Raadiation energy is too high to shield with leaded glass
The X-rays that got filtered out by ~1 cm of leaded glass in a CRT faceplate had energies of up to 25 KeV max. based on the TV's 25 KV anode voltage. That's pretty soft for X-rays.
The radiation making it through the water at Fukushima (ignoring suspended or dissolved radionuclides for the moment) is essentially all gamma rays, with orders of magnitude higher energy than CRT X-rays. As a result, leaded glass lenses wouldn't block enough of it to notice.
The other thing to keep in mind about radiation shielding, aside from having to shield your electronics from all angles, is that its effect is exponential rather than linear. If 1 cm of solid lead reduces exposure from a particular source by 50%, another 1 cm will only cut THAT dose by another 50% (= 25% of the original incoming dose), so twice the shielding thickness doesn't get you twice the effectiveness. Takeaway is this: Effectively shielding sensitive electronics from high radiation levels requires really bulky, massive hunks of stuff, or else staying far enough away that 1/R^2 is your friend.