I know Charlie is a writer, not a radiation physicist, nevertheless... major 'units' fail in his radiation calculation. 6 Trillion alpha particles per sq meter per second is 6 TBq per m^2; not 6 Tbq per m^2 per second. TBq as a unit already includes the "per second". In other words, you wouldn't get a Fukushima release every eight days - you'd just get about 1 millionth of a Fukushima... and that's it (per m^2, of course), as long as you are moving through an interstellar medium as thick as he posits at that speed.

160 Curies is a dangerous amount of radioactivity, but nothing outrageous. I often work with gamma sources much larger than that. I use a 1000 Curie source that easily fits in a sq meter, and it's used the same shielding for over 20 years.