Hi there! Here are my corrections, let me know if you have any questions about them!

Today I ('I' is always a capital letter even in informal writing.  Some people use a small I when writing informally, but it would still be considered incorrect)saw a video clip on Youtube which was recorded 2 years ago . Dr. Han, a Korean roboticist, explained that after the ('the' because people know about it)Fukushima nuclear accident, people realized that the development of humanoid robots was futile in reality because robots couldn't even go up the ladders to repair a nuclear generating station. People needed to put themselves in danger to get it fixed, one of them was exposed to radioactive rays which proved fatal / and he died as a result. it caused him to death. America's Defence Advanced Research Projects Agency (DARPA) came up with an idea of holding the DARPA Robotics Challenge (DRC). They set up some missions for the challenge, robots had to where robots should drive cars, open doors, go up the ladders and use tools to solve problems spontaneously in a catastrophic situation. Dr. Han had an interview on TV before they had the finals. They started with over 200 teams from all over the world and ranked finished 9th in the first round. While I was writing this, I started to wonder who won what the result of the challenge. I found out that the other team from Korea won the first prize and it got gave me goosebumps :0. I had (past perfect because this happened before you found out that a Korean team won. You are going further back into the past)expected the Japanese team to win the competitionmust have won this game. Anyway, Robots with advanced technology will keep us from doing the tasks that can spare humans from carrying out tasks that could possibly prove fatal, possibly take our life though there are pros and cons in to consider with this issue. Some worry that robots will take our jobs, but (we don't usually start sentences with 'but', better to put a comma here)did the jobs that we have now even exist 200 years ago? I think it's all a natural transformation of an ecosystem. We should make the strike a (we always use 'strike a balance')balance and prepare for dramatic change ahead as of us while technology develops at a dizzying pace. I am excited to see what will happen!