71203
With a careful reactor design , all the actinides in the fuel can be consumed , leaving only lighter elements with short half-lives .
 half-lives
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
Answer:
 half-lives