Realising the importance of proper management of radioactive substances

Negative effects of radioactive substances

Radioactive substances emit radiations that are harmful to living things. This is due to the ionisation and penetrating properties of these radiations.

As the radiations pass through living cells, they ionise the neighbouring atoms or molecules. The reactive ions that are produced will

i. Interfere with the chemical processes in the cell.
ii. Induce mutations in the genetic structure of the cell.

At the same time, the radiations might kill the cell in body tissues. If there are far too many cells that were destroyed, the organism may die.

The amount of damage inflicted to humans depends on the types of radiation, dosage and exposure period, methods of insertion into the body and location of exposure.

i. Types of radiation - Alpha particles outside the body are harmless because they can be stopped by the human skin.

ii. Dosage and exposure  - Exposure to high dosage of radiation in a short period of time results in immediate symptoms such as vomitting, increase in body temperature, blood composition change and many more.

iii. Methods of insertion into the body - The internal part of human body can be damaged by alpha particle that were ingested through food or inhaled through air, this is due to the high ionising effect of Alpha particles.

iv. Cells that are actively dividing are more vulnerable to radiations. Skin cells in  general can withstand higher dosage of radiation compared to the other internal organ.

The harmful effects of radiation on humans can be divided into two categories which can be categorised as Somatic effect or Genetic effect.

i. Somatic effect: includes damage to all parts of the body except the reproductive organs. Symptoms include: fatigue, vomiting, hair loss, infertility in male, severe skin burn and leukemia or cataracts (which may arise after a long period of time).

ii. Genetic effect: includes damage to reproductive cells. Genetic defect can be passed down to the next generations. Examples of genetic defects include Down Syndrome, Klinefelter Syndrome, Turner Syndrome.

Nuclear Reactor

1. A nuclear reactor gives massive amount of energy through nuclear fission.


Source: http://avasiyamillai.blogspot.com/2011/07/nuclear-power-plant.html

2. The energy freed from the fusion of nuclear fuel heats the water in the surrounding.

3. Consequently, this produces steam which  drives the turbines. The turbines then drive the electrical generators.

4. The table below summarises the main functions of each components.

Component	Function / Explanation
Graphite Moderator	Fast moving neutrons are slowed down by collisions with nuclei in the moderator so that they can cause further fissions. In some nuclear power plant, the moderator is water.
Uranium rod (Fuel)	Fission reactions take place in the uranium rod to create nuclear energy. The uranium used is often ‘enriched’ by increasing the proportion of the isotope uranium-235 above the natural value of 0.7% to 3%.
Control Rod	The rate of the fission reaction is controlled by inserting or withdrawing these rods. The nuclei in the rods absorb neutrons without undergoing any reaction. Sometimes the rod is made of cadmium.
Coolant	To take away heat from the nuclear reactor. Substances with high specific heat capacity such as ‘heavy’ water and carbon dioxide are used.
Thick Concrete Wall	To avoid the run off of harmful radiations.
Steam generator	Water in the generator is heated and changed into steam. The steam then drives the turbines.
Turbines	To revolve the dynamo in the electrical generator to generate electricity

5. Nuclear reactors are used in the production of:

a) High-intensity neutron beams for research
b) Artificial Radioactive Isotopes for medical research
c) Fissionable transuranic elements such as plutonium from uranium-238

Reasons for the use of Nuclear Energy

1. Production of nuclear energy from nuclear fuels involves a decreased cost. A small amount of nuclear fuel can provide a large amount of energy.
2. Nuclear reactors are relatively safe especially with the sophisticated technology constantly developed and improved.
3. The decreasing supply of fossil fuels make it essential for the use of alternative sources of energy.
4. The use of nuclear energy does not release greenhouse gases such as carbon dioxide.

Reasons against the use of Nuclear Energy

1. Radioactive residues from nuclear stations have quite a long half-lives.
2. There is a chance of leakage in the radioactive waste containers placed underground or underwater.
3. High cost of constructing a nuclear power station.
4. Accidents could happen due to human error no matter how sophisticated the technology is and this should be put into consideration.