[ RadSafe ] LNT

[Johansen, Kjell]

In May the NRC issued a notice of proposed rulemaking (NPR) to bring current US regulations more in line with ICRP-103.  This would put Part 20 (ICRP 26)  and  Appendix I (ICRP 2) of Part 50 on the same bases.  Recent RADSAFE discussions concerning LNT are of interest given that the supporting documents for the NRC's NPR states that the ICRP continues to recommend the use of LNT, which to my knowledge, has not been shown to be technically valid at the doses calculated from normally operating nuclear plant effluents.  ICRP-103 recommends a risk of 5E-02 per Sv, up from the current risk of 1.25E-02 per Sv in the current Part 20.  In their supporting documents, the NRC states that the radiation risk models and assessments contained in ICRP-103 are consistent with the main conclusions of the 2005 National Research Council report (Health Risks for Exposure to Low Levels of Ionizing Radiation).   Does anyone know whether LNT has been demonstrated to exist at doses <0.2 mSv?  If not, what is the lowest dose the LNT hypothesis has been statistically shown to exist and what would be the error associated with that estimate?  Comments and references would be appreciated.

Kjell Johansen
Sr. Nuclear Chemistry Analyst
Point Beach Nuclear Plant
Two Rivers, WI 54241
kjell.johansen at nee.com