MOSCOW, April 17 (RIA Novosti) - A leading Russian nuclear research center has built a simulator to train personnel to deal with accidents like the 1986 Chernobyl disaster, a researcher said Monday.

Viktor Sidorenko, a member of the Russian Academy of Sciences, told a conference ahead of the 20th anniversary of the world's worst nuclear-power disaster that the Kurchatov Institute's simulator would help operators run RBMK-type reactors and prepare for possible emergencies.

Sidorenko said the situation at the Chernobyl NPP on April 26, 1986, was extremely complicated, and that the simulator reflected this.

"Although operators knew what would happen, they could only avert simulated accidents once in three attempts," Sidorenko said, adding that RBMK reactors had been modernized and their safety enhanced follow the catastrophe.

The explosion, which happened during testing on the night of April 25, 1986, spewed radioactive clouds not only across Western parts of the Soviet Union, but also some countries in northern and Western Europe.

About 135,000 people were evacuated from within a 30-kilometer (18-mile) zone, which has left the surrounding area looking like a ghost town to this day. Many people, however, stayed or have returned to live there, although radiation is still leaking from the site.

The catastrophe caused enormous economic damage to the former Soviet Union, and claimed the lives of many local people and unprofessional clean-up workers.

Experts blame reactor degradation, a poor security system, poorly qualified personnel and negligence for the accident.

RMBK reactors are in use at three nuclear-power plants in Russia.