Gap Release : Release, especially in a reactor core, of fission products from the fuel pin gap, which occurs immediately after failure of the fuel cladding and is the first radiological indication of fuel damage or fuel failure
International Atomic Energy Agency IAEA, Department of Nuclear Safety and Security, IAEA Safety Glossary (Terminology Used In Nuclear Safety and Radiation Protection), IAEA, Vienna. Austria 2007. ISBN 92-0-100707-8, http://www-pub.iaea.org/MTCD/publications/PDF/Pub1 290_web.pdf, (Nucl Sfty and Rad Prot - Brit) {459}