Critical mass
Critical mass of a bare sphere

Critical mass

Section Title: Critical mass of a bare sphere
Table Section Text: None

Nuclide	Half life (y)	Critical mass (kg)	Diameter (cm)	Ref

uranium-233	159,200	15	11

uranium-235	703,800,000	52	17

neptunium-236	154,000	7	8.7

neptunium-237	2,144,000	60	18

plutonium-238	87.7	9.04–10.07	9.5–9.9

plutonium-239	24,110	10	9.9

plutonium-240	6561	40	15

plutonium-241	14.3	12	10.5

plutonium-242	375,000	75–100	19–21

americium-241	432.2	55–77	20–23

americium-242m	141	9–14	11–13

americium-243	7370	180–280	30–35

curium-243	29.1	7.34–10	10–11

curium-244	18.1	13.5–30	12.4–16

curium-245	8500	9.41–12.3	11–12

curium-246	4760	39–70.1	18–21

curium-247	15,600,000	6.94–7.06	9.9

berkelium-247	1380	75.7	11.8-12.2

berkelium-249	330 days	192	16.1-16.6

californium-249	351	6	9

californium-251	900	5.46	8.5

californium-252	2.6	2.73	6.9

einsteinium-254	275.7 days	9.89	7.1

Sentence(s)

The critical mass of uranium-235 is 52 kg.
A spherical critical mass of uranium-235 has a mass of 52 kg.
The Critical mass of uranium-235 has a mass of 52 kg.

final_sentence: The critical mass of uranium-235 is 52 kg.
final_sentence: A spherical critical mass of uranium-235 has a mass of 52 kg.
final_sentence: The Critical mass of uranium-235 has a mass of 52 kg.