• In the control room of reactor 4. (Building Chernobyl's Mega Tomb)Source: Building Chernobyl's Mega Tomb
It took only hours for Chernobyl to become the biggest nuclear accident in history. The clean-up has taken decades – and it’s not finished yet.
24 Jun 2019 - 5:32 PM  UPDATED 27 Jun 2019 - 10:45 AM

The 1986 explosion and following radiation leak at the nuclear power plant at Chernobyl was arguably the worst nuclear accident in history, thanks in large part to the bungled response by the Soviet-era bureaucracy. And with a nuclear accident, unlike a flood or cyclone, the disaster isn’t over once the immediate destruction subsides.

The recent HBO series Chernobyl shows how the disaster came to pass, but the disaster hasn’t passed; thirty years after it happened, people are still working to contain the damage. And as the documentary Building Chernobyl’s Mega Tomb makes clear, the word to focus on is “contain”.

The giant dome built to contain the radioactive remains is definitely an impressive achievement (the scenes where it’s manoeuvred into position are nail-biting stuff), but those remains will outlast the dome unless further action is taken. Removing the radioactive ruins and making the area safe is going to take decades more – if it’s ever done at all.

On April 26th, 1986, technicians at the Chernobyl nuclear reactor in the Ukraine were carrying out tests. If you’ve seen Chernobyl, you know things did not go according to plan. There was a steam explosion and fire; the official reaction was to deny, bluster and cover up rather than take action or listen to experts, and the result was a full-blown disaster.

The explosion and radiation directly killed 30 people; eventually half a million people were evacuated, never to return. Worse, radioactive dust was scattered across the surrounding countryside. In their version of decontamination, the Soviet authorities first sealed off a 30-kilometre zone around the reactor, then drafted 350,000 people (who became known as “liquidators”) to clean up the radioactive fallout.

It was extremely hazardous work, performed with crude equipment; the World Health Organisation estimates that at least 2000 liquidators have since died from their exposure to Chernobyl’s radiation, with more to come.

At Chernobyl itself, up to 200 tonnes of highly radioactive material, including fuel rods, was left basically out in the open. It had to be sealed away, so over the next six months workers braved extreme radiation at the site to encase the reactor inside a huge tomb made from steel and concrete that they called the Sarcophagus.

But even at the time it was flawed. The extreme radiation made it impossible to properly weld the Sarcophagus’ joints and it was built directly over the remains of the reactor without any real foundation. It was a rush job that everyone knew couldn’t last – and now, 30 years later, it’s crumbling. With a heavy snowfall already caving in a section of the roof, its time was up.

As Building Chernobyl’s Mega Tomb explains, the trouble with replacing the Sarcophagus is, unsurprisingly, radiation. The whole site is still too radioactive to do any major construction work there, and it will be so for the foreseeable future.

The documentary follows a team of international engineers as they race time, and the challenges of the elements, to make the site safe long-term.

Their plan involves building two halves of a 30-story high steel arch at a safe distance, mounting them on concrete runways built alongside the site, then moving them into position to connect up over the ruined reactor. Dragging the largest man-made structure ever moved on land wouldn’t be easy; the weather makes construction difficult (winter can bring things to a halt for months) and the radiation brings its own challenges.

And after all that, the dome will only last a century – unlike the Chernobyl radiation, which is estimated to endure for at least 20,000 years. The dome may not even last that long: no metal structure can survive that long exposed to the elements (think of how painting the Sydney Harbour Bridge is an ongoing job), but the radiation means they can’t send a team in to touch up the paint job. Instead a highly complex method of sealing the roof has to be used.

With a use-by date of 2119, the dome won’t be a permanent solution. So the idea is that once the dome is completed, robotic cranes built inside the arch will dismantle the former Sarcophagus so it and the radioactive remains of the reactor can be removed to a new containment site.

Disturbingly, though, it seems that this part of the plan has not been worked out. Chernobyl will be a blight on the landscape – and a possible threat – for generations to come.

Watch Building Chernobyl’s Mega Tomb on SBS On Demand.

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