• 제목/요약/키워드: Radiation pressure

검색결과 681건 처리시간 0.027초

사보타주 공격으로 인한 사용후핵연료 운반용기 격납 실패시 핵연료 손상에 따른 방사선 영향 평가 (Evaluation of Radiation Effect on Damage to Nuclear Fuel of Spent Fuel Transport CASK due to Sabotage Attack)

  • 박기호;김종성;차건일;박창제
    • 한국압력기기공학회 논문집
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    • 제18권2호
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    • pp.43-49
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    • 2022
  • The purpose of this study is to evaluate the radiation effect on damage when the external shield of the spent nuclear fuel transport cask is damaged due to impact as the cause of an unexpected accident. The neutron and gamma-ray intensities and spectra are calculated using the ORIGEN-Arp module in the SCALE 6.2.4 code package(1) and then using MCNP6.2(2) code calculate the dose rate. In order to evaluate the radiation dose according to the size of damage caused by external impact, various sized holes of 0.3~13.7% are assumed in the outer shield of the cask to evaluate the sensitivity to the dose. In the case of radiation source leakage, damage to the nuclear fuel assembly is assumed to be up to 6% based on overseas test cases. When only the outer shield is damaged, the maximum surface dose is calculated as 3.12E+03 mSv/hr. However, if the radiation source is leaked due to damage to the nuclear fuel assembly, it becomes 7.00E+05 mSv/hr which is about 200 times greater than the former case.

부구조물이 있는 유한길이의 쉘 구조물에서의 충격하중에 의한 음향방사 (Acoustic Radiation from a Finite-length Shell with Substructures Subjected to an Impulsive Load)

  • 최성훈
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 1995년도 추계학술대회논문집; 한국종합전시장, 24 Nov. 1995
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    • pp.62-67
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    • 1995
  • A method for determining impulsive responses and acoustic radiation for submerged shells of finite length has been presented. The method is a modal-based method, and uses a surface variational principle to obtain data in the frequency domain. The fast Fourier transform technique is used to convert the data to the time domain. The surface pressure responses of a cylindrical shell with endcaps wer compared with those of an infinite shell. It was shown that the surface pressures coincide exactly before any significant reflections from the endcaps occur. Traces of different types of waves were identified from the dispersion relations of the infinite shell. The contributions of flexural and longitudinal waves and these due to the direct radiation from the driving force to the fluid pressure were demonstrated using near-field plots. The exchange of energy between the shell and fluid was examined for shells with and without bulkheads. It was shown that a significant amount of the energy which enters the fluid returns to the shell and most of the energy is dissipated in the shell. It was also shown that the shell with bulkheads radiate significantly more energy into the far-field than the empty shell.

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Preserved Respiratory Function after Reconstruction of a Large Chest Wall Defect

  • Kim, Yu Jin;Kim, Yoon Ji;Lee, Jae-Ik
    • Archives of Reconstructive Microsurgery
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    • 제24권1호
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    • pp.28-31
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    • 2015
  • A case report of a patient who developed radiation-induced sarcoma in the left chest wall is presented. The patient had partial mastectomy and adjuvant radiation therapy (total dose, 5,220 cGy) and chemotherapy. Five years later, she visited with rapidly growing mass with central ulceration in the irradiated chest wall. The mass was diagnosed as malignant fibrous histiocytoma. The chest wall mass resected en bloc ($23{\times}18cm$) including five consecutive ribs. After the defected thoracic cage was reinforced using a polytetrafluoroethylene patch, omental flap and split thickness skin graft was done for soft tissue coverage. We applied negative pressure wound closer system for effective suction of omeantal exudate. The wound healed without complications. The patient suffered no perioperative pulmonary complications. Pulmonary function tests showed no significant changes. Each of Gore-Tex, omental flap, negative pressure wound therapy and skin graft is widely used method. However, If these methods are used in combination, we can reconstruct the large defect of chest wall including multiple ribs without any repiratory function problems.

