General comments
(1) Concrete numerical values that can be interpreted as annual regulation values should not be described (Circulatory System and Lens).
For circulatory system, this draft documents a misleading value of 12 mGy that was calculated as a threshold dose of 500 mGy divided by a working lifetime of 40 years (Paragraphs 667 and 668). Given its unclear relation to the current dose limits, a description about this value should be deleted. Taken together, similarly calculated value should not be mentioned for lens as well.
The Committee 4 should also carefully discuss the propriety and impacts regarding the application of this value for implementation of the system.
(2) A conceptual inconsistency between risks of cancer and non-cancer disease should be considered (Circulatory System).
On one hand, current dose limits for occupational exposures are provided as a lifetime cumulative dose of 1 Sv (20 mSv/year x 50 years) considering 4% detriments. On the other, this draft employed the 1% lifetime mortality risk to give a threshold dose for circulatory system. The relationship between such threshold dose for circulatory system and dose limits for cancer is unclear. For application in radiation protection, the essential difference between risks of stochastic effects and tissue reactions needs to be carefully discussed.
(3) Critical conclusions should be drawn after authorized by the international authority UNSCEAR (Circulatory System and Lens).
So far, it has been accepted that the international authorization by UNSCEAR precedes ICRP recommendations to make big changes. In this regard, current issues regarding circulatory system and lens have significant impacts on radiation protection system, and should be therefore discussed carefully as such.