Module Outline - hdbk-1130-98

DOE-HDBK-1130-98

Module 2 Biological Effects

Instructor's Notes

Introduce objectives

II. MODULE OUTLINE

Sources of Radiation

We live in a radioactive world and always have. In fact, the

majority of us will be exposed to more ionizing radiation

from natural background radiation than from our jobs.

1. Natural sources

There are several sources of radiation that occur naturally.

EO1 Identify the major

The radiation emitted from these sources is identical to

sources of natural

the radiation that results from manmade sources.

background and manmade

radiation.

The four major sources of naturally occurring radiation

exposures are:

Cosmic radiation

Sources in the earth's crust, also referred to as

terrestrial radiation

Sources in the human body, also referred to as

internal sources

Radon

Cosmic radiation (total average dose ~ 28 mrem/yr)

1) Cosmic radiation comes from the sun and outer space. It

consists of positively charged particles and gamma

radiation.

2) At sea level, the average annual cosmic radiation dose is

about 26 mrem.

3) At higher elevations, the amount of atmosphere shielding

cosmic rays decreases; therefore, the dose increases.

b. Sources in earth's crust (terrestrial) (total average dose ~

28 mrem/yr)

There are natural sources of radiation in the ground (i.e.,

rocks and soil).