• 제목/요약/키워드: energy integral

검색결과 576건 처리시간 0.026초

일체형 원자로의 공랭식 열교환기 개념 연구 (A Conceptual Study of an Air-cooled Heat Exchanger for an Integral Reactor)

  • 문주형;김우식;김영인;김명준;이희준
    • 한국유체기계학회 논문집
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    • 제19권2호
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    • pp.49-54
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    • 2016
  • A conceptual study of an air-cooled heat exchanger is conducted to achieve the long-term passive cooling of an integral reactor. A newly designed air-cooled heat exchanger is introduced in the present study and preliminary thermal sizing is demonstrated. This study mainly focuses on feasibility of an innovative air-cooled heat exchanger to extend the cooling period of the passive residual heat removal system(PRHRS) only in passive manners. A vertical shell-and-tube air-cooled heat exchanger is installed at the top of the emergency cooldown tank(ECT) to collect evaporated steam into condensate, which enables water inventory of the ECT to be kept. Finally, thermal sizing of an air-cooled heat exchanger is presented. The length and the number of tubes required, and also the height of a stack are calculated to remove the designated heat duty. The present study will contribute to an enhancement of the passive safety system of an integral reactor.

균열을 내재한 회전체의 에너지방출률 (The Energy Release Rate for Cracks in a Rotating Continuum)

  • 이태원
    • 대한기계학회논문집
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    • 제19권2호
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    • pp.330-337
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    • 1995
  • For a rotating body with cracks, the new energy release rate equation is presented. The derived equation is different from the other researcher's results. It is a path-independent integral which excluded the derivatives of displacements near the crack tip, thereby improving the numerical accuracy of the energy release rate computation. Moreover, as the equation was derived on basis of the energy principle and non-linear elasticity without assumptions, it can applied to the cracked body with arbitrary shape under elastic-plastic deformation. Several examples are treated to demonstrate the efficiency and accuracy of the proposed method compared to existing methods.

The effect of photon energy on intensity-modulated radiation therapy (IMRT) plans for prostate cancer

  • Sung, Won-Mo;Park, Jong-Min;Choi, Chang-Heon;Ha, Sung-Whan;Ye, Sung-Joon
    • Radiation Oncology Journal
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    • 제30권1호
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    • pp.27-35
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    • 2012
  • Purpose: To evaluate the effect of common three photon energies (6-MV, 10-MV, and 15-MV) on intensity-modulated radiation therapy (IMRT) plans to treat prostate cancer patients. Materials and Methods: Twenty patients with prostate cancer treated locally to 81.0 Gy were retrospectively studied. 6-MV, 10-MV, and 15-MV IMRT plans for each patient were generated using suitable planning objectives, dose constraints, and 8-field setting. The plans were analyzed in terms of dose-volume histogram for the target coverage, dose conformity, organs at risk (OAR) sparing, and normal tissue integral dose. Results: Regardless of the energies chosen at the plans, the target coverage, conformity, and homogeneity of the plans were similar. However, there was a significant dose increase in rectal wall and femoral heads for 6-MV compared to those for 10-MV and 15-MV. The $V_{20Gy}$ of rectal wall with 6-MV, 10-MV, and 15-MV were 95.6%, 88.4%, and 89.4% while the mean dose to femoral heads were 31.7, 25.9, and 26.3 Gy, respectively. Integral doses to the normal tissues in higher energy (10-MV and 15-MV) plans were reduced by about 7%. Overall, integral doses in mid and low dose regions in 6-MV plans were increased by up to 13%. Conclusion: In this study, 10-MV prostate IMRT plans showed better OAR sparing and less integral doses than the 6-MV. The biological and clinical significance of this finding remains to be determined afterward, considering neutron dose contribution.

Resonance Integral of Neptunium(237Np) from Energy Dependent Differential Neutron Capture Cross-Section by Using the Linac TOF Method and C6D6 Scintillation Spectrometer

  • Lee, Sam-Yol
    • 한국방사선학회논문지
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    • 제5권4호
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    • pp.217-221
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    • 2011
  • $^{237}Np$ is very important material in the fission products of nuclear reactors. Resonance integral(RI) tests of this material is necessary to check between the experiments and the evaluated data. Such feedback to the evaluated data is very important to correct data and improve of codes. The RI for the $^{237}Np(n,{\gamma})^{238}Np$ reaction were measured by using the 46-MeV electron linear accelerator (linac) at the Research Reactor Institute, Kyoto University (KURRI). The measurement was performed in the energy region from 0.005 eV and 10 keV. RI obtained as 804.7 barns, compared with those of the evaluated data in JENDL-4.0 and Mughabghab.