Tokyo, March 26 (DPA) Japanese nuclear authorities have identified eight radioactive substances in stagnant water in the basement of part of the Fukushima nuclear power plant, an analysis released Saturday by the Nuclear and Industrial Safety Agency showed.

The highest levels found in the water in block 1 of the plant were of caesium 137, a radioactive isotope that was released into the environment in the Chernobyl disaster. It appeared at levels of 1.8 million becquerel.

Caesium 137, in contrast to radioactive iodine, has a relatively long half life of 30.2 years. It is created during nuclear fission. The water also contained Caesium isotopes 134 and 136 as well as iodine-131.

The plant operator, Tokyo Electric Power Co (TEPCO), has vowed to clear the water as quickly as possible to allow workers to continue efforts to cool the reactors.

Three workers, who were working to restore cooling functions at reactor 3, were exposed radiation levels in water that was 10,000 times the normal level, Tokyo Electric Power Co (TEPCO), the plant's operator, said Friday.

Those levels suggested the vessel might have been damaged and leaked radioactive materials, Nishiyama told a news conference.

Seventeen workers at the plant have been contaminated since the plant was damaged in a March 11 earthquake and resulting tsunami, Kyodo news agency reported Saturday.

That figure includes only those who have been exposed to more than 100 millisieverts of radiation, the maximum exposure for a nuclear plant worker for an entire year.