GAIA Structural Mixing Spacer
Grid Combines Reliability and
Robustness of HTP
TM
with
Increased Thermal Performance
The GAIA structural mixing vane spacer grid ensures
high fretting resistance, low pressure drop and high
handling capability and provides excellent Critical
Heat Flux (CHF) performance considering its superior
mechanical performance.
• Fuel rod stability is provided by 8-line contact
spring confi guration to ensure the GAIA design
platform inherits the outstanding grid-to-rod fretting
resistance of the proven HTP™ spacer grid design.
• Mixing vanes provide very effi
cient fl uid mixing
for demanding fuel management operating
conditions and can support power up-rates.
• Outer strap design and the M5
®
material provide
dimensional stability without risk of excessive
fuel assembly interaction during core loading /
unloading operations.
• Intrinsic design provides the GAIA spacer grid
with high mechanical strength and a favorable
deformation mode under accident-induced
lateral loads.
Intermediate Flow Mixing Grids for
Enhanced Thermal Performance
The GAIA fuel design incorporates three (3)
intermediate GAIA mixers (IGMs) based on AREVA’s
AFA-3G mid span mixing grid design. IGMs are
fabricated with M5
®
alloy. IGMs augment thermal
hydraulic performance enabling optimal fuel
effi
ciency and fuel cycle economy.
M5
®
Cladding Provides Industry-
Leading Fuel Rod Performance
Worldwide fi rst in class M5
®
alloy is used as cladding
material for the fuel rods. The optimum chemical
composition of M5
®
and its refi ned microstructure
provide enhanced resistance to corrosion and
very low hydrogen uptake. This translates to less
embrittlement and greater reliability at higher
burnups, under normal operating conditions as well
as accident conditions, including LOCA.
GAIA Fuel Assembly
Maximum Fuel Robustness,
Performance and Reliability
Mixing vanes
Inner Strap
Line Contacts
Spring Hull
To shoulder the demands of PWR utilities in fuel assembly performance while
ensuring maximum robustness, AREVA has developed the GAIA PWR fuel
assembly design. It is the result of a worldwide AREVA R&D project, which
focused on reliability, robustness and thermal margin.
The GAIA fuel rod design also features a reduced
volume spring, which contributes to a reduction in the
end-of-life pin pressure. Optional Chromia (Cr2O3)
doping of the fuel pellet enhances fi ssion gas retention
and improves the fuel rod resistance to Pellet-Cladding
Interaction (PCI), allowing for increased uranium
loading in some applications. Fuel pellets are pressed
and sintered with dished ends and a slightly tapered
land area. Resinter density change, moisture content
and surface quality of the fi nished pellets are stringently
controlled during fabrication and ensure quality
performance of the fuel under operation.
HMP
TM
End Grid for Optimal
In-Reactor Performance
The HMP™ end grid is made of Alloy 718 and has
proven fl awless operating experience in the HTP™ fuel
assembly design platform. The enhanced strength and
relaxation characteristics of the HMP™ end grid makes
it ideal for stabilizing the fuel rods by providing decisive
margin against fl ow-induced vibration and reducing
the potential for fretting damage, while reducing
compressive loads to optimize fuel assembly growth
behavior and mitigating fuel rod bow.
GRIP
TM
Bottom Nozzle for Effi
cient
Debris Filtering
The GRIP™ bottom nozzle assembly has been
developed to provide the best level of fi ltering
effi
ciency, while ensuring low pressure drop. It also
provides high performance regarding fl ow-induced fuel
rod vibration and fuel assembly serviceability.
Welded Structure With
Reinforced MONOBLOC
TM
Guide Tubes Provides Highest
Dimensional Stability
The GAIA structural spacer grid is connected to
increased diameter MONOBLOC™ (where applicable)
guide tubes and instrumentation tube through a
two level resistance welding design, which provides
strong guide tube to grid attachment. These welded
connections provide increased fuel assembly lateral
stiff ness for fuel assembly straightness.
Furthermore, the guide tubes and instrumentation tube
are fabricated from Q12, a quaternary alloy developed
to optimize the creep behavior of the fuel assembly
structure, while maintaining a low hydrogen uptake.
Quick Disconnect
Features and Benefi ts
Optimized for a balance in Neutronic, Mechanical
and Thermal Performance, the GAIA off ers:
•
Maximum robustness against distortion
and seismic issues with Q12
™
material and
MONOBLOC
™
welded structure
•
Increased thermal hydraulic performance
with GAIA mixing grids and IGMs
•
First-class fuel reliability with 8-line contact
GAIA grid, HMP end grids to protect against
fretting and the high fi ltering effi
ciency of
GRIP
™
•
Superior performance under accident
conditions with Alloy M5
®
and Cr-doped fuel
•
High burnup capability based on an
extensive global irradiation and testing
database
M5 is a registered trademark of AREVA. HMP, HTP, GRIP
and MONOBLOC are trademarks of AREVA. The data and
information contained herein are provided solely for illustration
and informational purposes and create no legal obligations by
AREVA. None of the information or data is intended by AREVA
to be a representation or a warranty of any kind, expressed or
implied, and AREVA assumes no liability for the use of or reliance
on any information or data disclosed in this document. ©2014
AREVA Inc. All rights reserved.
6/14
ANP:U-395-V2-14-ENG
AREVA Inc. Corporate Headquarters
7207 IBM Drive
Charlotte, NC 28262
For more information,
contact your VP, Key Account:
Tel: 704 805 2305 – Fax: 434 382 5629
regional.manager@areva.com – www.us.areva.com
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