Emergencies

The following comments on the ICRP draft report were prepared based on the discussion among the members of the committee and the working group, which have responsibility for the radiological protection at the nuclear power stations in Japan, in The Federation of Electric Power Companies (FEPC). 1.General Comments This draft report is sure to be a significant guide describing details of the implementation of the commission�fs recommendations for emergency exposure situations in the 2007 Recommendations of the ICRP, Publication 103. However, the relationship between the �gintervention level�h recommended in ICRP Publication 63, and the �greference level�h is still not definite. So, the relationship, and the difference, between the �greference level�h and the �gintervention level�h should be described more clearly in order to avoid confusion about the implementation of the commission�fs recommendations. In the same way, it is necessary to define what �gprojected dose�h, �gresidual dose�h and �gaverted dose�h mean and how they are evaluated. Emergency situations occurring at the nuclear power plant range from small incidents, such as damage to the radioactive source, to very large incidents, such as large scale radiation emissions. It is important to discuss each category of emergency classified by the level of seriousness of each emergency situation. The most important optimization is not only to reduce exposure, but also to contain and remedy emergency situations in order to limit unpredictable radiation exposures in case of accident. It is necessary to consider emergency exposure situations where it may be difficult to decide the �greference level�h. It is useful for understanding clearly the commission�fs recommendations to describe some actual examples of emergency exposure situations in supporting documents. 2.Specific Comments Table 3 of ICRP Publication 63 describes 500mSv as the threshold �gintervention level�h of �gAdministration of stable iodine�h or �gEvacuation (< 1 week)�h, and 1,000mSv for �gRelocation�h. Meanwhile, in the ICRP draft report, the �greference level�h is recommended to be set between 20mSv and 100mSv, though the �gintervention�h is described as useful. The gap between the �greference level�h and the �gintervention level�h is enormous. So, it is necessary to clarify the relationship, and the difference, between the �greference level�h and the �gintervention level�h.