The effect of radial hydride on the room temperature fracture toughness of the Zr-2.5Nb pressure tube material with 100% radial hydrides and hydrogen content up to 320wppm was investigated using curved compact tension (CCT) specimens. The  hydride continuity coefficients ( HCC ) representing hydrogen content and hydrideorientation were determined between 0  and 1. It was observed that the role of plastic deformation on the fracture toughness mechanism decreases with increase in HCC . On a semi-log scale the fracture toughness of the Zr-2.5Nb pressure  tube varied linearly with HCC at room temperature and this is characteristic feature for the Zirconium alloys.