PrepTest 151, Section 4, Question 24
After a nuclear power plant accident, researchers found(82 more words not shown)
Of the following statements, which(9 more words not shown)
- ARadioactive material ejected(15 more words not shown)
- BThe radioactive material(18 more words not shown)
- CThe nuclear power(7 more words not shown)
- DThe researchers found(23 more words not shown)
- ESpent fuel rods(8 more words not shown)
Reading the argument
How did those three isotopes get out without the heavy ones?
We are given two possible origins: spent fuel rods or the core. The rods don't contain significant amounts of tellurium, which makes them a poor explanation for the full mixture the researchers found. But a direct release from the core should include heavy isotopes, and none were found. At this point, neither simple account fits comfortably.
What we’re looking for
Then the steam appears. It may have contacted the core, and it can dissolve the iodine, tellurium, and cesium found downwind. That gives us another way for material from the core to reach the atmosphere: carried out in steam, rather than ejected directly. For the most-supported statement, that is the explanation I'd expect the answer to draw together.
Working the answers
- A
The core contains tellurium isotopes. Nothing says a direct release would exclude them. The stated requirement for a direct release is that it would include heavy isotopes, not that it would lack tellurium. A mixes up which material is associated with which route.
- BCorrect
Steam could contact the core, dissolve the three detected isotopes, and carry them into the atmosphere. That connects the final facts with the otherwise puzzling findings. It gives us the core as an origin without requiring the direct ejection that would include heavy isotopes.
This is the best-supported explanation, not a claim that each detail was directly observed. The passage says the steam may have contacted the core, and the limitation on spent fuel rods concerns significant quantities of tellurium, not its absolute absence. Taken together, the clues favor steam as the carrier of the detected material.
- C
The fuel rods might have been damaged without explaining this particular mixture in the atmosphere. Information about the likely source of the detected material doesn't establish the condition of every part of the plant. C adds a conclusion about damage that the passage doesn't support.
- D
This includes material ejected directly from the core. But the passage tells us that such a release would include heavy isotopes, and the researchers found none. Combining that proposed release with material from the fuel rods doesn't remove the conflict.
- E
The passage limits the amount of tellurium in spent fuel rods. It doesn't give a corresponding rule about their heavy-isotope content. We can't replace one type of isotope with another merely because both appear elsewhere in the explanation.
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