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BITTER TRUTH

Nuclear power plant: Safety must be ensured
**Mankind cannot do without nuclear power, and that calls for finding a solution to the safety problem that will rule out another meltdown like Chernobyl or Fukushima resulting from human error, failure to follow instructions, design defects or technical malfunctions.
THE decision to revive the Rooppur nuclear power project after about 50 years raises some questions in the public mind. Power generation by nuclear reactor in a country lacking enough fossil fuels is definitely a viable option. But whether it is a boon or a bane has to be studied dispassion-
ately in the light of nuclear catastrophes that have struck some places with horrifying consequences.
Almost in all countries, people are having second thoughts in opting for a nuclear reactor for power generation. After the Chernobyl nuclear disaster, voters in Italy, a country that lacks fossil fuels, decided to go without nuclear energy. Almost everywhere, nuclear construction is winding up after the Chernobyl reactor meltdown. In the US, 104 nuclear reactors in 31states produce about 20% of the US's energy needs. As of 2010, the share of electrical power generated by nuclear power plants was about 14% of the total generation.
Nuclear reactors have been generating electricity for almost 50 years and about 435 are in operation worldwide, with an installed generation capacity of 368 Gigawatt (GW). 63 plants with an installed capacity of 61 GW are under construction inl5 countries. Nuclear construction almost came to a halt in the US mainly because of low gas price and two major accidents — Three Miles Island accident (1979) and Chernobyl accident in 1986 in Ukraine.
In the popular imagination, nuclear rectors are so many ticking nuclear time bombs — even if they do not explode they go on piling up waste that will ultimately cause a depopulated globe to glow in the dark. As a result, an energy source once hailed as a fuel for the future is in wide disrepute.
Confirming our concern is the Chernobyl reactor catastrophe. Few environmental nightmares strike a more frightening chord than this one. Its catastrophic ramifications are still being felt 25 years later — the exclusive zone remains uninhabitable. Over 100,000 people were evacuated after the disaster. The meltdown and fire spewed vast quantities of deadly radiation into the atmosphere. Nearby forests quickly died, fields and orchards became unusable as the soil sucked up radiation. The invisible cloud of radiation eventually spread across the Soviet Union, Central Europe, Scandinavia and beyond. Besides the radioactive mess left by the 1986 meltdown, 25 years later, some 19 ageing reactors are still ticking away, threatening the world because of the badly designed and carelessly run nuclear programmes that none of the independent republics of the former Soviet Union can afford to shut down. These power plants provide light, heat and power to parts of Russia, Ukraine and Lithuania, and their immediate shut down would create unacceptable economic disruption and civil unrest.
In the light of such catastrophic experiences, the proposed nuclear power plant at Rooppur needs to be manned by engineers with extensive training in reactor handling from the most developed countries using nuclear reactors for power generation.
There are two types of dangers involving nuclear energy. The first is an accident resulting from loss of control over the fission chain reaction occurring in the reactor by the bombardment of fast neutrons on the fissile atomic nucleus of uranium-235 or plutonium-239. The danger here is that the heat produced could outstrip the ability of the reactor coolant to cope, causing uncontrolled nuclear chain reaction. This could cause system failures which would release radioactivity into the environment.
In the case of an extreme failure, the result would be a nuclear meltdown like the ones in Chernobyl and Fukushima. In such situations, the reacting nuclear material burns or melts away through its containment vessel, into the ground and then into the water table. This would throw a huge cloud of radioactive steam and debris into the atmosphere. Accidents of this type have the potential to release radioactivity over an immense area.
In Fukushima nuclear plant, pumps in 6 boiling water reactors that circulate coolant water in the reactor during meltdown ceased to work for generator failure due to tsunami, causing the reactors to overheat. In the days that followed, reactors 1,2 and 3, which were in operation, experienced full meltdown. Lacking electricity to pump water to cool the atomic core, engineers
vented radioactive steam into the atmosphere to release pressure, leading to a series of explosions that blew out concrete walls around the reactors. Radiation readings spiked around Fukushima as the disaster widened, forcing the evacuation of 200,000 people and causing radiation levels to rise on the outskirts of Tokyo, 135 miles to the south.
As workers struggled to cool and shut down the reactors, several hydrogen explosions occurred. As no sweet water source was available near the site the Japanese government ordered spraying of sea water on the reactor, which ruined the reactors entirely. Experiences from Fukushima nuclear power plant meltdown suggest that vast sweet water source must be available near a nuclear plant used for power generation to avert a critical situation like meltdown, which can't be ruled out totally despite all preventive and precautionary measures. Experts warn that Japan faces more danger from radioactive particles in foodstuff after reports of a new toxic water leak from the Fukushima plant.
Unlike natural disasters, where death and destruction are immediate, nuclear disasters continue to take human lives and contaminate the environment for years. There is hardly any way to mitigate or get rid of the adverse effects even by the best possible scientific advances so far achieved. The accident raised concerns about the safety of nuclear power plants, slowing their expansion for a number of years, and has definitely hurt the nuclear power industry's credibility.
Nuclear energy generation in a densely populated country like Bangladesh raises alarming prospects. In the event of an accidental meltdown, we have hardly any space to evacuate people to safety. Even a vast country like USSR found it difficult to evacuate its people after the Chernobyl disaster. Soviet officials ordered permanent evacuation of villages within 30 km of the power plant, but heavy nuclear fallout covered a much wider area.
The second danger stems from the disposal of waste from the reactor. Spent fuels from a nuclear power plant are radioactive and highly toxic. Coming back to Rooppur nuclear plant, even though Russia has agreed to take away the spent fuels, there will still be some dangers in the transfer mechanism that must be taken care of well in advance.
Our opting for nuclear power must be geared with technical means that can guarantee its absolute safety. The best means for that, as Russian nuclear physicist Sakharov points out, is international legislation requiring all new nuclear reactors to be built deep enough underground so that they do not discharge radioactive material into the atmosphere even in the worst-case scenario. After the Chernobyl and Fukushima disasters, most countries having nuclear power plants in operation are reviewing their safety features and making necessary modifications.
To dispel fears in public mind, Russia made it clear that that the proposed Rooppur power plants would be based on generation 111 pressurised water reactors with dual containment now being undertaken in the US and Europe. The plants will include hydrogen to ensure recombiners and passive heat removal system. That will make the containment structures strong enough to prevent leakage or spread of radioactivity into the atmosphere. According to a director of Rosatom, the state owned nuclear organisation of Russia, the plants would be strong enough to withstand a massive earthquake and tsunami.
The world's reserve of fossil fuels is fast dwindling, creating a serious hurdle for development. That brings nuclear energy, which adds no greenhouse effects to the atmosphere, into focus as a viable option provided it can be run most efficiently. Complacency and overconfidence are alien to nuclear technology. According to Sakharov, Chernobyl was an example of tragic interaction of equipment failure and human error. Nevertheless, the aversion people might have for military application must not spill over to the peaceful use of nuclear energy.
Mankind cannot do without nuclear power, and that calls for finding a solution to the safety problem that will rule out another meltdown like Chernobyl or Fukushima resulting from human error, failure to follow instructions, design defects or technical malfunctions.
The writer is a columnist of The Daily Star.
E-mail : aukhandk@gmail.com