p-boron-11 (Score 1)

The Deuterium-3Helium reaction that this article describes does in fact produce MeV-scale energetic protons (in addition to the alpha particle), which in fact do make things very radioactive. This is not 'clean'. The other reaction to note here is p-11Boron, which is notable because it only produces alpha particles, which, being charged, do not leave magnetic confinement. Unfortunately, the cross-section for p-11B is smaller still than D-3He's cross section, which is smaller than D-Tritium.