In Photos: Inside the Fukushima No. 1 nuclear power plant

The No. 1 reactor at Tokyo Electric Power Co. (TEPCO)'s Fukushima No. 1 Nuclear Power Plant is seen here with the building cover removed, revealing its basic frame, in the town of Okuma, Fukushima Prefecture, on Feb. 24, 2017. (Mainichi)

Workers dismantle a flange-style tank designed to deal with contaminated water at TEPCO's Fukushima No. 1 Nuclear Power Plant in the town of Okuma, Fukushima Prefecture, on Feb. 24, 2017. (Mainichi)

A worker checks a frozen impervious wall with a hammer near the No. 4 reactor of TEPCO's Fukushima No. 1 Nuclear Power Plant in the town of Okuma, Fukushima Prefecture, on Feb. 24, 2017. (Mainichi)

A radiation measuring device shows a reading of 137.6 microsieverts near the No. 2 reactor of TEPCO's Fukushima No. 1 Nuclear Power Plant in the town of Okuma, Fukushima Prefecture on Feb. 24, 2017. (Mainichi)

A control rod drive mechanism that runs under the pressure vessel at the No. 5 reactor of TEPCO's Fukushima No. 1 Nuclear Power Plant is seen here in the town of Futaba, Fukushima Prefecture, on Feb. 24, 2017. (Mainichi)

A work platform directly beneath the pressure vessel inside the No. 5 reactor at TEPCO's Fukushima No. 1 Nuclear Power Plant is seen here in the town of Futaba in Fukushima Prefecture on Feb. 24, 2017. (Mainichi)

Piles of protective masks are seen here inside TEPCO's Fukushima No. 1 Nuclear Power Plant in the town of Okuma, Fukushima Prefecture, on Feb. 24, 2017. (Mainichi)

Workers walk in regular work clothes at TEPCO's Fukushima No. 1 Nuclear Power Plant in the town of Okuma, Fukushima Prefecture, on Feb. 24, 2017. (Mainichi)

A canteen inside TEPCO's Fukushima No. 1 Nuclear Power Plant is seen here in the town of Okuma, Fukushima Prefecture, on Feb. 24, 2017. (Mainichi)

A Lawson convenience store which operates inside TEPCO's Fukushima No. 1 Nuclear Power Plant is seen here in the town of Okuma, Fukushima Prefecture, on Feb. 24, 2017. (Mainichi)