That doesn't sound like a terrible idea. I am a proponent of nuclear power but an almost total reliance on it (70%) probably isn't the best idea. Still, I don't think a hard and fast reduction is the best idea. Just retire the more inefficient nuclear plants when as they age and replace with renewable energy. Some of the biggest cost associated with nuclear is in construction. Don't throw billions of $$ away of perfectly good nuclear base-load. Bring the renewables on slow and steady and truly make sure they can handle the load before disconnecting too much of your proven nukes that will operate 24/7/365. There is probably a really good way to go about bringing renewables into the fold but rabid "environmentalists" pushing their agenda always throw a wrench into good sense.