New Delhi, Aug 27 - Former president A.P.J. Abdul Kalam Thursday defended India's nuclear deterrence capability even as former National Security Adviser (NSA) Brajesh Mishra rubbished a top scientist's claim that the 1998 Pokhran tests were not successful.

Kalam, who mentored India's nuclear programme, said the only thermonuclear device tested in 1998 produced the 'design yield'.

K. Santhanam, who coordinated the Pokhran II tests, was Thursday quoted as saying that the only thermonuclear device tested was a 'fizzle'. A test is described as a fizzle when it fails to meet the desired yield.

Responding to a query from IANS, Kalam said: 'After the test, there was a detailed review, based on the two experimental results: (i) seismic measurement close to the site and around and (ii) radio active measurement of the material after post shot drill in the test site.

'From these data, it has been established by the project team that the design yield of the thermonuclear test has been obtained,' he added.

Months after the Pokhran tests, Kalam had said that the thermonuclear device produced a 45 kilotonne yield.

'The question is: Do we believe him or do we believe his boss (Kalam)?' Mishra retorted when asked by IANS about Santhanam's remarks.

'(Santhanam) is misleading the country. He is perhaps saying all this because he is so opposed to the CTBT (Comprehensive Test Ban Treaty),' Mishra said when asked why Santhanam was sowing seeds of doubt in the people's minds about India's nuclear capability.

Kalam had last year come out in support of the landmark India-US nuclear deal, saying New Delhi did not need to test again as its deterrence capability was strong enough.

According to Santhanam, a former official with the Defence Research and Development Organisation, 'we can't get into a stampede to sign CTBT.