本题目来源于试卷: Nuclear & Quantum Physics E.4 Nuclear Fission，类别为 IB物理学
[单选题]
In a nuclear reactor, what42933hk/h4; uwvmrp mb tt)jxi ue*e e is the nub+1 ih+ 4 3ee6qbthsj2hco. ; dfkeq-xem h*;ame given to the material used to slow down neutrons in o e1u6+3e oxsh4im e ;hct h2k;hb d*-j.fqqb+erder to cause successful fissions?
A. Control rod
B. Moderator
C. Heat exchanger
D. Chain reaction
参考答案: B
本题详细解析:
Explanation: The moderator slows down neutrons so that they can cause successful fissions. Without a moderator, neutrons that are the product of other fissions have too much energy to interact with new nuclei such that they cause further fissions to occur. Control rods block the neutrons to reduce the number of chain reaction fissions. The heat exchanger transfers thermal energy to the external steam generator circuit. A chain reaction is a process, not a specific material.
| 
