The petrenkos_workshop_rc2.zip file you have requested: Shadow of Chernobyl / Mods / Singleplayer / Petrenko's Workshop - 35.01kb is not available. Perhaps try browsing all files for the game S.T.A.L.K.E.R. Shadow of Chernobyl and upload any files you want to share or are missing. This is the only information we could locate:
A small mod that allows the player to bring various weapons and artifacts to Petrenko of the Duty faction in exchange for upgraded guns and armor.