Hot Cells

• Mission
• Research Programs
• The Units Staff
• Facilities
  
  

Post Irradiation Examination of Nuclear Fuel

Spent Fuel Characterization in View of Long Term Intermediate and Final Storage

Reprocessing & Separation of actinides from irradiated fuels and targets

Front view of the hot cell laboratory

Mission

The mission of the Hot Cell Technology (HCT) unit is to improve the safety of the nuclear fuel cycle. The programmes address research activities relative to the nuclear fuel

• to demonstrate a safe in-reactor operation under normal, transient and accident conditions.
• to improve the  spent fuel behavior under intermediate and final storage conditions 
• to reduce the amount and the toxicity of radioactive waste by partitioning and transmutation (P&T)

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Research Programmes

The fuel research aims at optimizingthe proper behavior of the fuel in a nuclear power plant. The goal is to maximize the fuel rod reliability and to guarantee efficient use of resources including the recycling of Pu in MOX fuel.

In-pile fuel behaviour studies include the following tasks:

• structural investigations and basic studies of fuel at high burn-up
• performance of high burn-up fuels including MOX
• fission product behavior and interaction of structural materials under accident conditions

Regarding the nuclear fuel cycle research, HCT is involved in the main waste management strategies. One of the major public concerns regarding the use of nuclear energy is the issue of radioactive waste. The European Commission supports the efforts of Member States in assuring the safest possible handling of this waste. The HCT unit is involved in research related to the two main waste management options.

One is to identify ways of significantly reducing the amount of long-lived radioactive material that will need to be disposed of through partitioning and transmutation, thereby shortening the very long times for which such waste must be stored safely. In the P&T case, HCT is in charge of verification of hydrometallurgical and pyrometallurgical process schemes using genuine fuels.

The second option is to guarantee a safe storage of spent nuclear fuel; either extended interim storage for several hundred years or final disposal in a geological repository, where detailed knowledge of the fuel behaviour in contact with the man-made barriers and the natural environment is required. In this field, HCT provides reliable source term data on spent fuel corrosion under repository conditions. Those data should be used in models developed for waste repository assessment programs.

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The unit and its staff

The HCT unit is divided into 8 groups, 7 in charge of scientific topics, one responsible for the technical maintenance of the laboratory. The unit is composed of about 50 permanent staff (11 academic and 39 technical) and welcomes around 10 fellows (doctoral, post-doctoral and visiting scientists) integrated in the various research topics.

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Facilities

The hot cell laboratory has 24 shielded hot cells (see picture on top of page) where up to 1 million curies can be handled including 2 decontamination cells.  Most of the cells are equipped with an alpha tight stainless steel containment, a so-called caisson, and has also a replacement caisson for each cell. The advantage of this concept is to allow a cell renovation with a minimum dead time, because the replacement caisson can be re-equipped and tested, while the "old caisson is still in operation.

Mechanical workshops, specialized in manipulator maintenance, provide the necessary technical support for the laboratory. For the various research programmes a large varity of techniques are available in the HCT unit.

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Post irradiation examination of Nuclear Fuel

• NDT, puncturing, X-ray radiography
• Microscopes: light, SEM, TEM etc
• EPMA, SIMS, laser ablation ICP-MS for elemental analysis
• Annealing furnaces (1500-2500 °C) in various atmospheres 
• Special annealing furnace (KÜFA) for coated gas cooled reactor fuel
• µ x-ray diffraction
• High temperature µ-indentor
• Acoustic probe for porosity measurement
• µ-gamma scanning
• hydrogen determination in irradiated cladding by hot inert gas extraction
• Burst and creep testing furnaces
• High Resolution ICP-MS 
• radiometric techniques including alpha- and gammaspectrometry and liquid scintillation counting
• Revaporisation facility for aerosol deposit analysis

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• Electrochemical cells to study the corrosion behavior partly combined with surface analytical techniques such as XPS 
• Special techniques (e.g. electrochemical noise) used to detect extremely slow corrosion
• Quartz micro-balance to measure corrosion rates in the sub-ng range
• Flow-through reactors  to study the leaching behavior under  dynamic conditions with on-line Eh measurement 
• ICPMS, radiometric techniques (alpha-, gamma-spectroscopy, liquid scintillation counting) for chemical analysis
• Oxidation furnaces to determine the fuel oxidation 
• x-ray for intermediate oxidation testing

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• Centrifugal contactor battery for continuous counter-current extraction
• Hollow fiber module to optimze extraction efficiency
• titration equipment for acidity determination
• Chemical Analysis: ICP MS radiometric techniques etc.
• Hot cell for pyroreprocessing under pure Ar atmosphere equipped with:
  - electrorefiner
  - molten salt
  - molten metal extractors 
  - chlorination device
• Double glove box to study basic thermodynamic data of actinides in molten salts 
• Glove box to study the conversion of oxide fuel into metals
• Glove box to study room temperature ionic liquids
  
  

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