Showing posts with label nuclear power plant explosion. Show all posts
Showing posts with label nuclear power plant explosion. Show all posts

Tuesday, March 15, 2011

malaysiakini: Japan's nuclear morality tale... by Brahma Chellaney

Japan's nuclear morality tale
Brahma Chellaney
Mar 15, 2011, 11:33am
COMMENT The troubles at the Fukushima nuclear power plant and other reactors in northeast Japan have dealt a severe blow to the global nuclear industry, a powerful cartel of less than a dozen major state-owned or state-guided firms that have been trumpeting a nuclear power renaissance.

NONEBut the risks that seaside reactors like Fukushima face from natural disasters are well known.

Indeed, they became evident six years ago, when the Indian Ocean tsunami in December 2004 inundated India's second-largest nuclear complex, shutting down the Madras power station.

Many nuclear power plants are located along coastlines because they are highly water-intensive. Yet natural disasters like storms, hurricanes and tsunamis are becoming more common, owing to climate change, which will also cause a rise in ocean levels, making seaside reactors even more vulnerable.

For example, many nuclear power plants located along the British coast are just a few metres above sea level. In 1992, Hurricane Andrew caused significant damage at the Turkey Point nuclear-power plant on Biscayne Bay, Florida, but, fortunately, not to any critical systems.

All energy generators, including coal- and gas-fired plants, make major demands on water resources.
But nuclear power requires even more. Light-water reactors (LWRs) like those at Fukushima, which use water as a primary coolant, produce most of the world's nuclear power.

The huge quantities of local water that LWRs consume for their operations become hot water outflows, which are pumped back into rivers, lakes and oceans.

azlanBecause reactors located inland put serious strain on local freshwater resources, including greater damage to plant life and fish, water-stressed countries that are not landlocked try to find suitable seashore sites.

But, whether located inland or on a coast, nuclear power is vulnerable to the likely effects of climate change.

As global warming brings about a rise in average temperatures and ocean levels, inland reactors will increasingly contribute to, and be affected by, water shortages.

During the record-breaking 2003 heat wave in France, operations at 17 commercial nuclear reactors had to be scaled back or stopped because of rapidly rising temperatures in rivers and lake. Spain's reactor at Santa Mara de Garoa was shut for a week in July 2006 after high temperatures were recorded in the Ebro River.

Paradoxically, then, the very conditions that made it impossible for the nuclear industry to deliver full power in Europe in 2003 and 2006 created peak demand for electricity, owing to the increased use of air-conditioning.

Indeed, during the 2003 heat wave, Electricite de France (EDF), which operates 58 reactors - the majority on ecologically sensitive rivers like the Loire - was compelled to buy power from neighbouring countries on the European spot market. The state-owned EDF, which normally exports power, ended up paying 10 times the price of domestic power.

Similarly, although the 2006 European heat wave was less intense, water and heat problems forced Germany, Spain and France to take some nuclear power plants offline and reduce operations at others.

Central dilemma


Highlighting the vulnerability of nuclear power to environmental change or extreme weather patterns, in 2006 plant operators in western Europe also secured exemptions from regulations that would have prevented them from discharging overheated water into natural ecosystems, affecting fisheries.

France likes to showcase its nuclear power industry, which supplies 78 percent of the country's electricity. But such is the nuclear industry's water intensity that EDF withdraws up to 19 billion cubic metres of water per year from rivers and lakes, or roughly half of France's total freshwater consumption.

Freshwater scarcity is a growing international challenge, and the vast majority of countries are in no position to approve of such highly water-intensive inland-based energy systems.

Nuclear plants located by the sea do not face similar problems in hot conditions, because ocean waters do not heat up anywhere near as rapidly as rivers or lakes. And because they rely on seawater, they cause no freshwater scarcity. But, as Japan's reactors have shown, coastal nuclear power plants confront more serious dangers.

When the Indian Ocean tsunami struck, the Madras reactor's core could be kept in safe shutdown condition because the electrical systems had been ingeniously installed on higher ground than the plant itself.
And, unlikjapan nuclear fukushima no 3 reactor explosion imagee Fukushima (left), which bore a direct impact, Madras was far away from the epicentre of the earthquake that unleashed the tsunami.

The central dilemma of nuclear power in an increasingly water-stressed world is that it is a water guzzler, yet vulnerable to water.

