A U.S. flag flies near the cooling towers of the Three Mile Island nuclear power plant, where the U.S. suffered its most serious nuclear accident in 1979, in Middletown, Pennsylvania March 15, 2011. U.S. regulators should press ahead with approving construction licenses for new nuclear power plants despite Japan's nuclear crisis, President Barack Obama's top energy official Energy Secretary Steven Chu said on Tuesday. REUTERS/Jonathan Ernst (UNITED STATES - Tags: ENERGY DISASTER BUSINESS IMAGES OF THE DAY) 

The Three Mile Island nuclear power plant, where the U.S. suffered its most serious nuclear accident in 1979, is seen across the Susquehanna River in Middletown, Pennsylvania in this night view taken March 15, 2011. U.S. regulators should press ahead with approving construction licenses for new nuclear power plants despite Japan's nuclear crisis, President Barack Obama's top energy official Energy Secretary Steven Chu said on Tuesday. REUTERS/Jonathan Ernst (UNITED STATES - Tags: ENERGY DISASTER ENVIRONMENT BUSINESS IMAGES OF THE DAY) 

A sign marks the Three Mile Island nuclear power plant, where the U.S. suffered its most serious nuclear accident in 1979, in Middletown, Pennsylvania March 15, 2011. U.S. regulators should press ahead with approving construction licenses for new nuclear power plants despite Japan's nuclear crisis, President Barack Obama's top energy official Energy Secretary Steven Chu said on Tuesday. REUTERS/Jonathan Ernst (UNITED STATES - Tags: ENERGY ENVIRONMENT POLITICS BUSINESS) 

Ernie Garrison rakes his son's front yard across from the Three Mile Island nuclear power plant, where the U.S. suffered its most serious nuclear accident in 1979, in Middletown, Pennsylvania March 15, 2011. U.S. regulators should press ahead with approving construction licenses for new nuclear power plants despite Japan's nuclear crisis, President Barack Obama's top energy official Energy Secretary Steven Chu said on Tuesday. REUTERS/Jonathan Ernst (UNITED STATES - Tags: ENERGY ENVIRONMENT POLITICS BUSINESS) 

The Three Mile Island nuclear power plant, where the U.S. suffered its most serious nuclear accident in 1979, is pictured through a dormant corn field in Middletown, Pennsylvania March 15, 2011. U.S. regulators should press ahead with approving construction licenses for new nuclear power plants despite Japan's nuclear crisis, President Barack Obama's top energy official Energy Secretary Steven Chu said on Tuesday. REUTERS/Jonathan Ernst (UNITED STATES - Tags: ENERGY ENVIRONMENT POLITICS BUSINESS) 

Cars travel on a road near the Three Mile Island nuclear power plant, where the U.S. suffered its most serious nuclear accident in 1979, in Middletown, Pennsylvania March 15, 2011. U.S. regulators should press ahead with approving construction licenses for new nuclear power plants despite Japan's nuclear crisis, President Barack Obama's top energy official Energy Secretary Steven Chu said on Tuesday. REUTERS/Jonathan Ernst (UNITED STATES - Tags: ENERGY ENVIRONMENT POLITICS BUSINESS) 

The Three Mile Island nuclear power plant, where the U.S. suffered its most serious nuclear accident in 1979, is seen across the Susquehanna River in Middletown, Pennsylvania in this night view taken March 15, 2011. U.S. regulators should press ahead with approving construction licenses for new nuclear power plants despite Japan's nuclear crisis, President Barack Obama's top energy official Energy Secretary Steven Chu said on Tuesday. REUTERS/Jonathan Ernst (UNITED STATES - Tags: ENERGY DISASTER ENVIRONMENT BUSINESS) 

Three Mile Island nuclear power plant, where the U.S. suffered its most serious nuclear accident in 1979, is seen across the Susquehanna River in Middletown, Pennsylvania March 15, 2011. U.S. regulators should press ahead with approving construction licenses for new nuclear power plants despite Japan's nuclear crisis, President Barack Obama's top energy official Energy Secretary Steven Chu said on Tuesday. REUTERS/Jonathan Ernst (UNITED STATES) 

