Calculation of the fission q-value and spatial energy deposition in the safari-1 nuclear reactor

Jurbandam, Linina
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The calculation of reactor-specific fission Q-values is important for the safety analyses of nuclear reactors. The recoverable energy from the fission Q-value is used to normalise reactor quantities to the total power of the reactor. In this work, a detailed recoverable energy from fission Q-value and spatial heat deposition calculations are presented for the SAFARI-1 nuclear reactor. The fission Q-value is composed of the energy released in a fission event by fission products, neutrons, prompt and delayed gamma rays, beta particles and neutrinos. The energy released by neutrinos is not recoverable; however, part of it is recovered by the gamma and beta radiation from the decay of activated materials. We present two methods to calculate the recoverable energy released per fission. The first one uses the Monte Carlo N-Particle (MCNP5) code. MCNP is a probabilistic transport code that has the capability of calculating most of the heating contributions due to particle interactions with matter. The second method uses the Evaluated Nuclear Data File, ENDF/B-VII and ENDF/B-VII.1 data libraries. The ENDF data libraries contains the information required to calculate all the fission Q-value components, excepttheenergyreleasedfromradiativecapture, sincethisquantity depends on the reactor materials. To calculate this, we use the radiative capture reaction rate in MCNP5 and the binding energy of the product of the activation. We obtained a final Q-value of 200.8±0.6 MeV/fission for SAFARI-1. Using the fission Q-value result, we obtained the spatial heat distribution for SAFARI-1 by ii calculating the heating rates of the Q-value components. It was established that 97% of the heat produced is deposited in the fuel and 3% is deposited in the surrounding region of the reactor.
A dissertation submitted to the Faculty of Science, University of the Witwatersrand, in fulfilment of the requirements for the degree of Master of Science, Johannesburg 2018
Jurbandam, Linina (2018) Calculation of the fission q-value and spatial energy deposition in the SAFARI-1 nuclear reactor, University of the Witwatersrand, Johannesburg,