Admiral Buzzkill wrote:
There's really no reason for lots of blue light spilling out of these engines/reactors which is why all previous designs now look silly.
True -- that much light bleeding out would be a needless inefficiency. What you'd want is something that fully contains the reaction and keeps its energies comfortably away from any inhabited area.
With respect to the shirtsleeve environment of TMP Main Engineering, the intermix chamber couldn't have been radiating any appreciable amount of power by its glow, relatively speaking, or the engineers would have been killed on the spot. In fact, that it was only as bright as it was, and not vaporizing the people in there with it, means that the shielding on the intermix chamber had to be pretty darn effective, >99.99%.
Why it was even necessary to see the reaction occurring is another issue; perhaps being able to see the reaction was important to gauging and regulating engine performance, in-universe. Even Forbidden Planet
allowed the Krell to view their nuclear reactions, via a special mirror.