Facing down the fear of fallout Brendan Nicholson and Stephen Matchett From: The Australian March 15, 2011 12:00AM
THE shadow of Chernobyl hangs over the desperate effort to prevent reactors melting down at Fukushima in Japan, and the terror the risk of a radiation cloud over Pennsylvania created in 1979 dances in evil attendance.
While nuclear energy has a strong safety record, even in countries such as Japan, which relies on it for 30 per cent of power, people still fear it.
And now they are waiting to see if those fears are justified, if the nuclear genie is almost out of the bottle, if the 80,000 people already evacuated from Fukushima's surrounds were at real risk of being poisoned by the broken reactors.
More modern Japanese plants such as Fukushima pose less of a threat than Chernobyl because they have a steel containment chamber that stops the enormous plume of radiation that spread across eastern Europe in 1986.
Fukushima also used water instead of the carbon employed at Chernobyl, reducing the threat posed by a giant shower of radioactive soot.
There is a view that nuclear power is safe in the hands of the highly organised Japanese and their success in building nuclear power stations in earthquake-prone areas is cited as a reason it would be safe to build nuclear power stations in areas of Indonesia in the so-called Ring of Fire that is prone to earthquakes and volcanoes.
But anxious Japanese have noted a tendency of their nuclear authorities to understate the danger from previous problems.
For people who have survived an earthquake and a tsunami, the threat of radiation poisoning is a grim fate, which reminds co-author Brendan Nicholson of what he saw when he visited Chernobyl five years after the 1986 disaster. Then, fear and fatalism lay heavily amid the silver birches and daffodils that surrounded the nuclear power station.
Three of its four reactors were still operating and most of the electricity they produced was carried on giant cables to Germany to earn Ukraine badly needed foreign exchange. But reactor No 4 lay buried within a giant concrete sarcophagus built to contain its active nuclear fuel.
Nuclear specialists insist the Japanese nuclear power stations hammered by the earthquake and tsunami are too robust to produce another Chernobyl. They argue that in nuclear-dependent countries such as Japan and France (which relies on this source of energy for half its electricity), Fukushima should not panic people.
Ziggy Switkowski, chancellor of RMIT University, former chairman of the Australian Nuclear Science and Technology Organisation and a strong proponent of nuclear power for Australia, says more nuclear power stations could be built in Japan but they'll be of tougher design with more robust reactors.
Switkowski says it is predictable that questions are being asked about why nuclear power stations operated in such a geologically active region.
"For an energy hungry but resource-poor country with skilled engineers, nuclear power was and is an obvious answer," he tells The Australian.
The industry has performed well for more than 40 years and has helped propel Japan to technical and economic leadership.
Switkowski says opponents of nuclear power are already pointing to the situation in Japan as evidence of the dangers of nuclear reactors, which conveniently sidesteps the loss of life and damage caused by exploding oil tanks, burst gas mains and electrical fires that come with conventional power generation.
"We will learn from the tragic Japanese experience how to build more robust reactors, how to ensure multiple layers of protection work properly, how to better contain radioactive gases," he says.
There are certainly lessons to learn, some still dating to April 26, 1986, in Ukraine, where design flaws and human error combined to create the disaster that has become the benchmark for everything that can go wrong in the nuclear power industry.
The four reactors at the Chernobyl power station produced electricity by heating water to steam that turned a generator turbine. Soviet reactors were badly designed and the reactor did not have the big containment walls common in Western reactors.
The reactor was designed to slow down if it overheated but an experiment to test this went badly wrong. The emergency shutdown procedure failed, the reactor fuel ruptured and a violent explosion of steam and gas blew the 1000-tonne roof off the reactor building.
That was followed by a second explosion. Temperatures reached over 2000C and the fuel rods melted. The graphite covering of the reactor caught fire and burned for 10 days, spewing vast amounts of radioactive material into the air.
In all, 57 people died as an immediate result of the explosions.
Nuclear regulators estimate that about 4000 people, most of them children, developed thyroid cancer as a result of their exposure to radiation and, by the end of 2002, 15 of them had died.
Doctors estimate a further 4000 people in the areas with highest radiation levels could eventually die of cancer caused by radiation exposure. About 6.8 million other people living farther from the explosion received a much lower dose of radiation and it has been estimated 5000 of them could die from illness caused by that exposure.
