A nuclear reaction is used to power the substation that generates the electric current induced (at t=0s) in the conducting magnets. What would be the energy expenditure on the system from t=5s to t=6s assuming that the reaction occurs once per second? [1u=930.1MeV/c^2, N=13.00175 u, C=13.0002 u, Mass of electron=0.00055 u]

The question seems to be incomplete. It doesn't provide enough information about the nuclear reaction taking place, the energy produced by the reaction, or how it relates to the power generation in the substation.

However, I can explain how to calculate energy expenditure if we know the energy produced per reaction and the rate of reactions.

1. First, we need to know the energy produced by each nuclear reaction. This is usually given in the problem or can be calculated if we know the masses of the reactants and products (using E=mc^2, where E is energy, m is mass, and c is the speed of light).

2. Next, we need to know the rate of reactions. In this case, it's given that the reaction occurs once per second.

3. To find the energy expenditure from t=5s to t=6s, we simply need to multiply the energy produced by each reaction by the number of reactions that occur in this time interval. Since the reaction occurs once per second, there would be 1 reaction between t=5s and t=6s.

4. Therefore, the energy expenditure from t=5s to t=6s would be equal to the energy produced by one nuclear reaction.

Without more specific information about the nuclear reaction and the energy it produces, I can't provide a more specific answer.