Power Core Shielding is a technology in Clone Campaigns that can be researched at the Power Core in Tech Level 4. It costs 125 Ore, and gives the Power Core self-shielding.
This technology makes Power Cores harder to destroy, particularly if combiend with Strengthened Assembly. This will make it harder for enemies to take out the player's Power Cores to slow down unit production.
"This Tech Level 4 enhancement grants Power Core structures a self-contained shielding system, making Power Cores much more damage-resistant."
—Manual description