Estimation of yield strength due to neutron irradiation in a pressure vessel of WWER-1000 reactor based on the correction of the secondary displacement model

  • Elaheh Moslemi-Mehni;Farrokh Khoshahval;Reza Pour-Imani;M.A. Amirkhani-Dehkordi
    • Nuclear Engineering and Technology
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    • 제55권9호
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    • pp.3229-3240
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    • 2023
  • Due to neutron radiation, atomic displacement has a significant effect on material in nuclear reactors. A range of secondary displacement models, including the Kinchin-Pease (K-P), Lindhard, Norgett-Robinson-Torrens (NRT), and athermal recombination-corrected displacement per atom (arc-dpa) have been suggested to calculate the number of displacement per atom (dpa). As neutron elastic interaction is the main cause of displacement damage, the focus of the current study is to calculate the atomic displacement caused by the neutron elastic interaction in order to estimate the exact amount of yield strength in a WWER-1000 reactor pressure vessel. To achieve this purpose, the reactor core is simulated by MCNPX code. In addition, a program is developed to calculate the elastic radiation damage induced by the incident neutron flux (RADIX) based on different models using Fortran programming language. Also, due to non-elastic interaction, the displacement damage is calculated by the HEATR module of the NJOY code. ASME E-693-01 standard, SPECTER, NJOY codes, and other pervious findings have been used to validate RADIX results. The results showed that the RADIX(arc-dpa)/HEATR outputs have appropriate accuracy. The relative error of the calculated dpa resulting from RADIX(arc-dpa)/HEATR is about 8% and 46% less than NJOY code, respectively in the ¼ and ¾ vessel wall.

천연산 활석에 대한 고압 X-선 회절연구 (High Pressure X-ray Diffraction Studies on a Natural Talc)

  • 김영호;이지은
    • 한국광물학회지
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    • 제12권1호
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    • pp.1-10
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    • 1999
  • Talc (Mg3Si4O10(OH)2), one of the sheet silicate minerals, which is the hydrothermal alteration product of serpentinite at Cheongarm mine was prepared for the high pressure compressibility studies. Energy dispersive X-ray diffraction experiment was carried out using the Synchrotron Radiation with the Mao-Bell type diamond anvil cell at room temperature. Polycrystalline talc was mixed with MgO powder for pressure sensor as well as pressure medium in the sample chamber. High pressure runs were performed at pressures up to 35.2 GPa. Talc shows no phase transition within the present high pressure region. Bulk modulus of this talc was determined by the Birch-Murnaghan equation of state to be 78 GPa assuming its first pressure derivative Ko' of 4.

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원전 종사자의 말단선량평가를 위한 고피폭 접촉 방사선장 특성분석 (An Analysis of Radiation Field Characteristics for Estimating the Extremity Dose in Nuclear Power Plants)

  • 김희근;공태영
    • Journal of Radiation Protection and Research
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    • 제34권4호
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    • pp.176-183
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    • 2009
  • 원전 계획예방정비기간 증기발생기 수실작업 등은 매우 높은 방사선량율을 보이는 지역으로, 짧은 시간 동안 작업으로 종사자는 높은 피폭을 받을 가능성이 있다. 특히, 방사성물질과 접촉작업을 하는 손 부위에서 고피폭이 예상된다. 이런 점을 고려하여 2004년 수행된 국내 원전의 복수선량계 알고리즘 적용성 시험의 TLD 판독결과를 이용하여 고피폭 접촉 작업의 방사선장을 분석하였다. 그 결과, 원전 고피폭 접촉작업의 입사방사선장은 고에너지 광자(High Energy Photon Field)에 의한 피폭으로 해석되었다. 한편 2009년 울진 4호기 계획예방정비기간 S/G 정비작업과 월성 1호기 압력관 교체작업에 참여한 방사선작업종사자에 대해 말단선량 현황과 방사선장을 분석하기위한 현장시험을 실시하였다. 그 결과 입사방사선장은 고에너지 방사선장으로 확인되었다.

온라인 건강교육프로그램이 남성근로자의 대사증후군 위험요인 및 영양소 섭취에 미치는 영향 (The Effects of a Worksite On-line Health Education Program on Metabolic Syndrome Risk Factors and Nutrient Intakes of Male Workers)

  • 강지연;조상운;이지영;성숙희;박유경;백윤미;최태인
    • Journal of Nutrition and Health
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    • 제43권1호
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    • pp.57-68
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    • 2010
  • Worksite health promotion programs have been associated with reductions in health risks but are labor-intensive and costly to implement. Therefore, innovative strategies to provide a cost-effective approach to health education program are needed. The purpose of this study was to investigate the effects of a worksite on-line health education program by email on metabolic syndrome risk factors and dietary intakes in male workers with metabolic syndrome. Anthropometric and biochemical parameters were measured and the nutrient intakes were assessed through FFQ. The diagnosis of metabolic syndrome was adapted from NCEP-ATP III with blood pressure, fasting blood glucose, triglyceride, HDL cholesterol, and Asia-Pacific definition with waist circumference. The education group consisted of 212 male workers and the non-education group of 236 age-matched male workers. The on-line health education program provided 10 sessions by e-mail. After a worksite on-line health education program, systolic blood pressure (p < 0.001), diastolic blood pressure (p < 0.001) and fasting blood glucose (p < 0.001) were significantly decreased and HDL cholesterol (p < 0.001) was significantly increased in the education group. Intakes of total energy (p < 0.05), carbohydrate (p < 0.05), sodium (p < 0.05) were significantly decreased in the education group, but there were no significant differences in dietary intakes in the non-education group after a worksite on-line health education program. The results indicate that online health education program by e-mail is effective for improving metabolic syndrome risk factors and dietary intakes in male workers and show potential for use in the working setting.

