Modeling the measurement of VVER-1000 reactor power by neutron and gamma radiation with MCNP code

The present study deals with a new method for measuring the power of a reactor. This method uses gamma and neutron radiation resulted from the entire reactor structure, without changing its structure (online). In terms of functionality, this method can measure the reactor power in real-time and report it instantly. In order to obtain the relationship between reactor power and gamma and neutron leakage radiation by simulation, the values of the F5 tally are calculated at different distances from the reactor wall, using the MCNP5 code (Monte Carlo N-Particles). Then, we plot the diagram to observe the variation trend. However, an increase in the distance from the reactor reduces both the amount of radiation and the energy of the radiation particles until the neutron leakage radiation reaches zero within five meters of the body, due to its good insulation. However, this number is only about four meters for gamma irradiation. The reactor power can be calculated by measuring the flux at the given point and any time by determining the point for a range of leakage radiation reduction to background and the linear relationship between power and leakage flux.