在棒的四周围着中子减速剂。
The rod is surrounded with a neutron-slower .
可以把铀做成棒状放在原子反应堆内，在铀棒的四周，围一层中子减速剂即节速剂。
The uranium may be put into the reactor in the shape of rods , and the rods surrounded with a neutron-slower , or moderator .
中子减速剂