单语范例（未经PONS编辑处理）
The contaminants might be seeped into the soil, contained within a sludge, or present within spent nuclear reactor cores.
en.wikipedia.org Propulsion was from a rocket engine (either chemical or nuclear) and the craft would also have contained an onboard nuclear reactor for electrical power generation.
en.wikipedia.org The spent fuel is primarily composed of uranium, most of which has not been consumed or transmuted in the nuclear reactor.
en.wikipedia.org After zirconium was chosen as material for nuclear reactor programs in the 1940s, a separation method had to be developed.
en.wikipedia.org During the first month of flight, the probe's main structures would be deployed, the nuclear reactor activated, and the thrusters tested.
en.wikipedia.org