Recycling of norm-contaminated equipment

Eight oil companies, under the auspices of the Petroleum Environmental Research Forum, have sponsored a study to evaluate the feasibility of recycling NORM-contaminated equipment as scrap Metals. The focus-of the study is to identify advantages and assess radiation exposures and risks associated with the recycling of such equipment. Laboratory benchtop tests, using steel and NORM-contaminated scale, were used to study the fate of NORM in steel mill furnaces. The test results revealed that nearly 100% of the added 226Ra, 228Ra, and 228Th activity were recovered in slag. This behavior prevailed whether conditions were oxidizing or reducing. The radioactivity retained in steel was less than 2% of that added in the furnace. The presence of 210Pb and 210Po were not determined, as analyses revealed their presence in steel, slag, and scrubber solutions to be within detection limits. The presence of 226Ra in off-gases was calculated to be 0.04% of the added activity. Risk assessment analyses were conducted to estimate radiation doses and risks associated with stack emissions from electric-arc and basic oxygen furnaces. For the maximum exposed individual, the results indicated that offsite annual doses (EDE) vary from 6.9 E-04 to 2.3 E-06 μSv. Lifetime doses were estimated to range from 5.0 E-02 to 1.6 E-04 μSv. The corresponding lifetime risks for fatal cancers range from 1.1 E-09 to 2.6 E-12, well under the range of 1.0 E-4 to 1.0 E-06 deemed acceptable by the EPA under NESHAPS regulations