ENDURANCE TESTS for PTFE CATALYST

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ENDURANCE TESTS for PTFE CATALYST

• National Institute of Cryogenics and Isotope
  Technologies
• ICSI Rm. Valcea Romania
• M. Vladu, S Brad, F. Vasut, M. Vijulie, M.
  Constantin

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BRIEF DESCRIPTION OF THE TASK DELIVERABLES

• WDS the key systems to control the tritium
  contents
• Expanding the FZK tests
• Catalyst based on platinum material and charcoal
  support

The degradation of the WDS catalyst will strongly
affect its separation performances and
consequently will increase the tritium releases
into the environment. If a catalyst based on
Teflon material will be used for the LPCE column
of WDS, the fluoride that may be released as an
effect of tritium environment causes the
corrosion of the LPCE column with unpredictable
effects. Therefore the quantification of catalyst
degradation and the amount of fluoride released
is needed for planning the maintenance activities
and to predict the operation life time of the WDS
components
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Technology

• The main parts of the experimental stand are
• Process pump BranLuebbe process pump for
  tritiated water
• Catalyst Pt/C/PTFE column
• Tritiated water vessel
• Electric heater
• Water heater
• Normal water pump
• Tritiated and normal water filling trap
• Draining system.

The experimental setup at ICIT Rm. Valcea, for
this task TW6-TTFD-TR64, consists in a small LPCE
column filled with the same type of catalyst as
in the TLK LPCE column. The column will be in
operation for one year with tritiated water of
100 Cikg-1. For the experiments ICIT Rm.Valcea
manufacture the necessary hydrophobic catalyst.
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Design Basis
The tritiated water (100Ci/L) is filled up in
the vessel V1. The normal water is filled in the
vessel V2 The normal water enters through the
bottom of the column jacket and get out from the
upper part and filled the V2 vessel. Pump P2
circulates the normal water from vessel V2
through the H101 heater to the column jacket, and
the cycle is repeating. From vessel V1, the
tritiated water is circulating by the P1 pump,
through the heating coil from vessel V2 into the
LPCE column. The tritiated water temperature is
measured in three points, at the inlet, middle
and outlet of the column. If the medium
temperature, obtained from these three
measurements, is different than 80 Celsius
degree, the temperature feedback control loop
decrease/increase the power supply to the
regulating resistance from H101.
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Technology

• The catalyst was made by mixing
  politetrafloroethylene with platinum charcoal,
  then manufacturing like pellets with 2,5 mm
  diameter and 15 mm length. The concentration of
  platinum in the catalyst is 2.

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Technology

Images of platinum catalyst on charcoal in the
SEM (Scanning Electron Microscopy)
From the Scanning Electron Microscopies we can
notice that the platinum particles dimensions are
in the range of tens or hundred of microns, the
pores are in the same size range. In comparison
with the results obtained through the X-ray
diffraction technique, we can conclude that the
platinum particles contain numerous crystallites.
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Technology
ICIT contribute to this task by exploring
improvements in the manufacturing process for
catalysts to be used in the water detritiation
process - New catalysts. Based on the
experience in the field of hydrophobic catalysts
used in isotopic exchange reaction, ICIT produce
and characterize new types of catalysts. - New
catalyst manufacturing techniques. Taking into
account the properties of the proposed metallic
oxides (hydrophobic and binding properties), new
manufacture techniques will be designed and
developed. - Catalysts testing. The testing
activity will be focused on endurance tests to
evaluate the influence of tritium on catalyst
properties. Then, a suitable catalysts
regeneration procedure shall be developed.
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Technology
- Work related to these topics belongs to the
task TW6-TTFD- (Art.5.1a) from the EFDA
Technology Work Program 2006 and was done in
collaboration with Horia Hulubei National
Institute of Physics and Nuclear Engineering
(IFIN HH). - Part of this work has been
performed during the Mobility Secondment at
Forshungszentrum Karlsruhe Tritium Laboratory,
Germany.
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Conclusion

• Isotopic exchange catalysts stability was
  analyzed by
• evaluating the absorbed dosed in tritiated water
  solutions
• simulating by quanto-chemical methods the
  isotopic exchange catalysts behaviour, which
  were exposed to tritiated water. Radio-chemical
  yields determination
• stimulating radiolytic processes by exposing the
  catalyst which was immersed in water to a gamma
  radiation field
• studying the behaviour of the isotopic exchange
  catalyst in presence of tritiated water.
• The results obtained by mathematical moulding
  show an exposure to very high doses of the
  superficial layer of the isotopic exchange
  catalyst for contact periods exceeding 30 days.
  The determined absorbed doses a lot higher than
  the stability limit of the PTFE polymers (0,3
  MGy).
• The analysis of the primary and secondary
  radiolytic processes by quanto-chemical
  simulations shows different degradation
  mechanisms, associated with similar effects,
  respectively
• the break up of the main polymeric bound and
• the HF significant emission

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Thank you for your attention !