Radiation negligible dose

Billen, D. 1990. Spontaneous DNA damage and its significance for the negligible dose controversy in radiation protection. Radiation Res. 124 242-245. 

A negligible dose would be generally applicable to all man-made sources of radiation and would define a dose below which further control of sources by regulatory authorities is deemed to be unwarranted. If all doses were below a negligible level, no further reductions in dose using the ALARA principle would be attempted (see... 

Section 3.3.1). A negligible dose is based on consideration of a negligible risk from radiation exposure, without regard for whether such a dose is reasonably achievable for any particular exposure situation. 

Our exposure to man-made radioactive sources, such as from nuclear power plants, is negligible when compared to the total radiation we receive. Man-made radiation accounts for less than 3% of the total radiation we receive in the United States, but in some countries, this figure is higher. The vast majority of the 3% of man-made doses of radiation we receive in our lifetime results from medical uses, and the vast majority of the 97% of the total exposure to all radiation we receive comes from natural sources. 

T wo aspects of the radiation chemistry of polyethylene terephthalate (PET) are reviewed here the dependence of product yields on radiation dose and on dose rate. The review is limited to work with thin films from which air and water were pumped prior to irradiation. Moreover, it is judged that in the experiments described postirradiation effects were negligible. 

The approach to risk management for radionuclides, when they are regulated under AEA, incorporates a limit on acceptable dose (and therefore risk) and a requirement that doses be reduced below the limit as low as reasonably achievable (ALARA), economic and social factors being taken into account this approach conforms to NCRP s recommendations on radiation protection. In this approach, risks to individuals are divided into three categories of significance, which are commonly termed unacceptable, acceptable, and negligible. ... 

An important function of NCRP is to develop basic recommendations on radiation protection NCRP s current recommendations are contained in Report No. 116 (NCRP, 1993a). With regard to radiation protection of the public, two recommendations are potentially relevant to the development of a risk-based waste classification system. These recommendations involve limits on radiation dose and a negligible individual dose. 

NCRP has recommended that annual effective doses to individuals from any practice or source of 10 p.Sv or less are negligible (see Section 4.1.2.5.3). This dose is one percent of the dose limit for continuous exposure to all man-made sources combined discussed in the previous section, and it also is about one percent of the dose from natural background radiation, excluding radon (NCRP, 1987b). The recommended negligible individual dose corresponds to an estimated lifetime fatal cancer risk of about 4 X 10 5. 

The effect of y-radiation at doses 102—106 rad on starch sols is negligible at the outset of the irradiation. Sedimentation then becomes slower and progressive turbidity is observed. Both phenomena are dose-related for com192 and potato193 starch. According to Khenokh,193194 neither the increase of reducing power of 0.3% potato starch sols nor the decrease of its pH and relative viscosity are linear with respect to time of exposure at constant -irradiation intensity (Fig. 26). 

Effect of Radiation Dose on Micellar Properties. Figure 1 shows the concentration dependence of the micellar diffusion coefficient at 40° as determined by quasi-elastic light scattering (QELS) for solutions subjected to radiation doses of up to 4.56 Mrad. Limiting diffusion coefficients, D0>were obtained by extrapolation of data for dilute solutions (<0.05%) to zero concentration, the critical micelle concentration (CMC) being negligibly low for this poloxamer ( 1 ). 

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