Looking for a mod that had a specific nuclear thermal engine

[adamonmun]

During KSP 1.11 I played with a mod that added a rocket visually identical to the vector engine, but was nuclear thermal with a specific impulse of ~900, it was fun to use and had about 1100kn of thrust, is anyone aware what mod had this?

[JadeOfMaar]

@adamonmun If this engine has the following characteristics as well it can only be from the huge mod KSP Interstellar Extended:

• It is involved with WasteHeat and/or ThermalPower resource
• It has a very generous propellant switch
• It must be directly attached to a nuclear reactor or it's useless

If it's from another mod I would like just as much to know the name of that mod