[en] This report provides estimates of maximum annual individual doses to personnel for given set of scenarios associated with intrusion by drilling into a deep repository for high level waste (HLW) and recovery to the surface of contaminated material. Geological and engineering judgment has been used to formulate the manner of this intrusion and the parameters which would determine the resulting doses to field workers and to others who might be involved subsequently in procedures carried out in a geotechnical laboratory. Calculations have been performed to quantify the magnitudes of doses resulting from drilling into the HLW spent fuel matrix, the bentonite buffer and the adjacent rock. Doses have been calculated in the basis of the potential for external irradiation, inhalation of suspended contamination, and inadvertent ingestion of small amounts of contaminated material. The results show that intrusion doses into spent fuel within a few decades of disposal could be very high, in the range about 10 to 100 Sv. At this stage all three exposure pathways make a significant contribution to the total dose. Beyond about 100 y, as ¹³⁷Cs decays away, the contribution from external irradiation falls off sharply. However the doses from ingestion and inhalation have only fallen by about a factor of 5 after 10³ y, and the total dose still in the range from about 2 to 25 Sv. Apart form the direct consequences of intrusion discussed above, drilling might influence safety in other ways. Thus, a borehole might modify the groundwater flow system around the waste, and provide a direct permeable flow path to the near surface; it might results in the introduction of drilling fluids which modify groundwater chemistry; it might results in the early failure of a fuel canister, leading to earlier release to groundwater; or, in the extreme, some combination of all three. (au)