Showing posts with label nuclear. Show all posts
Showing posts with label nuclear. Show all posts

Friday, July 6, 2012

Why Japan still needs nuclear power



NO ONE can accuse Japanese Premier Yoshihiko Noda of being gutless. On Sunday, he pushed through the controversial restarting of the Oi nuclear reactor in western Japan - more than a year after a tsunami damaged reactors at Fukushima.

Following the Fukushima disaster, all the country's nuclear reactors had been shut down amid popular opposition to nuclear po-wer.

On the surface, the prognosis for nuclear power is not good. Soon after the Fukushima disaster, Germany said it would shut down half of its nuclear plants and abandon the use of nuclear power by 2022. Likewise, Switzerland said no new plants would be built, and that five existing plants would be mothballed by 2034. In a recent special report titled The Dream That Failed, The Economist magazine underscored the growing coolness towards nuclear power.

Does this mean the death of nuclear power? Not quite.

It is worth noting that before the Fukushima disaster, nuclear power had enjoyed 25 years of safety after the 1986 crisis at Chernobyl.
Widespread concerns about energy security and climate change had also led to an alliance between environmentalists and advocates of nuclear power. The strongest argument then - and now too - is that nuclear power generates virtually no greenhouse gases. And compared to other non-carbon sources of power, nuclear power is still the only viable large-scale alternative to fossil fuels.

Future plans for the use of nuclear power validate this. In a recent report, the Economist Intelligence Unit (EIU) forecast that Japan would still have 44.7 gigawatts (gw) of nuclear capacity in 2020 - marginally lower than the 46.8gw in 2010. In a December report, the European Commission said that nuclear energy remained an important option for decarbonising energy supplies. Around the world, 60 new reactors are being constructed in 14 countries, many located in Asia. China, for instance, is aiming to increase the number of its reactors from 14 to 80 by 2030.

Mr Jitsuro Terashima, an official at Japan's Ministry of Economy, Trade and Industry who is reviewing Japan's energy policies in the wake of the Fukushima accident, said that nuclear energy should not be discarded altogether, but used in tandem with renewable sources. The 'best mix', he told the EIU, should be 20 per cent of energy from nuclear sources, 30 per cent from renewable sources and 40 per cent from fossil fuels by 2030. This is different from Tokyo's earlier plan to stick to a ratio of 50 per cent, 20 per cent and 30 per cent respectively.

'I am not 'pro-nuclear' (to the exclusion of other energy sources). I was proposing renewable energy as early as the 1970s, and I intend to help turn the wheel as much as possible towards renewable energy at this crossroads for Japan's energy strategy,' he said.

Japan's realistic approach after Fukushima is laudable. Even Germany's attempt at eradicating nuclear power in the long term has run into problems. Recently, it was reported that it had to import energy due to supply shortfalls.

This is not to say nuclear power is problem-free. The disposal of nuclear waste is problematic, while the construction of reactors can suffer from cost over-runs. And arguably, the word 'nuclear' has put a historical burden on Japan. In 1945, it was the first country to be attacked by nuclear weapons. The Fukushima disaster also meant that Japan became the first Asian country to suffer from radiation fallout following a nuclear accident. In psychological terms, the Japanese are suffering from the availability heuristic - that is, the nuclear crisis of last year has captured so much attention that the risks of another nuclear accident have been exaggerated.

Indeed, experts say that the impact on public health resulting from accidents such as Chernobyl and Fukushima are not as bad as originally envisaged. Professor Gerry Thomas, the chair in molecular pathology at Imperial College in London, said that the only public health effect caused by the Chernobyl accident has been a large increase in thyroid cancer cases among those who were children at the time of the accident. Of the 6,000 thyroid cancer cases, only 15 had proved fatal by 2005. The predicted death rate going forward is about 1 per cent, she said in an e-mail.
Over at Fukushima, the number of cancer-related deaths will probably not increase, The Japan Times reported.

Said Prof Thomas: 'Personally, I do think that nuclear energy is a safe option, providing we learn the lessons of past accidents and are ready to put into place mitigating procedures as they did in Japan.'
Indeed, if Japan takes a realistic approach to nuclear power, it could provide a model for other countries contemplating nuclear power.

'I believe Japan must remain the symbol and exemplar of countries that resist the temptation of nuclear militarisation and focus instead on its peaceful use. Japan can help other countries that have the same aim,' said Mr Terashima.

