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George Griffith
LWRS Advanced LWR Nuclear Fuels George GriffithLightwater Reactor Sustainability Advanced LWR Nuclear Fuel Pathway Lead
Second Workshop on U.S. Nuclear Power Plant LifeFebruary 2011
Technology Drivers
Advanced LWR nuclear fuel development Advanced LWR nuclear fuel development – Nuclear fuel technology helps define safety margin at LWRs – Increased safety margin can be used to compensate for aging that is
related to loss of safety marginy g– Reduced operating and economic risks
Higher capability fuels allow for increased reactor economics– Improved economic optimization – fuel cycle length, power uprates, less p p y g p p
used fuel, and more reliable fuel Improved understanding allows for shorter design and test cycles
– Faster response to reactor needs– Improved fuel design process and better margin maintenance
Technology demonstration can allow step improvement in fuel designs– Step improvement allowed by higher risk/reward design work
SiC Ceramic Matrix Composite (CMC) Potential Benefits
SiC Clad – Application to Current LWRS IssueSiC Clad Application to Current LWRS Issue– Flagship approach to LWRS advanced nuclear fuels
development– High-temperature strength and low chemical activity allows
cladding to operate at very high temperatures– Allows longer service life and exposureg p– Thermal creep may not be an issue at operational
temperaturesSiC fiber reinforced composite may exhibit better– SiC fiber-reinforced composite may exhibit better mechanical characteristics for PCI
– Use of SiC composite may mitigate flow-induced modes and subsequent fretting
Supporting the nuclear renaissance
LWR Cladding Outside Surface Nanometer-Scale Coating f C i d C d C l
Create zirconium cladding that is less susceptible to fretting failures and
for Corrosion and Crud Control Haiyan Wang Texas A&M University
hydrogen reactions than conventional cladding Lower risk technology than fuel SiC cladding technology
Zircaloy-4 tube for TiN coating(a) Before polishing
(a)
(b)
(c)
( ) p g(b) Cut and polished(c) Mounted zircaloy-4
tube on heater of PLD chamber
(d)
PLD chamber(d) TiN-coated tube.
Supporting the nuclear renaissance
•Simulation of heat
Tconduction in a UO2 fuel pellet, coupled to a mesoscale simulation of void nucleation under irradiation
BISON
k
irradiation
BISONte
(1/s
) 10-7
10-6
= 1.0x1018 n/m2s = 0.5x1018 n/m2s
thermal creep = f(T )
Irradiation creep (Hoppe empirical model) Secondary thermal creep (power law)
Cre
epst
rain
rat
10
10-9
10-8
irradiation creep = f ( )
f(T, ) creep (power law)Plasticity with linear strain hardeningThermal expansion
Temperature (K)500 600 700 800
10-10
Status Commercial prototype SiC cladding is being irradiated
at the Oak Ridge HFIR reactorat the Oak Ridge HFIR reactor Fabrication of advanced SiC/metallic hybrid cladding is
ongoing completed.ATR i di ti l h d l f FY 2011 ATR irradiation plans are on schedule for FY 2011
Transient, Loop and Failure irradiations are being planned.
Thin ceramic films have been applied to zirconium samples
Advanced modeling is providing design inputsAdvanced modeling is providing design inputs Mechanical modeling has started A shared technology project on SiC reactor structures
is being developedis being developed