A few more details from the paper:
Because of its high fission production rate, the amount of technetium on Earth may ultimately exceed that of rhenium, its heavier congener.
In a typical light water nuclear reactor, 99Tc production is around 2 g/day for every 100 MW of thermal energy.
Technetium has a range of oxidation states, from 7+ to 1–, and its chemistry has considerable similarities to rhenium; e.g., it has extensive pentavalent chemistry.
The overall trends clearly demonstrate increasing technetium–technetium interactions with decreasing oxidation state.