The Three Mile Island nuclear power plant, where the U.S. suffered its most serious nuclear accident in 1979, is seen across the Susquehanna River in Middletown, Pennsylvania March 15, 2011. U.S. regulators should press ahead with approving construction licenses for new nuclear power plants despite Japan's nuclear crisis, President Barack Obama's top energy official Energy Secretary Steven Chu said on Tuesday. REUTERS/Jonathan Ernst (UNITED STATES) 

The Three Mile Island nuclear power plant, where the U.S. suffered its most serious nuclear accident in 1979, is seen across the Susquehanna River in Middletown, Pennsylvania March 15, 2011. U.S. regulators should press ahead with approving construction licenses for new nuclear power plants despite Japan's nuclear crisis, President Barack Obama's top energy official Energy Secretary Steven Chu said on Tuesday. REUTERS/Jonathan Ernst (UNITED STATES) 

Two defunct cooling towers at the Three Mile Island nuclear power plant, where the U.S. suffered its most serious nuclear accident in 1979, are seen across the Susquehanna River in Middletown, Pennsylvania March 15, 2011. U.S. regulators should press ahead with approving construction licenses for new nuclear power plants despite Japan's nuclear crisis, President Barack Obama's top energy official Energy Secretary Steven Chu said on Tuesday. REUTERS/Jonathan Ernst (UNITED STATES - Tags: ENERGY DISASTER BUSINESS ENVIRONMENT) 

A car passes by the Three Mile Island nuclear power plant, where the U.S. suffered its most serious nuclear accident in 1979, in Middletown, Pennsylvania, March 15, 2011. U.S. regulators should press ahead with approving construction licenses for new nuclear power plants despite Japan's nuclear crisis, President Barack Obama's top energy official Energy Secretary Steven Chu said on Tuesday. REUTERS/Jonathan Ernst (UNITED STATES - Tags: ENERGY DISASTER BUSINESS) 

A general view shows houses of residents near the Three Mile Island nuclear power plant, where the U.S. suffered its most serious nuclear accident in 1979, in Middletown, Pennsylvania March 15, 2011. U.S. regulators should press ahead with approving construction licenses for new nuclear power plants despite Japan's nuclear crisis, President Barack Obama's top energy official Energy Secretary Steven Chu said on Tuesday. REUTERS/Jonathan Ernst (UNITED STATES - Tags: ENERGY ENVIRONMENT POLITICS BUSINESS) 

A vehicle is reflected in a mirror on a road near the Three Mile Island nuclear power plant, where the U.S. suffered its most serious nuclear accident in 1979, in Middletown, Pennsylvania March 15, 2011. U.S. regulators should press ahead with approving construction licenses for new nuclear power plants despite Japan's nuclear crisis, President Barack Obama's top energy official Energy Secretary Steven Chu said on Tuesday. REUTERS/Jonathan Ernst (UNITED STATES - Tags: ENERGY ENVIRONMENT POLITICS BUSINESS) 

A general view shows the Three Mile Island nuclear power plant, where the U.S. suffered its most serious nuclear accident in 1979, in Middletown, Pennsylvania March 15, 2011. U.S. regulators should press ahead with approving construction licenses for new nuclear power plants despite Japan's nuclear crisis, President Barack Obama's top energy official Energy Secretary Steven Chu said on Tuesday. REUTERS/Jonathan Ernst (UNITED STATES - Tags: ENERGY ENVIRONMENT POLITICS BUSINESS) 

A general view shows the Three Mile Island nuclear power plant, where the U.S. suffered its most serious nuclear accident in 1979, from the shores of the Susquehanna River in Middletown, Pennsylvania March 15, 2011. U.S. regulators should press ahead with approving construction licenses for new nuclear power plants despite Japan's nuclear crisis, President Barack Obama's top energy official Energy Secretary Steven Chu said on Tuesday. REUTERS/Jonathan Ernst (UNITED STATES - Tags: ENERGY ENVIRONMENT POLITICS BUSINESS) 

A sign sits across the road from defunct cooling towers at the Three Mile Island nuclear power plant, where the U.S. suffered its most serious nuclear accident in 1979, in Middletown, Pennsylvania March 15, 2011. U.S. regulators should press ahead with approving construction licenses for new nuclear power plants despite Japan's nuclear crisis, President Barack Obama's top energy official Energy Secretary Steven Chu said on Tuesday. REUTERS/Jonathan Ernst (UNITED STATES - Tags: ENERGY ENVIRONMENT POLITICS BUSINESS)