JP-8 is kerosene with some additives.
For the improvement of the corrosion protection they add:
– Apollo PRI-19 or
– Octel Am. DCI-4A or
– Hitec 580 or
– Nalco/Exxon 5403 or
– Mobilad F800 or
– IPC 4410 or
– IPC 4445

to the prevention of the freezing up they add:
– Fuel System Icing Inhibitor (FSII) or
– Anti Icing Additive (AIA) or
– PRIST or
– DICE

The difference between JET-A and JP-8 ist the additional anti icing additive.

EDITED TO ADD:
For the optimization of thermal stability they add a detergent/dispersant additive on soap basis in mixture with phenolic antioxidants.
Its composition is patent protected an not known.

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"Who does not know anything, must believe everything."
Baroness Marie von Ebner-Eschenbach 1830-1916