Welcome To Radiation

Safety Training

Center for Health Sciences

Module #1

The OSU-CHS radiation safety program will be conducted in such a manner so that exposure to faculty, staff, students, the public, and the environment will be maintained as low as reasonably achievable and that no radiation exposure will be received without societal benefit. This will be accomplished without impeding legitimate research, or realistic teaching objectives in accord with State and Federal regulations.

OSU Radiation Safety Program

Module #1

Chernobyl Atomic Bomb

Module #1

Radiation Environment

Module #1

Natural Sources

• Cosmic

• Terrestrial

• Internal

• Inhaled

Module #1

Cosmic Radiation

• High energy particles and photons from the sun and other sources outside the earth's atmosphere– Atmosphere provides

shielding from cosmic radiation

– An increase in altitude results in an increase in exposure (measured in millirem)

– 26 mrem/yr @ sea level

50 mrem/yr in Denver .5 mrem/hr @ 39,000 feet

Module #1

Terrestrial Radiation

• Radiation from radioactive materials occurring naturally in the earth’s crust– Lowest on the Atlantic

coast (16 mrem/yr)– Highest on eastern slopes

of the Rockies (63 mrem/yr)

– About 30 mrem/yr in the remainder of the U.S.

Module #1

Inhaled Radiation

• Primarily Radon (Rn-222) and its daughters– Rn-222 is released from the soil as Radium-

226 decays– Radium is part of Uranium-238 decay chain– Levels vary widely from area to area – Average dose is 200 mrem/yr– May be enhanced by poor ventilation or the

use of Uranium containing building materials

Module #1

Internal Radiation

• Radiation from radioactive materials incorporated in the human body– Primarily Carbon-14 (C-14) and

Potassium-40 (K-40)– Total dose of 39 mrem/yr (due mostly to

K-40)

Module #1

Man-Made Sources

• Medical Uses

• Consumers Products

• Industrial Uses

• Nuclear Power

Module #1

Medical Sources

• Diagnostic X-ray– General

Radiography– Dental

Radiography– Fluoroscopy– CT– Etc.

39 mrem/yr – U.S. average

• Nuclear Medicine– Imaging using I-

131, Tc-99m, Tl-201

– Therapy using I-131

14 mrem/yr – U.S. average

Module #1

Medical Sources (cont.)

• Radiation Therapy– Use of external beams and sealed

sources for treatment of cancers

2.3 mrem/yr – U.S. average

Module #1

Industrial Sources• Industrial

Radiography– Use of X-rays or

sealed gamma-ray sources for imaging structures and components

• Level Gauges―Use of sealed sources

to check the level of materials in a tank or vat.

• Well Logging– Use of sealed sources

to measure soil porosity, soil density, or underground structure & composition

• Static Elimination– Use of radiation to

remove static electricity

Module #1

Nuclear Power

• Doses are calculated for maximally exposed member of the general public

• Uranium Mines = 26-61 mrem/yr• Processing = 1-8 mrem/yr• Nuclear Power Plants = < 1 mrem/yr• Waste Storage = < 1 mrem/yr• Transportation = 20 mrem/yr

Module #1

Consumer Products

• Smoke Detectors (Am-241)

• Tobacco Products (Pb-210 & Po-210)

• Building Materials

(Sheetrock; gypsum board)

• Airport Baggage Inspection – (x-rays)

• Welding Rods (Thorium)

• Luminous Paints for watch and instrument dials

(H-3, Ra-226, Pm-147)

Module #1

Consumer Products (cont.)

• Television and VDT (Low energy x-rays)

• Radium Hot Springs (Ra-226, Rn-222)

• Fiesta-ware (Uranium oxide coating)

Module #1

Contributions to the Public Dose*