The power coefficient of reactivity (PCR) is a measure of whether a particular reactor's nuclear neutron population will tend to increase or decrease after an increase in the reactor's power.

PCR是一座反应堆的核中子数会在反应堆能量增加后增加或减少的衡量标志。

youdao

"This neutron star was born so hot that nuclear fusion happened on its surface, producing a carbon atmosphere just 10 centimetres thick."

这颗中子星产生时温度如此之高，其表面还在进行核子融合，从而产生了只有10厘米厚的碳大气层。

youdao

The nuclear reaction can be controlled utilizing rods made of neutron-absorbing material, such as boron, essentially shutting down the fission process.

核反应可以通过使用由吸附中子的材料构成的棒条，比如硼，来减慢裂变过程，从而控制其反应。

youdao

This alloy isn't new--it's been used as a neutron absorber in nuclear power plants--but hafnium's use as a chip insulator required a fabrication breakthrough.

FORBES: Magazine Article

The product can be used as a neutron initiator: the component of a nuclear bomb that triggers an explosion.

BBC: Ahmadinejad denies Iran nuclear bomb trigger tests

Ceradyne also sells neutron-absorbing materials that can be used for nuclear fuel storage.

FORBES: Magazine Article