I have cured 2 SMC 1,4/50 Takumars under an OSRAM Vitalux 300 W lamp in a distance of about 20 cm (about 8''). I think this is similar to what is described above as UV-A reptile lamp. It took about 2-3 days. The lens was wrapped in aluminium foil an I put a metal sheet with a roud opening for the rear lens over it, but nevertheless it got about 60° C warm. I neither had lens separation nor problems with migrating lubricant. Not only the UV irradiation but also heat causes the bleaching, but you have to be careful not to to melt the lens cement. Besides the radioactive lens (contains Thorium, an alpha-emitter) is in the rear element (affirmed by a Geiger counter), so put this towards the light source. I put a little mirror under the front lens (without filter!), so the light is reflected and can work two times. I want to warn to do the same with the 1:2/35 mm Takumar since this lens will suffer lens separation in the rear element by the resulting heat (the glas types seem to have different thermal expansion)!
Some weeks ago I have read that a LED lamp from the international furniture house IKEA (the name was JANSJÖ) was successfully used for this and had success in less than one day! So I assume that every strong LED lamp (MAGLITE; LED lenser; CREE LED) could do the same job without producing so much heat like a UV-A reptile lamp and does not need so much electrical energy, only a set of batteries.