Hello, your looking for ShipComponentsDef.xml in the Data\Gameplay folder. Although, the challenge is you would need to have a source of durantium to mine durantium. But play around with it. You can also increase the construction cost. I don't know your experience with modding but I would start with the guide on steam (link below) if your new.
https://steamcommunity.com/sharedfiles/filedetails/?id=3053849809