Interesting couple of articles here on America’s nuclear power plants and regulatory compromises.
http://old.news.yahoo.com/s/ap/20110620/ap_on_re_us/us_aging_nukes_part1
http://www.theatlantic.com/national/archive/2011/04/atomic-snowflakes/73227/
Seems the NRC is pretty flexible when it is evaluating safety rules. Maybe the rule of thumb is ‘we will know the correct limit when we exceed it’. Unfortunately, we learned from the Japan Fukishima disaster and the BP Gulf Oil spill that when the limit is exceeded, there really isn’t a plan on how to deal with a disaster.