By Olga Vyshnevska (Reuters) – Halyna and Valeriy, a Ukrainian couple in their 60s, were evacuated from their home near the Chernobyl plant where they worked as engineers when a reactor exploded in 1986, triggering the world’s worst nuclear accident. Now they are trapped, as Russian troops shell towns and bridges around their home near Chernihiv in northern Ukraine and concerns rise in the West over the security of nuclear sites seized by advancing forces. “God forbid if we had to be evacuated again,” Halyna told Reuters during a Zoom interview from their home. The couple declined to give thei…