Now small, hen-egg sized robots, can directly monitor nuclear reactors and pinpoint corrosion.
Being designed by Harry Asada, professor of mechanical engineering at Massachusetts Institute of Technology (MIT), and his team, these underwater patrollers, equipped with cameras, can withstand a reactor's extreme radioactive environment - transmitting images in real-time from within.
Currently, plant inspectors use indirect methods to monitor buried piping, ultrasound for instance, to screen lengths of pipe for cracks, or dig them up -- a costly and time consuming operation.
Direct monitoring of nuclear reactors has become crucial in the light of a year-long investigation into the oldest running facilities in the US, throwing up evidence of "unrelenting wear" in many of them.
"We have 104 reactors in this country," said Asada. "Fifty-two of them are 30 years or older, and we need immediate solutions to assure the safe operations of these reactors."