Nuclear power revival
K.S. Parthasarathy
On June 19, the International Youth Nuclear Congress (IYNC), the organisation of young nuclear professionals from 52 countries around the world urged international leaders to acknowledge the contribution that nuclear energy can make in fighting climate change. Last month, the International Nuclear Societies Council, an organisation made up of 26 nuclear societies called upon the G8 Heads of States and Governments to encourage the deployment of advanced nuclear power stations.

Power-frugal e-gadgets
Does the battery of your mobile phone require frequent recharging?
As gadgets like cellphones and I-pods shrink in size, scientists say technology is being developed to reduce power consumption by such gadgets.

Prof Yash Pal

Nuclear power revival
K.S. Parthasarathy

On June 19, the International Youth Nuclear Congress (IYNC), the organisation of young nuclear professionals from 52 countries around the world urged international leaders to acknowledge the contribution that nuclear energy can make in fighting climate change. Last month, the International Nuclear Societies Council, an organisation made up of 26 nuclear societies called upon the G8 Heads of States and Governments to encourage the deployment of advanced nuclear power stations.

Sun is capricious and fickle minded, wind often lazy and slow; together they may contribute a small percentage to the grid. Let us keep them. If you need power continuously, you have to rely on nuclear or coal or hydropower. During an exclusive interview, I asked Dr Roald Hoffmann, Nobel Laureate and Professor, Department of Chemistry, Cornell University, whether promoting nuclear power as a clean source is appropriate.

“The enhanced greenhouse effect due to fuel combustion is established….People can be easily sensitised to issues of climatic changes. So nuclear power protagonists can have a natural alliance with informed environmentalists”, he said (AERB Newsletter, 1998).

Now several leading environmentalists, including James Lovelock, Patrick More and Stewart Brand, the founder of the Whole Earth Catalogue support nuclear power for its Green credentials. Fred Krupp, executive director of Environmental Defence, James Gustave Speth, Dean Yale School of Forestry and Environmental Studies, and Jonathan Lash, head, World Resource Institute, have stopped short of endorsing nuclear power (UPI, May 15)

The public support for nuclear power outweighs opposition in the UK for the first time in over five years (Nuclear Engineering International April 2005).Officially, nuclear power is back on the agenda in the UK. This month, French president Jacques Chirac and British Prime Minister Tony Blair announced a forum to discuss Franco-British nuclear cooperation.

A Swedish four-party political alliance has promised that if it wins the September election and forms a coalition government, it will not phase out nuclear power plants for political reasons. The Swedish government has approved an application to increase the electrical power output of the country’s Oskarshamn-3 boiling water reactor unit from 1,200 MW to 1,450 MW. The Swiss government last year ended its moratorium on building nuclear power plants and extended the operating life time of its existing reactors. Finland is constructing a pressurised water reactor of 1600 MWe. The French government approved construction of a similar plant in France. Western Europe is quietly backing away from planned nuclear phase-outs.

The US Nuclear Regulatory Commission expects to receive 13 applications for new nuclear power plants, mostly in 2007 and 2008; approximately half would seek two reactors. The NRC offered 20- year extensions to 42 reactors. Canada plans to spend C$ 40 Billion on two new reactors and upgrades of old reactors. Policy makers within Japan’s governing Liberal Democratic Party have asked for the country’s fast breeder programme to be accelerated. China plans to invest $50 billion to build about 30 new nuclear reactors by 2020.Australia is keenly debating whether to build nuclear power reactors or not.

Nearer home, Unit 4 of the Tarapur Atomic Power Project (TAPP), India’s largest nuclear power reactor became commercial in December 2005. On May 20 this year, Unit 3 of TAPP went critical. In 2007, five units, including the first unit (1,000 MWe) of the Kudankulam Power Project are scheduled to go commercial. India expects to have 20,000 MWe nuclear capacity on line by 2020. The mood is upbeat in nuclear industry.

— Dr K.S. Parthasarathy is former Secretary, Atomic Energy Regulatory Board

Power-frugal e-gadgets
Does the battery of your mobile phone require frequent recharging?

