Smartly ensuring environmental security using bio fuel

‘Smart’ biofuel crops ensure food and environmental security

The leftover stalks after juice extraction, can be used for animal feed

Sweet harvest:Dr. Belum V.S. Reddy, Principal Scientist, Icrisat, at a sweet sorghum field.

While the global debate rages on whether the biofuel revolution is causing imbalances in food security systems and increasing the greenhouse gas emissions the ‘smart’ biofuel crops developed, utilized and promoted by the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, Andhra Pradesh, ensure energy and environmental security.

According to Dr William Dar, Director General of ICRISAT, the time has come to ensure that only smart biofuel crops are developed and utilized so that they can link poor dryland farmers with the biofuel market, without compromising on their food security, or causing environmental damage.

Energy security

“Smart biofuel crops are those that ensure food security, contribute to energy security, provide environmental sustainability, tolerate the impacts of climate change on shortage of water and high temperatures, and increase livelihood options,” he said.

Through its BioPower Strategy, ICRISAT is developing and promoting sweet sorghum as a major feedstock for producing bioethanol.

Sweet sorghum is a carbon dioxide neutral crop, which is a big contributory factor to being called a smart crop.

ICRISAT-bred sweet sorghum varieties and hybrids have increased sugar content in their stalks.

It has a strong pro-poor advantage since it has a triple product potential, that is grain, juice for ethanol, and bagasse (waste) for livestock feed and power generation.

Its highlight is that there is no compromise on farmers’ food security, since the grain is available for the farmers, along with sugar-rich juice from the stalk that can be distilled to manufacture ethanol.

Cost-effective

There are other benefits also. It is a cost-effective and competitive feedstock. It has a shorter crop cycle of 4 months compared to sugarcane, which is a 12-month crop and requires lesser water.

It requires only half of the water required to grow maize and one eighth of the water required to grow sugarcane. The cultivation cost is less when compared to sugarcane.

The juice from the stalks is used for fuel alcohol production. The leftover stalks (called sillage), after juice extraction, can be used for animal feed, according to Dr. Belum Reddy, Principal Scientist, Sorghum Breeding, of the Institute.

Sweet sorghum is tolerant to water scarcity and high temperatures, two qualities which will keep the crop in good stead in the context of climate change. It also has high water use efficiency.

Environment friendly

It is a carbon dioxide neutral crop that makes it environment friendly, and does not add to greenhouse gas emissions. During its growth cycle, a hectare of sweet sorghum cultivation absorbs about 45 tonnes of carbon.

It has been found from studies that gasoline blended with ethanol has lower emissions when run through an automobile engine than pure gasoline.

Field experiments conducted have proved that from one hectare of sweet sorghum, a farmer can harvest about 30 tonnes of fresh stalk. The cost of cultivation of sweet sorghum works out to Rs.10,500 per hectare. It generates a total income of Rs. 21,000 with a net return of Rs 10,500.

Good animal feed

The stalks of sweet sorghum are relished by cattle and the digestibility is higher compared to grain sorghum. In the absence of a distillery, the farmer can sell the stalks to animal feed manufacturers. The sillage from sweet sorghum stalk is a good animal feed like grain sorghum.

ICRISAT’s initiative to produce biofuels is not limited to bio ethanol from sweet sorghum alone.

Water shed project

Through its watershed development project, it is promoting the cultivation of Pongamia and Jatropha also from which biodiesel can be extracted.

For more information readers can contact Dr. Belum V.S. Reddy, Principal Scientist, email: b.reddy@cgiar.org, GT-Crop Improvement, email: b.reddy@cgiar.org , phone: 040-30713487 and 040-30713348, ICRISAT P. O., Patancheru, Medak district, Andhra Pradesh: 502324.

Now cancer patients can safeguard their fertility

Safeguarding cancer patients’ fertility

Scientists have found a way to store and grow a woman’s immature eggs in the laboratory using a technique which could be used to protect the fertility of women undergoing chemotherapy.

