Where T1/2 is the half-life time (in seconds) and lamda is the decay constant.
[tex]\begin{gathered} T_{\frac{1}{2}}=\frac{\ln2}{\lambda}\rightarrow\lambda=\frac{\ln2}{T_{\frac{1}{2}}} \\ T_{\frac{1}{2}}=30y\cdot(\frac{3.154\times10^7}{1y})=9.462\times10^8 \\ \lambda=\frac{\ln2}{9.462\times10^8_{}}=0.000000000732=7.32\times10^{-10} \end{gathered}[/tex]