Nuclear hazard
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Transcript of Nuclear hazard
• Radioactive pollution is a special type of
physical pollution which is related to all major life
supporting systems like air, water and soil.
• Risk or danger to human health or the
environment posed by radiation eminating from the
atomic nuclei of a given substance, or the possibility
of an uncontrolled explosion originating from a
fusion or fission reaction of atomic nuclei.
Generally radiation hazards in environment comes
from UV rays, cosmic rays, visible, microwave
radiation.
Among these X rays 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
materials are hazardous.
Nuclear waste materials also emit radiation. (ie)Radio active pollution.
Generally ,the radiation exposure is measured bythe unit called roentgen (R).
One Roentgen is defined as the quantity ofradiation which produces 1.6 × 1012 pairs ofions in 1gm of air.
Natural sources :
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.
Man-made sources : include the nuclear wastes
produced during
Mining and processing of radioactive ores.
Use of radioactive materials in power plants.
Use of radioactive isotopes in medical technology (x-raymachines, radioisotopes used in medicine.
Industrial applications include wastes from nuclearreactors.
Research applications: radioactive fallouts during nuclearweapons testing.
In a nuclear power plant, any leak or accident takingplace emit nuclear radiation. In either case it results innuclear hazard.
Nuclear tests conducted under the ground or underoceans which also release radiation.
Uranium mining and milling, nuclear reactors andreprocessing of nuclear fuel cause nuclear pollution.
.Nuclear hazard effects can be either initial or residual.
Initial effects occur in the immediate area of explosionand are hazardous immediately after the explosion where asthe residual effects can last for days or years and causedeath.
The principal initial effects are blast and radiation. Blastcauses damage to lungs, ruptures eardrums, collapsesstructures and causes immediate death or injury. ThermalRadiation is the heat and light radiation, which a nuclearexplosion’s fireball emits producing extensive fires, skinburns, and flash blindness.
Nuclear radiation consists of intense gamma rays andneutrons produced during the first minute after theexplosion. This radiation causes extensive damage to cellsthroughout the body. Radiation damage may causeheadaches, nausea, vomiting, diarrhea, and even death,depending on the radiation dose received.
Health effects due to radiation are dependent on the
level of dose, kind of radiation, duration of exposure
and types of cells irradiated.
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.
600R - Severe radiation sickness. 100% deaths in two weeks
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 Wastes (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 wastes (MLW): Medium level wastes(e.g., filters, reactor components, etc.,) are solidified and aremixed with concrete in steel drums before being buried indeep mines or below the sea bed in concrete chambers.
3) Low liquid wastes (LLW): Low liquid wastes (e.g.,solids or liquids contaminated with traces of radioactivity)are disposed of in steel drums in concrete- lined trenches indesignated 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.