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Indian N-data on thorium unique: IAEA

With these new evaluations on thorium, India has joined select band of criticality safety benchmark.

india Updated: Mar 12, 2006 13:46 IST
Lalitha Vaiddyanathan(PTI)
Lalitha Vaiddyanathan(PTI)

The International Atomic Energy Agency's coordinated Research Project has described the Indian nuclear data on thorium as unique and of high quality and its contribution very valuable for the international nuclear community.

The nuclear data on thorium is much better than the six-decade data on natural uranium U-238 in both light water and pressurised heavy water reactors.

"With these new evaluations done through the CRP on thorium, India has joined select band of criticality safety benchmark," Andrej Trkov, IAEA Scientific Secretary of Coordinated Research Project (CRP) said.

The main Indian contribution is completion of the KAMINI reactor benchmark, which has already been accepted for the prestigious Handbook on International Criticality Safety Benchmark Experiments, Trkov said.

He added a benchmark on post-irradiation examination of irradiated thorium fuel is still in preparation and will be completed as part of this activity.

The CRP on "Evaluated Nuclear Data for the Thorium-Uranium Fuel Cycle" was organised by IAEA to produce the library of evaluated neutron cross section data for transactinide nuclei important for the Th-U fuel cycle.

The third and final meeting concluded at Vienna last month and India was represented there by Dr S Ganesan of Bhabha Atomic Research Centre as CRP's Chief Scientific Investigator, Trkov said.

"The Indian contribution is extremely valuable and is greatly appreciated by the international nuclear community," he said.

India has an active R&D projects on utilisation of the thorium-uranium fuel cycle and will, therefore, directly benefit from the improved nuclear data resulting from the project, he pointed out.

Thorium-based nuclear fuel cycle offers many advantages -- thorium fuel is more proliferation-resistant due to highly radioactive constituents, which cannot be separated out by chemical means.

Handling of such material in improvised clandestine laboratories is practically impossible, Trkov said.

Other advantages are -- the Neutron capture in Thorium-232 yields U-233, which is a highly efficient nuclear fuel. A thermal breeder (or near-breeder) reactor concept based on thorium fuel is feasible.

Also, the build-up of long-lived higher actinides, which are the main source of long-term residual radioactivity in the waste, is much smaller in thorium fuel.

This fact can be used with advantage in the design of critical as well as subcritical accelerator-driven systems, the IAEA official said.

"The burn-up bench mark on thorium done by India is unique in the world as no other country has done it," Trkov said.

India is the only country, which has irradiated thorium rods indigenously to high burn ups and it is valuable and unique information that India is sharing with the world nuclear community, Trkov added.

India was invited by International Atomic Energy Agency for the coordinated CRP on thorium and has contributed KAMINI and thorium irradiation data, according to BARC sources.

India is initiating a number of its own basic data by using advanced facilities including accelerators. India is also providing nuclear data mirror website of IAEA from BARC.

Number of integral experiments will be conducted independently and indigenously using advanced heavy water reactor critical facility, which is under construction in India.

The data of thorium is superior to the natural uranium and "this has been possible because of new high resolution cross section data measurements at the leading particle physics facility CERN in Geneva, Ganesan said.

World reserves of thorium are much larger than reserves of uranium. Due to the advantages, there is rising interest in innovative fuel cycle concepts based on thorium fuel.

Unfortunately, due to the previous lack of interest in thorium fuel cycle, the quality of nuclear data for the relevant materials is lower than for the comparable materials in the uranium or mixed oxide (plutonium) fuel cycle.

First Published: Mar 12, 2006 10:55 IST