Anti-cancer drugs can often destroy the ovary’s follicles, where immature eggs remain dormant from birth until they are matured by the body.

This means a woman may survive cancer but become infertile as a result.

Several centres in the U.K. already offer to store pieces of ovary tissue from women about to undergo cancer treatment in the hope that, one day, techniques can be found to mature the eggs and use them for IVF.

The new research, led by Evelyn Telfer of the University of Edinburgh, has taken a major step towards that goal.

She took pieces of ovary tissue and, by adding artificial growth hormones in the laboratory, successfully grew the eggs within the follicles.

Advanced stage

The ovary tissue she used was donated by six women who gave birth by elective caesarean section, and about a third of the follicles within them went on to reach the advanced stage of development.

Eventually, said Tefler, fully matured eggs using this technique could be used in assisted reproduction procedures such as IVF. Telfer said the new technique had several advantages over standard practices. It took just 10 days for an egg to mature using the new method, while it might take several months for an egg to mature inside the ovary, and one piece of tissue can provide many dozen eggs, rather than the 10 or so harvested during IVF.

No hormone injections

In addition, the technique would avoid the need for a woman to take hormone injections, which are needed in standard IVF to stimulate her ovaries to over-produce eggs.

Telfer said that there was still work to do before the laboratory-matured eggs were suitable for fertilisation, but she had high hopes because animal studies had already shown that eggs matured in this way could be suitable.

Good evidence

“We believe there’s good evidence that we can get normal [eggs], but of course you would never apply this technique clinically until you are sure,” said Telfer. Jane Stewart, a consultant in reproductive medicine at the Newcastle Fertility Centre, said the procedure to collect a biopsy from a woman’s ovary was relatively simple and could be done at short notice.

But she added: “The storage and use of such biopsies, which may contain abundant but immature eggs, remains experimental, however.”

— Guardian Newspapers Limited

The metal consuming fast breeders

Metallic fuel for fast breeders after 2020

The scientists are aiming at a breeding ratio of 1.5 for the metallic fuel

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Going metallic: The entire fuel core of the Fast Breeder Test Reactor (FBTR) will be changed to metallic fuel by 2017

Fast breeder reactors (the sixth reactor onwards) that would come up after 2020 will be 1,000 MW and not 500 MW reactors. And they would have metallic fuel and not mixed oxide fuel.

The entire fuel core of the Fast Breeder Test Reactor (FBTR) would be changed to metallic fuel by 2017. “We are getting ready to irradiate advanced metallic fuel in FBTR by 2010,” said Dr. Baldev Raj, Director of the Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam.

Pilot facility

A facility to fabricate, reprocess and refabricate metallic fuel would come up at IGCAR and become operational by 2014. IGCAR is first setting up a pilot reprocessing facility at its complex.

The need to go in for a metallic fuel is understandable. The ability to put up new fast breeder reactors depends on the amount of plutonium available. Breeder technology, as the name indicates, produces or “breeds” more plutonium than it consumes for producing energy.

Self-sustaining

Hence fast breeder reactors are not only self-sustaining but have the capability to produce extra plutonium to start new reactors.

The rate at which surplus plutonium is produced depends on the fuel used in a fast breeder reactor. In the case of mixed carbide fuel used in the FBTR, the extra plutonium produced would be 0.2-0.3 (breeding ratio being 1.2-1.3); it would be just 0.1 (breeding ratio being 1.1) in the case of oxide fuel.

However, in the case of metallic fuel the plutonium gain would be 0.3-0.5. The breeding ratio is 1.3-1.5.

“We are aiming at a breeding ratio of 1.5 against 1.3 which is the norm,” said Dr. Raj.

Faster doubling time

The higher the breeding ratio, the faster would be the doubling time — (time taken to produce surplus plutonium to start a new reactor).

So the doubling time would be the least in the case of metallic fuel and the most in the case of oxide fuel.

“We would have at least 15 years’ advantage to get the necessary fuel [plutonium] for another 1,000 MW reactor,” said Dr. Raj.

