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Radiological Safety

Requirements come from the Nuclear Regulatory Commission (NRC), Environmental Protection Agency, and Department of Transportation
New York State has accepted regulatory authority from the NRC.
- NYS Department of Health (DOH) governs the use of radioactive material and radiation-producing devices in NYS
- Department of Environmental Conservation governs the release of radioactive material to the general public
University of Rochester is licensed by the NYS DOH
- UR’s Radiation Safety Unit (RSU) administers the University’s radiation safety program.
- UR’s Radiation Safety Committee establishes the procedures for the RSU and oversees their operations.
- LLE operates under a permit issued by the RSU

Activity: number of transformations per unit time
Curie: 3.7 x 10¹⁰ disintegrations per second
Dose: the energy imparted to matter by radiation
Rad: unit of dose equal to absorption of 100 ergs/gram of material
Dose equivalent: biological damage caused by absorbed dose
DE = dose x quality factor,
Where: QF = 1 for gamma and beta
= 20 for alpha
= 3 to 10 for neutrons
rem – roentgen equivalent man, a unit of dose equivalent
1 rem = 100 erg/gram of biological equivalent damage
Half-life: time required for activity of a substance to decrease by half

Neutron radiation from fusion
- Maximum credible yield shot of 3 x 10¹⁵ neutrons yields 516 rem at surface of the OMEGA target chamber (OMEGA EP maximum is ~10¹²neutrons)
Gamma radiation from neutron activation of structural components
- Principal sources are Na²⁴ (15 d) and Mn⁵⁴ (312 d)
- Maximum radiation after ten years not expected to exceed 5 mr/hr shortly after a target shot
Beta radiation from tritium
- Up to 15,000 Ci in Tritium Fill Station
High-energy x-ray radiation (up to 10 Mev) via bremsstrahlung from fast electrons produced by high-intensity photon bombardment of high-Z target (primary radiation source for OMEGA EP)

To protect people from any harmful effects, radiation exposure from other than natural sources is limited by law to the following:
Radiation worker exposure limit	5,000 mrem/year
General public exposure	100 mrem/year

Surface contamination
- Limit: 1,000 DPM/100 cm²
  Basis: Control spread of radioactive material, not exposure (continuous exposure to 10⁸ DPM/100cm² ⇒ 5 rem/yr)
Airborne limit
- Limit for radiation workers: 20 µCi/m³
  Basis: Exposure to this level for 2000 h/yr gives a dose of 5 rem
- Limit for general public: 0.1 µCi/m³
  Basis: Continuous exposure to this level will give an individual one half of their yearly limit of 100 mrem
Annual limit on intake (ALI):
- Limit: 80 mCi
  Basis: 5 rem

Natural radiation sources and exposure levels are as follows:
Cosmic rays (from outer space)	45 mrem/year/person
Terrestrial (from natural minerals)	65 mrem/year/person
Internal (from elements in the body)	25 mrem/year/person

Radiation can damage individual cells by (if damage occurs slowly, it can be repaired as it happens)
- ionization of atoms within the cell
- free-radical formation within cell (e.g, H⁺ and OH^– )
- hydrogen peroxide poisoning of cell
- breakage of DNA strands
Genetic effects (studies indicate that the increased mutation rate due to most radiation doses is statistically insignificant)
- Damage to ova in ovaries
- Damage to sperm-forming cells
- Mutations of genetic material in ova or sperm
Effects on the organism
- Increased risk of ~2 cancers per 10,000 person rem of exposure assuming the linear model (less under threshold model) – compared to risk of 1,600 cancers per 10,000 from all other factors

Dose (mR/yr)	Source
4	Reading glossy magazines for 1 h/d from U and K
25 to 4,000	Wearing enameled jewery 10 h/wk from U
100 to 200	Radon gas inhalation
100 to 200	Foods and fertilizers from K and U
100	Flying 5,000 miles per month
2,000 to 5,000	Smoking 1 pack of cigarettes/day From Po and Pb for U decay series

Dose (rem)	Effect
0 to 50 rem	No obvious effects, some blood chemistry changes
100 rem	Minor radiation sickness in about 10% of population
150 rem	Minor radiation sickness in about 25% of population
200 rem	Radiation sickness in about 50% of population
300 rem	Radiation sickness in all exposed, about 20% death rate within one month
450 rem	About 50% death rate without medical treatment
500 rem	Radiation sickness within 4 h, over 50% death rate
1000 rem	Radiation sickness in 1 to 2 h, 100% death rate

SWIMS