Baffle plate

From Memory Alpha, the free Star Trek reference.

A baffle plate was a component on at least some starships in the 23rd and 24th centuries, presumably part of the ship's warp drive. A ruptured or warped baffle plate could cause a warp core breach.

Such a fate befell the Antares in 2266 when Charles Evans used his telekinetic powers to remove the ship's baffle plate. (TOS: "Charlie X") Also during that year, Fleet Captain Christopher Pike was exposed to delta radiation when a baffle plate ruptured on board a Class J training vessel. (TOS: "The Menagerie, Part I")

The baffle plate was among the items removed from the SS Santa Maria after it had crash-landed on Orellius Minor in 2360. (DS9: "Paradise")