Not far from the old Silk Road, Chinese government scientists have begun boring holes deep into granite in the first steps toward building what could become the world's largest tomb for nuclear waste.

As governments worldwide look at nuclear power as a possible answer to global warming, China has embarked on a nuclear-plant construction binge that eventually could exceed the one the United States undertook during the technology's heyday in the 1960s.

Under plans already announced, China intends to spend $50 billion to build 32 nuclear plants by 2020. Some analysts say the country will build 300 more by the middle of the century. That's not much less than the generating power of all the nuclear plants in the world today.