Take a final look inside the 1,500ft-deep underground tunnels that will soon be shut off to humans for 100,000 YEARS

THIS underground tunnel is set to be blocked up for 100,000 years as Finland carries out a world first when it comes to nuclear waste.

Around 4,000 generations of humans will be unable to set foot in the underground tunnel in Eurajoki, on the west coast of Finland.

This is because the country has built the first-ever tomb for spent nuclear fuel.

The site called Onkalo is hailed as a “model for the entire world” when it comes to the sustainable storage of nuclear energy.

Onkalo is 1,480 feet below ground and the waste will be deposited deep in the bedrock.

The nuclear energy tomb near the Olkiluoto Nuclear Power Plant will officially be sealed off to humans in 2025.

Some have been lucky enough to tour the history-making facility before its closure.

BBC journalist Erika Benke who walked around the underground tunnel detailed her tour of the site, that the idea of burying “highly radioactive waste for 100,000 years…makes me nervous.”

After finding herself alone in the dark tunnel, Benke said: “I feel a moment of dread – I’m standing at a spot where starting from 2025, no human should set foot for 100,000 years.”

The group were given safety wear including helmets fitted with tracking devices and were then taken through a security gate and driven to the impossibly dark service tunnel.

For 15 minutes, the group descend into the bedrock to get to the Onkalo service station at 1,430 feet below the ground.

The 2.8 mile-long tunnel took them further down and warned the driver of the 12mph speed limit as well as regular signs showing how deep down they were.

“We’re shown a demonstration deposition tunnel,” Benke explained.

“Its entrance is a lot darker than the service area and the floor is uneven and wet, muddy in places.

“The walls are bare bedrock that glints in the torchlight.”

Posiva Oy, a radioactive waste management company is constructing the disposal system.

The spent nuclear waste will be placed inside a cast-iron and copper cylinder and then wrapped in bentonite clay to enclose the sealed canister.

There is then a tunnel which backfills the gaps with swellable clay, seal structures to close off the tunnels and surrounding area as well as enclosing rock.

Each canister will be picked up by robotic vehicles to be taken to the deposition holes where they will remain forever.

A joint functional test was carried out at the site last year which did not include the use of nuclear fuel.

After this test, the excavation of the first five final disposal tunnels began, Posiva Construction Manager Juha Riihimaki told .

“Actual final disposal activities will begin in one of the tunnels around 2025,” he added.

The £860 million project has reportedly inspired other countries including the UK, US, France and Canada to take on similar solutions to nuclear energy storage, Gareth Law, professor of radiochemistry at the University of Helsinki told the BBC.

Law is not involved in the project in Finland but says that the country is “at least a decade ahead of everybody else.”