Nuclear Power Plants are Really Safe?
With the depleting oil and coal resources and cost of producing electricity with fossil fuels increasing every day shifting to sustainable alternatives for generating power for longer duration is the need of the hour. Renewable resources includes solar and wind power is less efficient and costly to produce electricity. Power generated from renewable resources can able to provide power to few electrical appliances at home but they do not have capacity to run huge industrial loads. Therefore nuclear power is the only option which can harness electricity for thousands of years in the future and it is clean and green power (No global warming gases are released) most importantly nuclear power is cheap in cost. But it has significant threats attached and even can affect the survival of mankind if radiation is released. But lot of engineering and safety features with which nuclear plants built can promise a bright future. In this article we will see weather the present day nuclear power plants are safe enough to operate
With Fukoshima incident one question came in to limelight after several years-
How far present day modern Nuclear Power Plants safe ?
In order to understand this question first we have to understand how nuclear power is converted to electricity. Nuclear power plants are similar to coal based or gas based power plants. In case of coal based power plant coal is burned in the boiler which heats up the water to steam. This steam is utilized to roll the turbine. Similarly in Nuclear power plants using nuclear fission heat is generated. This heat is utilized to drive the turbine.
Then why is Nuclear power plant is dangerous?
Nuclear power plant itself is not dangerous. While carrying out chain reaction fission products are produced and along with fission products other particles includes (alpha, beta , Gamma and x rays) are produced. These particles can able to mutate the genetic structure when it interacts with living being. These particles generally have half life of hundreds to thousands of years, i.e, presence of these fission products will remain for several hundred decades making the area inhabitant. Until these radiation particles present inside the reactor core there will be no significant threat. Once it comes out to atmosphere these radiations will have adverse effects
Modern day nuclear plants - Defence in depth:
In Nuclear industry safety is the primary criteria or priority rather than producing power. Modern day nuclear plants are well engineered to face any odd situations. Most of the cost while designing a nuclear plants goes to safety aspects involved.
All the equipments in the nuclear plant is seismically qualified. And other qualification involves design has to qualify flash floods, aircraft crash and now plants are designed to withstand tsunami.
Equipment which involve plant safety redundancy is followed to avoid the failure of critical equipment during critical conditions
Shut down systems:
For any abnormal events two independent shut down systems will be coined. One shut down system involves shutting the nuclear plants by shut down rods inserting in to the core. These rods absorbs all neutrons and halts the fission reaction and other shut down system involves injection of liquid poison which will absorb all the neutrons
Passive Cooling Systems:
After the reactor shut down still reactor core produces heat (10% of full power). This heat has to be removed else it results in fuel melt down (This has happened in fukoshima. Reactor was shut down due to earthquake and power supply to the plant is lost due to earthquake all transmission towers fallen down. Emergency Diesel Generators were started and continued to supply power for safety loads so that decay heat generated by core is removed. However due to tsunami DGs are flooded with water results in partial melt down of core). Modern day power plants are provided with passive cooling circuits such that decay heat generated in the reactor core is removed by natural convection process and no electrical power is required. (In Fukoshima also these circuits are available, however opening of these valves are motor driven. As there was no power they could not able to open the valves)
State of art safety systems:
Modern plants are equipped with Sate of art monitoring and safety features were integrated in to plant safety systems which can monitor core parameter and safety parameters and display in real time to take control actions
Nuclear power is the clean, green and cheap power which can provide us electrical power for thousands of years in the future. Therefore this is the best option at present and cannot be ruled out.
Fukoshima and other disasters occurred in older plants, Technology has developed many folds in the past decade. Therefore modern plants will not be vulnerable as older plants for such events. Hence nuclear power should be used to full extent without compromising the safety aspects of the plant until some other effective source is invented for our energy needs