(Adds background on when Shell could get full approval)
WASHINGTON, March 31 (Reuters) - The U.S. InteriorDepartment on Tuesday upheld a 2008 lease sale in the ChukchiSea off Alaska, moving Royal Dutch Shell a step closerto returning to oil and gas exploration in the Arctic since itsuffered mishaps in the region in 2012.
"The Arctic is an important component of theAdministration's national energy strategy, and we remaincommitted to taking a thoughtful and balanced approach to oiland gas leasing and exploration offshore Alaska," said InteriorSecretary Sally Jewell.
Interior's Bureau of Ocean Energy Management will nextconsider Shell's exploration plan and perform an environmentalassessment on it, which could take at least 30 days.
Shell lost control of a massive oil rig called the Kulluk in2012, which eventually ran aground. But in anticipation ofreturning to the region for the first time since then, Shell hasalready moved rigs to Alaska.
Many environmentalists oppose energy exploration in theoffshore Arctic, saying that once production comes on line anyoil spill would be extremely difficult to clean up in a remotearea with rough and frigid seas.
Oil industry interests say the Arctic will be important tothe country's energy security in coming decades when output fromshale formations wanes.
(Reporting by Timothy Gardner; Editing by Eric Beech)