Transcript Recommendation for the MOX fuel conductivity and heat

Recommendations for the MOX fuel
conductivity and heat transfer correlations
to be used in the XT-ADS design and
safety calculations
D. Struwe, W. Pfrang
Forschungszentrum Karlsruhe
Institut für Reaktorsicherheit
D. Sruwe, W. Pfrang: “Recommendation for the fuel conductivity of the MOX fuel to be used for the XT-ADS
core design” (December 2006)
W. Pfrang, D. Struwe:” Assessment of correlations for the heat transfer to the coolant necessary for heavy
liquid metal cooled core designs” (May 2007)
EUROTRANS DESIGN WP 1.5 Meeting May 22nd/23rd 2007 Stockholm, Sweden
Correlations for the MOX fuel conductivity
MOX fuel conductivity is dependent on
- temperature,
- porosity,
- oxygen to metal ratio and
- burn-up
Correlations of special interest here are the following ones
- the Duriez-correlation with the LUCUTA model for burn-up
- the Duriez-NFI correlation used in the FRAPCON-3 code,
- the mod. Martin correlations used in the CABRI project
- the correlations of Philipponneau used in the EFR project.
(Fast Reactor Data Manual, issue 1, Nov. 1990 consistent
with Del 3.4 Version 1.0 of the AFTRA project)
EUROTRANS DESIGN WP 1.5 Meeting May 22nd/23rd 2007 Stockholm, Sweden
Correlations for the MOX fuel conductivity
Burn-up dependence
Burn-up correction factor of the fuel thermal conductivity correlations of
Lucuta and Duriez-mod NFI mod (FRAPCON) for different temperatures over burn-up
qualified for LWR fuels
EUROTRANS DESIGN WP 1.5 Meeting May 22nd/23rd 2007 Stockholm, Sweden
Correlations for the MOX fuel conductivity
Burn-up dependence
Burn-up correction factor of the fuel thermal conductivity correlations of SAS4A mod. Martin
and Duriez-mod NFI mod (FRAPCON) for different temperatures over burn-up qualified for
fast reactor or LWR fuels respectively
EUROTRANS DESIGN WP 1.5 Meeting May 22nd/23rd 2007 Stockholm, Sweden
Correlations for the MOX fuel conductivity
Porosity dependence
Porosity correction factor of the fuel thermal conductivity correlations
SAS4A mod. Martin, Lucuta and Philipponneau over porosity qualified for fast reactor and
And LWR fuels respectively
EUROTRANS DESIGN WP 1.5 Meeting May 22nd/23rd 2007 Stockholm, Sweden
Correlations for the MOX fuel conductivity
Temperature dependence of green fuel
Fuel thermal conductivity correlations SAS4A mod. Martin and Duriez-mod NFI mod
(FRAPCON) for 0.025 2-O/M, 0 at% burnup and 5% porosity
EUROTRANS DESIGN WP 1.5 Meeting May 22nd/23rd 2007 Stockholm, Sweden
Correlations for the MOX fuel conductivity
Temperature dependence of green fuel
EUROTRANS DESIGN WP 1.5 Meeting May 22nd/23rd 2007 Stockholm, Sweden
Correlations for the MOX fuel conductivity
Temperature dependence of green fuel
• In Duriez et.al. it is explicitly stated on basis of experimental
data evaluations for green fuel that the behaviour difference
between FBR and LWR mixed oxide fuels is to be taken as a
fact
• Equations recommended for the determination of the light
water reactor fuels should not be used to calculate the
conductivity of hypo- stoichiometric oxide fuels if the Puconcentration is higher than 15 %.
EUROTRANS DESIGN WP 1.5 Meeting May 22nd/23rd 2007 Stockholm, Sweden
Correlations for the MOX fuel conductivity
Fuel thermal conductivity correlations of SAS4A mod. Martin and Philipponneau for
different 2-O/M-ratios, 0 at% burn-up and 5% porosity
EUROTRANS DESIGN WP 1.5 Meeting May 22nd/23rd 2007 Stockholm, Sweden
Correlations for the MOX fuel conductivity
Burn-up correction factor of the fuel thermal conductivity of correlations
SAS4A mod. Martin and Philipponneau for different temp. over burn-up
EUROTRANS DESIGN WP 1.5 Meeting May 22nd/23rd 2007 Stockholm, Sweden
Correlations for the MOX fuel conductivity
• Theoretical interpretation of the CABRI projects at FZK i.e.
pre-test and post test calculations revealed that use of the recommendations according to mod. Martin led to the relatively
best agreement between experimental observations and
calculated results especially in case of low power preirradiations.
• The international fuels specialists group of the EFR project
came to the conclusion that the recommendations provided
by Philipponneau should be taken as reference for the EFR
project evaluations.
• Differences between mod. Martin and Philipponneau are
small except for low power operation conditions.
EUROTRANS DESIGN WP 1.5 Meeting May 22nd/23rd 2007 Stockholm, Sweden
Correlations for the MOX fuel conductivity
• Correlations for determination of the influence of burn-up on
the fuel conductivity as proposed by Lucuta leads partly to
curious results of correction factor dependencies from burnup which cannot be accepted.
