• Nuclear Engineering and Technology
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• 제54권7호
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• pp.2736-2747
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• 2022

The operations in the design lifecycle of a nuclear power plant targeted to be decommissioned lead to neutron activation. Operations in the decommissioning process include cutting, decontamination, disposal, and processing. Among these, cutting is done close to the target material, and thus workers are exposed to radiation. As there are only a few studies on pressurizers, there arises the need for further research to assess the radiation exposure dose. This study obtained the specifications of the AP1000 pressurizer of Westinghouse and the distribution of radionuclide inventory of a pressurizer in a pressurised water reactor for evaluation based on literature studies. A cutting scenario was created to develop an optimal method so that the cut pieces fill a radioactive solid waste drum with dimensions 0.571 m × 0.834 m. The estimated exposure dose, estimated using the tool VISIPLAN SW, in terms of the decontamination factor (DF) ranged from DF-0 to DF-100, indicating that DF-90 and DF-100 meet the ICRP recommendation on exposure dose 0.0057 mSv/h. At the end of the study, although flame cutting was considered the most efficient method in terms of cutting speed, laser cutting was the most reasonable one in terms of the financial aspects and secondary waste.

• 한국잠사곤충학회지
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• 제5권
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• pp.25-38
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• 1965

I. Breeding of tussah silkworm(preliminary report). The preliminary examination for bleeding has been carried out since 1963 in tussah silkworms. 1) The strain(l-MG-B)of the heaviest silk quantity was the green silkworm and brown cocoon in univoltine, and the strains(2-G-B, 2-MG-B) of the heaviest silk quantity were also the green silkwom and brown cocoon in bivoltine in both spring and fall in 1965. 2) It looks like the voltinism, the body color and the cocoon color have reached to pure line up to 1965. II. Best place for the winter of tussah pupa. This work was aimed to find out good ways for the winter of tussah pupa. 1) The hatch of bivoltine was better than that of univoltine. 2) The cocoons covered with the leaves were good in the emergence of moth. 3) The cocoons which were kept at natural temperature till the first emergence of moths would show bad in both hatch and emergence. 4) If some of the pupae kept under natural condition were controled at proper temperature for a few days, hatch and laying eggs were best. 5) The best places for the winter were the egg storage and the rearing room. III. Relation between incubation temperature and voltinism. 1) When the tussah pupa are kept at natural temperature during winter, the moths do not come out of the pupa. 2) There is no difference between about 18$^{\circ}C$ and about 25$^{\circ}C$ during incubation in hatching ratio. 3) The tussah silkworms of univoltine in mortality are stronger than that of bivoltine. 4) There is not any relation between voltinism and high or low temperature for pupa and eggs. IV. Induced mutation by gamma-ray and neutron in tussah silkworm. This work was carried out in order to induce the mutation by treating the pupa or the eggs of tussah silkworm with gamma my and neutron. The results obtained are as follows. 1. Though the whole pupa treated with neutron become moths, the moths have no ability to copulate each other. The only moths emerged from pupa treated with neutron, 4000${\gamma}$ are able to lay all un-fertilized eggs, some of which have a hole on the surface and nothing of contents. 2. The non-diapause eggs are treated with neutron in spring, but the hatching ratio is 50∼60 percent, but the whole eggs treated with gamma ray are never hatched. 3. The sensitivity of the pupa to neutron is weaker than that of the eggs. 4. The hatching ratio is in direct proportion to the gamma ray dose. 5. Author find out a new mutant which is excellent in the cocoon quality, so he will do the progeny test next hear.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 1999년도 Japanese Journal of Medical Physics
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• pp.54-57
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• 1999

• Nuclear Engineering and Technology
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• 제52권10호
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• pp.2410-2414
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• 2020

