The NRC staff "doesn't understand where that adds an additional safety margin" as proposed by the company.
Mike Short, an Edison consultant, told regulators that the company "had not intended" to characterize the system as an important safeguard, technically known as "defense-in-depth," or multiple layers of systems designed to prevent accidents or the release of radiation from a nuclear power plant. Short said the data collected by the system could be used in future research examining vibrations picked up by the monitors.
"It's our plan ... to make sure that's clear," he
The original monitoring system was at issue in a federal investigation after the plant was shut down in January.