What is the fuel used in an atomic pile?

Statement $1$: The nuclide $_{13}^{30}Al$ is less stable than $_{20}^{40}Ca$. Statement $2$: Nuclides containing an odd number of neutrons are generally unstable.

Nuclei tend to have more neutrons than protons at high mass numbers because

What is the packing fraction of $_{26}^{56}Fe$ (Isotopic mass $= 55.92066$)?

In a radioactive decay,an emitted electron comes from

India conducted an underground nuclear test at