A novel wiregauze supported Pt-Ru bimetallic
nanoparticles catalyst for the application of
hydrogen mitigation under LOCA ...
Introduction
Nuclear Energy
 Nuclear energy - one
of the non-renewable
but clean sources of
energy.
 Nuclear power - a
s...
Safety - one of the key aspect.
As

concern

with

any

organization, its safety

is

one

of

the

most

prominent questi...
Inside of Nuclear Reactor
1. Fuel bundle
2. Calandria (reactor core)
3. Adjuster rods

4. Heavy water pressure reservoir
5...
Inside of Nuclear Reactor

Residual Heat Removal
after reactor Shutdown
Radioactive
Fission
Products generate heat in
form...
HYDROGEN IN NUCLEAR REACTORS

Design Basis Accident
Radiolytic generation (0.001 – 0.05 Kg/s)

Severe Accident

(LOCA + Fa...
METAL STEAM REACTION
Zr (s) + 2 H2O (g) → ZrO2 (s) + 2 H2 (g)
ΔH = -147.2 Kcal/g.mole
• 10 times higher kinetics compared ...
65.0k
60.0k

Hydrogen Generation (gm-moles)

55.0k
50.0k
45.0k
40.0k

Cumulative

35.0k
30.0k

Metal-steam reaction

25.0k...
THREATS POSED BY HYDROGEN
Hydrogen
conc. in air

Possible reaction

0% - 4%

noncombustible

4% - 13%

Combustible

13% - ...
Hydrogen Mitigation systems
Deliberate ignition system
Pre and post inerting
Dilute Venting
Passive Autocatalytic recombin...
Objectives of the present study
 Pt+Pd/SS efficient catalysts for PAR; limited to 50 ppm of CO
 New breed of catalysts w...
Experimental
S.

Catalysts

Dil. HCHOa

Pt

90

02

PtR1

90

03

PtR2

90

04

PtR3

90

05

PtR4

90

06

PtPd

120

07
...
Coating kinetics of plating bath

Absorbance verses wavelength for
Pt-Ru solution with time.
ICAER -2013, IITB, 10th Decem...
XRD

~7.0 nm Crystallite Size

~24.0 nm Crystallite Size

ICAER -2013, IITB, 10th December 2013

14/23
Surface morphology - SEM
a

b

SEM images of
(a) Bare wiregauze
c

d

(b) Etched Wiregauze
(c) PtR1at 2.5K,
(d) PtR4 at 2....
TEM

TEM image and particle size distribution of PtR1 catalyst respectively.
Particle size is varied from 0-20 nm mostly.
...
Catalytic activity
G. Hydrogen monitor
E. & F. mV meter
E

F

G

S. Catalytic sample
B. Air pump
circulating

H

D

B

A. ...
Catalytic activity for various Pt-Ru
samples and their temperature rise for
recombination of 4 % hydrogen in air.
ICAER -2...
Catalytic activity of PtR1 catalyst in presence of
CH4, CO2, relative humidity and after flushing

ICAER -2013, IITB, 10th...
Catalytic activity in presence of Carbon monoxide
For Pt, PtPd, PPR and
PtR1 catalysts

Catalytic activity of PtR1
catalys...
Reproducibility of Catalytic Activity of
PtR1 catalyst

ICAER -2013, IITB, 10th December 2013

21/23
Conclusions
 Pt-Ru bimetallic catalyst prepared by electroless deposition
method on Stainless Steel support.

