Allison Macfarlane, President Obama's nominee to head the body that regulates Nuclear Safety in the US is a geologist and expert on nuclear waste disposal though she describes herself as a nuclear agnostic. If confirmed, she will replace Gregory Jaczko whose 8 year tenure was plagued by battles with the industry and Congress as he attempted to bring in new safety regulations. The United States is home to nearly a quarter of the world's commercial nuclear reactors.