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Fukushima lessons for Pakistan

by A H Nayyar, 21 March 2011

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Karachi Nuclear Power Plant (KANUPP) is now forty years old. It is rated among the worst functioning reactors of the world. Situated on the Arabian Sea, it was originally far away from populated areas of Karachi, but now many residential schemes have moved close to it. The reactors at Chashma are relatively new. The site is on the bank of River Indus, situated between Indus and Chashma-Jehlum Link Canal. The reactor site is known to be on top of a series of tectonic plates

The horrendous destruction caused by the earthquake and the tsunami in Japan is unparalleled with any other in the living memory. All the recent incidents of natural disasters – flash floods in Pakistan, Brazil, Sri Lanka and Australia, hurricanes in the Caribbean and the Gulf of Mexico, earthquakes in Pakistan and New Zealand, the tsunamis in Indonesia, Sri Lanka, India, etc – pale before the ferocity of the Japanese earthquake and the resultant tsunami. We sympathise with the people of Japan and hope and pray that they face the calamity with strength.

What has turned the destruction of earthquake and tsunami into catastrophe was their effect on the nuclear reactors situated on the eastern coast. The reactor systems went out of control, explosions occurred, fires broke out, smoke was emitted from them and radioactivity has been leaking out of them. The situation continued to be critical by the Wednesday afternoon and was still worsening. It seems that saving them is a losing battle, and of foremost concern is the need to save the population and environment from the hazards of leaking radioactivity.

Daiichi site, called Fukushima-1, contains 6 reactors with two more under construction. They are all boiling water reactors, meaning that unlike the Pressurized Water Reactors (PWRs) which are kept under high pressures to keep water in the liquid state even at very high temperatures, these reactors work at lower temperatures and pressures to allow steam formation in the reactor vessels for turning electricity turbines. As a result, the reactor vessels are not made to resist very high temperatures and pressures.

When the earthquake struck, the reactor followed the script and the control rods automatically slammed into the fuel in the reactor core, stopping the chain fission reaction. But even when fission reaction stops, the core remains very hot and continues to generate heat. It needs to be continuously cooled down by circulating coolant, in this case water, through it for nearly ever. Reactors always have such cooling systems built into the rector. And if such a system fails for any reason, there is an Emergency Core Cooling System (ECCS) consisting of water tanks and pumps running on an external electricity source. That fateful day, earthquake destroyed the normal cooling system and tsunami destroyed the ECCS. The ECCS control was situated in a basement structure for the sake of securing it from environmental elements. Tsunami filled the basement, making ECCS unusable.

The loss of water caused the fuel rods to break open and melt and produce hydrogen from water. Steam formation and hydrogen formation are the two most dangerous developments in a reactor as they can cause explosions. Two reactor buildings in Daiichi have lost roof tops from such explosions.

As of 7 pm Japan time on March 17, units 1, 2 and 3 were in a most dangerous state. Their cores have all melted, but were confined to reactor vessels. Sea water is being pumped in continuously to keep their temperature down. Unit number 4 was not even working at the time of earthquake and tsunami, yet fire has broken out in it too. Each unit had a spent fuel pond at an elevated position inside the outer containment structure. The breached containment structures have therefore exposed the spent fuel ponds to atmosphere. Spent fuel contains the most highly radioactive substances, and if they leak out they can pose severe danger to environment and living organisms.

All of this has happened in Japan, a country that is technologically very advanced and a manufacturer of nuclear reactors that it supplies to other countries. Japanese expertise in nuclear technology is second to none. A loss of control over the destroyed nuclear reactor is not because of any technological weakness. It is in spite of sound technical expertise. It is in the nature of nuclear technology. Severe reactor accidents have happened before too. And each time for a different reason. Note that since the Three Mile Island reactor accident in 1973, no new reactor orders have been placed in USA, although USA has the largest number of nuclear power reactors, and depends heavily on them. But the 1973 accident was serious enough to stop it in its stride. The Chernobyl accident in Ukraine happened nearly 25 years ago. And now this. When the Soviet nuclear scientists visited Three Mile Island, they said “Oh, but our reactors are free of this fault, so they may not face an accident.” But then Chernobyl happened. Others said it was the absence of containment structure that caused the damage. With containment structures, nuclear power would be safe. In fact, the nuclear power industry had recently gone on a publicity offensive claiming that the technology had come so far, becoming so safe, that there was no need to fear it any more. On top of it, the industry claims that it mitigates climate change.

