Know of .. yes.

Off hand, I'm not familiar with any public facing portals for downloading raw data.

Bear in mind, these are "snapshot" static, historic, broad area spectrum maps - they're not live, they won't show new leaks, changes, etc.

They are, however, "training data" for forming a kernel of a NASVD - Noise Adjusted Singular Value Decomposition - a bundle of all the major features of typical regular environmental radiation for some locale.

If you fly about or have an instrument taking live readings and subtracting a normalised background kernel .. you get the faint trace "weird arse stuff" lighting up instead of being buried.

Finland's the home of the NASVD author, the country used to run "find a barrel of waste" in a forrest compitions back in the day, they're adjacent to some radiometrically filthy submarine docks and pens just over a border.

The game goes thus - fly at about 70m/sec about 80m above the deck in some kind of frame carrying 30 to 40 litres of doped crystal packs .. and pick out a signature in near real time from one second spectrum windows.

They have data, I don't know about portals.

https://www.helsinkitimes.fi/finland/finland-news/domestic/2...

Can confirm, though, Cresco STOL's make a good platform: https://www.youtube.com/watch?v=1_MO5Wfomks