We have already learned that ions are atoms that are either missing or have extra electrons. They are just a little different from every other atom of the same element. Electrons don't have much of a mass when compared to a neutron or proton.
Let's say an atom is missing a neutron or has an extra neutron. An atom is still the same element if it is missing an electron. For example, there are a lot of carbon (C) atoms in the Universe. Atomic masses are calculated by figuring out the amounts of each type of atom and isotope there are in the Universe.
If you have looked at a periodic table, you may have noticed that the atomic mass of an element is rarely an even number. If you are an atom with an extra electron, it's no big deal.
As you learn more about chemistry, you will probably hear about carbon-14. C-14 is considered an isotope of the element carbon.
Initial scoping calculations on the latter suggested that the rate at which LNAPL is able to migrate from a waste package is likely to be very small and insignificant for likely representative displacement pressure data: this represents a key result.
Adopting a conservative displacement pressure, however, allowed the effect of other features and processes in the system to be assessed.
High LNAPL viscosity together with low density contrast with water reduces LNAPL migration potential.
‘As-disposed’ LNAPL emplaced with the waste is not expected to pose a significant issue.
When we look at sand in an hourglass, we can estimate how much time has passed based on the amount of sand that has fallen to the bottom.
Radioactive rocks offer a similar “clock.” Radioactive atoms, such as uranium (the parent isotopes), decay into stable atoms, such as lead (the daughter isotopes), at a measurable rate.
This paper provides a contribution to the assessment of this issue through multiphase-flow numerical modelling underpinned by a review of the UK's ILW inventory and literature to define the nature of the associated ILW LNAPL source term.
Examination has been at the waste package–local GDF environment scale to determine whether proposed disposal of ILW would lead to significant likelihood of LNAPL migration, both from waste packages and from a GDF vault into the local host rock.