 Catalyst ...
153 salil varma
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153 salil varma

  1. 1. A novel wiregauze supported Pt-Ru bimetallic nanoparticles catalyst for the application of hydrogen mitigation under LOCA condition Salil Varma1, Kiran K. Sanap1,2, Suresh B. Waghmode2 and Shyamala R. Bharadwaj1 1Bhabha Atomic Research Centre - Mumbai 2University of Pune - Pune ICAER -2013, IITB, 10th December 2013 1/23
  2. 2. Introduction Nuclear Energy  Nuclear energy - one of the non-renewable but clean sources of energy.  Nuclear power - a source of sustainable energy which reduces carbon emissions.  Nuclear power plants provide about 13% of worlds electricity. ICAER -2013, IITB, 10th December 2013 2/23
  3. 3. Safety - one of the key aspect. As concern with any organization, its safety is one of the most prominent questions. Accidents at Fukushima (Japan) and Three Mile Island (USA) nuclear power plants brought hydrogen related issues into the forefront. ICAER -2013, IITB, 10th December 2013 3/23
  4. 4. Inside of Nuclear Reactor 1. Fuel bundle 2. Calandria (reactor core) 3. Adjuster rods 4. Heavy water pressure reservoir 5. Steam generator 6. Light water pump 7. Heavy water pump 8. Fueling machines 9. Heavy water moderator 10. Pressure tube 11. Pressure tube 12. Cold water returning from turbine 13. Containment building made of reinforced concrete ICAER -2013, IITB, 10th December 2013 4/23
  5. 5. Inside of Nuclear Reactor Residual Heat Removal after reactor Shutdown Radioactive Fission Products generate heat in form of Decay Products, a and b particles and grays. Heat generated and g-ray lead to generation of hydrogen in the containment ICAER -2013, IITB, 10th December 2013 5/23
  6. 6. HYDROGEN IN NUCLEAR REACTORS Design Basis Accident Radiolytic generation (0.001 – 0.05 Kg/s) Severe Accident (LOCA + Failure of ECCS) Zirconium steam reaction (0.1 – 5.0 Kg/s) Uranium steam reaction Molten core concrete interaction ICAER -2013, IITB, 10th December 2013 6/23
  7. 7. METAL STEAM REACTION Zr (s) + 2 H2O (g) → ZrO2 (s) + 2 H2 (g) ΔH = -147.2 Kcal/g.mole • 10 times higher kinetics compared to Radiolytic decomposition of water. • 95 % hydrogen within 10 minutes. • Oxidation of 30 % fuel sheath. • Oxidation of 20 % Zirconium. • 23500 gm moles of hydrogen in half an hour Source: KAPP Safety report II ICAER -2013, IITB, 10th December 2013 7/23
  8. 8. 65.0k 60.0k Hydrogen Generation (gm-moles) 55.0k 50.0k 45.0k 40.0k Cumulative 35.0k 30.0k Metal-steam reaction 25.0k 20.0k 15.0k Radiolytic decomposition of moderator 10.0k Radiolytic decomposition of coolant 5.0k 0.0 10 100 1000 10000 100000 1000000 Time (sec) Cumulative time dependent hydrogen generation from metal-water reaction and radiolytic decomposition of water Source: KAPP Safety report II ICAER -2013, IITB, 10th December 2013 8/23
  9. 9. THREATS POSED BY HYDROGEN Hydrogen conc. in air Possible reaction 0% - 4% noncombustible 4% - 13% Combustible 13% - 59% Combustible, possibly detonable 59%- 75% Combustible 75% - 100% noncombustible K. Fischer et. al., Nuclear Engineering and Design, 209 (2001) 147. ICAER -2013, IITB, 10th December 2013 9/23
  10. 10. Hydrogen Mitigation systems Deliberate ignition system Pre and post inerting Dilute Venting Passive Autocatalytic recombiner (PAR) Advantages of PAR  Auto initiation.  Not depend on external power supply.  Can be placed at any location in containment.  No pressure build up.  Free access to all containment area, No life support required for working staff during regular operation/maintenance of plant. ICAER -2013, IITB, 10th December 2013 10/23
