Nuclear Hazards

By

R.YuvarajAravind

Radioactive pollution is a special type of physical pollution which is related to all major lifesupporting systems like air, water and soil.

Nuclear hazards

• Radioactive (nuclear) pollution is a special form of physical pollution related to all major life- supporting systems – air,water and soil.

• Radioactivity is the phenomenon of emission of energy from radioactive isotopes (i.e., unstable isotopes), such as Carbon- 14, Uranium- 235, Uranium- 238, Uranium- 239, Radium- 226, etc.

• The emission of energy from radioactive substances in the environment is often called as 'Radioactive Pollution'.

• Generally radiation hazards in envt. Comes from UV rays, cosmic rays, visible,microwave radiation.

• Among these X rays which produce out 95% of radiation exposure.

• Nuclear energy(power plants) is used to produce electricity .But fuel used in power plants is radioactive,which is very dangerous & waste matrls are hazardous.

• Here the nuclear waste matrls also emit radiation. (ie) Radio active pollution.

• Generally ,the radiation exposure is measured by the unit called roentgen (R).

• One Roentgen is defined as the quantity of radiation which produces 1.6 × 1012 pairs of ions in 1 gm of air.

Sources of nuclear hazards

1.Natural resources :1) Cosmic rays from outer space. The quantity

depends on altitude and latitude; it is more at higher latitudes and high altitudes.

2) Emissions from radioactive materials from the Earth's crust.

2.Man-made sources :Nuclear power plants.X-rays.Nuclear bombs.Nuclear accidents.Mining and processing of radioactive

ores.Use of radioactive materials in nuclear

weapons.

EFFECTS• The biological effects of nuclear radiation can be

divided into three groups(i) Short term recoverable effects(small effect

which leads to loss of hair)(ii) long term irrecoverable effects and(iii) genetic effect

• Internal bleeding & blood vessel damage may show up as red spots on the skin.

• Cancer is considered to be major health problem from radiation exposure.

• Radiation can cause changes in DNA which is known as MUTATION.

• Acute exposures appears as burns & radiation sickness(nausea,hair loss, weakness …)

Radiation Effects • 0-50R No visible effects• 50-200R Brief periods of nausea on day

of exposure. 50% may experience radiation sickness (nausea and vomiting), 5%

may require medical attention, no deaths are expected.

• 200-450R Most members of the group will require medical attention because of serious radiation sickness. 50% deaths within two to four weeks.

• 450-600R Serious radiation sickness in all members of the group, medical attention required.

Death to more than 50% within one to three weeks.Over

• 600R Severe radiation sickness. 100% deaths in two weeks

Control Measures• Leakages from nuclear reactors, careless handling,

transport and use of radioactive fuels, fission products and radioactive isotopes have to be totally stopped;

• Safety measures should be enforced strictly;• Waste disposal must be careful, efficient and effective;• There should be regular monitoring and quantitative

analysis through frequent sampling in the risk areas;• Preventive measures should be followed so that

background radiation levels do not exceed the permissible limits;

• Appropriate steps should be taken against occupational exposure; and Safety measures should be strengthened against nuclear accidents.

Disposal of nuclear wastes:

1) High Level Wast es (HLW): High level wastes have a very high- radioactivity per unit volume. Since these wastes are too dangerous to be released anywhere in the biosphere, therefore, they must be contained either by converting them into inert solids (ceramics) and then buried deep into earth or are stored in deep salt mines.

2) Medium level wast es (MLW): Medium level wastes (e.g., filters, reactor components, etc.,) are solidified and are mixed with concrete in steel drums before being buried in deep mines or below the sea bed in concrete chambers.

3) Low liquid wast es (LLW): Low liquid wastes (e.g., solids or liquids contaminated with traces of radioactivity) are disposed of in steel drums in concrete- lined trenches in designated sites.

Safety Measures• Monitoring radioactivity around the disposal

sites.

• Prevention of erosion of radioactive waste disposal sites.

• Prevention of any drilling activity in and around the waste disposal site.

• Periodic and long- term monitoring of such disposal sites and areas of naturally occurring uranium rich rocks.