with grain size. Index of geoaccumulation by heavy metals at every sampling station is classified as practically unpolluted. The radioactivities of the sediments were measured for 15 isotope elements, and 2 elements of K-40 and Cs-137 were detected in most sediments. The K-40 is the natural nuclide and the artificial nuclide of Cs-137 was thought to be derived from the fallout of past nuclear weapon test. The results of correlation coefficient between grain size and radioactivity shows that the activity of Cs-137 significantly increases in finer grain.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.45 no.6
• /
• pp.48-54
• /
• 2008

Biochemical weapons, called as a poor nation's nuclear-weapon, are most favorable Weapons of Mass Destruction(WMD). At the beginning of war, these biochemical weapons, which can threaten the operations of our forces and cause the anxiety and chaos of people, should be used to attack our principle facilities. And these attacks might be conducted as a long term scenario over the war. Consequentially, our military training as well as civilian-military joint training have been focused on these circumstances to improve defense capability against the invasion of biochemical weapons. Add to these efforts, there have been a lot of researches to develop advanced decontaminations that can secure our troops and equipments. In this study, applicability of the water-soluble decontaminant for the contaminated aircraft was evaluated. The water-soluble decontaminant has been applied to the military stations and ground weapon systems only. According to the theoretical analyses and published papers, the water-soluble decontaminant has been shown better decontamination capability than commercial cleaner by roughly 50%. Furthermore, as a result of experiment efforts in this study, it was showed that the water-soluble decontaminant can reduce corrosion risk which is primary concern for the aircraft structures.

• Strategy21
• /
• s.42
• /
• pp.5-52
• /
• 2017

Debates about introducing nuclear submarines have been a main issue in Korea. The highest officials and the government has started to think seriously about the issue. Yet there were no certain decision to this issue or any agreements with US but it is still necessary to review about introducing nuclear submarines, the technologies and about the business. The reason for such issues are the highest officials of Korea to build nuclear submarine, nK's nuclear development and SLBM launching. ROKN's nuclear submarine's necessity will be to attack(capacity to revenge), defend(anti-SSBN Operation) and to respond against neighboring nation's threat(Russia, Japan, China). Among these nations, US, Russia (Soviet Union), Britain, France had built their submarines in a short term of time due to their industrial foundation regarding with nuclear propulsion submarines. However China and India have started their business without their industrial foundation prepared and took a long time to build their submarines. Current technology level of Korea have reached almost up to US, Russia, Britain and France when they first built their nuclear propulsion submarines since we have almost completed the business for the Changbogo-I,II and almost up to complete building the Changbogo-III which Korea have self designed/developed. Furthermore Korea have reached the level where we can self design large nuclear reactors and the integrated SMART reactor which we can call ourselves a nation with worldwide technologies. If introducing the nuclear submarine to the Korea gets decided, first of all we would have to review the technological problems and also introduce the foreign technologies when needed. The methods for the introduction will be developments after loans from the foreign, productions with technological cooperations, and individual production. The most significant thing will be that changes are continuous and new instances are keep showing up so that it is important to only have a simple reference to a current instances and have a review on every methods with many possibilities. Also developing all of the technologies for the nuclear propulsion submarines may be not possible and give financial damages so there may be a need to partially introduce foreign technologies. For the introduction of nuclear propulsion submarines, there must be a resolution of the international regulations together with the international/domestics resistances and the technological problems to work out for. Also there may be problem for the requirement fees to solve for and other tough problems to solve for. However nuclear submarines are powerful weapon system to risk everything above. This is an international/domestically a serious agenda. Therefore rather than having debates based on false facts, there must be a need to have an investigations and debates regarding the nation's benefits and national security.

• Journal of Radiation Protection and Research
• /
• v.24 no.3
• /
• pp.155-160
• /
• 1999

