The operators at Japan’s Fukushima nuclear plants are fighting the most deadly battles in hazardous circumstances trying to bring the nuclear plants under control. After an earthquake followed by a tsunami, Japan is now facing the biggest threat – a possibility of a nuclear meltdown. After a series of explosions at the reactors, latest reports say “that a second reactor unit at the stricken Fukushima Daiichi plant in northeastern Japan may have ruptured and appeared to be releasing radioactive steam”. ‘Radioactive steam’ indicates that a meltdown of the fuel rods inside the reactor is already in progress. While radiation from Xenon and cesium are expected to be detected, experts say they decay quickly and that may avert big casualties.
Japan’s rich disaster mitigation and prevention
Even as the 5 day ordeal seems to unravel, it is noteworthy that Japan, due to its history with natural calamities, sitting as it is in a seismic zone, consistently spent big money and efforts on disaster mitigation and prevention. According to FEMA, Japan routinely spent around 5-8% (about 0.8% of GDP) of its national budget since 1950s. It is technologically well-equipped, well-trained to handle earthquakes and tsunamis. But all that fell short to take on an earthquake measuring 8.9 quickly followed by a tsunami of 13-14 foot wall of water. The quake is fifth largest ever recorded. The tsunami too was too big to handle for the protective walls build on Japan’s coast to stop the tides. However, with its preparedness Japan could mitigate to some extent the damages due to these calamities. What is glaring now dangerously at Japan more than the above natural calamities is the nuclear threat from the nuclear reactor that rests on an outdated safety mechanism.
The design issue Fukushima-Daiichi nuclear power plant
Soon after the earthquake on 11 March, Fukushima-Daiichi nuclear power plant, as per its security procedures, slowed down and shut down it’s fission reactions in about 10 minutes. The tsunami too struck in about the same time and interfered with the plant’s post-shutdown process. Apparently, even after the fission reactions cease, the fission products continue to emit huge amounts of heat and these are supposed to be cooled. Only when this is done, the nuclear fuel’s temperatures are controlled. The cooling was being done through water being pumped by diesel generators through water chambers around the nuclear container. The fuel resides within the container. The tsunami washed away the generators and the water supply stopped circulating into and out of the reactor. The static water got heated and the temperatures rose in the container resulting in steam with radioactivity flowing out of it. In addition, the chemical reactions resulted in hydrogen gas that blew the tops out of the nuclear installations.The reactors within, the nuclear containers, did not seem to be disrupted for now. But the melting fuel rods seem to leak out radiation.
Experts now say the boiling water reactors (BWR) built by G.E. in 1960s are not up to safety standards followed today. Firstly, the external cooling system powered by diesel pumps is considered a design flaw that didn’t take into consideration how extreme calamities can occur and disrupt the external cooling systems, let the nuclear reactor get heated, and result in a radiation leak. Secondly, the very use of plutonium in nuclear reactors is an offshoot of nuclear weaponisation program of cold war era. While use of Thorium through Liquid Fluoride Thorium Reactor (LFTR) is said to be far less dangerous and less prone to the meltdown scenario we are seeing now, not much headway is made in commercial use of LFTR. Incidents like in Japan can happen elsewhere and it is imperative we look at making nuclear reactors safe to operate, drawing lessons from Japans’ catastrophe.
Lessons for India
India is a pioneer in LFTR technology as it spent considerable time and resources building thorium reactors after the west refused to supply it Uranium as fuel for its nuclear power plants. India developed an experimental thorium reactors like Kamini through Indira Gandhi Centre for Atomic Research (IGCAR) at Kalpakkam. India should build on this foundation to see if it can commercially make use of the technology instead of limiting the exercise to research.
India can learn well that it shouldn’t plan its nuclear sites should not be located on geological fault lines. The Jaitapur nuclear plant has evoked concerns on this front as its is prone to earthquakes and is located right on coast. While the altitude of the coast on western ghats is quite high and affect in case of tsunami is unlikely, It can not be overruled.
The Jaitapur nuclear reactor is of Pressurised water reactor (PWR) type which again depends on water to cool the reactor in case of a shutdown. Using fluoride salts as coolant is said to be less prone to risk. With water supply disrupted at Fukushima, Japanese are even trying to pour from the sky – through helicopters! But in vain. The radiation at the plant is too dangerous for the helicopters to go nearer.
Japan's disaster management system, despite its preparedness, is seen wanting in view of the big quake and tsunami. Countries like India with far poorer disaster mitigation systems should wake up for the possibility of calamities of this magnitude.
