A Prototype Antineutrino Detector for Monitoring Plutonium Content in Nuclear Reactors

A joint Lawrence Livermore National Laboratory/Sandia National Laboratories collaboration has designed a cubic-meter-sized antineutrino detector that can monitor the plutonium content of operating nuclear reactors in real time. The detection method is non-intrusive, robust and automatic, and can be applied to a wide variety of nuclear reactor types, including power, research, and plutonium production reactors. The antineutrino spectrum changes by about ten percent over the fuel cycle of a typical power reactor, and this change correlates directly to changes in the isotopic composition of the core. An antineutrino detector can thereby detect changes in the fissile composition (and power) of the reactor core without the need for direct access to the core or fuel. This paper describes the technique, estimates its precision, and sets forth a design of a prototype detector now being tested at the Unit 2 nuclear plant at the San Onofre Nuclear Generating Station in Southern California. This paper is a companion to a previous article introducing the subject of reactor safeguards with antineutrino detectors1. That article has more details on IAEA safeguards and on the range of applicability of the technique. We also note that a Russian group investigated the general concept of reactor monitoring in experiments done at the Rovno reactor in the early 1990s.2