Therein lie two paths mapped out by Germany and Japan: The former has opted for a little or no nuclear future, while the latter is moving along a road with some nuclear power involved.

For countries like Singapore, which have indicated an interest in nuclear power, the two futures constitute much food for thought.
 www.straitstimes.com
Published on Jul 5, 2012
 By William Choong

Saturday, June 9, 2012

Nuclear plant accidents


Mayak or Kyshtym nuclear complex (Soviet Union): 29 September 1957
A fault in the cooling system at the nuclear complex, near Chelyabinsk, results in a chemical explosion and the release of an estimated 70 to 80 tonnes of radioactive materials into the air. Thousands of people are exposed to radiation and thousands more are evacuated from their homes. It is categorised as Level 6 on the seven-point International Nuclear Events Scale (INES).

Windscale nuclear reactor (UK): 7 October 1957
A fire in the graphite-core reactor, in Cumbria, results in a limited release of radioactivity (INES Level 5). The sale of milk from nearby farms is banned for a month. The reactor cannot be salvaged and is buried in concrete. A second reactor on the site is also shut down and the site decontaminated. Subsequently part of the site is renamed Sellafield and new nuclear reactors are built.

Idaho National Engineering Laboratory (USA): 3 January 1961
A steam explosion in reactor SL-1 during preparation for start-up destroys the small US Army experimental reactor and kills three operators.

Three Mile Island power plant, Pennsylvania (US): 29 March 1979
A cooling malfunction causes a partial meltdown in one reactor, resulting in a limited release of radioactivity (INES Level 5).
The site's first reactor (TMI One) on the Susquehanna river was closed for refuelling. The second was at full capacity when two malfunctions occurred: first there was a release of radioactive water, then radioactive gas was detected on the perimeter. No deaths or injuries were reported.
It is considered the United States' worst nuclear accident and led to major safety changes in the industry.

Chernobyl power plant (Soviet Union): 26 April 1986
One of four reactors explodes after an experiment at the power plant (INES Level 7). The resulting fire burns for nine days and at least 100 times more radiation than the atom bombs dropped on Nagasaki and Hiroshima is released into the air. Radioactive deposits are found in nearly every country in the northern hemisphere.
Two people die in the explosion and another 28 from acute radiation sickness in the immediate aftermath. Some experts predict thousands of extra cancer deaths as a result of the disaster.
A huge cover, known as the New Safe Confinement, is being built over the existing sarcophagus. It is expected to cover the site by 2013.

Severesk, formerly Tomsk-7 (Russia): 6 April 1993
A tank at a uranium and plutonium factory inside the plant explodes, resulting in radioactivity being dispersed into the atmosphere contaminating an area of over 120 sq km (INES Level 4). A number of villages are evacuated and left permanently uninhabitable.

Tokaimura nuclear fuel processing facility (Japan): 30 September 1999
Workers break safety regulations by mixing dangerously large amounts of treated uranium in metal buckets, setting off a nuclear reaction (INES Level 4).
Two of the workers later die from their injuries, and more than 40 others are treated for exposure to high levels of radiation.
Hundreds of residents living nearby were evacuated from their homes while the nuclear reaction continued, but were allowed home two days later.

Mihama power plant (Japan): 9 August 2004
Five people die in an accident at the plant in the Fukui province (INES Level 1). Seven people are also injured when hot water and steam leaks from a broken pipe.
Officials insist that no radiation leaked from the plant, and there is no danger to the surrounding area.

Fukushima Daiichi power plant (Japan): 11 March 2011
A powerful tsunami generated by a magnitude-9.0 earthquake out at sea slams into the Fukushima Daiichi nuclear power plant, damaging four of six reactors at the site.
A series of fires are set off, after cooling systems fail. Venting hydrogen gas from the reactors causes explosions, forcing engineers to use seawater in an effort to cool overheating reactor cores.
Originally classified as INES Level 5, the severity was raised to INES Level 7 on 12 April 2011 when a new estimate suggested higher levels of radiation than previously thought had leaked from the plant.
Despite the classification, the incident is said to be much less severe than Chernobyl, and officials insist there is only a minimal risk to public health.

Macoule nuclear site (France), 12 September 2011
One person is killed and four are injured - one with serious burns - after an explosion in a furnace used to melt down nuclear waste and recycle it for energy. No radiation leaks nor damage to the plant are detected.