One of the pioneering countries in nuclear power development and once the predominant supplier of civilian nuclear technologies worldwide, the U.S. began to witness a decline in its civil nuclear sector shortly after Three Mile Island (TMI). TMI initiated a trend of growing regulatory burdens upon the U.S. nuclear industry, and also halted new nuclear construction in the U.S. for many decades. These developments contributed to the escalating costs of nuclear power in the U.S.