The Karachi Nuclear PowerComplex is on an earthquake-prone seafront less than 20 miles from downtown Karachi. (Max Becherer/Polaris Images for The Washington Post) KARACHI, Pakistan — World leaders have fretted for years that terrorists may try to steal one of Pakistan’s nuclear bombs and detonate it in a foreign country. But some Karachi residents say the real nuclear nightmare is unfolding here in Pakistan’s largest and most volatile city. On the edge of Karachi, on an earthquake-prone seafront vulnerable to tsunamis and not far from where al-Qaeda militants nearly hijacked a Pakistan navy vessel last fall, China is constructing two large nuclear reactors for energy-starved Pakistan. The new reactors, utilizing a cutting-edge design not yet in use anywhere in the world, will each provide 1,100 megawatts to Pakistan’s national energy grid. They are being built next to a much […]