Excise exemption for enriched boron compounds conditioned on production at specified heavy water and atomic facilities. Inserts a new tariff entry exempting enriched KBF4 (enriched potassium fluoroborate) and enriched elemental boron by prescribing a Nil effective rate of duty for those goods, conditional on their production or processing at specified heavy water plants, atomic research centres, and the public-sector entity supplying the Prototype Fast Breeder Reactor at Kalpakkam.