> Fuel Stored Energy: 942.42 TJ/kg

This seems implausibly high. Are you sure of your numbers here? It seems at least 50% higher than optimistic approximations of D-3He fusion, which seem to assume a rather optimistic burnup fraction.

> Pellet Efficiency: 97.25% Thermal, 0.125% Neutrons, 2.625% X-Ray, etc Radiation

Your exhaust velocity figures seem to imply a fairly low propellant density, but a low density propellant (or hohlraum or whatever) and a comparatively small pellet is going to have a hard time absorbing all the neutrons and x-rays from whatever fusion reaction you're using. The chances of it doing so and thermalising nicely to get the figures you're quoting here are slim, to say the least.

> Thrust at 127,471.96kN and an exhaust velocity of 3,794,355 m/s, and a mass flow rate (mDot) of 33.596kg/s.

Those numbers all seem to be basically OK, other than your slightly high exhaust velocity. It also matches the ~240TW power figure.

What is missing are the workings you used to compute your 1000TW figure, and without those it is hard to say where you went wrong with that. Maybe you could include your working in your question?