And then Fukushima happened, exposing the fragility of the arguments in favour of nuclear power.

Pakistan has three nuclear power reactors, and three plutonium production reactors. The latter are meant to produce plutonium for nuclear weapons. One power reactor is situated at the Karachi coast, and two newer ones are situated on the bank of River Indus at Chashma.

All three power reactors have been bought from other countries – the Karachi one from Canada and the Chashma ones from China. Pakistan continues to need assistance of their manufacturers to resolve problems arising in them from time to time. Karachi Nuclear Power Plant (KANUPP) is now forty years old. Like many others in the world, its life was extended for another ten years after 30 years of service, and works at nearly 50% of its original design capacity. It is rated among the worst functioning reactors of the world. The lifetime capacity factor has been less than 28%. Situated on the Arabian Sea, it was originally far away from populated areas of Karachi, but now many residential schemes have moved close to it. A Northward sea breeze goes past the plant to northern parts of Karachi. A tsunami hitting the plant and affecting it the way the Japanese reactors were affected, would expose dense population centres of Karachi to radioactivity. Orangi, Baldia and SITE are all within a radius of 20 km from the reactor. Depending on how serious the accident is, radiation levels could in principle touch as high a level as from the Chernobyl accident of 1986. People, especially children could get exposed to radioactive iodine and caesium. Iodine has affinity for thyroid glands where its radioactive isotopes can cause thyroid cancer, especially in children. Caesium can affect bones and bone marrow.

In the post-tsunami Japan, the population within 20 km of the reactors has been evacuated and that up to 30 km has been told to remain confined to their homes to avoid being contaminated by radioactivity. It is unthinkable that such an arrangement would be possible in Pakistan.

The reactors at Chashma are relatively new. Chashma-1 came into operation in the year 2000, and Chashma-2 has just made a few test runs. It is yet to go commercial. The reactor site is on the bank of River Indus, situated between Indus and Chashma-Jehlum Link Canal. They take cooling water from CJL Canal and throw it in the Indus.

The reactor site is known to be on top of a series of tectonic plates. The soil is known to undergo liquefaction under earthquake, and the recorded ground acceleration by earthquakes has been large, meaning that when earthquakes struck it in the past, the ground moved by several meters and very fast, precisely the conditions that would make the site unsuitable for a nuclear reactor.

These and other objections were raised against the reactor site in a report published by a couple of concerned Pakistani scientists, but these were brushed aside. The study had raised alarm about the consequences of the different parts of the reactor system getting disconnected as a result of a severe earthquake. It had also estimated the damage that could result from a loss of coolant and core meltdown accident and the consequent spread of radioactivity in the environment. It would do the nuclear establishment good to revisit the study to at least plan for an unforeseen emergency.

In case Pakistan succeeds in getting Chashma-3 and -4 also, the magnitude of disaster estimated in the study would become four-fold.

Then there are the plutonium production reactors in Khushab, the first of which was built in 1998, a second has already come on line, and a third is near completion, and the ground breaking of a fourth one has been very recently discovered by satellite imagery. These are small reactors, nearly 20 times smaller than the Chashma reactors. Their fuel load is also correspondingly smaller. But they are all indigenously built, and all use fission reaction. The cores of all of them contain highly radioactive substances which are transported to long distances for reprocessing to extract bomb grade plutonium from them. The Khushab site is at the other end of the Chashma-Jehlum Link Canal where it meets the Jehlum river. Any accident at this site can in principle contaminate the water of river Jehlum.

In summary then, nuclear power is inherently unsafe and perilous. The mantra of solving our energy needs through nuclear power is not acceptable any more after the Fukushima event. It is in our interest to stop the strong nuclear lobby from imposing itself upon our safety and security.

The author A. H. Nayyar is a visiting professor of physics at LUMS, Lahore.