Civilian radiation sources can and have killed by unshielded contact or proximity.
Such as the one used in medical devices, food chain irradiation or RTG.
Fuel rods, probably not, unless exposed to fluor based acids, and someone breath the fumes ? I think there was such a case at one time.
Some real life deadly accidents :
https://en.wikipedia.org/wiki/List_o...tion_accidents
Some of those match your descriptions, such as the ones on September 13, 1987, or December 2, 2001 (RTG)
Not to mention
https://en.wikipedia.org/wiki/Demon_core
(weapon core that went supercritical by mishandling)
However, I am not sure how to calculate the Accumulated Dose for Gurps consequences.
I am on my phone, but I think there was information in either space or THS, I will check later.