• Journal of Radiation Protection and Research
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• v.20 no.4
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• pp.227-236
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• 1995

Using beam data and accurate 3D dose model, a study of the spatial dose distribution for various arcs was carried out. The dose dirstibution generated by the accurate dose model could be represented by a simple approximate analytic form which is convenient and very efficient for calculating dose distribution iteratively in the optimization procedure. We developed an empirical cylindrical dose model to compute dose for one full rotational arc or partial rotational arc. After a tedious search for fits to a collection of 200 points of accurate dose data, we found simple formular with 7 parameters search. As a consequence, the programs required approximately less than 1 second to compute dose for one single arc on a 20 by 20 matrix (400 points) using fast approximate dose model. In conclusion the fast approximate dose model give dose distributions similar to the accurate dose model, which makes this fast dose model an attractive alternative to the accurate 3D dose model.

• Journal of Radiation Protection and Research
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• v.31 no.2
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• pp.105-113
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• 2006

The oxidizing species are generated from the radiolysis of groundwater in the pore of buffer material around the canister used for the disposal of spent fuels. A mathematical model was introduced to calculate the cathodic current density induced by the oxidant around the canister, which determined the corrosion of carbon steel. An analytical solution was derived to get the cathodic current density in the cylindrical coordinate. The cathodic current densities from both the rectangular coordinate and cylindrical coordinate were compared with each other. The source terms and absorbed dose rate for the calculation of the radiolysis were calculated using the ORIGEN2 and MCNP computer code, respectively. The radius of the canister was determined with the new model in order to prevent the local corrosion. The results showed that the new solution made the cathodic current density around 25 % lower than the Marsh model.

• Journal of the Korea Concrete Institute
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• v.16 no.1 s.79
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• pp.43-53
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• 2004

The current Korean Concrete Design Code(KCI Code) requires the minimum and maximum content of shear s in order to prevent brittle and noneconomic design. However, the required content of the steel reinforcement In KCI Code is quite different to those of the other design codes such as fib-code, Canadian Code, and Japanese Code. Furthermore, since the evaluation equations of the minimum and maximum shear reinforcement for the current KCI Code were based on the experimental results, the equations can not be used for the RC members beyond the experimental application limits. The concrete tensile strength, shear stress, crack inclination, strain perpendicular to the crack, and shear span ratio are strongly related to the lower and upper limits of shear reinforcement. In this research, an evaluation equation for the minimum content of shear reinforcement is theoretical proposed from the Wavier's three principals of the mechanics of materials.