• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• 제3권2호
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• pp.125-133
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• 2005

Methodologies of NEWTRIT model, NRC model and AIRDOS-EPA model, which are off-site dose assessment models for regulatory compliance from routine releases of tritium into the environment, were investigated. Using the domestic data, if available, the predictive results of the models were compared. Among them, recently developed NEWTRIT model considers only doses from organically bounded tritium (OBT) due to environmental releases of tritiated water (HTO) . A total dose from all exposure pathways predicted from AIRDOS-EPA model was 1.03 and 2.46 times higher than that from NEWTRIT model and NRC model, respectively. From above result, readers should not have an understanding that a predictive dose from NRC model may be underestimated compared with a realistic dose. It is because of that both mathematical models and corresponding parameter values for regulatory compliance are based on the conservative assumptions. For a dose by food consumption predicted from NEWTRIT model, the contribution of OBT was nearly equivalent to that of HTO due to relatively high consumption of grains in Korean. Although a total dose predicted from NEWTRIT model is similar to that from AIRDOS-EPA model, NEIIfTRIT model may be have a meaning in the understanding of phenomena for the behavior of HTO released into the environment.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 한국방사성폐기물학회 2005년도 춘계 학술대회
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• pp.464-473
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• 2005

Methodologies of NEWTRIT model, NRC model and AIRDOS-EPA model, which are off-site dose assessment models for regulatory compliance from routine releases of tritium into the environment, were investigated. Using the domestic data, if available, the predictive results of the models were compared. Among them, recently developed NEWTRIT model considers only doses from organically bounded tritium (OBT) due to environmental releases of tritiated water (HTO). A total dose from all exposure pathways predicted from AIRDOS-EPA model was 1.03 and 2.46 times higher than that from NEWTRIT model and NRC model, respectively. From above result, readers should not have an understanding that a predictive dose from NRC model may be underestimated compared with a realistic dose. It is because of that both mathematical models and corresponding parameter values for regulatory compliance are based on the conservative assumptions. For a dose by food consumption predicted from NEWTRIT model, the contribution of OBT was nearly equivalent to that of HTO due to relatively high consumption of grains in Korean. Although a total dose predicted from NEWTRIT model is similar to that from AIRDOS-EPA model, NEWTRIT model may be have a meaning in the understanding of phenomena for the behavior of HTO released into the environment.

• Proceedings of the Korean Nuclear Society Conference
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• 한국원자력학회 1996년도 춘계학술발표회논문집(3)
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• pp.139-144
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• 1996

핵분열 생성물 방출량을 계산하는 모델들에 대한 비교 분석을 위해 GAPCON-THERMAL-2 Revision 2 (GT2R2) 코드를 이용하여 Beyer-Hann , Beyer-Hann with NRC High Burnup Correction, ANS5.4와 Modified ANS5.4 핵분열 생성물 방출 모델들을, RISO-M2-2C 핵연료봉의 실험결과와 비교하였다. Beyer-Hann 모델은 실험결과보다 낮게 예측한반면 ANS5.4 모델은 실험결과 보다 높게 예측하였다. 한편 NRC High Burnup Correction을 한 Beyer-Hann 모델과 Modified ANS5.4 모델은 실험 결과와 비슷한 방출비를 예측하였다. 이러한 결과를 확인하기 위해 국부적인 핵연료 온도와 연소도를 검토한 결과 ANS5.4 모델이 Modified ANS5.4 모델보다 온도와 연소도에 따라 더 민감한 반응을 보이고 있으며, Beyer-Hann 모델은 연소도 영향이 없이 각 온도 영역에서 일정하였고, Beyer-Hann with NRC High Burnup Correction 모델은 20,000MWd/MTU 연소도 이상영역에서 연소도 영향을 보이고 있다.

• Proceedings of the Korean Nuclear Society Conference
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• 한국원자력학회 1996년도 춘계학술발표회논문집(3)
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• pp.98-104
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• 1996

핵분열 생성물 방출량을 계산하는 모델들에 대한 비교 분석을 위해 GAPCON-THERMAL-2 Revision 2 (GT2R2) 코드를 이용하여 Beyer-Hann , Beyer-Hann with NRC High Burnup Correction, ANS5.4와 Modified ANS5.4 핵분열 생성물 방출 모델들을, RISO-M2-2C 핵연료봉의 실험결과와 비교하였다. Beyer-Hann 모델은 실험결과보다 낮게 예측한반면 ANS5.4 모델은 실험결과 보다 높게 예측하였다. 한편 NRC High Burnup Correction을 한 Beyer-Hann 모텔과Modified ANS5.4 모델은 실험 결과와 비슷한 방출비를 예측하였다. 이러한 결과를 확인하기 위해 국부적인 핵연료 온도와 연소도를 검토한 결과 ANS5.4 모델이 .Modified ANS5.4 모델보다 온도와 연소도에 따라 더 민감한 반응을 보이고 있으며, Beyer-Hann 모텔은 연소도 영향이 없이 각 온도 영역에서 일정하였고, Beyer-Hann with NRC High Burnup Correction 모델은 20,000MWd/MTU 연소도 이상영역에서 연소도 영향을 보이고 있다.

