Reinvestment risk arises when a bank has fixed rate interest-earning assets, such as housing loans, where the borrower has the right to repay those loans early. If interest rates fall and borrowers repay their loans the bank will have to reinvest the proceeds received at the then prevailing lower rates.
Operational risk is a catchall category for other things that could go wrong. It includes potentially catastrophic events such as earthquakes, flooding and fire and other more mundane factors such as power, computer or telecommunications failures.
Insurance companies sell policies that pay out in the event of death or disability. The premiums charged on these policies are based on actuarial assumptions about factors such as mortality rates. If those assumptions prove to be incorrect such policies may be loss making.
A US bank with operations in a foreign country is, for example, at risk from the imposition of capital controls preventing it from remitting any profits or other funds it has in that country. In extreme cases foreign banks may even have their assets appropriated.