It is a radiological poison, specifically absorbed by bone marrow, and is used, especially the highly fissionable isotope Pu 239, as a reactor fuel and in nuclear weapons.

尤其是其极具可裂变性的同位素钸239，被用作一种核反应燃料并用在核武器中。

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The CIA said it believes al Qaeda will rationalize the use of chemical, biological or radiological weapons based on the large number of casualties the United States may inflict in its military campaign.

CNN: Terror alert level raised to 'orange'

The annual report, the first since the September 11 attacks, also noted growing U.S. concerns that terrorist groups could use chemical, biological, radiological or nuclear weapons for future attacks.

CNN: Report lauds global effort in terror war

Recent terrorist plots have been of a different scale to the kind of terrorism Britain has faced previously, in that they often involve suicide bombings with the potential threat of chemical, biological, radiological and nuclear weapons.

BBC: Key points: Brown speech