In comparison, the Three Mile Island accident barely rates. According to a report from the US Nuclear Regulatory Agency the crisis began when the feedwater pumps that cooled the reactor failed and the reactor automatically shut down in the early morning of March 28, 1979. This inevitably led to a pressure increase that triggered a safety valve automatically opening. But the valve, designed to close when the pressure dropped, also failed. Even worse, a second system failure meant plant operators thought everything was working properly.
The result was cooling water continued to pour out of the valve, causing the core of the reactor to overheat.
Alarms were sounding across the system, alerting operators to contradictory problems, but with no evidence that the temperature of the nuclear core was compromised they reduced the coolant flow to it, thus making the situation worse.
Without the required cooling, the tubes holding nuclear pellets ruptured and the fuel itself began to melt, resulting in a severe core meltdown. This could have led to a breach of the walls containing the reactor and a large release of radiation into the atmosphere, but the defences held.
This first stage of the crisis occurred across 12 hours or so and, although there was a small release of radioactive gas in the late morning, by evening the core had cooled and the reactor seemed stable.
However, on March 30, repair measures led to a second problem: radioactive gases from the reactor cooling system had built up in a tank in the auxiliary building and plant operators were pumping it to tanks designed to allow it to decay. But the compressors pumping the gas leaked and radiation was released into the atmosphere. The news generated panic in Harrisburg, Pennsylvania, the closest city to the plant.
The crisis finally concluded at the end of April when the reactor core cooled and was shut down.
For all the terror Three Mile Island created, it caused no fatalities and the World Nuclear Association claims the amount of radiation released was a fraction of that used in chest X-rays.
A 1984 survey of doctors in the region found no increase in illness among locals that could be attributed to the accident and a 1993 state government survey found no rise in radiation-related cancer.
Comparisons are being made between the explosion at the Fukushima nuclear power plants and these two crises.
But the Japanese crisis is nowhere near over and, while there is hope the dimensions of Japan's disaster will be more of a Three Mile Island than a Chernobyl catastrophe, last night there was an explosion in the outer chamber of another reactor.
What all three accidents have in common is human error. The mistakes at Fukushima were made long before Friday's earthquake. According to The New York Times, the diesel generators intended to provide back-up power for the pumps that cooled the reactor core failed because they were built behind a sea wall on low-lying coastal ground. It was a barrier Friday's tsunami easily overwhelmed. Once the generators went out, the back-up batteries could not last for long and, as in Ukraine and Pennsylvania, the water level in the reactor started to fall.
According to the Japanese nuclear safety agency, at one stage half the length of each 3.6m long fuel rod in the Fukushima No 1 plant was out of the water. By late Saturday night officials of the Tokyo Electric Power Company made a desperate decision that demonstrated how hot things were getting.
Even after a nuclear chain reaction is stopped, a reactor continues to emit heat, which has to be cooled by water, and the ocean was the only available source. To reduce the temperature of the reactor core, TEPCO started injecting sea water (reportedly using fire engines) mixed with the chemical element boron, which can squelch a nuclear reaction. In the process TEPCO accepted that the corrosive sea water will permanently disable the plant's core.
It was hopefully as close as Japan has come to a Chernobyl moment, its equivalent of entombing the Ukrainian plant in concrete. Fortunately, TEPCO was able to act before a complete meltdown or large release of radiation from more explosions, while the Japanese government has ordered evacuations for a 20km radius around the Fukushima complex; this appears to be a precaution. But whether flooding, and writing off, reactors will work is not yet known: there are reports of other plants that are too hot for comfort.
Tilman Ruff, associate professor in the University of Melbourne's Nossal Institute for Global Health and chairman of the international campaign to abolish nuclear weapons, says companies running nuclear power plants in Japan have covered up potentially dangerous problems in the past.
Leaving aside the latest accident, Ruff says the increased threat of nuclear proliferation and problems disposing of waste are good reasons to avoid using nuclear power. "In terms of power generation . . . it's way too dangerous to be a safe or sustainable way to boil water."
But Switkowski insists what is happening in Japan is not close to what happened at Chernobyl.
The combined impact of the earthquake and tsunami has been many times greater than any disaster envisaged at the Japanese plan, Switkowski says, adding the Soviet reactor was a poor design and the technicians involved had much less understanding of the proper processes to follow.
"Having said that, we will learn from the Japanese experience. That will expose some gaps in our response mechanisms. . . . They will be quickly incorporated into revised protocols and then followed by the industry." Japan had a choice of developing nuclear power or relying on imported energy. "They'll study the infrastructure that survived the earthquake and tsunami and incorporate those lessons into new designs."
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