I don't know of anything specifically to rid the body of radiation.
Drinking only home distilled water would be a good first step. LBB or similar to keep the bowels moving. Liver flushes to help the lymph stay flowing. Maybe those foot pads that suck the toxins out of your lymph system.
Fasting allows the body to throw off most everything that it dosen't want to keep.
Lots of sunshine, fresh air and walking barefoot help the feet to expel toxins.
Sorry I don't know any specific herb to reccomend. Maybe MH will know of something when he gets back. He should be back the first week in July.