MITR Low-Enriched Uranium Conversion Fluid-Structure Interaction Preliminary Design Verification

Abstract

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University of Missouri Research Reactor (MURR) LEU Fuel Fluid-Structure Interaction Analysis

“…The node-averaged channel 24 gap reduction of Case 1 (with comb) at LSSS flow is shown in Table 5. 13. The maximum node-averaged channel reduction at LSSS flow is 0.28 mil, which is 79.6% of the maximum node-averaged channel reduction at nominal flow.…”

“…Since the current FSI analysis of the fuel element will be the first attempt at an analysis performed at the element level, the feasibility of these different ways of coupling the CFD and the CSM solutions is not known up front. However, it is expected that the computational cost of the two-way coupling will be significant, judging from the experience gained in the prior plate-level FSI analyses [6,13]. Thus, a feasibility study of the one-way and two-way coupling is performed at the plate level.…”

“…In the plate-level FSI analysis [6,13], it is often assumed that the long edges of the plate are fixed, which means that the displacements and rotations of the edges are constrained, as shown in Figure 4.1 (a). The fuel plates of MURR are connected to the side plates by swaging; the support provided to the fuel plates by the side plate is not necessarily the same as the fixed constraint.…”

“…It was shown analytically that for a sandwiched plate structure like a fuel core with cladding, if the half thickness of the fuel core is comparable to the thickness of the cladding, the contribution to the plate stiffness from the fuel core is significantly lower than that from the fuel cladding [13], which means the impact of the fuel core Young's modulus is lower. In addition, a prior FSI analysis with a separate solid domains of fuel core and cladding performed for another USHPRR confirmed that variations in Young's modulus of the fuel core do not significantly affect the plate's deflection, and the homogeneous all-aluminum plate assumption is found acceptable [13]. This assumption has also been confirmed by the experimental results of the Generic Test Plate Assembly campaign [17].…”

“…The MURR fuel elements with LEU plates have not been manufactured yet, and their as-built shape cannot be predetermined. In the previous work [13], the effects of the non-ideal plate shapes (including the slanted plate and pre-deformed plates) were analyzed. It was found that among all non-ideal plate shapes analyzed, the slanted-plate case predicted the highest displacement.…”