|ICRP continues to provide protection standards only for radon-222 at home and work places. However, no recommendations are forthcoming for an all important radon-220 and their daughters, which paly an important role in thorium fuel cycle operations. Can we expect some recommendations for this in the new ICRP-100?
Dosimetric studies have shown that for a given exposure in the units of WLM, the internal dose due to radon-220 daughters is three times LOWER than the radon-222 daughters. Hence, it may be appropriate to use exposure limit which is three times higher, i.e., (4 WLM x 3) = 12 WLM for radon-220 daughters.
What is the view of ICRP on this?