Perfectly fine meaning #2:
To shed light on; illuminate.
irradiate
ir·ra·di·ate (ĭ-rādē-āt)
v. ir·ra·di·at·ed, ir·ra·di·at·ing, ir·ra·di·ates
v. tr.
To expose to radiation. To treat with radiation: irradiate farm produce so as to destroy bacteria.
To shed light on; illuminate.
To manifest in a manner suggesting the emission of light; radiate: irradiate goodness.
v. intr. Archaic
To send forth rays; radiate.
To become radiant.
[Latin irradiāre, irradiāt-, to illuminate : in-, on; see in-2 + radiāre, to shine; see radiate.]