[en] Tendencies of Zr-2.5%Nb alloy welded joints to hydrogenation with various structural state were studied in sulfuric acid. Zr-2.5%Nb alloy welded joints independent of structural state were shown practically not to tend to hydrogenation in 0.9-50% sulfuric acid solution at elevated temperatures and pressure (450 K and 1.5 MPa). The welded joints preserved high stability of mechanical properties under samples static and impact bending in case of durable exposure in 3- and 50-% solution of H₂SO₄