• Journal of Radiation Protection and Research
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• 제38권2호
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• pp.60-67
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• 2013

A diffusion coefficient is an important parameter in the prediction of atmospheric dispersion using a Gaussian plume model, and its modelling approach varies. In this study, dispersion coefficients recommended by the U. S. Nuclear Regulatory Commission's (U. S. NRC's) regulatory guide and the Canadian Nuclear Safety Commission's (CNSC's) regulatory guide, and used in probabilistic accident consequence analysis codes MACCS and MACCS2 have been investigated. Based on the atmospheric dispersion model for a hypothetical accidental release recommended by the U. S. NRC, its influence to atmospheric dispersion factor was discussed. It was found that diffusion coefficients are basically predicted from a Pasquill- Gifford curve, but various curve fitting equations are recommended or used. A lateral dispersion coefficient is corrected with consideration for the additional spread due to plume meandering in all models, however its modelling approach showed a distinctive difference. Moreover, a vertical dispersion coefficient is corrected with consideration for the additional plume spread due to surface roughness in all models, except for the U. S. NRC's recommendation. For a specified surface roughness, the atmospheric dispersion factors showed differences up to approximately 4 times depending on the modelling approach of a dispersion coefficient. For the same model, the atmospheric dispersion factors showed differences by 2 to 3 times depending on surface roughness.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제45권3호
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• pp.217-225
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• 2017

This research represents comparison and validation of static aerodynamic results in different wind tunnel organizations and EFD-CFD results. KAFA conducted wind tunnel tests with Standard Dynamics Model(SDM) which is based on the NRC model, the same configuration of KARI; and then compared and analyzed similarities and differences of the data from KARI and NRC results for verifying the accuracy of wind tunnel tests. Also, We compared the result of CFD with that of wind tunnel tests and examined strakes effect in static characteristics which are attached on the forward fuselage of SDM for investigating the cause of some discrepancies. From this analysis, there are some discrepancies in Cm tendency between EFD-CFD and it did not show the big difference of aerodynamic characteristics by strake effects. Thus, we need to research additionally for analyzing the different cause of some discrepancies such as vortex structures by the rear strut or intake of SDM and regenerating grid resolution of CFD.

• Computational Structural Engineering
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• 제4권1호
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• pp.17-19
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• 1991

본 글에서는 ANS(American Nuclear Society)에서 규정하고 있는 Safety Class 구조물 중 격납건물의 내진해석모델에 대해 주로 언급하며, 기타 건물(Non-Nuclear Safety "NNS")은 일반건물과 차이점이 없음으로 언급하지 않는다. U.S. NRC(Nuclear Regulatory Commision)는 참고문헌[1]에 의해 원자력 발전소내 여러건물중 SSE(Safe Shutdown Earthquake)하중에도 견디도록 규정하여 정확한 동력학적 계산이 요구되어지나, 그 이외의 건물들은 대개 등가정적 방법에 의해 해석되어진다. 이 해석방법은 여러 빌딩규정들에서 제안된 것으로 지진에 의한 동적하중을 밑면적 단력 또는 각층에 작용하는 층전단력이라는 등가의 정적하중으로 바꿔 계산되며 이 때 사용되는 해석모델은 건물의 기본진동만을 표시할 수 있는 간단한 것이다.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• 제11권2호
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• pp.103-114
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• 2013

The Korea Atomic Energy Research Institute has developed a performance assessment model implementing the A-KRS concept, which was constructed with the GoldSim. In the A-KRS concept, spent nuclear fuel produced from pressurized-water-reactor operations would be pyroprocessed to reduce waste volume and radioactivity. The wastes to be disposed of in a geologic repository are comprised of metal and ceramic waste forms. In this study, results of simulations conducted to establish credibility and build confidence for the A-KRS model are presented. Specifically, release rates and breakthrough times simulated using the A-KRS model were compared to corresponding results from the U.S. NRC SOAR model. In addition, the A-KRS model results were compared to published release rates from the SKB repository performance assessment. This comparison of the A-KRS model results to other independent performance assessments is expected to form part of a suite of model verification and validation activities to provide confidence that the A-KRS model has been implemented appropriately.

• Journal of Radiation Protection and Research
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• 제25권4호
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• pp.233-239
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• 2000

The sensitivity analysis of input parameters was Performed fer an ingestion dose assessment model (U. S. NRC's Regulatory Guide 1.109 model) from routine releases of radionuclides. In this study, three kinds of typical Korean foodstuffs (rice, leaff vegetables, milk) and two kinds of radionuclides $(^{l37}Cs,\;^{131}I)$ were considered. The values of input parameters were sampled using a Latin hypercube sampling technique based on Monte Carlo approach. Sensitivity indices, which represent the influence or the importance of input parameters for predictive results, were quantitatively expressed by the partial rank correlation coefficients. As the results, the ratio of the interception fraction to the yield of agricultural plants and the human consumption rate were sensitive input parameters for the considered foodstuffs and radionuclides. Additionally, in case of milk, the transfer factor of radionuclides from animal intake to milk and the daily intake rate of feedstuffs were sensitive input parameters. The weathering removal half-life and the delay time from food production to human consumption were relatively sensitive for $^{137}Cs$ and $^{131}I$ depositions, respectively.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 한국전산구조공학회 2001년도 가을 학술발표회 논문집
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• pp.561-568
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• 2001

For obtaining the time history nodal responses of reactor building, a lumped-mass beam model composed of two sticks for the reactor building and the reactor support structure is developed. The time history responses for the non-isolated and isolated reactor buildings are calculated under an artificial time history, generated using the seismic spectrum curve of US NRC RG1.60. The analysis results show that the horizontal accelerations of the isolated building are dramatically decreased to one-tenths of the non-isolated one, but the vertical responses are increased by about 40%.