TOKYO – A giant crane removed two fuel rods from the damaged Fukushima nuclear plant Wednesday, starting the long and delicate process to reduce the risk of more radiation escaping into the environment.

All of the 1,535 rods in a spent-fuel pool next to reactor No. 4 at the Fukushima Dai-ichi plant in northeastern Japan must eventually be moved to safer storage — an effort expected to take until the end of next year, according to the government.

The building containing the pool and reactor was destroyed by an explosion following the failure of cooling systems after a massive earthquake and tsunami on March, 11, 2011. The cores of three reactors melted in the world’s second-worst nuclear disaster after Chernobyl.

Fears run deep about the large amounts of radioactive material stored in the pool, which unlike fuel in the cores of the reactors is not protected by thick containment vessels.

Japanese TV showed cranes removing the 13-foot rods. Plant operator Tokyo Electric Power Co. declined comment, citing the need for secrecy in handling nuclear material.

According to a worst-case scenario prepared by the government about Fukushima’s conditions, a loss of coolant in the spent-fuel pool at reactor No. 4 could have caused a massive release of radiation and forced millions of people to flee. About 150,000 residents fled after last year’s nuclear disaster, and a 12-mile zone around the plant remains off limits.

A year and a half after the disaster, the pool’s cooling system has been fixed and reinforcements have been built. But TEPCO recently said the wall of the building is bulging, although the pool has not tilted.