Maralinga, a barren stretch of land in South Australia’s remote western desert, is the country’s only former nuclear test site open to tourists. And Robin Matthews is Australia’s only nuclear tour guide.

Visitors to Maralinga, a deserted military installation the size of Manhattan, who expect to find their tour guide dressed in a yellow jumpsuit and ventilator mask are bound to be disappointed.

Instead, Mr. Matthews, 65, can be found wearing a baseball cap pulled low over his eyes and a cigarette hanging from chapped lips. His skin, deeply tanned, is covered with a narrative of faded tattoos inked long before they were fashionable.