The first option is the most sensible. The second, like other renewable energies that have not convinced the public, has, on occasion, shown that its advantages outweigh its dangers.
Arnaldo González Arias
Thermoelectric power use emits CO2, a principal greenhouse gas that, along with others, produces acid rain.
All thermo-electric power stations send thousands of tons of ash, residues from coal and heavy metals, and even concentrates amounts of radioactive material into the atmosphere. For their part, modern nuclear reactors emit almost no contaminants into the air, although they periodically emit small quantities of radioactive gases. Their residues are smaller in volume (to the order of a million times) and are better controlled than those of thermoelectric power.
Pros and Cons
The main disadvantage of nuclear power is the enormous danger of possible accidents, above all in the risk of radioactive residues and their contaminating potential in the environment, which can last for hundreds and even thousands of years.
In the Nuclear Centre of Fukushima, wherein the controlled nuclear reaction is located in the nucleus of the reactor, enriched uranium divides and is transformed into other elements, generating heat and a great quantity of neutrons and other subatomic particles during the process.
The neutrons come in contact with other uranium atoms that then also divide and emit more neutrons. The generated heat is used to heat water through pressure, which then only evaporates at 600 degrees.
The process is more efficient if carried out at atmospheric pressure, when water boils at 100 degrees.
The vapour passes to an exchanger, where it liquefies and returns to the core of the reactor to then repeat the process.
A secondary circuit containing clean water absorbs the heat from the exchanger and produces steam, which is sent to a turbine generator to produce electricity.
The last step is similar to that of a thermal power station, where heat is generated from burning fuel.
The danger
The reactor and pressurized water are confined in a secure facility to avoid the escape of radioactive substances. The neutrons destroy living cells; high concentrations are instantly lethal.
The residues of radioactive elements, including those at low concentration, seep into tissuesand produce changes in cellular DNA, causing illnesses that can be irreversible in the long term. Contaminated water, in contact with the radioactive core, never mixes with the water used to propel the turbines, so that an accident does not occur. In this case, in spite of the precautionary measures taken for these contingencies, more than once the safety features have proved inadequate when an accident happened.
After the reaction is interrupted to shut down the power station, the most important problem is cooling the nucleus at high temperatures without causing harm. To ensure this, the electrical supply to water pumps and other auxiliary equipment for cooling must be guaranteed.
Even if the electrical supply fails, there are alternative systems, usually diesel generators, to provide the necessary electricity.
But in practice, in a compound accident like that of Fukushima (earthquake + tsunami), all systems failed; the nucleus of the reactor could not be cooled in time, the pressure of vapour increased beyond what was predicted, there were explosions, and the contaminated vapour, along with other radioactive substances, escaped to the exterior.
New security designs are in sight which, in case of accident, guarantee the cooling of the nucleus without using electricity or workers, instead using water flow by gravity. Nonetheless, the risk can never be reduced to zero.
Renewable energy
The alternative is clean, renewable energy that comes from solar panels, waves and tides, fuel batteries or windmills, as not everyone has the option of hydraulic or geothermic energy.
For the moment this energy only serves to cover an extremely small portion of energy needs. Other renewable sources in ample supply, like the bio-energy of ethanol obtained from corn or sugar cane, have been heavily criticized.
Bio-energy does not cause increases of CO2 in the atmosphere because in each harvest, that which was generated to burn the previous one is reabsorbed.
But using farmland to obtain fuel could contribute to food shortages in many parts of the world and create famine.
Obviously, the energy crisis presents many nuances, and it poses a serious dilemma for the immediate future, more so for countries that rely on very limited resources. PL
(Translated by: Collin Reyman – Email: pprbackwriter@gmail.com) – Photos: Pixabay