SEOUL (AFP) - North Korea has repaired extensive rain damage at its nuclear test facility and could conduct a detonation on two weeks notice, a US think-tank said Friday, citing satellite imagery analysis. With the UN Security Council debating possible sanctions against the North following the launch earlier this month of a long-range rocket, there has been widespread speculation that Pyongyang may carry out its third nuclear test. Satellite photos as recent as December 13 show that Pyongyang is determined to maintain a state of readiness at the Punggye-ri nuclear test site, the US-Korea Institute at Johns Hopkins University said.