Low-temperature behavior of elastomeric seals. Material property determination for the use in transport and storage casks for radioactive materials

Elastomers are used as sealing materials for radioactive waste transport and storage casks. Due to the valid laws and guidelines for these containers the tightness of the elastomeric seals has to be demonstrated for temperature down to -40 C. Therefore the low-temperature behavior of elastomeric seals and the failure mechanism inducing leak rates above the limiting value are of interest. Material properties of elastomeric polymers are significantly temperature dependent, in the low temperature range due to the rubber-glass transition. The measurement of the dynamic storage modulus and the glass transition temperature was performed using dynamic mechanical analysis. Further measurements are necessary to determine the failure temperature of elastomeric seals. The authors show that EPDM is still in the rubber-elastic range at -40 C.