The Biological Effect of Large and Small Doses (p.102)

Date: 2015-10-07; view: 352.

1. Biological changes result from large doses of internal and external irradiation lead to radiation syndrome or radiation disease.

2. They distinguish acute radiation disease and chronic radiation disease.

3. At free air exposure from 100 to 200 rads we observe light form of acute radiation disease.

4. At mid-line absorbed dose from 200 to 400 rads in two weeks there is malfunction of the main system of the living organism – blood system, central nervous system.

5. At extremely high exposures 400-600 rads we observe heavy form of the acute radiation disease.

6. The central nervous system is damaged with death in 24 hours.

7. There are three effects of small doses to living matter.

8. Cells may not be killed by a given dose of radiation but they may be unable to divide and die after a few cell divisions.

9. Another possibility – cells undergo mutation.

10. Mutation is a new form of gene which affects the following generation.

14. Radiation Monitoring(p.108)

1. Monitoring may be defined as a detection and measurement of radioactive contamination.

2. The instruments differ in their construction depending on the type of radiation detected.

3. Because of alpha particles low penetrating power, a - detectors must have minimal material between the sensitive volume and the particle source.

4. The main instruments used for alpha contamination detection are the air proportional counter, the gas-flow proportional counter and scintillation counter.

5. Beta-gamma radiations are considered together because most radioactive materials emit both radiations.

6. Beta-gamma monitoring instruments can have thicker walls than alpha instruments, and the radiations can be detected farther from the source.

7. For beta-gamma radiation monitoring the ionization chamber and the GM counters are the primary instruments.

8. Portable GM counters are counters with battery operated power suppliers and amplifiers.

9. Neutrons are among the most difficult radiations to measure.

10. They are not directly ionizing and must be detected indirectly from ionizing radiations produced.

Instruments for neutrons monitoring are: proportional – counter tube filled with gas, a scintillation counter with lithium used, or thermoluminescent dosimeters for fast neutrons.

15. World Energy Resources(p.119)

1. Energy is the available resource of all the rest.

2. Humans must use resources in order to exist.

3. Exhaustible resources are nonrenewable resources present in a fixed amount on Earth.

4. Renewable resources are those that can be replenished.

5. At present most of energy consumed by humans is produced from fossil fuels.

6. The greatest recoverable fossil fuel is in the form of coal and lignite.

7. Although world coal resources are enormous and potentially can fill energy needs for a century or two, their utilization is limited by environmental disruption from mining and emissions of carbon dioxide and sulfur dioxide.

8. Total recoverable reserves of nuclear fuel are roughly about the same as fossil fuel reserves.

9. Extraction of only 2% of the deuterium would yield about billion times as much energy controlled by nuclear fusion as was present in fossil fuels.

10. Geothermal power has the potential for providing a high percentage of energy worldwide.

11. The same limited potential is characteristic of several renewable energy sources such as hydroelectric energy, tidal energy and wind power.

12. Renewable nonpolluting solar energy is an ideal source and has a bright future.