You're reading: Tainted water swells at Japan nuke plant

The operator of Japan's crippled Fukushima Dai-ichi nuclear plant is preparing to open a door of a reactor building to allow workers to install a cooling system and equipment to prevent an explosion.

Tokyo Electric Power Co. says radiation that will be released by ventilating the Unit 2 reactor will be too small to threaten human health.

Meanwhile, more radioactive water is pooling at the tsunami-hit nuclear plant as workers scramble to restart a key cleanup system. It was shut down Saturday, hours after beginning full operations, because a component reached its radioactivity limit faster than expected.

Contaminated water could overflow within two weeks if action is not taken. At one location, water is 14 centimeters (5.6 inches) from spilling.