For producing radionuclides which were mostly used in medical purposes, for instance, Positron Emission Tomography (PET), there were about 1,200 PET cyclotrons operated in 95 countries based upon IAEA database (2020). Besides, including PET cyclotrons, demands for particle accelerators are continuously increasing. In Korea, about 40 PET cyclotrons are in operating phases (2020). Considering design lifetime (about 30–40 years) of cyclotrons, there will be demands for decommissioning cyclotron facilities in the near future. PET cyclotron produces radionuclides by irradiating charged particles to the targets. During this phase, nuclear reactions (18O(p,n)18F, 14N(d,n)15O etc.) produce secondary neutrons which induce neutron activation of accelerator itself as well as surrounding infrastructures (the ancillary subsystems, peripheral equipment, concrete walls etc.). Most of the ancillary systems including peripheral equipment can be neutron activated, since, most of them were made of steels. Steels like stainless steel or carbon steel may contain some impurities, typically cobalt. Although, there were several researches evaluating activation of concrete walls and accelerator components, estimating the activation and influence on neutron interaction of the other surrounding infrastructures were insufficient. In this study, by using computational neutron transport code (MCNP 6.2), and source term calculation code (FISPACT- II), we estimated neutron distribution in cyclotron vault and activation of ancillary subsystems including some peripheral equipment. Also, using Au foil and Cd cover, we measured thermal neutron distribution at 16 points on the concrete wall, and compared it to calculated results (MCNP). Even though, the compared results matches well, there was a discrepancy of neutron distributions between presence and absence of those equipment. Additionally, in estimating activation distributions by calculating, most of the steel-based subsystems including peripheral equipment should be managed by radioactive wastes after 20 years of operation. Throughout this study, we could find that influence on neutron interaction of those equipment can affect neutron distribution in concrete walls. This results vary the activation depth as well as location of the hot contaminated spot in concrete wall. For estimating or evaluating activation distributions in cyclotron facilities, there was need to consider some equipment located in cyclotron vault.

현재 중국 중고차시장은 급성장단계에 있다. 시장진입 초기인 2000년대 초반부터 자동차산업시장의 발전 흐름을 타고 성장 움직임을 보였다. 중국 정부는 2004년 ｢자 동차산업발전정책(汽车产业发展政策)｣을 마련하며 중고차시장 발전 의지를 공식적으로 드러냈다. 이어서 로컬기업뿐만 아니라 대형 외자기업에도 중고차판매를 허용하 며 본격적으로 시장 규모를 확대해가고 있다. 중국 중고차시장에 대한 기존의 관망적 관점에서 벗어나 새로운 접근 전략을 모색해야 할 적절한 시기에 당면하였다. 이 에 따라 본 연구에서는 중국 자동차산업 시장의 환경 변화와 관련하여 최근 급성장 하고 있는 중국 중고차시장의 유통 활성화 추세와 특징을 고찰하고 발전을 저해하는 제도적 요인들에 대해 살펴보고자 한다. 이를 통해 향후 관련 거래 기준 정책이 정비되는 과정에서 발전을 저해해온 문제 요소들이 차츰 해결되고 거대시장으로 성장 할 수 있을 지에 대한 종합적 검토가 필요할 것으로 보인다.