Japan has commenced the construction of an underground ice wall at the defunct Fukushima nuclear plant as part of its efforts to stymie the spread of radioactive contamination.

An official from Tokyo Electric Power (TEPCO) has confirmed the commencement of work on a 1.5-kilometre underground ice wall at Fukushima just a week after obtaining the green light for its construction from Japan’s Nuclear Regulation Authority.

“We started construction of the frozen earth wall this afternoon,” a TEPCO representative announced at an official press conference in Tokyo on Monday.

The subterranean ice wall is intended to stymie the spread of radioactive contamination caused by the flow of groundwater from adjacent mountain slopes below the damaged nuclear plant.

Since the tsunami disaster and subsequent triple reactor meltdown at Fukushima in 2011, polluted water runoff has been one of chief means by which radioactive contamination has entered the surrounding environment.

Water flowing underground from nearby mountain slopes passes beneath the defunct reactors, where it mingles with contaminated water before continuing its passage to the sea.

The construction of the ice wall involves burying a set of 1,550 refrigeration pipes deep below the earth in order to freeze a 1.5-kilometre stretch of soil which can block the passage of subterranean groundwater.

The method was first floated last year as a means for dealing with worsening water contamination from the nuclear plant.

While similar measures have been adopted in the past for the construction of tunnels in close proximity to waterways, this marks the first occasion that an underground ice wall is being built on such a large scale and for such a lengthy time period.

The project is being funded by the Japanese government as it scrambles to contain the continuing ill-effects of the worst nuclear disaster in a generation.

Construction of the ice wall comes just a month after TEPCO commenced work on a bypass system which seeks to diminish the amount of contaminated groundwater by diverting its passage through a more direct path toward the sea.

The full decommissioning of the Fukushima plant is expected to take several decades, with experts warning that a number of nearby communities may have to relocate as a result of  rising levels of radiation.