It would need to be replentished, but it would theoretically be easier/safer to refill only hydrogen propellant than to refill both a fuel and an oxidizer. I don't think that refueling is in DRACO's mission parameters, though. Future NTP spacecraft may be reusable in that manner.

Liquid hydrogen takes the place of water in a terrestrial reactor. The hydrogen is pumped into the reactor core (cooling the nozzle and reactor casing on its way) where it is superheated. It then passes to the nozzle, where it expands and is focused into the thrust plume that propels the spacecraft.

This diagram may make more sense.

NTP hasn't really gone anywhere yet, but work on that line of research hasn't really stopped, either.

DARPA is due to announce its Phase 2/3 (ground validation and flight demonstration) contract award for the DRACO project anytime now. Time will tell how far that actually gets.

NASA is continuing to make slow progress on its own NTP project, though that's still entirely a drawing board exercise.

Celsius or Fahrenheit? (/s)

Columbia University sociologist Diane Vaughan wrote The Challenger Launch Decision to illustrate the theory of "normalization of deviation", in which accepting small deviations from requirements leads to a slippery slope and eventually places a project in an extreme state of nonconformance. She added a section on Columbia in the second edition to show that NASA hadn't actually learned anything from earlier disasters.

I made it mandatory reading when I was the supervisor of a flight safety engineering team.