Section 33.1-10-23-26 - Acceptable surface contamination levels for TENORM1. Where surface contamination by both alpha and beta-gamma emitting nuclides exists, the limits established for alpha and beta-gamma emitting nuclides shall apply independently.2. As used in this section, "disintegrations per minute" means the rate of emission by radioactive material as determined by correcting the counts per minute observed by an appropriate detector for background, efficiency, and geometric factors associated with the instrumentation.3. Average contamination level. a. For surface contamination by alpha emitting nuclides, the average contamination level shall not exceed five thousand disintegrations per minute per one hundred square centimeters of surface area.b. For surface contamination by beta-gamma emitting nuclides, the average contamination level shall not exceed five thousand disintegrations per minute per one hundred square centimeters of surface area.c. Measurements of average contamination level shall not be averaged over more than one square meter. For objects of less surface area, the average shall be derived for each object.d. The average radiation levels associated with surface contamination resulting from beta-gamma emitters shall not exceed two microgray per hour [two tenths millirad per hour] at one centimeter and ten microgray per hour [one millirad per hour] at one centimeter, respectively, measured through not more than seven milligrams per square centimeter of total absorber.4. Maximum contamination level.a. For surface contamination by alpha emitting nuclides, the maximum contamination level shall not exceed fifteen thousand disintegrations per minute per one hundred square centimeters of surface area.b. For surface contamination by beta-gamma emitting nuclides, the maximum contamination level shall not exceed fifteen thousand disintegrations per minute per one hundred square centimeters of surface area.c. The maximum contamination level applies to an area of not more than one hundred square centimeters.d. The maximum radiation levels associated with surface contamination resulting from beta-gamma emitters shall not exceed two microgray per hour [two tenths millirad per hour] at one centimeter and ten microgray per hour [one millirad per hour] at one centimeter, respectively, measured through not more than seven milligrams per square centimeter of total absorber.5. Limits on removable contamination.a. For surface contamination by alpha emitting nuclides, the removable contamination shall not exceed one thousand disintegrations per minute per one hundred square centimeters of surface area.b. For surface contamination by beta-gamma emitting nuclides, the removable contamination shall not exceed one thousand disintegrations per minute per one hundred square centimeters of surface area.c. Measurements of average contamination level shall not be averaged over more than one square meter. For objects of less surface area, the average shall be derived for each object.d. The amount of removable radioactive material per one hundred square centimeters of surface area shall be determined by wiping that area with dry filter or soft absorbent paper, applying moderate pressure, and assessing the amount of radioactive material on the wipe with an appropriate instrument of known efficiency. When removable contamination on objects of surface area A (where A is less than one hundred square centimeters) is determined, the entire surface shall be wiped and the contamination level multiplied by the quantity [one hundred divided by A] to convert to a "per one hundred square centimeter" basis.e. The maximum radiation levels associated with surface contamination resulting from beta-gamma emitters shall not exceed two microgray per hour [two tenths millirad per hour] at one centimeter and ten microgray per hour [one millirad per hour] at one centimeter, respectively, measured through not more than seven milligrams per square centimeter of total absorber.N.D. Admin Code 33.1-10-23-26
Adopted by Administrative Rules Supplement 370, October 2018, effective 1/1/2019.General Authority: NDCC 23.1-03-04; S.L. 2017, ch. 199, § 1
Law Implemented: NDCC 23.1-03-03, 23.1-03-04; S.L. 2017, ch. 199, § 18