As gadgets like cellphones and I-pods shrink in size, scientists say technology is being developed to reduce power consumption by such gadgets.

A team led by an Indian scientist, Jagadesh Moodera at Massachussets Institute of Technology (MIT) has developed a new material that not only increases the computing power and flexibility of these and other electronic devices, but also dramatically reduces their power consumption.

“We currently have multifunctional cellphones that act as phones, cameras and music players. Our research could create even greater multifunctionality in the future,” says Jagadesh Moodera, Senior Research Scientist, Magnet Lab, MIT, in his paper about the research.

Moodera and his team have developed a magnetic semiconductor material—a chromium doped indium oxide which is seen as a major development in the field of “Spinotronics.”

Spin electronics or spinotronics is the science of integrating the functionality of both charge and spin of the electrons in the computer chips for better functionality. The increase in the growth in hard disk capacity from 100 MB to 500 GB is largely credited to spinotronics.

Spintronics could also reduce the power consumption of information devices. Spin states are considered “nonvolatile,” meaning they retain stored information even when the power is switched off - this is why magnetic hard drives hold information without power.

It could also could create circuits that operate similarly, storing and passing information without the need for a continuous current to retain the data.

Moodera team’s work was reported in the April issue of Nature Materials.

“The beauty of spin electronic devices is that they can integrate several functionalities like optical, electrical and magnetic properties on a single chip,” says John Philip, another Indian scientist in Moodera’s team.

Talking about his team’s invention, Moodera says that its ability to inject spin at room temperature and its compatibility with silicon makes it particularly useful. “Its optical transparency means it also could find applications in solar cells and touch panel circuitry” says Moodera.

“We have shown that Cr doped Indium oxide is a magnetic semiconductor and it retains its magnetic behavior even at room temperatures,” says, John Philip. — PTI

THIS UNIVERSE
PROF YASH PAL 

A question that has been bugging me for a long time is “what is the actual reason at the atomic level that decides the transparency and colour of a medium?” Can you explain?

Glass is transparent for visible light. It is not so transparent in infrared, or other frequencies like x-rays, for example. Our atmosphere is conveniently transparent in the visible region of the spectrum, where sun gives out most of it radiation and where our eyes are most sensitive. But the very same atmosphere is opaque in most frequencies of far infrared, ultra-violet, x-rays and gamma-rays.

Therefore, as you suspect, the transparency, or otherwise, depends on the detailed structure of the material. Atomic, and molecular structure enter centrally in determining the scattering and absorption of radiation.

Atoms and molecules have specific energy levels. They determine which part of the spectrum would be absorbed and which would pass through unhindered. Indeed in most of experimental science, atomic physics, molecular physics, lot of chemistry and biology, astronomy and even nuclear physics we use different radiations to probe structures at the basic level.

The experiments are interpreted with the help of known theory and depending on the results a new theory often emerges.

The question you have asked is basic to much of modern-day science activity. An example from the current concerns about depletion of the ozone layer might illuminate the discussion given above. Long ultraviolet would get down to the earth if there were no ozone. This is because the atmosphere does not have other molecules in enough quantity to absorb this radiation.

Ozone molecules that are formed in the upper atmosphere are structures of three oxygen atoms with relatively loose binding with each other. The energy levels of these molecules are such that they are capable of absorbing the ultraviolet to break up into an oxygen molecule and an oxygen atom. Ozone molecules are destroyed but in dying they manage to save us from harmful ultraviolet.

Of course we need continuous replenishment of ozone to compensate for the warriors that perish in trying to save us!

Is there any possibility that the earth might stop rotating because of friction due to lot of cosmic dust in space?

Please do not be paranoid. Any interaction with dust would be very low. What can happen in a few tens of million years is that there might be a collision with an asteroid or a comet. But such an event may or may not alter the rotation period of the earth but would certainly cause lot of devastation.

Remember, you are talking of a big ball that has been rotating reliably for over four billion years perhaps slightly changing with time.

The tidal friction does have an effect and there is some evidence that the length of the day has changed because of that. Now that the moon is not as close to the earth as it once was, that effect is somewhat less now. Cosmic dust is not significant in this regard.