All the nuclear plants in S.C. are old. The most recently completed one came online in 1986. Power from old depreciated plant can indeed be cheap (although sometimes not cheap enough; TMI 1 was cash flow negative the last six years it was in operation). Trying to REPLACE those plants, or build new ones to provide additional power, is another matter entirely. Look at the sad experience at V. C. Summer, also in S.C.

A similar story is playing out in France, with Flamanville 3.