Heavy ions have a high potential for destroying deep tumors that carry the highest dose at the peak of Bragg. The peak caused by a single-energy carbon beam is too narrow, which requires special measures for improvement. Here, carbon-12 (¹²C) ion with different energies has been used as a source for calculating the dose distribution in the water phantom, soft tissue and bone by the code of Monte Carlobased FLUKA code. By increasing the energy of the initial beam, the amount of absorbed dose at Bragg peak in all three targets decreased, but the trend for this reduction was less severe in bone. While the maximum absorbed dose per bone-mass unit in energy of 200 MeV/u was about 30% less than the maximum absorbed dose per unit mass of water or soft tissue, it was merely 2.4% less than soft tissue in 400 MeV/u. The simulation result showed a good agreement with experimental data at GSI Darmstadt facility of biophysics group by 0.15 cm average accuracy in Bragg peak positioning. From 200 to 400 MeV/u incident energy, the Bragg peak location increased about 18 cm in soft tissue. Correspondingly, the bone and soft tissue revealed a reduction dose ratio by 2.9 and 1.9. Induced neutrons did not contribute more than 1.8% to the total energy deposited in the water phantom. Also during ¹²C ion bombardment, secondary fragments showed 76% and 24% of primary 200 and 400 MeV/u, respectively, were present at the Bragg-peak position. The combined treatment of carbon ions with neutron or electron beams may be more effective in local dose delivery and also treating malignant tumors.

• 방사성폐기물학회지
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• 제9권2호
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• pp.73-80
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• 2011

한국방사성폐기물관리공단 주관 하에 개념 설계된, 연소도이득효과 적용 대용량 수송용기에 대해 방사선 차폐 안전성을 평가하였으며 여러 방사선원들이 수송용기 주변 선량률 분포에 미치는 영향을 분석하였다. 가능한 모든 방사선원(중성자선원, 감마선원, 방사화선원)들을 고려하였으며 보수적인 가상의 핵연료(너비: WH 17 RFA, 축방향: CE Type)를 선정, 실제 상황과 동일한 조건이 되도록 계산모델을 구축하였다. 모든 조건(정상 및 가상사고 조건)에서 표면선량률과 외부선량률이 법적기준치를 만족하고 있었으며 축방향 높이에 따라 각 선원들의 기여도가 변하고 있었지만 정상조건에서의 최대 표면선량률과 외부선량률은 방사화선원에 의한 영향이 가장 높은 것으로 확인되었다. 가상사고 조건에서는, 중성자선원의 선량률 기여도가 대략 90%에 달하고 있었으나 수송용기 끝단에서는 방사화선원에 의한 선량률이 급격하게 상승함에 따라 BUC 적용 수송용기의 방사선 차폐해석시 충분히 보수적으로 해석되도록 방사화선원을 정밀하게 분석하여 설정하여야 할 것으로 판단되었다.

• Radiation Oncology Journal
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• 제27권4호
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• pp.218-227
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• 2009

목 적: 전립샘암 세포주 DU 145에서 엑스선과 중성자선에 의한 HIF-$1\alpha$와 아포프토시스 발현의 차이를 비교함으로써 엑스선과 중성자선의 방사선생물학적 차이의 기전을 알아보고자 한다. 대상 및 방법: 누드 마우스에 DU 145 전립샘암 세포주를 주입한 후 2 Gy 엑스선, 10 Gy 엑스선, 0.6 Gy 중성자선, 3.3 Gy 중성자선을 각각 조사했다. 엑스선을 조사한 군과 중성자선을 조사한 군에서 HIF-$1\alpha$, Bcl-2, Bax, 아포프토시스 발현 정도를 면역조직화학 염색과 western blotting을 이용하여 비교하였다. 아포토시스의 정도는 terminal deoxynucleotidyl biotin-dUTP nick end labeling (TUNEL) 염색을 이용하여 비교하였다. 결 과: 방사선 조사 1일째, X선을 조사한 군과 비교했을 때, 중성자선을 조사한 군에서 HIF-$1\alpha$와 Bcl-2의 발현은 감소하였고, Bax와 아포프토시스 세포의 수는 증가하였다. Bcl-2/Bax 비는 중성자선을 조사한 군에서 의미 있게 감소하였다. 이러한 HIF-$1\alpha$, Bcl-2, Bax, Bcl-2/Bax 비, 아포프토시스 발현의 차이는 방사선 조사 5일째에도 동일하게 유지되어 나타났다. 또한, HIF-$1\alpha$ 발현은 방사선 조사 5일째 Bcl-2 (p=0.031), Bax (p=0.037), TUNEL (p=0.016) 발현과 연관성을 보였다. 결 론: 중성자선 조사한 경우 엑스선에 비해 HIF-$1\alpha$와 Bcl-2 발현, Bcl-2/Bax 비가 감소하고, Bax 발현은 증가하였다. 중성자선 치료의 광자선과 다른 방사선생물학적인 반응은 HIF-$1\alpha$와 그로 인한 아포프토시스 관련 단백질 발현의 차이와 연관성이 있을 것으로 생각한다.

