Swiss comments concerning the ICRP draft “The Optimisation of Radiological Protection“ Optimisation of radiological protection is a central dynamic process to achieve a sound protection of population groups against ionising radiation and to assist decision making. Optimisation should only occur for justified practices. The main remarks from Switzerland concerning this draft can be summarizing as follow: • ICRP 60 remains valuable with increasing implementation of safety culture, stakeholders’ involvement, dialogue between operators and regulatory bodies, Quality assurance and introduction of source-related values of individual dose (dose constraint). • Also the precautionary principle combining ALARA-BAT appears a reasonable strategy focusing the objective of protection on emission reduction rather than on health-effect/probability-of-effect reduction. • Precisions concerning the use of collective dose and stimulations for dose estimates taking into account exposure distributions rather than a single point estimate are welcome. • Nevertheless as we suggested in our annexed previous position paper (point 9), the recommendation of an annual dose limit of 20 mSv instead of 50 mSv (Annexe A1 of the present draft) for exposed workers would be a positive courageous forward step in the sense of optimisation and improved radiological protection. This major change also would be a strong point motivating new recommendations. We still feel that here the Commission has a good opportunity not to miss moving things forward. • We propose that the edition of this document is postponed until the new ICRP recommendations are widely accepted. The document should than be updated accordingly. • We suggest that the document becomes smaller (max 10 pages) and more straightforward. General remarks and historical aspects should not be repeated in each document again. The usability of document should be analysed critically. We think that it is too theoretical. • The annex A3 on radon should be updated taking into account the results from the pooling of epidemiological studies (Darby et al, Krewski et al). It should also be clearly stated that a significant reduction of lung cancer cases cannot be achieved with mitigation of houses. The radon level in new constructions must be reduced in order to achieve a reduction of the population weighted average. We suggest that a level of 100 Bq/m3 is recommended for new constructions. The maximum concentration proposed (600 Bq/m3) in the draft is rather too high.