Fukushima officials failed to probe cause of faulty filters

TOKYO (AP) — Technicians at Japan’s wrecked Fukushima nuclear power plant have acknowledged neglecting to investigate the cause of faulty exhaust filters key to preventing radioactive pollution, after being forced to replace them twice.

Representatives of the Tokyo Electric Power Company (TEPCO) made the revelations on Monday during a regular review of the Fukushima Daiichi plant at a meeting with Japanese regulatory authorities. The plant suffered triple meltdowns following a massive earthquake and tsunami in 2011.

“At the core of this problem is TEPCO’s attitude,” said Nuclear Regulation Authority commissioner Nobuhiko Ban at the meeting.

TEPCO has been repeatedly criticised for coverups and delayed disclosures of problems at the plant.

In February, it said two seismometers at one reactor remained broken since last year and failed to collect data during a powerful quake.

Tanks storing water that was treated but is still radioactive after it was used to cool down spent fuel at the Fukushima Daiichi nuclear power plant. PHOTO: AP

Company officials have said that 24 out of 25 filters attached to water treatment equipment had been found damaged last month, after an alarm went off as workers were moving sludge from the unit to a container, temporarily suspending the water treatment.

The operation partially resumed last week after filter replacement.

The filters are designed to prevent particles from escaping into the air from a contaminated water treatment system — called Advanced Liquid Processing System, or ALPS — that removes selected radioactive isotopes in the water to below legally releasable limits.

TEPCO said it had detected similar damages in all of the filters two years ago, but never investigated the causes of the problem or taken preventive steps after replacing the filters.

Another regulatory commissioner Satoru Tanaka, said at the meeting that the utility company should have responded to the problem more quickly to minimise the risk of possible radiation leakage into the environment.

TEPCO officials said dust monitors indicated no radiation leaks to the outside or exposures to plant workers inside the water treatment facility.

Head of TEPCO’s decommissioning unit Akira Ono said he regretted the utility’s failure in addressing the problem earlier. He promised to improve safety management.

Officials are working with the International Atomic Energy Agency to prepare for the safe discharging of the wrecked plant’s cooling water, treated so its radioactivity levels are below the legal limits.

Slated for the spring of 2023, the controversial plan is fiercely opposed by Fukushima’s fishing community, as well as local residents and nearby countries.

Fully decommissioning the nuclear plant is expected to take decades, experts said.