• Radiation Oncology Journal
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• 제29권3호
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• pp.135-146
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• 2011

With the advance of modern radiation therapy technique, radiation dose conformation and dose distribution have improved dramatically. However, the progress does not completely fulfi ll the goal of cancer treatment such as improved local control or survival. The discordances with the clinical results are from the biophysical nature of photon, which is the main source of radiation therapy in current field, with the lower linear energy transfer to the target. As part of a natural progression, there recently has been a resurgence of interest in particle therapy, specifically using heavy charged particles, because these kinds of radiations serve theoretical advantages in both biological and physical aspects. The Korean government is to set up a heavy charged particle facility in Korea Institute of Radiological & Medical Sciences. This review introduces some of the elementary physics of the various particles for the sake of Korean radiation oncologists' interest.

• Nuclear Engineering and Technology
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• 제55권4호
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• pp.1210-1217
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• 2023

The assessment of radiation fields in the lithium loop pipes and dump tank during the operation were performed for International Fusion Materials Irradiation Facility - DEMO-Oriented NEutron Source (IFMIF-DONES) in order to obtain the radiation dose-rate maps in the component surroundings. Variance reduction techniques such as weight window mesh (produced with the ADVANTG code) were applied to bring the statistical uncertainty down to a reasonable level. The biological dose was given in the study, and potential shielding optimization is suggested and more thoroughly evaluated. The MCNP Monte Carlo was used to simulate a gamma particle transport for radiation shielding purposes for the current Li Systems' design. In addition, the shielding efficiency was identified for the Impurity Control System components and the dump tank. The analysis reported in this paper takes into account the radiation decay source from and activated corrosion products (ACPs), which is created by d-Li interaction. As a consequence, the radiation (resulting from ACPs and Be-7) shielding calculations have been carried out for safety considerations.

• Nuclear Engineering and Technology
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• 제55권6호
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• pp.1949-1958
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• 2023

The International Commission on Radiological Protection (ICRP) Publication 116 was released to provide a comprehensive dataset of the dose coefficients (DCs) for external exposures produced with the adult reference voxel phantoms of ICRP Publication 110. Although an advanced skeletal dosimetry method for photons and neutrons using fluence-to-dose response functions (DRFs) was introduced in ICRP Publication 116, the ICRP-116 skeletal DCs were calculated by using the simple method conventionally used (i.e., doses to red bone marrow and endosteum approximated by doses to spongiosa and/or medullary cavities). In the present study, the photon and neutron DRFs were used to produce skeletal DCs of the ICRP-110 reference phantoms, which were then compared with the ICRP-116 DCs. For photons, there were significant differences by up to ~2.8 times especially at energies <0.3 MeV. For neutrons, the differences were generally small over the entire energy region (mostly <20%). The general impact of the DRF-based skeletal DCs on the effective dose calculations was negligibly small, supporting the validity of the ICRP-116 effective DCs despite their skeletal DCs derived from the simple method. Meanwhile, we believe that the DRF-based skeletal DCs could be beneficial in better estimates of skeletal doses of individuals for risk assessments.

• Journal of Radiation Protection and Research
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• 제19권2호
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• pp.133-145
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• 1994

최근, 개인방사선피폭선량평가에 관한 기술기준이 과학기술처에 의해 고시됨에 따라 국내에서도 개인선량계를 이용한 체외피폭선량평가결과의 신뢰성 문제가 크게 대두되고 있다. 한국원자력연구소에서는 이러한 국내의 상황을 인식하고 자체적인 신뢰성 확보를 위해 미국의 Oak Ridge국립연구소의 주관하에 개인피폭선량의 평가에 관한 국제상호비교검증시험(Personnel Dosimet Intercomparison Study ; PDIS)을 수행하였다. 비교검증시험에는 한국원자력연구소에서 사용하고 있는 Teledyne PB-3 열형광선량계가 사용되었으며 선량계산 알고리즘은 Teledyne PB-3 version 1.5-1989를 사용하였다. 본 연구에서는 지금까지 실시 된 PDIS의 결과를 요약하고 현재 PB-3 시스템의 개인선량평가성능에 대해 고찰하였으며, 선량평가절차에 대한 문제점 도출을 통하여 직업적 방사선피폭선량 평가능력의 향상을 위한 방안을 제시하였다.