-ll- concept intended for planning purposes. It will seldom be possible to ensure that no single individual exceeds this dose limit. Even when individual exposures are sufficiently low so that the risk to the individual is acceptable small, the sum of these risks may justify the effort required to achieve further limitation, Where the source of exposure is subject to control, it is desirable and reasonable to set specific dose limitations. In this manner the associated risk is judged to be appropriately small in relation to the resulting benefits. The limitation must be set at a sufficiently low level so that any further reduction in risk would not justify the effort required to accomplish it. Such risks to members of the public from man-made sources of radiation should be less than or equal to other risks regularly accepted in everyday life. They should also be justifiable in terms of benefits that would not otherwise be received. ICRP has stated that when dose limits have been exceeded by a small amount, it is generally more significant that there has been a failure of control than that one or more individuals have slightly exceeded the limits. "Dose limits" for members of the public are intended to provide standards for design and operation of radiation sources so that it is unlikely that individuals in the public will receive more than a specified dose. The effectiveness is appraised by assessments through sampling pro- cedures in the environment, by statistical calculations, and by a control of the sources from which the exposure is expected to arise. A TF Measurement /, x S nee Aonreen en? Gon oon hen. ot riD 10, oR Eee ee yee To ey oy