The existing technology of krypton and xenon concentration in the air separation plants doesn’t allow to produce the concentrate with the total content of Kr and Xe exceeding 0,4…0,5 %. The option is proposed for the accumulative distillation consisting in concentration of semi-volatile components of mixture in the column still with a constant feed with-out the bottom product withdrawal. Considered is the diagram of the accumulative distillation plant for krypton and xenon concentration from the mixture wherein oxygen is preliminary displaced with nitrogen. Given are the results of calculation of the mixture composition change in time in the accumulative vessel. The possibility of significant increase in the content of Kr and Xe in the product concentrate withdrawn from the ASP is shown. The suggested method allows to reduce costs for the concentrate transportation and further processing.