The plutonium content of 20-25 per cent in metallic fuel would be the same as in carbide or oxide fuel.

“But there are no lighter elements like oxygen or carbon to absorb the neutrons [in metallic fuels],” explained Dr. Raj on why metallic fuels have a higher breeding ratio and hence faster doubling time.

The reprocessing of metallic fuel will be very different from other fuels.

“The reprocessing technology is very difficult,” he said, “it will be a pyro-metallurgical route.”

Though the FBTR fuel core would be changed from carbide to metallic, it would not be possible to do the same with the Prototype Fast Breeder Reactor (PFBR) or the two reactors coming up at Kalpakkam.

Design constraint

“We can’t put metallic fuel in these reactors as the design does not permit it,” he said, “though it is a desired situation.”

But he and the scientists at Kalpakkam have not given up on the idea. “We will continue to explore ways of doing this,” he said, sounding optimistic.

algae for rescue

Algae’s surprising new application

Some varieties of algae, a kind of unicellular plant, contain an enzyme called hydrogenase that can create small amounts of hydrogen gas.

Many believe this is used by nature as a way to get rid of excess reducing equivalents that are produced under high light conditions, but there is little benefit to the plant.

Algae for production

Scientists at U.S. Department of Energy’s Argonne National Laboratory are working to chemically manipulate algae for production of the next generation of renewable fuels – hydrogen gas. The move is in direct response to soaring gasoline prices.

“We believe there is a fundamental advantage in looking at the production of hydrogen by photosynthesis as a renewable fuel,” senior chemist David Tiede said.

“Right now, ethanol is being produced from corn, but generating ethanol from corn is a thermodynamically much more inefficient process.”

Enzyme hydrogenase

Tiede and his group are trying to find a way to take the part of the enzyme hydrogenase, that creates the gas and introduce it into the photosynthesis process, according to an Argonne National Laboratory press release.

The result would be a large amount of hydrogen gas, possibly on par with the amount of oxygen created.

“Biology can do it, but it’s making it do it at 5-10 percent yield that’s the problem,” Tiede said.

“What we would like to do is take that catalyst out of hydrogenase and put into the photosynthetic protein framework.

We are fortunate to have Professor Thomas Rauchfuss as a collaborator from the University of Illinois at Champaign-Urbana who is an expert on the synthesis of hydrogenase active site mimics.”

Several benefits

Algae has several benefits over corn in fuel production. It can be grown in a closed system almost anywhere including deserts or even rooftops, and there is no competition for food or fertile soil.

It is also easier to harvest because it has no roots or fruit and grows dispersed in water. “If you have terrestrial plants like corn, you are restricted to where you could grow them,” Tiede said.

“There is a problem now with biofuel crops competing with food crops because they are both using the same space.

Algae provides an alternative, which can be grown in a closed photo ioreactor analogous to a microbial fermentor that you could move any place.”

Tiede admitted the research is its beginning phases, but he is confident in his team and their research goals.

The next step is to create a way to attach the catalytic enzyme to the molecule.

checking losses in FBTR

Putting the FBTR to the litmus test

IGCAR is taking up yet another challenge. The scientists are putting the reactor to the litmus test of automatically shutting down at the very first instance of a fuel leakage.

“We want to take one subassembly [that contains the fuel pins] beyond the 1,55,000 MW days/tonne burn-up till the clad [metal casing] fails,” said Dr. Raj.

Scientists feel that they would be able to increase the burn-up by another 9,000 MW days/tonne before the clad gives way. The post irradiation examination (PIE) of the fuel indicates that it has already reached the natural end of its life. But the metal casing (clad) has not given way.

The fuel undergoes continuous fission and it swells. It then comes in contact with the metal casing leading to stress build-up at the casing.

The casing ruptures after some time, unable to accommodate the swelling fuel. “There are specific instruments to detect clad [metal casing] failure. These instruments were checked for their responses recently by putting fuel pins with perforated clad [to simulate failed clad] in the core, and these instruments responded well,” said Dr. P.V. Ramalingam, Director of Reactor Operation and Maintenance Group, IGCAR.

