Story highlights CNN was granted exclusive access to the heart of Fukushima's nuclear plant

Workers are using a crane to remove 1500 fuel rods submerged in water in Reactor 4

Three other reactors that suffered meltdowns pose an even bigger problem

The area around the plant, once a bustling community, is now a ghost town

It was 11 March 2011, and I remember standing in the newsroom that Friday afternoon glued to the television watching the horrific images coming out of Japan.

The aerial pictures of the tsunami as it engulfed the coastline swallowing up everything in its path filled me with dread. That image will be etched in my memory forever. Little did I know that 24 hours later I would be on the ground in Japan covering the nation's biggest disaster.

While we were focused on the mass devastation and the countless victims from the earthquake and tsunami, there was another catastrophe unfolding -- a nuclear crisis. The disaster had caused meltdowns at the Fukushima Daiichi Nuclear Power Plant and it was threatening Armageddon. No reporter was allowed anywhere near Fukushima -- it was too unsafe. It would be more than two and a half years before I'd finally set foot in Fukushima.

We've been invited by the plant operator TEPCO to inspect the progress being made -- it's the first time any media crew has been allowed that close to the decommissioning work underway inside Fukushima.

As we drive towards the plant I notice empty houses, overgrown gardens and fields and realize these homes haven't been touched since their residents evacuated during the crisis in 2011.

This once bustling community of 60,000 people is now a ghost town; the only sign of life, a checkpoint in the middle of the road.

We've entered the "exclusion zone."

The only people passing through are the 3,500 workers who travel each day to Fukushima to undertake dangerous clean-up work, exposing themselves to high levels of radiation.

Contaminated water storage tanks at Fukushima.

We arrive at the plant under a TEPCO escort and are taken to a building to measure our radiation levels. We'll do this again at the end of the tour to see how much radiation we've each absorbed. Then it's time get kitted up in protective clothing.

The ensemble includes a Tyvek suit, two pairs of socks, rubber boots, three pairs of gloves, a hat and mask -- no skin is left exposed. We also carry a dosimeter to measure the external radiation levels.

With the appropriate attire and equipment, we are taken on a tour of the plant situated at the base of mountains, right on the coast. As we look out at the calm sea, it's hard to imagine how the ocean could have been so deadly and destructive that day back in 2011.

The single success story for TEPCO is Reactor 4 -- it suffered a hydrogen explosion during the crisis, but received the least amount of damage of all four reactors. The reason? It was under maintenance and wasn't operational the day the earthquake and tsunami hit.

Inside the giant building that has been rebuilt is a large cooling pool. Above the pool is an enormous crane that has begun to successfully move the 1500 fuel rods covered in the deep green water.

TEPCO has described this as "a milestone." They're being transported to a storage pool next door where they will stay for the next 20 years. It's a delicate and slow process that's expected to be completed by the end of 2014 -- decommissioning reactor 4.

But these milestones are few and far between.

TEPCO's main challenge is working out how to shut down Reactors 1, 2 and 3 that all suffered meltdowns and remain dangerously radioactive. The other big problem is contaminated water.

TEPCO is collecting 400 tonnes of it each day, storing it in newly built tanks on the site. There is a real fear this radioactive water is seeping into the ground and into the sea.

As I look around the plant from a high vantage point on top of one of the buildings I see a broken Fukushima desperately trying to heal itself and a country that came so close to a nuclear catastrophe.

Japan is indebted to the thousands of workers, who risk their life each day, continuing their mission to finish the job and close this painful and frightening chapter in Japan's history.