US 11,990,249 B2
Fuel element with multi-smear density fuel
Jesse R. Cheatham, III, Bellevue, WA (US); Ryan N. Latta, Bellevue, WA (US); and Samuel J. Miller, Bellevue, WA (US)
Assigned to TERRAPOWER, LLC, Bellevue, WA (US)
Filed by TerraPower, LLC, Bellevue, WA (US)
Filed on Jul. 22, 2019, as Appl. No. 16/518,890.
Application 16/518,890 is a division of application No. 15/245,594, filed on Aug. 24, 2016, granted, now 10,410,753.
Claims priority of provisional application 62/210,609, filed on Aug. 27, 2015.
Prior Publication US 2020/0027577 A1, Jan. 23, 2020
Int. Cl. G21C 3/30 (2006.01); G21C 1/02 (2006.01); G21C 3/04 (2006.01); G21C 3/16 (2006.01); G21C 7/00 (2006.01); G21C 21/08 (2006.01); G21D 3/00 (2006.01); G21C 3/42 (2006.01)
CPC G21C 3/04 (2013.01) [G21C 1/026 (2013.01); G21C 3/16 (2013.01); G21C 7/005 (2013.01); G21C 21/08 (2013.01); G21D 3/001 (2013.01); G21C 3/045 (2019.01); G21C 3/047 (2019.01); G21C 3/42 (2013.01); Y02E 30/30 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A method of manufacturing a fuel element, the method comprising:
modeling fuel strain along a longitudinal axis of a fuel element;
modeling a smear density profile along the longitudinal axis of the fuel element to offset the modeled fuel strain such that at least one region of locally decreased strain corresponds to a region of locally increased smear density wherein the smear density profile approximates an inverted Gaussian shape and wherein the fuel element comprises twelve zones and at least three sections, the first section proximate a first longitudinal end of the fuel element, a third section proximate a second longitudinal end of the fuel element, and a second section between the first and third sections, wherein an average smear density of the first section is greater than an average smear density of the second section, wherein an average smear density of the third section is greater than the smear density of the second section, and wherein the first section comprises five zones and the smear density profile of the zones of the first section varies according to a decreasing step function, wherein the second section comprises two zones and the smear density profile of the zones of the second section is constant, and wherein a third section comprises five zones and the smear density profile of the zones of the third section varies according to an increasing step function; and
constructing the fuel element to have a tubular interior volume storing a fissionable composition, the fissionable composition in thermal transfer contact with an interior surface of the fuel element and having at least five different smear densities that vary along the longitudinal axis of the fuel element based on the modeled smear density profile.