Back in the US, three nuclear power reactors remained shut down and a fourth on alert after Hurricane Sandy wreaked havoc with transmission networks and high waters threatened cooling systems.

Amid worries that waters could overwhelm the reactors as happened in Japan's Fukushima nuclear emergency last year, authorities yesterday said there were no risks to the public.

New Jersey's main power company PSEG Nuclear shut down its Salem 1 unit at Hancocks Bridge on the Delaware river, saying most of its water circulation pumps had been rendered unusable "due to weather impacts".