Alert

Due to a lapse in appropriations, the NRC has ceased normal operations. However, excepted and exempted activities necessary to maintain critical health and safety functions—as well as essential progress on designated critical activities, including those specified in Executive Order 14300—will continue, consistent with the OMB-Approved NRC Lapse Plan.

Thorium-228

Atomic No.	Radionuclide	Class	Table 1 Occupational Values			Table 2 Effluent Concentrations		Table 3 Releases to Sewers
			Col. 1	Col. 2	Col. 3	Col. 1	Col. 2	Table 3 Releases to Sewers
			Oral Ingestion ALI (µCi)	Inhalation		Air (µCi/ml)	Water (µCi/ml)	Monthly Average Concentration (µCi/ml)
			Oral Ingestion ALI (µCi)	ALI (µCi)	DAC (µCi/ml)	Air (µCi/ml)	Water (µCi/ml)	Monthly Average Concentration (µCi/ml)
90	Thorium-228	W, see ²²⁶Th	6E+0 Bone Surf	1E-2 Bone Surf	4E-12	-	-	-
		W, see ²²⁶Th	(1E+1)	(2E-2)	-	3E-14	2E-7	2E-6
		Y, see ²²⁶Th	-	2E-2	7E-12	2E-14	-	-

Page Last Reviewed/Updated Thursday, March 25, 2021