Uranium-235 (U-235), an isotope of Uranium, is a metallic element that is used in atom and hydrogen bombs. It is also used as a fuel in nuclear reactors. Under sanctions in the post-Pokharan-I era, uranium was hard to come by. Scientists were analysing the possibilities of alternative fuel. A scientific paper published in Current Science asserted that earlier calculations made by BARC research teams establishing Pa-231 as a better fissile missile than U-235 was erroneous.

Apparently, the earlier BARC research found that a football-sized Pa-231 would attain ``criticality''. The authors of the Current Science report, said even a moon-sized Pa-231 would also not besufficient to attain criticality. In fact, the study showed that there was no possibility of Pa-231 going critical, even if infinitely sized.

The report in Current Science was picked up by a news agency which interpreted it as a major embarrassment for BARC.

``This is mischievous,'' said an angry Anil Kakodkar the BARC chief, when The Indian Express reached him for comments. ``The thorium fuel cycle is of special interest to us,'' Kakodkar said, ``hence, there is a lot of experimentation related to data generation. The earlier study was based on data that was available prior to 1994 when the theoretical model was developed. The article was based on data that became available in 1994. Protactinium is not relevant as a fissile device or as fuel in the reactor. The assessment of critical mass was purely an academic exercise. The authors (of the latest article) too are very perturbed (that their paper has been interpreted the way it has been).''

Scientific Officer (H) Dr V Jagannathan of theTheoretical Physics Division to issued a rejoinder in the form of a ``letter to the editor''. ``In sensationalising the news item, the reporter has tried to kill the scientific spirit embodied in the paper and has attempted to bring out an imaginary notion of an unpleasant and non-existent element of discontent for the authors,'' he noted and added that the entire process was a matter of ``ongoing scientific activity, which includes continuous updating of our data base.''