  Antineutrinos from nuclear reactors have the potential to be used for reactor
monitoring in the mid- to far-field under certain conditions. Antineutrinos are
an unshieldable signal and carry information about the reactor core and the
distance they travel. Using gadolinium-doped water Cherenkov detectors for this
purpose has been previously proposed alongside rate-only analyses. As
antineutrinos carry information about their distance of travel in their energy
spectrum, the analyses can be extended to a spectral analysis to gain more
knowledge about the detected core. Two complementary analyses are used to
evaluate the distance between a proposed gadolinium-doped water-based liquid
scintillator detector and a detected nuclear reactor. Example cases are shown
for a detector in Boulby Mine, near the Boulby Underground Laboratory in the
UK, and six reactor sites in the UK and France. The analyses both show strong
potential to range reactors, but are limited by the detector design.
