• Title, Summary, Keyword: release characteristics of radionuclides

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The Prediction Methods of Iodine-129 release rate : Model Development

  • Park, Jin-Beak;Lee, Kun-Jai;Kang, Duck-Won;Shin, Sang-Woon;Park, Kyung-Rok
    • Proceedings of the Korean Nuclear Society Conference
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    • pp.879-884
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    • 1995
  • The results of performance assessment analyses have shown that the long-lived radionuclides such as I-129 control the potential individual dose impact to the public. I-129 is difficult-to-measure(DTM) in low-level waste because it is non-gamma emitting radionuclides and exists at extremely low concentrations in radioactive waste generated by nuclear reactors. In this study, computer modeling technique to predict release rate of I-129 is developed to provide another tools far performance assessment of land disposal facilities and characteristics of radwaste. Model suggested in this study will give conservative values of I-129 release rate far determination of radwaste characteristics. More detailed approach is implemented to account for release conditions of fuel source-nuclides. 1-131 concentration measured from reactor coolant and released fraction from tramp fuel have dominant roles in calculating release rate of I-129 with fuel defect conditions.

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A Practical Methodology for Determination of Derived Intervention Levels on Relocation Following a Nuclear Accident (원자력 사고후 주민의 이주를 위한 유도개입준위 산정의 실용적 방법론)

  • Hwang, Won-Tae;Kim, Eun-Han;Suh, Kyung-Suk;Jeong, Hyo-Joon;Han, Moon-Hee;Lee, Chang-Woo
    • Journal of Radiation Protection and Research
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    • v.29 no.2
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    • pp.91-96
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    • 2004
  • A practical methodology for the determination of derived intervention levels (DILs) on relocation following an accidental release of radionuclides was designed based on dose rate on the ground. The influence of DILs was investigated with respect to the change of parameter values, which are dependent on socio-environmental characteristics in distinction from temporary and permanent relocations. The DILs on relocation showed a distinct difference depending on effective removal half-life of radionuclides following a deposition, delay time in measurement and residential characteristics. In particular, the delay time. In measurement was an important factor in determination of DILs in the case of an assumption that dose rate on the ground declines in a power function, not in an exponential function. The DILs showed lower numerical values as longer effective half-life, longer delay time In measurement and longer exposure time.

Radionuclides Transport from the Hypothetical Disposal Facility in the KURT Field Condition on the Time Domain (KURT 부지 환경에 위치한 가상의 처분 시설에서 누출되는 방사성 핵종의 이동을 Time Domain에서 해석하는 방법에 관한 연구)

  • Hwang, Youngtaek;Ko, Nak-Youl;Choi, Jong Won;Jo, Seong-Seock
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.10 no.4
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    • pp.295-303
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    • 2012
  • Based on the data observed and analyzed on a groundwater flow system in the KURT (KAERI Underground Research Tunnel) site, the transport of radionuclides, which were assumed to be released at the supposed position, was calculated on the time-domain. A groundwater pathway from the release position to the surface was identified by simulating the groundwater flow model with the hydrogeological characteristics measured from the field tests in the KURT site. The elapsed time when the radionuclides moved through the pathway is evaluated using TDRW (Time Domain Random Walk) method for simulating the transport on the time-domain. Some retention mechanisms, such as radioactive decay, equilibrium sorption, and matrix diffusion, as well as the advection-dispersion were selected as the factors to influence on the elapsed time. From the simulation results, the effects of the sorption and matrix diffusion, determined by the properties of the radionuclides and underground media, on the transport of the radionuclides were analyzed and a decay chain of the radionuclides was also examined. The radionuclide ratio of the mass discharge into the surface environment to the mass released from the supposed repository did not exceed $10^{-3}$, and it decreased when the matrix diffusion were considered. The method used in this study could be used in preparing the data on radionuclide transport for a safety assessment of a geological disposal facility because the method could evaluate the travel time of the radionuclides considering the transport retention mechanism.

A Conservative Safety Study on Low-Level Radioactive Waste Repository Using Radionuclide Release Source Term Model (선원항 모델을 사용한 저준위 방사성폐기물 처분장의 보수적인 안전성고찰)

  • Kim, Chang-Lak;Lee, Myung-Chan;Cho, Chan-Hee
    • Nuclear Engineering and Technology
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    • v.25 no.1
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    • pp.63-70
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    • 1993
  • A simplified safety assessment is carried out on rock-cavern type disposal of LLW using the analytical repository source term (REPS) model. For reliable prediction of the leach rates for various radionuclides, degradation of concrete structures, corrosion rate of waste container, degree of corrosion on the container surface, and the characteristics of radionuclides are considered in the REPS model. The results of preliminary assessment show that Cs-137, Ni-63, and Sr-90 are dominant. For the parametric uncertainty and sensitivity analysis, Latin hypercube sampling technique and rank correlation technique are applied. The results of the potential public health impacts show that radiological dose to intruder in the worst case scenario will be negligible and that more attention should be given to near-field performance.

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Comparison of Measured and Predicted $^3H$ Concentrations in Environmental Media around the Wolsung Site for the Validation of INDAC Code (주면피폭선량 평가코드(INDAC)의 검증을 위한 월성원전 주면 삼중수소 농도 실측치와 예측치의 비교 평가)

  • Jang, Si-Young;Kim, Chang-Kyu;Rho, Byung-Hwan
    • Journal of Radiation Protection and Research
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    • v.25 no.2
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    • pp.75-80
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    • 2000
  • The predicted results of INDAC code were compared with measured $^3H$ concentrations in air and pine-needle around the Wolsung site. The optimal sets of input data to INDAC were in addition selected by comparing the measured values with the predicted values of INDAC based on various conditions such as the release modes of effluents into the environment, the classification of wind classes, and the consideration of terrain. The predicted $^3H$ concentrations in air and pine-needle were shown to have good agreement with measured values, although there are some limitations such as uncertainties in measured values, complex topology around the site, and the land-sea breeze effects. The assumption on the $^3H$ behavior in vegetables or plants that the ratio of $^3H$ concentration in plant water to $^3H$ concentration in atmospheric water is 1/2 was shown to be conservative in terms of the audit calculation performed by the regulator. It was also found that data sets based on mixed mode and no terrain data were not appropriate for the audit calculation ensuring the compliance with regulations. Thus, if the mixed mode is considered as the release mode of effluents into the environment, meteorological data measured at 58 m height and terrain data should be used to evaluate the atmospheric dispersion factor.

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