Whether Input tax credit availed on refractory bricks, moulds and dies, jigs and fixtures is to be reversed in case of supply of such goods?

Yes. In terms of proviso to Section 18(6) of CGST Act, in case of supply of such goods as scrap, the registered person is required to pay the tax on the transaction value of such goods. Thus, in this case, unlike section 18(6), no comparison is required to be made between ITC taken on the capital goods/plant and machinery reduced by the specified percentage points and the tax on the transaction value of such goods

(ICAI FAQ PUBLICATION 06-09-2017 -: Availability of Credit in special circumstances: FAQ NO.32)