Applicability of Swaging as an Alternative for the Fabrication of Accident-Tolerant Fuel Cladding

Abstract

We suggest an alternative to conventional coating methods for accident-tolerant fuel (ATF) cladding. A Zircaloy-4 tube was inserted into metal tubes of different materials and the inserted tubes were subjected to physical force at room temperature. The manufactured tube exhibited a pseudo-single tube (PST) structure and had higher thermal stability than a Zircaloy-4 tube. Optical microscopy and scanning electron microscopy images showed that the PST had a uniform and well-bonded interface structure, i.e., no gaps or voids were found at the interface between the inner and outer tubes. Energy-dispersive X-ray spectroscopy analysis confirmed that the metal components did not interdiffuse at the interface of the PST, even after being kept at 600 and 900 °C for 1 h and rapidly cooled to room temperature. Unlike pure Zircaloy-4 tubes, Zircaloy-4/stainless use steel (SUS) 316 PST did not show significant structural collapse, even after being stored at 1200 °C for 1 h. Based on these results, if a PST was fabricated using a Zircaloy-4 tube thinner than the Zircaloy-4 tube used in this study and an outer tube of micron-scale thickness, swaging may be a feasible alternative to Zircaloy-4-based ATF cladding.

Daily Load-Follow Operation in LEU+-Loaded APR1400 Using Mode-K+ Control Logic

“…The proposed solution to address this issue is by employing the swaging technique to enclose the conventional zircaloy clad with an additional SS316 tube. The process involves the use of a 10 μm thick inner tube and a 30 μm thick outer SS tube, which surround the standard zircaloy clad [20,21]. These extra layers serve the purpose of protecting the fuel clad from the simultaneous interaction of coolant and fuel material.…”