| dc.description.abstract | Due to the limit in storage room for spent fuels in nuclear power plants, it is proposed that the spent fuels be stored by dry storage measure. The structure of dry storage measure is mainly made of concrete, and thus the service life of concrete is of great concerns. The concrete used in storage room is expected to endure the decay heat of the nuclear fuel and the environment and weather condition in Taiwan. Further, the concrete might be damaged or degraded under the tough situations to be expected.
The research is aimed at investigating the effects of environment on the degradation and durability of concrete in a dry storage facility, with emphasis on the influence of high decay heat to be encountered. We learned from the tests that: (1) Concrete perform well within 250℃, in terms of its compressive strength. (2) After the high temperature attack, the splitting strength, ultrasonic pulse velocity, dynamic and static modulus of elasticity deteriorate remarkably, however, with the passage of time, its deteriorating rate becomes gentle. (3) When the concrete is heated, its volume extracts. The higher the temperature, the more it extracts; (4) The replacement of a portion of cement with pozzolanic materials was found to help the concrete to resist the sulfate attack. (5) In case of high exposure temperature, the permeability coefficient of the concrete would be high. (6) When the temperature climbs to 250℃, concrete’s ability of resist chloride ingress deteriorates. The use of pozzolanic materials help to improve its ability in resisting chloride ingress. (7) The results of the microstructure observations show that concrete does not degrade under a temperature of 250℃. | en_US |