TRITON11® is Westinghouse’s advanced 11x11 BWR fuel design. This new product on the market has been designed to be highly reliable, eliminating fuel failures, and provide a superior fuel economy and flexibility in operation. Significant efforts were invested to carefully optimize the fuel bundle geometry, including numbers, lengths and locations of fuel and water rods.
Top of Assembly
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Middle of Assembly
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Bottom of Assembly
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The two lifting lugs at the top end of the fuel channel are a unique design feature for the Nordic plants. The fuel assembly is lifted by the lifting lugs, but the handle on the fuel bundle is also secured to the grapple for redundancy.
The handle attaches to three water rods, providing redundancy for lifting the fuel assembly with two being sufficient under all conditions. The Nordic design is equipped with leaf springs to keep the assembly positioned at the top of the core.
A balance plate between the handle and the nuts distributes handling loads evenly between the water rods at all conditions, covering all manufacturing tolerance outcomes and any differential water rod growth during operation.
Compression springs between the water rod top end plugs and the handle keep the fuel bundle upper end components fixed during operation. They carry the gravitational load of these components and any downward loads during handling.
The water rod top end plugs have exit holes to release the non-boiling water passing through the water rods. They are welded to the water tubes and connected to the top components of the fuel bundle.
These grids achieve enhanced corrosion resistance and added mechanical strength with no openings where debris can get stuck. A four-line support system adds grid-to-rod fretting margin. No mixing vanes enables ultra-low pressure drop.
All 109 rods rest on top of the bottom tie plate and are free to grow through the spacer grids. They are not exposed to any handling or spacer loads. The end plugs have been optimized to simplify manufacturing and facilitate fuel service.
These grids achieve enhanced corrosion resistance and added mechanical strength with no openings where debris can get stuck. A four-line support system adds grid-to-rod fretting margin. Mixing vanes enable best-in-class dryout performance.
Resistant to irradiation growth and hydrogen pickup, the water tubes ensure reliable lifting of the assembly at high burnup. Small heads are welded to each water tube above each spacer grid to limit spacer axial movement.
The eight 2/3 part-length rods end above the seventh spacer grid. They are carefully positioned to improve shutdown margin and dryout performance and reduce two-phase pressure drop.
Expanded inside flow area and optimized corner thickness at 2/3 axial level, reduces two-phase pressure drop and neutron parasitic absorption. Dimples provide support for the spacer grids in the expanded upper region.
A UO2 pellet doped with chromia (Cr2O3) and alumina (Al2O3) that facilitate diffusion during sintering, resulting in a higher density and an enlarged grain size which enhances the accident tolerance of the fuel.
The eight 1/3 part-length rods end above the fourth spacer grid. They were carefully positioned to improve shutdown margin and dryout performance as well as to reduce two-phase pressure drop.
Proven lower hydrogen pickup, enabling higher burnup and longer irradiation time. The cladding has an optimized soft inner liner which provides superior resistance against pellet-cladding interaction (PCI).
This material has an impressive record of no accelerated channel growth or bow at high burnup, even under challenging 24-month cycle conditions. Thick corners in the lower region and lower creep rate provide resistance against outward bulge.
Machined from stainless steel bar with through slots for coolant flow, this feature provides axial support to the fuel rods.
Demonstrated game changing debris capture performance based on improved and rigorous testing. Captures 100% of thin metal wires longer than 5mm of any shape by leveraging the advanced capability of additive manufacturing.
For Nordic plants, the stainless-steel transition piece is permanently bolted to the bottom end of the channel. This design eliminates leakage flow at the bottom of the channel. The StrongHold AM filter is fitted inside and locked by spotwelding.
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