Tokyo Electric Power Co. must speed up plans to cover reactors at its crippled nuclear plant and drain tainted water to prevent more radiation leaks as Japan’s cyclone season approaches, engineering professors said.

In 2004, eight cyclones passed over or skirted Japan’s Tohoku region, where the Fukushima Dai-Ichi power station is spewing radiation after an earthquake and tsunami on March 11. The earliest was in May that year, according to Japan’s weather agency data. The eyes of two storms passed within 300 kilometers of Tohoku last year, the data show.

Last month’s disaster wrecked the plant’s cooling systems, triggering the worst nuclear crisis since Chernobyl in 1986. The roofs of three buildings were damaged in blasts as water inside reactor cores and spent-fuel ponds boiled away. The utility known as Tepco plans to install temporary covers within nine months, and concrete ceilings over the “medium term.”

“The buildings should be covered at least before the typhoon season is in full swing by late July,” said Tadashi Narabayashi, a professor of nuclear engineering at Hokkaido University. “Tepco’s actions are like a game of Whack-a-Mole because the company keeps reacting after the event.”

Tepco said on April 17 it will start erecting temporary covers for the damaged building within three months provided radiation falls to levels at which workers can begin construction. The work is expected to be completed in the next three to six months, according to the action plan, which lists the “possibility of the cover being damaged by a big typhoon” as a risk.

Typhoon at nuclear reactor site : ‘Quite Possible’

The Japan Meteorological Agency doesn’t make forecasts for how many tropical storms or typhoons are expected to approach Japan, Hajime Takayama, a weather forecaster at the bureau, said by telephone.

“It’s quite possible for a typhoon to hit the Tohoku region while maintaining its strength, although most tend to make landfall in the south,” Takayama said.

The temporary covers are the only measures planned at the moment to protect against typhoons, Takeo Iwamoto, a Tepco spokesman, said by phone. The company may install them faster than the plan announced on April 17, he said.

The Fukushima plant, 220 kilometers (137 miles) north of Tokyo, has six reactors, three of which were shut for maintenance when the earthquake and tsunami struck, leaving almost 28,000 people dead or missing.

Reactor buildings weakened by explosions may suffer further damage if a typhoon hits them, while strong winds and rain could scatter radioactive materials and water, said Hironobu Unesaki, a nuclear engineering professor at Kyoto University.

Pouring Water

Tepco has been pouring millions of liters of water to cool the reactors and spent fuel after the accident, which has flooded basements and trenches near the buildings that house them. Some highly contaminated water leaked into the sea and the utility has dumped less toxic fluids into the ocean.

“Heavy rain may cause radioactive materials to soak further into the ground and enter the water table," Unesaki said. ‘‘This could affect drinking water.’’

Tepco started pumping contaminated water out of trenches near one of the reactor buildings that were damaged by the blasts, Junichi Matsumoto, a Tepco general manager, said April 19. The company aims to move 10 million liters (2.6 million gallons) of the contaminated water to a storage unit and expects to complete the transfer in 26 days.

‘‘It will be too late to start preparations once a typhoon approaches,’’ said Narabayashi of Hokkaido University. ‘‘It’s a basic risk principle that you proactively take measures against circumstances that are predictable.’’