Surface Contaminated Object - SCO - Material [Energy] Law and Legal Definition

According to 10 CFR 71.4 [Title 10 – Energy; Chapter I -- Nuclear Regulatory Commission; Part 71 -- Packaging and Transportation of Radioactive Material; Subpart A -- General Provisions], the term Surface Contaminated Object (SCO) means “a solid object that is not itself classed as radioactive material, but which has radioactive material distributed on any of its surfaces. SCO must be in one of two groups with surface activity not exceeding the following limits:

(1) SCO-I: A solid object on which:

(i) The nonfixed contamination on the accessible surface averaged over 300 cm<2> (or the area of the surface if less than 300 cm<2>) does not exceed 4 Bq <2> (10<-4> microcurie <2>) for beta and gamma and low toxicity alpha emitters, or 0.4 Bq <2> (10<-5> microcurie <2>) for all other alpha emitters;

(ii) The fixed contamination on the accessible surface averaged over 300 cm<2> (or the area of the surface if less than 300 cm<2>) does not exceed 4 x 10<4> Bq <2> (1.0 microcurie <2>) for beta and gamma and low toxicity alpha emitters, or 4 x 10<3> Bq <2> (0.1 microcurie <2>) for all other alpha emitters; and

(iii) The nonfixed contamination plus the fixed contamination on the inaccessible surface averaged over 300 cm<2> (or the area of the surface if less than 300 cm<2>) does not exceed 4 x 10<4> Bq <2> (1 microcurie <2>) for beta and gamma and low toxicity alpha emitters, or 4 x 10<3> Bq <2> (0.1 microcurie <2>) for all other alpha emitters.

(2) SCO-II: A solid object on which the limits for SCO-I are exceeded and on which:

(i) The nonfixed contamination on the accessible surface averaged over 300 cm<2> (or the area of the surface if less than 300 cm<2>) does not exceed 400 Bq <2> (10<-2> microcurie <2>) for beta and gamma and low toxicity alpha emitters or 40 Bq <2> (10<-3> microcurie <2>) for all other alpha emitters;

(ii) The fixed contamination on the accessible surface averaged over 300 cm<2> (or the area of the surface if less than 300 cm<2>) does not exceed 8 x 10<5> Bq <2> (20 microcuries <2>) for beta and gamma and low toxicity alpha emitters, or 8 x 10<4> Bq <2> (2 microcuries <2>) for all other alpha emitters; and

(iii) The nonfixed contamination plus the fixed contamination on the inaccessible surface averaged over 300 cm<2> (or the area of the surface if less than 300 cm<2>) does not exceed 8 x 10<5> Bq <2> (20 microcuries <2>) for beta and gamma and low toxicity alpha emitters, or 8 x 10<4> Bq <2> (2 microcuries <2>) for all other alpha emitters.”