Simulation of 16O (n, p) 16N reaction rate and nitrogen-16 inventory in a high performance light water reactor with one pass core

The rate of activation of the isotope 16O to 16N in a typical HPLWR one pass concept was calculated using MCNP code. A mathematical model was used to track the inventory of the radioisotope 16N in a unit mass of coolant traversing the system. The water leaving the moderator channels has the highest activity in the circuit, but due to interaction with fresh coolant at the lower plenum, the activity is downscaled. The calculated core exit activity is higher than values reported in literature for commercial boiling water reactors.