Pit start Plutonium production is on the rise.But why?

On New York's Staten Island the US army corps of engineers began last month to remove the radioactive remnants of Robert Oppenheimer's Manhattan Project that produced the atomic bombs that ended the second world war.

-  Edward Helmore

Meanwhile, 3,200km away, at the Los Alamos national laboratory north of Santa Fe in New Mexico, on the same site that developed and assembled the bombs dropped on Hiroshima and Nagasaki, work is being ramped up to produce plutonium "pits" - spherical shells about the size of bowling balls that are a vital component of warheads in the US nuclear arsenal.

Both in their own way tell the story of the nuclear age, but one is historic housekeeping-in 1939, 1,200 tons of high-grade uranium ore was purchased and transferred from the Belgian Congo to Staten Island, where there are still traces of radioactive contamination - the other is far more controversial and current.

Increasing geopolitical tensions with Russia and a militarily expansionist China are behind a $1.5tn US effort to modernise the US nuclear arsenal, including tens of billions of dollars to replace aging, silo-launched Minuteman intercontinental ballistic missiles stationed in Wyoming, Montana and North Dakota with a successor, the Sentinel.