A nuclear power plant operates at a steady electrical power output of \(1.0 \times 10^9 \text{ W}\) with an overall thermal efficiency of \(33.3\%\) (\(\eta = \dfrac{1}{3}\)). The reactor core generates thermal power via fission by converting rest mass into energy, while the turbine-generator system converts a fraction of this thermal power into electricity and rejects the remainder to the environment. Given that there are \(8.64 \times 10^4 \text{ s}\) in one day, what is the total rest mass converted into energy in the reactor core during \(1.0 \text{ day}\) of continuous operation?