• Journal of the Korean Society of Radiology
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• v.13 no.1
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• pp.45-53
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• 2019

This study is a neutron activation for concrete that shields medical linear accelerator facilities. Comparison of general concrete and low activation concrete. The simulation method was simulated using MCNPX (Ver. 2.5.0) and FISPACT-2010, and the shielding ability for photon and neutron beams was calculated and neutron activation evaluation was carried out. As a result, the shielding capacity was 20 ~ 50 cm efficient in general concrete, and activate evaluation in low activation concrete was calculated to be low in radioactivity concrete, but all were estimated to not exceed their own allowable concentration in self - disposal. As a result of the comprehensive analysis, it is considered effective to use ordinary concrete.

• The Journal of the Korea Contents Association
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• v.17 no.9
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• pp.69-76
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• 2017

This study evaluated the activation of the shielding wall and the components around the accelerator by using the medical linear accelerator. We performed simulations for energy values of 20 MV with the operating time ranging from day 1 to 30 years, and linear accelerator head and shielding wall concrete were also evaluated. The results showed that neutrons in large quantities were analyzed using high energy around thetarget point where photons were formed. Based on the activation analysis with these results, radioactivity increased with an increase in operation time and activated nuclides usually start saturating in10 years. Furthermore, the general types of nuclides formed owingto the activation were Co-60, W-181, 185, 187, Na-24, Ca-45, Mn-54, 56, and Fe-55, 59.

• Journal of the Korean Society of Radiology
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• v.15 no.4
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• pp.415-427
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• 2021

Korea Institute of Radiological and Medical Sciences has provided various beam irradiation services to researchers using a 50 MeV cyclotron beam line. In particular, since the neutron beam service uses the nuclear reaction between protons and beryllium, the possibility of activation of the irradiated sample increases by using a high current. In this study, MCNP 6.2 and FISPACT-II 4.0 were used to evaluate the possible activation during the 35 MeV 20 ㎂ neutron beam service, which is preferred by the researchers. As a result of the calculation, if the iron, copper, and tungsten samples were irradiated for more than 1 hour, long-lived radioisotopes were produced and their radioactivity exceeded the standard level for self-disposal. Under the conditions of 2 hours of daily irradiation, no activation occurred in the building materials, and the internal exposure of workers due to air activation inside the irradiation room was very insignificant. And when this air was discharged to environment, the radioactivity including this air was also satisfied the emission standard.

• 대한방사선방어학회:학술대회논문집
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• 2011.04a
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• pp.54-55
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• 2011

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2008.11a
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• pp.421-422
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• 2008

• Journal of Radiation Protection and Research
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• v.37 no.4
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• pp.202-207
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• 2012

The radioactivity inventory significantly affects all steps of decommissioning projects including planning, cost estimation, risk assessment, waste management and site remediation. The decommissioning project of the KRR-2 was completed in 2009 and a large amount of activated concrete waste was generated. The bioshield concrete, containing minute amount of impurity elements, was activated by neutron reaction during the operation of the reactor. A variety radionuclides was generated in the concrete, including $^3H$, $^{14}C$, $^{55}Fe$, $^{60}Co$ $^{63}Ni$, $^{134}Cs$, $^{152}Eu$ and $^{154}Eu$. In this paper, the comparison between the calculated results and previous measured results was carried out to estimate the inventory of the bioshield concrete of the KRR-2. The combined computer codes of MCNP5 and ORIGEN 2.1 for calculation of the distribution of neutron flux, cross-section and generation of radionuclides were used. The results were shown that 99.8% of the total radioactivity of $^3H$, $^{55}Fe$, $^{60}Co$ and $^{152}Eu$ in the bioshield concrete 12 years after shutdown. The effects on the variation of inventory were analysed depending on the operation periods and the cooling times in the bioshield concrete.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2016.05a
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• pp.247-248
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• 2016

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2016.05a
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• pp.437-438
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• 2016

• The Journal of the Korea Contents Association
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• v.16 no.10
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• pp.758-765
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• 2016

This study analyzed for the radioactive shielding wall, which shields the medical linear accelerator. This allows to evaluate the level of waste with respect to the shield wall, which accounts for more than half of the cost of dismantling later linac facility. In addition, by analyzing the waste processing method according we discuss the way to obtain the benefits in terms of dismantling cost. Results of the simulate, the amount sufficient to screen the amount of neutron radiation occurring in the shielding wall linac was measured. And neutron activation analysis results were analyzed nuclides more than about 20. This analysis was in excess of that, $^{24}Na$, $^{45}Ca$, $^{59}Fe$ nucleus paper deregulation concentration. The value is reduced is greater the deeper the depth of the shielding wall concentration. Based on this, three specific areas (E, F, G) was estimated to be impossible to landfill or recycling. The rest area was estimated to be buried or recycled if possible more than a predetermined depth.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.4 no.3
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• pp.265-273
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• 2006

In the decommissioning and decontamination(D&D) planning stage, it is important that the scenarios are evaluated from an engineering point of views because the decommissioning work has to be executed economically and safely by following the best scenarios. Therefore, we need to develope several modules to evaluate the decommissioning scenarios. In this paper, the digital mock-up system is constructed in the virtual space to simulate the whole decommissioning process. The schedule evaluating equation and cost evaluation equation are derived to calculate the working time and the expected cost. And in order to easily identify the radiation level about the activated objects, the radiation visualization module is developed. Finally, on the basis of the obtained results from the Digital Mock-up and other important factors, the evaluating method of the scenarios that can indicate the best scenario is described.