GitHub Repo
https://github.com/arkidbera/Fission-product-release
Fission product release has been a matter of study since many years. Its importance lies in the fact that the release of radionuclides affect radiological impact due to a postulated accident scenario. The fission product gases released mainly consist of Xenon and Krypton, due to their low boiling point temperature and insolubility in the fuel matrix. These gases are released from fuel pellets due to the rupture of cladding to the coolant in the primary heat transport system. No standard method for calculation of fission product release gases has yet been found, due to the involvement of numerous factors, leading to variance in results. In our project, we have attempted to do the same, by creating a fission release model using various relations and carrying out certain computations on MATLAB, which includes vectorized implementations, iterative computations and plotting various curves to visualize the results obtained. The aim of our model is to find the fractional release of fission product gases with respect to fuel temperature, which depends on linear heat rating (i.e. power extracted per unit length of fuel pin) and burnup of the fuel. Our model also finds certain curves representing the behaviour of fractional release with respect to burnup, by varying grain radius and Diffusion Coefficient. The model has further been used as a tool for certain time varying analyses, where we have simulated a condition where the average temperature of the fuel pellets is changing with time, and thus, found the value of release fraction for those time instants. Finally, certain statistical analyses have been carried out, which include input parameter uncertainty, model parameter uncertainty and time-varying error analysis. We have used algorithms like Box-Muller transform in our study. Also, tolerance bands have been derived using confidence interval values for time-varying error analysis.
