In 1986, Sergii Mirnyi, the platoon commander of Chernobyl radiation reconnaissance, was honored for his service in the catastrophe there. After the nuclear facility was closed, he continued to work as a physical chemist and produced a book, screenplay and documentary about the disaster.

I was woken up by a phone call from Ukrainian national radio in the middle of the night. The concerned voice informed me that combat was raging at the Zaporizhzhya nuclear power plant, the largest in Europe with six nuclear reactors. I was asked to comment on the potential consequences and scale of this Russian attack.

As a commander of a radiation reconnaissance platoon in the Chernobyl zone, I saw the devastation of the notorious 1986 nuclear disaster up close. In my worst nightmares, I had never imagined that I would be asked to provide comments and advice regarding the ongoing siege of a nuclear facility.

My efforts to contain the aftermath of the Chernobyl disaster took a heavy toll, to say the least both mentally and physically.

After 35 days of working round-the-clock, it took me over six months to recover physically from exhaustion and bodily radiation trauma and over two years to overcome the first acute phase of the psychological trauma. The scars of what I saw at Chernobyl will last a lifetime.

Now, as an international expert in the field of nuclear, I find myself transported back to the darkest days of Ukraines history, as Chernobyl makes headlines again in the days since Vladimir Putins forces shelled and eventually stormed the Zaporizhzhya nuclear facility.

The scale of potential devastation at Zaporizhzhya could dwarf that of Chernobyl. The failure of just one reactor could have a domino effect. To put this bluntly, Europe which is still living in the shadow of the single-reactor Chernobyl accident could see a six-reactor catastrophe at Zaporizhzhya.

Thankfully Putins assault on the site, consisting largely of motorized infantry platoons reinforced by tanks, not heavy artillery fire or missile attack, caused no radiation contamination.

But there is little room for complacency with the scale of Russian recklessness. Moscows military forces and their government have already shown brutal neglect of all civilized norms, human rights and the international laws of conflict. It has already become quite obvious that nothing prevents them from laying siege to the nuclear infrastructure of this country.

Not only did Russian forces shell a nuclear facility, they refused to let Ukrainian firefighters into buildings engulfed in flames. Since the capture of Zaporizhzhya, staff have worked at gunpoint, further intensifying the pressure cooker situation.

Throughout Ukraine, there are 15 working nuclear reactors across four major sites and a further four (now defunct) reactors at Chernobyl. Not content with the occupation of Chernobyl and Zaporizhzhya, the Russians now turn their attention to the South Ukrainian power plant, located roughly a hundred miles from the frontline.

Other nuclear facilities are likely to receive further missile attacks and air raids, with the potential that the ensuing radioactive cloud would engulf not only Ukraine but all of Europe.

What stuns and scares me in equal measure is the lack of response from the international community and relevant authorities in the face of blatant nuclear terrorism.

For decades, the world policed attempts to smuggle even minuscule amounts of radioactive material; grams or pounds of fission materials were hawkishly monitored. Now, thugs lawless, ignorant and armed have control of hundreds of tons of highly radioactive matter but no understanding of the destructive power directly in the palm of their hands.

In response, we have seen silence from the United Nations organization, national governments in the West, and even the International Atomic Energy Agency. Article II of the IAEAs statute declares it shall ensure, so far as it is able, that assistance provided by it or at its request or under its supervision or control is not used in such a way as to further any military purpose. Surely Putins actions contravene this in the strongest possible terms?

The lack of strong condemnation or better yet, real sanctions from the international community and professional nuclear authorities shows they are either blind or impotent. Perhaps both.

Putin and the Russian state have gone beyond destroying principles and are now destroying power plants. If we do not act now, we will all need to revive the fallout shelters of my Chernobyl nightmares.