And, decades after Lewis L Strauss, the chaiperson of the US Atomic Energy Agency, claimed that nuclear power would become “too cheap to meter”, the nuclear industry everywhere still subsists on munificent government subsidies.

While the appeal of nuclear power has declined considerably in the West, it has grown among the so-called nuclear newcomers, which brings with it new challenges, including concerns about proliferation of nuclear weapons.

Moreover, with nearly two-fifths of the world's population living within 100km of a coastline, finding suitable seaside sites for initiation or expansion of a nuclear power programme is no longer easy.

Fukushima is likely to stunt the appeal of nuclear power in a way similar to the accident at the Three Mile Island plant in Pennsylvania in 1979, not to mention the far more severe meltdown of the Chernobyl reactor in 1986.

If the fallout from those incidents is a reliable guide, however, nuclear power advocates will eventually be back.


BRAHMA CHELLANEY is Professor of Strategic Studies at the Centre for Policy Research in New Delhi and the author of, among others, 'Asian Juggernaut: The Rise of China, India, and Japan' (Harper Paperbacks, 2010) and 'Water: Asia's New Battlefield' (Georgetown University Press, 2011).

Saturday, March 12, 2011

malaysiakini: Another Chernobyl in the making?... by Stratfor

Another Chernobyl in the making?
Mar 12, 2011 6:17pm

Today's explosion at the earthquake-damaged Fukushima Daiichi nuclear power plant in Okuma, Japan, appears to have caused a reactor meltdown.

The key piece of technology in a nuclear reactor is the control rods. Nuclear fuel generates neutrons; controlling the flow and production rate of these neutrons is what generates heat, and from the heat, electricity.

Control rods absorb neutrons - the rods slide in and out of the fuel mass to regulate neutron emission, and with it, heat and electricity generation.

A meltdown occurs when the control rods fail to contain the neutron emission and the heat levels inside the reactor thus rise to a point that the fuel itself melts, generally temperatures in excess of 1,000 degrees Fahrenheit, causing uncontrolled radiation-generating reactions and making approaching the reactor incredibly hazardous.

japan tsunami and earthquake 2011 nuclear power plant fukushima no 1A meltdown does not necessarily mean a nuclear disaster. As long as the reactor core, which is specifically designed to contain high levels of heat, pressure and radiation, remains intact, the melted fuel can be dealt with.

If the core breaches but the containment facility built around the core remains intact, the melted fuel can still be dealt with - typically entombed within specialised concrete - but the cost and difficulty of such containment increases exponentially.

However, the earthquake in Japan, in addition to damaging the ability of the control rods to regulate the fuel - and the reactor's coolant system - appears to have damaged the containment facility, and the explosion almost certainly did.

There have been reports of “white smoke,” perhaps burning concrete, coming from the scene of the explosion, indicating a containment breach and the almost certain escape of significant amounts of radiation.

At this point, events in Japan bear many similarities to the 1986 Chernobyl disaster. Reports indicate that up to 1.5 meters of the reactor fuel was exposed. The reactor fuel appears to have at least partially melted, and the subsequent explosion has shattered the walls and roof of the containment vessel - and likely the remaining useful parts of the control and coolant systems.

Nightmare scenario

And so now the question is simple: Did the floor of the containment vessel crack? If not, the situation can still be salvaged by somehow re-containing the nuclear core. But if the floor has cracked, it is highly likely that the melting fuel will burn through the floor of the containment system and enter the ground.

This has never happened before but has always been the nightmare scenario for a nuclear power event - in this scenario, containment goes from being merely dangerous, time consuming and expensive to nearly impossible.

Radiation exposure for the average individual is 620 millirems per year, split about evenly between man-made and natural sources. The firefighters who served at the Chernobyl plant were exposed to between 80,000 and 1.6 million millirems.

The Nuclear Regulatory Commission estimates that exposure to 375,000 to 500,000 millirems would be sufficient to cause death within three months for half of those exposed. A 30-kilometer-radius no-go zone remains at Chernobyl to this day. Japan's troubled reactor site is about 300 kilometers from Tokyo.


The latest report from the damaged power plant indicated that exposure rates outside the plant were at about 620 millirems per hour, though it is not clear whether that report came before or after the reactor's containment structure exploded.

- Stratfor