In the natural, there exist several kinds of radioactive isotopes. From atmospheric weapon tests and then some isotopes are naturally radioactivity above all things, nuclear power plant operation and man-made radioactive isotopes concern steadily growing in the environment. During the fission process of nuclear weapon tests and nuclear power plant operation, more than 200 radioactive isotopes are generated. Among them, $^{90}Sr$ and $^{137}Cs$ has been regarded as very important isotopes due to characteristics. In this paper, a quantitative analysis method of environment low level $^{90}Sr$ is studied. Radioactivity level of the environmental $^{90}Sr$ is very low, and it emits continuous beta spectrum, and $^{90}Sr$ exists together with $^{89}Sr$, $^{90}Y$ and other radioactive isotopes. It very difficult to make the quantitative analysis of $^{90}Sr$. For the analysis of low level radioactive strontium, enrich and chemical separation of strontium from the other radioactive isotopes are needed. For the estimation of strontium recovery ratio, so called SGAT(Strontium Gravimetric Analysis Technique) was generally used among the domestic research groups, and chemical procedures were developed appropriation for the SGAT, Recently, by using ICP(Inductively Coupled atomic Plasma emission spectrophotometer), amounts of stable atoms can be measured easily and accurately to the extend of ppm or ppb. In this paper, new chemical procedures are developed to exploits the ICP technique. New developed method has simpler chemical treatment procedures and then it gives more accurate results compared with the traditional SGAT.

• Nuclear Engineering and Technology
• /
• v.40 no.3
• /
• pp.183-190
• /
• 2008

Pyroprocessing is the optimal means of treating spent metal fuels from metal fast fuel reactors and is proposed as a potential option for GNEP in order to meet the requirements of the next generation fuel cycle. Currently, efforts for research and development are being made not only in the U.S., but also in Asian countries. Electrorefining, cathode processing by distillation, injection casting for fuel fabrication, and waste treatment must be verified by the use of genuine materials, and the engineering scale model of each device must be developed for commercial deployment. Pyroprocessing can be effectively extended to treat oxide fuels by applying an electrochemical reduction, for which various kinds of oxides are examined. A typical morphology change was observed following the electrochemical reduction, while the product composition was estimated through the process flow diagram. The products include much stronger radiation emitter than pure typical LWR Pu or weapon-grade Pu. Nevertheless, institutional measures are unavoidable to ensure proliferation-proof plant operations. The safeguard concept of a pyroprocessing plant was compared with that of a PUREX plant. The pyroprocessing is better adapted for a collocation system positioned with some reactors and a single processing facility rather than for a centralized reprocessing unit with a large scale throughput.

• Journal of Radiation Protection and Research
• /
• v.44 no.3
• /
• pp.118-126
• /
• 2019

Background: Government conducts environmental radioactivity surveillance for verification purpose around nuclear facilities based on the Nuclear Safety Law and issues a surveillance report every year. This study aims to evaluate the short and the long-term fluctuation of radionuclides detected above MDC and their origins using concentration ratios between these radionuclides. Materials and Methods: Sample media for verification surveillance are air, rainwater, groundwater, soil, and milk for terrestrial samples, and seawater, marine sediment, fish, and seaweed for marine samples. Gamma-emitting radionuclides including $^{137}Cs$, $^{90}Sr$, Pu, $^3H$, and $^{14}C$ are evaluated in these samples. Results and Discussion: According to the result of the environmental radioactivity verification surveillance in the vicinity of nuclear power facilities in 2017, the anthropogenic radionuclides were not detected in most of the environmental samples except for the detection of a trace level of $^{137}Cs$, $^{90}Sr$, Pu, and $^{131}I$ in some samples. Radioactivity concentration ratios between the anthropogenic radionuclides ($^{137}Cs/^{90}Sr$, $^{137}Cs/^{239+240}Pu$, $^{90}Sr/^{239+240}Pu$) were similar to those reported in the environmental samples, which were affected by the global fallout of the past nuclear weapon test, and Pu atomic ratios ($^{240}Pu/^{239}Pu$) in the terrestrial sample and marine sample showed significant differences due to the different input pathway and the Pu source. Radioactive iodine ($^{131}I$) was detected at the range of < $5.6-190mBq{\cdot}kg-fresh^{-1}$ in the gulfweed and sea trumpet collected from the area of Kori and Wolsong intake and discharge. A high level of $^3H$ was observed in the air (Sangbong: $0.688{\pm}0.841Bq{\cdot}m^{-3}$) and the precipitation (Meteorology Post: $199{\pm}126Bq{\cdot}L^{-1}$) samples of the Wolsong nuclear power plant (NPP). $^3H$ concentration in the precipitation and pine needle samples showed typical variation pattern with the distance and the wind direction from the stack due to the gaseous release of $^3H$ in Wolsong NPP. Conclusion: Except for the detection of a trace level of $^{137}Cs$, $^{90}Sr$, Pu, and $^{131}I$ in some samples, anthropogenic radionuclides were below MDC in most of the environmental samples. Overall, no unusual radionuclides and abnormal concentration were detected in the 2017's surveillance result for verification. This research will be available in the assessment of environment around nuclear facilities in the event of radioactive material release.