# Intro - Nuclear Weaponry Some people are introduced to the 'nuclear' field by power plants; they're mesmerised by the possibility of "infinite" energy, drawn into the spent nuclear fuel rod tank by the shimmering blue of Cerenkov radiation. Others are exposed to the more *violent* excesses of nuclear technology, choosing to delve into physics after seeing mushroom clouds on ancient documentaries. Whatever's the case, there's no denying that nuclear technology, and further advances within it, can make or break the human species. Increasingly efficient thorium reactors reduce our dependence on dwindling Uranium stocks, for starters! And so we delve into the wild world of nuclear energy. Starting from the basics, of course! %%cover image pls%% # Simplifying Mass - The Mass Unit Introduced in high school, the **Unified Atomic Mass Unit**, or $u$, is given by 1/12th the mass of a carbon atom. In terms of kilograms, it's given by: $u = 1.66 \times 10^{-27} \ \mathrm{kg}$ So if we want to find the *number of atoms* in one kilogram, aside from using Avogadro's constant (link later), we can use: $\frac{m(u)}{n \times 1.66 \times 10^{-27}} = \mathrm{kg}$ So for this equation, we'll treat the mass of the nucleus as given in terms of 'u' - so it'll be given by the atomic mass unit (also called the **Dalton**). $n$ in this case represents the number of nuclei. Performing operations like these are really, really important when it comes to fusion questions - so make sure you practice the unit conversions between the two! ...especially when you're not properly warmed up with the subject as a whole. Speaking from personal experience. Oops. You can use this unit to find better, more accurate estimates for the mass of something required to produce a set amount of energy - examples below! %%THROW IN IB EXAMPLES HERE!%% # Types of Decay ## Alpha ## Beta ## Gamma