Tokyo Electric Power Co. quickly learned that Twitter users find nothing lovely, endearing or irresistibly cute about a damaged reactor building at its crippled Fukushima No. 1 nuclear power plant.

The utility apologized after coming under fire for posting a tweet carrying the hashtag “#kojo-moe” (love-factory) in Japanese along with a picture of the spent fuel pool on the top part of the No. 4 reactor building on Oct. 29.

“Kojo” is a term for factory or industrial plant. “Moe” is a slang word used to describe something that melts one’s heart or is irresistibly pretty or cute.

In recent years, the term “kojo-moe” has been used by factory enthusiasts for industrial structures considered beautiful, such as plants illuminated at night. It has also appeared in a number of photobooks of factories.

Soon after TEPCO’s tweet was posted, the utility’s official account was bombarded with critical replies.

One said, “How many lives do you think the nuclear accident ruined?”

The Great East Japan Earthquake and tsunami in March 2011 caused the meltdowns of three reactors at the Fukushima No. 1 plant. Radioactive substances were released into the atmosphere, and about 80,000 people in 11 municipalities in Fukushima Prefecture were forced to evacuate their homes.

More than 43,000 residents remain displaced.

The No. 4 reactor did not melt down, but its building was seriously damaged in a hydrogen explosion.

TEPCO swiftly deleted the tweet and posted an apology: “We deeply apologize for upsetting you.”

The account has reposted the photo but with no hashtag.

A TEPCO official in charge of public relations said the intention of the original tweet was to “widen public interest in (nuclear) technology and facilities.”

“We were not considerate enough in using a certain term for the hashtag,” the official said. “We offer our deepest apology.”

(This article was written by Daiki Ishizuka and Hiroshi Ishizuka.)