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US-12620500-B2 - Cladding and assembly for nuclear applications

US12620500B2US 12620500 B2US12620500 B2US 12620500B2US-12620500-B2

Abstract

An assembly for nuclear applications includes a tubular cladding for containing nuclear fuel. The tubular cladding comprises a ceramic matrix composite. An assembly tube surrounds the tubular cladding, and a collar is positioned between the tubular cladding and the assembly tube. The collar extends circumferentially around the cladding and comprises the ceramic matrix composite. The tubular cladding may be centered within the assembly tube by the collar.

Inventors

  • Sujit Nanda

Assignees

  • ROLLS-ROYCE HIGH TEMPERATURE COMPOSITES INC.

Dates

Publication Date
20260505
Application Date
20230623

Claims (8)

  1. 1 . An assembly for nuclear applications, the assembly comprising: a tubular cladding for containing nuclear fuel, the tubular cladding comprising a ceramic matrix composite and a plurality of cladding tubes positioned end-to-end and bonded together; an assembly tube surrounding the tubular cladding; and a collar disposed between the tubular cladding and the assembly tube, the collar extending circumferentially around the cladding and comprising the ceramic matrix composite, wherein the collar is in contact with the assembly tube and provides a standoff between the tubular cladding and the assembly tube, said standoff resulting in a longitudinal gap extending between the tubular cladding and the assembly tube, wherein the collar is positioned at a joint between ends of at least two cladding tubes of the plurality of cladding tubes, the at least two cladding tubes being positioned end-to-end, and wherein the collar comprises one or more radially-inward projecting extensions positioned within the joint.
  2. 2 . The assembly of claim 1 , wherein the tubular cladding is centered within the assembly tube by the collar.
  3. 3 . The assembly of claim 1 , wherein the collar is integrally formed with the tubular cladding.
  4. 4 . The assembly of claim 1 , wherein the collar is bonded to the tubular cladding.
  5. 5 . The assembly of claim 1 , wherein the collar extends completely around a circumference of the tubular cladding.
  6. 6 . The assembly of claim 1 , wherein the collar extends only partially around a circumference of the tubular cladding.
  7. 7 . The assembly of claim 1 comprising a plurality of the collars spaced longitudinally apart along the tubular cladding.
  8. 8 . The assembly of claim 1 , wherein the ceramic matric composite includes: a ceramic matric comprising silicon carbide; and ceramic fibers comprising silicon carbide embedded in the ceramic matrix.

Description

TECHNICAL FIELD The present disclosure relates generally to claddings for nuclear applications and more particularly to claddings based on ceramic matrix composites. BACKGROUND Ceramic matrix composites, which include ceramic fibers embedded in a ceramic matrix, exhibit a combination of properties that make them promising candidates for industrial applications that demand excellent thermal and mechanical properties along with low weight. A ceramic matrix composite that includes a matrix comprising silicon carbide reinforced with silicon carbide fibers may be referred to as a silicon carbide/silicon carbide composite or SiC/SiC composite. Fabrication of a SiC/SiC composite may include slurry and melt infiltration steps to densify a silicon carbide fiber preform. Accident tolerant fuel (ATF) assemblies refer to cladding and fuel pellet designs for nuclear reactors that are being developed to provide performance, safety and economic advantages over current nuclear cladding and fuels. Besides land-based nuclear reactors, ATF assemblies may have mobile and space applications, such as in nuclear thermal propulsion (NTP) systems being developed for rockets used in deep space missions, and bimodal nuclear thermal propulsion/nuclear electric propulsion (NTP/NEP) systems that use nuclear reactors to provide both heat and electricity to generate thrust. Existing ATF assemblies based on metal claddings have temperature and other limitations that warrant development of new cladding materials and components. BRIEF DESCRIPTION OF THE DRAWINGS The embodiments may be better understood with reference to the following drawing(s) and description. The components in the figures are not necessarily to scale. Moreover, in the figures, like-referenced numerals designate corresponding parts throughout the different views. FIG. 1 shows a cross-sectional view of an exemplary assembly for nuclear applications, where the assembly includes a tubular cladding centered within an assembly tube by collars bonded to the tubular cladding. FIG. 2 shows a cross-sectional view of an exemplary assembly for nuclear applications, where the assembly includes a tubular cladding centered within an assembly tube by collars integrally formed with the tubular cladding. FIG. 3 shows a top-view schematic of an exemplary collar configured to extend completely around the circumference of the tubular cladding. FIGS. 4A and 4B show top-view schematics of exemplary collars configured to extend partway around the circumference of the tubular cladding. FIG. 4C shows an exemplary collar configured to be positioned about the circumference of the tubular cladding that includes separate collar sections. FIG. 5A shows a cross-sectional view of a portion of an exemplary assembly that includes a tubular cladding having a multi-piece structure. FIG. 5B shows a cross-sectional view of a portion of an exemplary assembly that includes a tubular cladding having a multi-piece structure. FIG. 6 shows a flow chart of a method of manufacturing a cladding and optionally an assembly for nuclear applications. FIG. 7 shows a flow chart of another method of manufacturing a cladding and optionally an assembly for nuclear applications. DETAILED DESCRIPTION FIG. 1 shows an assembly for nuclear applications that may in some examples be referred to as an accident tolerant fuel (ATF) assembly. The assembly 102 includes a tubular cladding 104 for containing nuclear fuel. More particularly, the tubular cladding 104 includes a channel 110 sized to contain one or more nuclear fuel pellets. The tubular cladding 104 comprises a ceramic matrix composite. An assembly tube 106 surrounds the tubular cladding 104, and a collar 108 is positioned between the tubular cladding 104 and the assembly tube 106. The collar 108 extends circumferentially around the cladding 104 and also comprises a ceramic matrix composite. The collar 108 may function to provide standoff support for the tubular cladding 104 within the assembly tube 106, which may comprise a metal alloy, a ceramic, or another suitable material. In particular, the tubular cladding 104 may be centered within the assembly tube 106 by the collar 108. Accordingly, the collar 108 and the tubular cladding 104 may have a concentric arrangement with each other and with respect to the assembly tube 106. The dotted lines in FIGS. 1 and 2 show for each assembly 102 the central longitudinal axis. The collar 108 may be bonded to the tubular cladding 104 as illustrated in FIG. 1. Alternatively, the collar 108 may be integrally formed with the tubular cladding 104, as shown in FIG. 2. In other words, in the example of FIG. 1, the tubular cladding 104 and the collar 108 may have a bonded multipiece structure including bonded joints or interfaces 112, or, as shown in FIG. 2, the tubular cladding 104 and the collar 108 may have a monolithic structure. The bonded joints or interfaces 112 between the collar 108 and the tubular cladding 104 may be formed by sintering