[en] The second draft for R and D of geological disposal (second draft) was arranged in 1999. The idea of security of geological disposal in the second draft is explained. The evaluation results of the uncertainty analysis and an example of evaluation of the effect of separation nuclear transmutation on the geological disposal are shown. The construction of strong engineered barrier is a basic idea of geological disposal system. Three processes such as isolation, engineering countermeasures and safety evaluation are carried out for the security of geological disposal. The security of geological environment for a long time of 12 sites in Japan was studied by data. Provability of production and enforcement of engineered barrier were confirmed by trial of over pack, tests and the present and future technologies developed. By using the conditions of reference case in the second draft, the evaluation results of dose effects in the two cases: 1) 90 to 99% Cs and Sr removed from HLW (High Level radioactive Waste) and 2) high stripping ratio of actinium series are explained. (S.Y.)