Overall Health Effects of Nuclear Radiation

    Note: The following is an excerpt from my book “Nuclear Power Technologies Explained Simply".

Overall Health Hazards of Each Type of Radiation

In the following pages we will look at each type of radiation and summarize the overall hazards.

Alpha decay releases Helium atoms. Natural helium is not really dangerous. However, alpha particles at very high speeds can ionize human cells. The likelihood of Helium entering your body is small. Helium atoms can be stopped by protection as thin as a piece of paper or regular clothing. The only way for an alpha particle to get into the body would be to inhale it.

Beta decay is the release of electrons from the nucleus. Electrons from beta decay harm us by ionizing the cells. Skin lesions, called radiation burns, are the most common result of exposure to beta decay. Radiation damage from beta decay is usually limited to the surface of the body. Beta particles rarely go beyond the skin into the internal organs.

Beta decay can enter your body relatively easily, and they can ionize cells easily. However, they do not travel far. Beta particles (electrons) tend to go only a limited distance in a human body (at most only a few millimeters). In air, beta particles will travel only a few feet. A relatively thin protection, such as certain plastics and thin metals, can prevent beta particles from reaching a person.

Gamma decay is a small, highly energetic wave. Because gamma is small, it can enter your body easily.  Gamma decay can reach the internal organs. Because gamma is highly energetic, it can do much more damage to your cells than beta or alpha. Gamma decay is the main form of radiation that causes cancer. Therefore, gamma decay can be the most hazardous of all forms of radiation.

The energy of gamma radiation will spread out over distance. The further the gamma burst travels, the less energy at any point in the spread. Eventually, the energy from gamma will be so small as to not affect humans. Gamma decay can only be stopped by lead, concrete, or large tanks of water.

 

Dosage and Health Effects of Gamma Radiation

    There are many studies of radiation absorption and health effects. The data varies from report to report. This variation in data is not so much a variation in biology as it is a variation in how the measurements were taken and what units were used in the final report. However, to get an approximate understanding of radiation dosage and biological effects, the data I have compiled below offers a composite of several reports, with values reported in the units of rem.

As you read the data below, keep in mind the following:

1. If the rem is only gamma radiation, then 1 rem = .01 Joules energy absorbed per kilogram body.

2. Also note that the “dosage” value assumes: a) the energy of radiation was absorbed by the body, and b) this total amount of radiation was absorbed at one time. 

Approximate rem value (dose equivalent) and biological effect

• 0 to 25 rem absorbed: No detectable clinical effect in humans.

• 25 to 100 rem absorbed: Slight reduction in number of blood cells, short-term.

• 100 to 200 rem absorbed: Longer-term reduction in number of blood cells.

• 200 to 300 rem absorbed: Nausea first day of exposure; sickness after two weeks; Recovery in about three months unless complicated by infection.

• 300 to 600 rem absorbed: Nausea in first few hours, sickness in 1-2 weeks. Some deaths in two to six weeks. Eventual death for 50% if exposure is above 450 rem; others recover in about six months.

• 600 rem absorbed and greater: Sickness in first few days, eventual death of nearly 100%.

*This is an excerpt from my book “Nuclear Power Technologies Explained Simply". To read more of the book click here.