Any prepreg material you use will not offer long term impermeability to jet fuel all by itself. A rubber based coating like PRC or similar fuel selant has to be used to serve as a barrior.
The Prepreg material you choose should have a resin content of upwards of 35 % to provide a smooth glossy surface for the fuel sealant compound.
Prepreg Glass : NB321 7781 ( Newport Adhesives and Composites)
Prepreg Carbon Fabric : NB 321 3K 70P ( Newport )
Please let me know if you need further details.
Thanks,
AK