Conventional
plants have a number of systems to prevent the core from being uncovered, but modular
reactors sidestep the problem entirely by housing all the system
components, including the steam generators, inside a single vessel.
Well before the first 20 - year relicensing period ends, power
plant owners will have to know what new
components and equipment upgrades will be required to extend the lives of current
reactors to 80 years, and how high the costs and regulatory hurdles will be, before deciding whether to take that route or decommission the
plants and shutter them, industry officials say.