I don't have the actual numbers for you. The main difference between the Chinese icebreaker fleet and the South Korean and Japanese icebreaker fleet is that the South Korean and Japanese icebreaker building capacity can be allocated for private use. When companies want to build Arctic ships to do, say, LNG shipping in the north, they will likely task a South Korean company because South Korea makes the best ships. Chinese icebreakers, by contrast, are likely to be used either for Chinese government research purposes or will be flagged by China, so they will be shipping Chinese goods on a Chinese ship, Chinese crude, across the Arctic.
As to what China intends to do with the fleet, I suspect it's related to improving research capacity and the transportation of goods.