Void 5 : Nuclear Energy and Nuclear Disasters. In a nuclear power reactor, an area of lower density in a moderating system (such as steam bubbles in water) that allows more neutron leakage than does the more dense material around it
U.S. Nuclear Regulatory Commission (NRC), Full-Text Glossary, Washington, DC, USA 2014. http://www.nrc.gov/reading-rm/basic-ref/glossary/f ull-text.html, (Dzstr/ Disabl Mass Care - Amer) {826}