North Korea's bomb is more powerful, but worry is miniaturization

By James Pearson SEOUL (Reuters) - North Korea tested its most powerful nuclear device on Friday, but the more worrying aspect for its rivals was Pyongyang's claim that it had advanced its ability to make a nuclear weapon, by miniaturizing and mounting a warhead on a missile. Its KCNA news agency said the test had used a nuclear warhead that had been "standardized to be able to be mounted on strategic ballistic rockets". "The standardization of the nuclear warhead will enable the DPRK to produce