  11. 11. Objectives of the present study  Pt+Pd/SS efficient catalysts for PAR; limited to 50 ppm of CO  New breed of catalysts which initiate room temperature H2-O2 recombination in presence of all feasible contaminants  Optimisation of electroless deposition method in terms of precursor and reducing agent concentration, the rate of noble metal deposition and its loading  To study the influence of different poisons like CO2, CH4, CO and moisture on catalytic activity ICAER -2013, IITB, 10th December 2013 11/23
  12. 12. Experimental S. Catalysts Dil. HCHOa Pt 90 02 PtR1 90 03 PtR2 90 04 PtR3 90 05 PtR4 90 06 PtPd 120 07 PPR 120 No 01 Noble Metal Precursor (ml) H2PtCl6 = 32 H2PtCl6 = 32 Time of Wt gain (%) RuCl3 = 5 H2PtCl6 = 32 RuCl3 = 5 H2PtCl6 = 32 RuCl3 = 5 H2PtCl6 = 32 PdCl2 = 7 H2PtCl6 = 32 76 Coating (h) 20 61 7 0.9 61 8 1.1 61 8 1.4 61 8 1.6 71 7 0.83 79 RuCl3 = 5 H2PtCl6 = 32 PdCl2 = 2.5 HCHO:NMb 8 0.85 0.85 RuCl3 = 2.5 a = 1:10 diluted formaldehyde ICAER -2013, IITB, 10th December 2013 b = Noble Metal 12/23
  13. 13. Coating kinetics of plating bath Absorbance verses wavelength for Pt-Ru solution with time. ICAER -2013, IITB, 10th December 2013 Absorbance at λmax = 260 nm for PtR1 and Pt catalysts bath solution 13/23
  14. 14. XRD ~7.0 nm Crystallite Size ~24.0 nm Crystallite Size ICAER -2013, IITB, 10th December 2013 14/23
  15. 15. Surface morphology - SEM a b SEM images of (a) Bare wiregauze c d (b) Etched Wiregauze (c) PtR1at 2.5K, (d) PtR4 at 2.5K, (e) PtR1 at 10K and e ICAER -2013, IITB, 10th December 2013 f (f) PtR4 at 10K. 15/23
  16. 16. TEM TEM image and particle size distribution of PtR1 catalyst respectively. Particle size is varied from 0-20 nm mostly. But average particles size is in the range of 0-10 nm. ICAER -2013, IITB, 10th December 2013 16/23
  17. 17. Catalytic activity G. Hydrogen monitor E. & F. mV meter E F G S. Catalytic sample B. Air pump circulating H D B A. Fixed volume injector (0.25 l) D. Pressure gauge S C A H. Thermocouple C. SS reactor (40 l) Block diagram representing the experimental setup for catalytic activity evaluation. ICAER -2013, IITB, 10th December 2013 17/23
  18. 18. Catalytic activity for various Pt-Ru samples and their temperature rise for recombination of 4 % hydrogen in air. ICAER -2013, IITB, 10th December 2013 H2 Concentration and temperature as a function of time for H2-O-2 reaction in presence of PtR1catalyst 18/23
  19. 19. Catalytic activity of PtR1 catalyst in presence of CH4, CO2, relative humidity and after flushing ICAER -2013, IITB, 10th December 2013 19/23
  20. 20. Catalytic activity in presence of Carbon monoxide For Pt, PtPd, PPR and PtR1 catalysts Catalytic activity of PtR1 catalyst in presence Carbon Monoxide ICAER -2013, IITB, 10th December 2013 20/23
  21. 21. Reproducibility of Catalytic Activity of PtR1 catalyst ICAER -2013, IITB, 10th December 2013 21/23
  22. 22. Conclusions  Pt-Ru bimetallic catalyst prepared by electroless deposition method on Stainless Steel support.  Catalyst with noble metal loading of 0.9 % found to be optimum.  Catalyst found to be active for room temperature initiated catalytic recombination of H2 and O2 in air.  Catalytic activity of this catalyst remain unaffected in presence of CH4, CO2 and relative humidity.  Catalyst is found to exhibit enhanced catalytic activity in presence of 400 ppm of carbon monoxide.  The platinum-ruthenium catalyst with 0.9 wt% noble metal loading on stainless steel wire gauze is found to comply with various requirements for application in PAR. ICAER -2013, IITB, 10th December 2013 22/23

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