But the children born long after its eruption are still living with the poisoned land and food grown in the two countries.
Alexander's immune system has packed up. He was one of the so-called liquidators sent into the area immediately around Chernobyl to clear up.
One of those areas is the Red Forest. It used to be green like any other, but the pine trees turned ginger-brown after they died following the absorption of high levels of radiation.
Marian says: 'Alexander and many others felled the trees and dug the trenches in which the trees were then buried. Then he buried the machinery used to fell the forest because it too was so highly contaminated.
'All he was given was an apron with a little bit of lead in it and a pair of lead-lined boots.'
He stayed with Marian at her home in Blakemere Crescent, Paulsgrove, Portsmouth, in April, because he has spent the past 26 years working tirelessly for the victims of Chernobyl. He wanted to see for himself what people like Marian and her team do for the children.
Marian first took in youngsters seven years ago. She's not missed a year since. Every year she takes two lads for the whole of June.
'I'd lost a son who was stillborn. My husband was diagnosed with bowel cancer. I was 39 and he was 49. I knew there would be no more children for us.
'Two friends of mine answered an advertisement in The News desperately seeking a host family for two girls. I helped out and I realised this was for me.
'Of course, like everyone else I knew about Chernobyl when it happened, but I had no idea about the effects of radiation which will last for 1,000 years...
