U.S. President Barack Obama ratified on Monday an agreement for civilian nuclear cooperation with Vietnam that would allow American firms to tap into the market considered the second largest in East Asia. 

AP reported that U.S. Congress has 90 days to review the 123 Agreement that will go into effect if American lawmakers do nothing with it after the period.

Vietnam and the U.S. signed the agreement in October of last year to open the way for U.S. investment in Vietnam's burgeoning nuclear power market that is second only to China in size in the East Asian region, Reuters said.     

Under the agreement, Vietnam will rely on the international market for its nuclear fuel supply but will not enrich uranium or reprocess plutonium itself.

Demand for energy has grown rapidly in the Southeast Asian country in response to domestic economic growth of around 5 percent a year.

U.S. Secretary of State John Kerry said at a summit in Brunei last year that the Vietnamese nuclear power market is expected to grow to US$50 billion by 2030.

Vietnamese Prime Minister Nguyen Tan Dung said last month that the construction of Vietnam’s first nuclear power plant in the central province of Ninh Thuan could be delayed until 2020, citing advice from the International Atomic Energy Agency.

Work on the nuclear power plant was expected to begin this year.

The Vietnamese government has approved a plan to put five nuclear power plants into operation in the central region between 2020 and 2030, forecasting that the country will face a serious power shortage by 2020.