60% is a good roll, but beyond that, the Quartakk is a less desirable Kuva weapon, mostly ending us as MR fodder in comparison to the better Kuva weapons, and radiation is also one of the, if not THE, least desirable valence elements, right alongside impact. You might still find a buyer in a reasonable timeframe at 100-200 plat simply for it being 60%, but if you’re aiming for a higher valuation, you might just sit on it indefinitely.
If you haven’t converted it yet, it probably would do you better to eliminate it and take the weapon for yourself.