My two bob worth. I reckon the Chinese Naval Ships [PLAN] had pinged the US SSN and in a hurry it tried to escape detection [ reputed to be the quitetest sub on earth, so says the US] and hit some underwater objects.  So it continues with its damaged hull underwater.  Was there any radiation leak and damage the marine environment?

The US should own up!  So far dead silent.  Something to hide? Same on the US!