Self-study
After a nuclear power plant accident, researchers found radioactive isotopes of iodine, tellurium, and cesium—but no heavy isotopes—in the atmosphere downwind. ████ ████████ ████ ██████ ████ █████ ████ ████ ██ ████ ███ ███████ █████ █████ ████ ████ █████ ███████ ███████████ ██████████ ██ █████████ █████████ ███████████ ████████ ███████ ████ ███ ██████████ ████████ ████ ███ ████ █████ ███████ █████ █████████ █████ ███ █████████ ██████ █████ ███ ████ ████ ██ ███████ ████ ███ █████ ███ ████████ ████ ███ ██████ ███ ████ ████████ ███████ ██████████ ███ ██████ █████████ █████ ███ ██████ █████████ ██ ██████
Summary
After a nuclear power plant accident, radioactive isotopes of iodine, tellurium, and cesium were found in the atmosphere downwind. No heavy isotopes were found.
The material either came from spent fuel rods or the plant’s core. Spent fuel rods never contain significant quantities of tellurium. Material ejected directly from the core would include heavy isotopes.
However, steam which may have been in contact with the core was released from the plant. The core contains iodine, tellurium, and cesium, which are easily dissolved by steam.
Strongly Supported Conclusions
The radioactive material found in the atmosphere did not come from spent fuel rods and was not ejected directly from the core.
The radioactive material found in the atmosphere was carried from the core by the steam released from the plant.
24.
Of the following statements, which ███ ██ ████ ████████ █████████ ██ ███ ███████████ ██████
a
Radioactive material ejected ████ ███ ███████████ ████████ ████ █ ███████ █████ ███████ ████ █████ ███ ███████ █████████ █████████
This answer is unsupported. We know for a fact that the core contains tellurium, and there's no other reason to think that material ejected directly from the core would not contain tellurium.
b
The radioactive material ████████ ██ ███ ███████████ ███ ███████ ████ ███ ██████████ ██ ███ █████ ████ ███ ████████ ████ ███ ██████
This answer is strongly supported. All three isotopes found are easily dissolved by steam, all three are found in the plant’s core, and steam may have been in contact with the core. So, the material was likely carried into the atmosphere by steam. This also explains why heavy isotopes, which would have been ejected directly from the core, were not found.
c
The nuclear power ███████ █████ ████ ████ ████ ███ ████████
This answer is unsupported. We don’t know from the stimulus whether the spent fuel rods were damaged or not. We can only infer that the material found did not come from spent fuel rods.
d
The researchers found ████ ███████████ ████████ ████ █████ ████ ████ ██ ████ ██ ████ ████████ ████ ███ ███████ ████ ███ ██████████ ████████ ████ ███ ███████ █████
This answer is anti-supported. We know from the stimulus that material ejected directly from the core would include heavy isotopes, yet the researchers did not find any heavy isotopes.
e
Spent fuel rods ██ ███ ███████ █████ ████████ ██ ███████████ ███████████
This answer is unsupported. We don’t know from the stimulus whether spent fuel rods do not contain heavy isotopes. We only know that spent fuel rods do not contain significant amounts of tellurium.