Actually lots of money has been spent on upgrades that do just those things in Japan over the past few years. https://blogs.platts.com/2016/03/29/nuclear-safet

Actually lots of money has been spent on upgrades that do just those things in Japan over the past few years. https://blogs.platts.com/2016/03/29/nuclear-safety-upgrades-post-fukushima/ https://blogs.platts.com/2016/03/29/nuclear-safety-upgrades-... "Power companies in Japan are willing to spend billions of dollars on reactor upgrades because they expect the investments will help them reduce substantial costs spent on replacement fossil fuels. Restarting the two Takahama reactors, for example, could save about Yen 10 billion/month for Kansai Electric Power Co., a company spokesman said March 22."