Utilisation of 16N in Nuclear Power Plants

This study investigates the use of 16N in nuclear power plants. Production of 16N in a nuclear power plant derives from the 16O(n,p)16N reaction. The produced nuclide is radioactive with a half-life of 7.13 s, emitting mainly photons of 6.1 MeV. Since oxygen is mainly found in the water in the reactor tank, the gamma radiation can be used to obtain information about the water in the reactor. This report is divided into four parts: Determination of the water level in the reactor tank. Two methods have been developed to measure water level. Firstly, the water level in the reactor tank can be determined by using a vertical line of detectors outside the reactor tank. Secondly, the water level in the steam generator can be measured using three detectors placed at different positions around the steam generator. Experimental feasibility test for 16N measurements: An experimental feasibility study for measuring water level has also been performed at the Department of Reactor Physics. It has been found that water level could be determined by using a simple detector set-up. Determination of coolant flow rate: The primary coolant flow rate can be determined by two different methods, the cross correlation method and the absolute method. Both methods use two detectors at different positions along the pipe. The cross-correlation method uses the fact that the 16N is not homogeneously distributed in the pipe. The absolute method uses the fact that the 16N will decay between the detectors. A comparison between the methods is made and it seems that the cross-correlation method gives more accurate results. Determination of thermal power by coolant activity monitoring: Here the thermal power of the reactor is determined by using a single detector measuring the 16N in the primary flow. The 16N activity in the pipe will depend on the thermal power in the reactor and thus the thermal power can be determined from a single measurement. A mathematical theory was developed in 1958 and experimental tests of the method have been made by Russian scientists between 1981 and 1994