S.C. Code Regs. § § 61-63.I.RHB 1.3

Current through Register Vol. 48, No. 10, October 25, 2024

Section 61-63.I.RHB 1.3 - Inspections

1.3.1 "Dose" means the quantity of radiation absorbed, per unit of mass, by the body or by any portion of the body. When these regulations specify a dose during a period of time, the dose means the total quantity of radiation absorbed, per unit of mass, by the body or by any portion of the body during such period of time. Several different units of dose are in current use. Definitions of units as used in these regulations are set forth in the following paragraphs: 1.3.2 and 1.3.3.

1.3.2 The "rad" is a measure of the dose of any radiation to body tissues in terms of the energy absorbed per unit mass of the tissue. One rad is the dose corresponding to the absorption of 100 ergs per gram of tissue. (One millirad [mrad] = 0.001 rad.)

1.3.3 The "rem" is a measure of the dose of any radiation to body tissue in terms of its estimated biological effect relative to a dose of one roentgen (R) of x-rays. (One millirem [mrem] = 0.001 rem.) The relation of the rem to other dose units depends on the biological effect under consideration and upon the conditions of irradiation. For the purpose of these regulations, any of the following is considered to be equivalent to a dose of one rem:

1.3.3.1 A dose of 1 R due to × -or gamma radiation;

1.3.3.2 A dose of 1 rad due to ×-, gamma, or beta radiation;

1.3.3.3 A dose of 0.1 rad due to neutrons or high energy protons;

1.3.3.4 A dose of 0.05 rad due to particles heavier than protons and with sufficient energy to reach the lens of the eye.

If it is more convenient to measure the neutron flux, or equivalent, than to determine the neutron dose in rads, as provided in sub-paragraph 1.3.3.3 of this paragraph, one rem of neutron radiation may, for the purposes of these regulations, be assumed to be equivalent to 14 million neutrons per square centimeter incident upon the body; of, if there exists sufficient information to estimate with reasonable accuracy the approximate distribution in energy of the neutrons, the incident number of neutrons per square centimeter equivalent to one rem may be estimated from the following table:

Neutron Energy (Mev)	NEUTRON FLUX DOSE EQUIVALENTS Number per square centimeter equivalent to a dose of 1 rem (Neutrons/cm 2)	Average Flux to deliver 100 millirem in 40 hrs. (Neutrons/cm 2/sec.)
Thermal	970 x 106	670
0.0001	720 x 106	500
0.005	820 x 106	570
0.02	400 x 106	280
0.1	120 x 106	80
0.5	43 x 106	30
1.0	26 x 106	18
2.5	29 x 106	20
5.0	26 x 106	18
7.5	24 x 106	17
10.0	24 x 106	17
10 to 30	14 x 106	10

1.3.3.5 For determining the doses specified in RHA 3.2 a dose from ×- or gamma rays up to 3 mev may, for purposes of these regulations, be assumed to be equivalent to the exposure measured in air at or near body surfaces in the region of the highest dose rate by a properly calibrated appropriate instrument.

S.C. Code Regs. § 61-63.I.RHB 1.3