Comment by pfdietz

Using plasma volume is clearly not appropriate, since the point of the comparison is to compare cost of the equipment, by comparing the volume and size of the equipment between the two approaches (and ignoring that fusion equipment is much more complex and sophisticated than that in a fission reactor.)

The fuel comparison is silly, since fuel is not a major cost driver for either approach. The misconception that fuel costs matter is one of the errors that leads people to think fusion is desirable.