Tightly coupled neutronics and thermal-hydraulics using open-source software

coupling neutronics;tight coupling;thermal-hydraulics

Wu, Hsingtzu

关键词: coupling neutronics;    tight coupling;    thermal-hydraulics;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/46658/Hsingtzu_Wu.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Coupling the neutronic and thermal-hydraulic analyses of a nuclear reactor core is important because it helps identify the most relevant safety issues. Currently all coupledcomputations solve the same set of governing equations using different coupling methods, which can be sorted into two categories: loose coupling and tight coupling. Thisdissertation proposes and verifies a third coupled approach called “the Integrated TightCoupling (ITC) method”. The mathematical equations in the nuclear fuel are rearrangedto be integrated via a novel concept of group temperature. In addition, the data from theneutron cross section library can be used directly.The ITC method is implemented using two open-source codes: the DRAGON code andOpenFOAM. Additionally, a coupled computation using these two codes is new and hasnot been done in the past. The ITC method is verified using two 1.5-D (1-D neutronicsand 2-D thermal-hydraulics) examples: a symmetric unit cell and an asymmetric unit cell.The mesh of the tightly integrated computation is 25 % and 12 % coarser than the looselycoupled one for the symmetric case and the asymmetric case, respectively. Starting fromthe similar initial guess, the number of iterations for the ITC method is 24 % and 14 %fewer than those for the loosely coupled computation to reach the same accuracy for thesymmetric case and the asymmetric case, respectively. In addition, the ITC method istested with different initial guesses. For all cases tested, the scheme converged to thesame solution. With further improvement and additional testing, the scheme developedand tested here has the potential to be incorporated with other neutronics and thermal-hydraulics codes.