흉복부 방사선 치료 시 압력 기반 복부압박장치 적용에 따른 치료 간 재현성 평가 (Reproducibility evaluation of the use of pressure conserving abdominal compressor in lung and liver volumetric modulated arc therapy)

  • 박가연;김주호;신현경;김민수
    • 대한방사선치료학회지
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    • 제33권
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    • pp.71-78
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    • 2021
  • 목 적: 폐암과 간암 환자에 대해 압력 기반 복부압박장치를 적용하여 입체적 세기변조 회전 방사선치료(VMAT)를 시행하였을 때의 치료 간(interfraction) 위치 재현성과 호흡 재현성을 평가함으로써 그 유용성을 평가하고자 한다. 대상 및 방법: 압력 기반 복부압박장치를 사용해 입체적 세기변조 회전 방사선치료를 받은 6명의 폐암 환자와 3명의 간암 환자를 대상으로 하였다. 치료 간 위치 재현성 평가를 위해 모의치료 CT 영상과 매일 획득한 CBCT 영상 174건을 비교하여 이미지 정합의 이동 값을 비교, 분석하였다. 치료 간 호흡 재현성 평가를 위해 모의치료 4DCT 영상과 매주 획득한 4D CBCT 영상 54건을 비교하여 호흡량 오차를 구하였다. 결 과: 수평수직 세 방향의 3D 벡터값인 전체 위치변화(Overall position variation, Overall VP)값은 폐와 간에서 각각 평균 1.1 ± 1.4 mm, 4.5 ± 2.8 mm로 나타났다. 호흡 변화(respiratory variation, Vr)값은 폐에서 평균 0.7 mm ± 3.4 mm (p=0.195), 간에서 평균 3.6 mm ± 2.6 mm (p<0.05)로 나타났다. 결 론: 흉복부 방사선 치료 시 압력 기반 복부압박장치의 적용은 복부 압박 재현을 통해 치료 간 종양의 호흡 변이뿐만 아니라 위치 변이를 안정적으로 조절하는 데에 유용한 것으로 사료된다. 보다 안정적인 재현성을 위해 치료 계획 시 적절한 PTV 여유가 고려되어야 하고, 매 치료 전 영상 유도에 따른 표적의 위치와 호흡 검증이 필요하다.

Estimation of Insolation over the Oceans around Korean Peninsula Using Satellite Data

  • Park, Kyung-Won;Kim, Young-seup;Sang, Chung-Hyo
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 1999년도 Proceedings of International Symposium on Remote Sensing
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    • pp.227-230
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    • 1999
  • Surface solar radiation over the sea is estimated using Visible and Infrared Spin Scan Radiometer data onbord Geostationary Meteorological Satellite(GMS) 5 for January, 1997 to December 1997 in clear and cloudy conditions. The hourly insolation is estimated with a spatial resolution of 5$\times$ 5 km grid. The island pyranometer belonging to the Japan Meteorological Agency is used for validation of the estimated insolation. It is shown that the estimated hourly insolation has RMSE(root mean square) error of 104 W/$m^2$. The variability of the hourly solar radiation was investigated on 3 areas over seas around Korean Peninsula. The solar radiation of East Sea is similar to Yellow Sea. The maximum value of solar radiation is on June of year. The maximum value in south sea is on August because weather is poor by low pressure and front in June

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항공기 엔진 소음 전파에 대한 수치적 연구 (A Numerical Study on Radiation of Duct Internal Noise)

  • 정철웅;이수갑
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2000년도 춘계학술대회논문집
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    • pp.98-103
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    • 2000
  • The cut-off is a unique feature associated with duct acoustics due to the presence of duct walls. Duct geometry effect on sound radiation is another issue of duct acoustics. The radiation of duct internal noise to ambient from duct open ends with various geometries is studied via numerical methods. The linearized Euler's equations in generalized curvilinear coordinates are solved by the DRP finite difference scheme. A number of accurate boundary conditions are used at boundaries for the computational domain to minimize the non-physical reflections. The far field sound pressure levels are computed by the Kirchhoff integration method. We investigate the cut off phenomana and duct geometry effects on sound radiation with numerical results.

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