• The modified approach followed in the FRAPCON-3 code
was investigated in view of experimental results obtained
within the CABRI – programs. It could be demonstrated that
application of this recommendation leads to an overestimation of the fuel temperatures by up to 350 K especially
for high burn-up conditions and thus to erroneous results
concerning fission gas release and clad loading in case it is
applied to fast reactor fuel pins.
• To maintain consistency with the EFR project
recommendation it is appropriate to apply the set of
correlations developed by Philipponeau for the fast reactor
fuels of the XT-ADS project
EUROTRANS DESIGN WP 1.5 Meeting May 22nd/23rd 2007 Stockholm, Sweden
Correlations for the MOX fuel conductivity
Philipponneau’s correlation [T in K]
Thermal conductivity: λ = (1/(A+BT) + CT ** 3 )* FP
A = 1.320 √(x+0.0093) – 0.0911 + 0.0038 τ
B = 2.493 10 -4 m W -1 (constant)
C = 88.4 10 -12 W m -1 K -4 (constant)
FP – correction factor representing the effect of porosity
FP = (1 – P) / (1 + 2P)
P – porosity; x – deviation from stoichiometry; τ – burn-up in at%
EUROTRANS DESIGN WP 1.5 Meeting May 22nd/23rd 2007 Stockholm, Sweden
Review of heat transfer correlations for HLM
Evaluated dependencies:
- Correlations for tube flows
- Correlations for flows in triangular rod bundles
(influence of P/D - ratio)
- Correlations for flow in square rod bundles
(influence of P/D - ratio)
- Influence of spacers and axial power profiles
EUROTRANS DESIGN WP 1.5 Meeting May 22nd/23rd 2007 Stockholm, Sweden
Review of heat transfer correlations for HLM
Triangular arrays
P/D = 1.409
EUROTRANS DESIGN WP 1.5 Meeting May 22nd/23rd 2007 Stockholm, Sweden
Review of heat transfer correlations for HLM
Triangular arrays
P/D = 1.563
EUROTRANS DESIGN WP 1.5 Meeting May 22nd/23rd 2007 Stockholm, Sweden
Review of heat transfer correlations for HLM
• Experimental investigations to study the heat transfer in
liquid metals have preferably used mercury (Hg) and
sodium–potassium alloy (NaK), sometimes also sodium (Na)
and, for tube flows, also a lead-bismuth alloy (LBE) has been
used.
• The Prandtl numbers of lead and LBE are in the same
range as those of Hg and NaK .
• Some developers of correlations assessed experimental
data from campaigns using different coolants and none of the
respective publications reported on differences which could
be attributed to the differences of the fluids.
• Therefore, correlations considered here, which are not
explicitly dependent from the Prandtl number, can be used for
lead and LBE without restriction.
EUROTRANS DESIGN WP 1.5 Meeting May 22nd/23rd 2007 Stockholm, Sweden
Review of heat transfer correlations for HLM
• The correlation of Subbotin/Ushakov recommended for P/D
ratios between 1.2 and 2.0 appears to be the one with the
best experimental qualification
• The data base for rod bundles with triangular rod arrangements, which has been used to adjust the correlations, is
relatively extended, but it has to be noted, that the respective
experiments for triangular arrays have all been performed
before 1975.
• It has been shown that spacers can enhance the heat
transfer substantially, especially in the vicinity of the spacer.
This has to be kept in mind if spacers are used which alter
the local coolant flow considerably.
EUROTRANS DESIGN WP 1.5 Meeting May 22nd/23rd 2007 Stockholm, Sweden
Review of heat transfer correlations for HLM
• The consequences of possible oxide layers on the cladding
should not be covered by the Nusselt number correlations but
modelled separately in the computer codes.
1 / alpha total = 1 / alpha conv + 1 /alpha cond
alpha conv – convective heat transfer
alpha cond = lambda / layer thickness
lambda - thermal conduction of the layer, f (density,
temperature)
layer thickness – f (temperature, residence time, etc.)
EUROTRANS DESIGN WP 1.5 Meeting May 22nd/23rd 2007 Stockholm, Sweden
SAS4A/Ref05R0LBE
calculation for XT-ADS hot pin
Peak linear rating:
252 W/cm
HTF-corr. LBE => clad:
Subbotin/Ushakov
Coolant inlet temperature:300 °C
Standard calculation:
corrosion layer / GESA treatment not taken into account.
Modified calculation:
Oxide layer with λ = 1 W/(mK) and variable thickness added.
(Thermal conductivity of steel in the respective temperature
range is about 28 W/(mK)).
Only thermal aspects considered here.
EUROTRANS DESIGN WP 1.5 Meeting May 22nd/23rd 2007 Stockholm, Sweden
XT-ADS Hot Pin: Axial profiles of clad and coolant
temperature
EUROTRANS DESIGN WP 1.5 Meeting May 22nd/23rd 2007 Stockholm, Sweden
XT-ADS Hot Pin: Axial profiles of the clad inner temperature
(Modified calculation with different additional oxide layers)
EUROTRANS DESIGN WP 1.5 Meeting May 22nd/23rd 2007 Stockholm, Sweden