Will the metal casing failure leading to fuel leakage not cause problems? “The clad is the first barrier, the primary sodium system is the second, and the reactor containment building is the last barrier,” said Dr. Ramalingam. “So when the clad fails, it is only the first barrier that would have failed. The fission products released would be contained in the sodium system barrier.”

When this happens, the systems are supposed to detect it and shut down the reactor.

The temperature would then drop and the cracks in the clad would get sealed. “The contamination will be only minimal,”

carbide fuel reprocessing.....

FBTR: ‘We don’t see any problems with reprocessing’

The carbide fuel that had reached a burn-up of 1,55,000 MW days/tonne was reprocessed

Easy task: Unlike the carbide fuel, reprocessing the oxide fuel that will be used in the PFBR should not be difficult, says Dr. Baldev Raj, Director of IGCAR, Kalpakkam. The Kalpakkam based Indira Gandhi Centre for Atomic Research (IGCAR) has squeezed the most out of the uranium-plutonium mixed carbide fuel in the Fast Breeder Test Reactor (FBTR).

The fuel has proved its capability to light up a 100 watts bulb continuously for 14,880 hours for 620 days using just one gram of the fuel.

Technically speaking, the carbide fuel had reached the maximum burn-up of 1,55,000 MW days/tonne some time ago without any failure of fuel. Burn-up is the cumulative amount of energy that can be extracted from a unit mass of the fuel.

So the higher the burn-up, the greater is the amount of energy that can be extracted from a given amount to fuel.

Closing the fuel cycle

And in what may be termed as closing the fuel cycle, the IGCAR scientists have successfully reprocessed the spent fuel that has undergone 1,55,000 MW days/tonne burn-up.

Reprocessing is very important as only about 17 atoms per cent of the fuel would have undergone fission to produce energy.

So reprocessing helps to extract the valuable plutonium and separate the fission products from the spent fuel. The reprocessed plutonium is refabricated as fuel.

Reprocessed fuel

It was in 2005 that IGCAR reprocessed the fuel that had undergone 1,00,000 MW days/tonne burn-up.

‘Fast breeder’ reactor, as the name indicates, breeds or produces more plutonium than what it consumes for producing energy. This is what gives it the name “breeder.”

So perfecting the reprocessing technology is a must to extract the unspent plutonium for use in a new reactor.

There are other advantages as well. Reprocessing goes a long way in removing the long lived fission products (actinides) and in the process it makes waste management much easier.

Many challenges

For all its advantages, reprocessing is fraught with many challenges, especially when the fuel has undergone higher burn-ups.

Dissolving the 1 lakh MW days/tonne burn–up fuel with nitric acid, among other steps, was done without much of a problem.

“Our assessment was right about the additional challenges of reprocessing the fuel [that has undergone 1,55,000 MW days/tonne burn-up],” said Dr. Baldev Raj, Director of IGCAR.

“There was more radioactivity, more problems with shielding, the separation process, maintenance and degradation of solvents. But there were no surprises.” An additional challenge came in the form of handling the fuel that has undergone a shorter cooling.

Shorter cooling

“We reprocessed the fuel after just 18 months cooling period. This is comparable to commercial reactors,” he said. It may be recalled that the 1 lakh MW days/tonne burn-up fuel was reprocessed after six years of cooling.

“Today we can say that we don’t see any problems with fuel reprocessing,” he said confidently. So he is thirsting for more challenges. “We would like to reduce the cooling period from 18 to 12 months,” Dr. Raj noted.

Experience gained

While IGCAR has gained much experience and hence confidence in reprocessing the mixed carbide fuel used in the fast breeder test reactor, the PFBR would have a mixed oxide fuel.

So will its experience with carbide fuel help in reprocessing the oxide fuel to be used in the PFBR? “Reprocessing [mixed] carbide fuel is difficult unlike [mixed] oxide fuel. We don’t see any difficulty,” said the Director, sounding confident.