EFFECT OF β ON EFFECTIVE MULTIPLICATION FACTOR IN 1/f β SPECTRUM RANDOM SYSTEM

We investigated the effect of β on effective multiplication factor(k eff ) in the 1/f β spectrum random system. The random system was generated by the 1/f β noise model. The model is a continuous space model based on the Randomized Weierstrass function and describes the component spatial distribution with a power spectrum of 1/f β , where f and β are the frequency domain variable and the characteristic parameter related to randomness, respectively. In this work, the two-group Monte Carlo calculations were performed to obtain the k eff for a simple cubic geometry that consisted of two materials (fuel burned to 12 GWd/t and concrete). A large number of replicas having different spatial distribution and characterized by the representative β values were generated using the model, and the distribution on k eff was analyzed. We found the dependency on β of standard deviation, skewness, and kurtosis of k eff distribution. This result is expected to help to predict the k eff distribution due to the randomizing model.