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The Irradiation Devices

The development of JHR experimental devices offers a unique opportunity to develop a new generation of devices meeting up-to-date scientific and technological state of art as well as anticipated users’ needs.

Development of experimental devices and related programs requires international collaborations to benefit from the available large experience and to increase the critical mass of cross-disciplinary competences.

CEA with international collaborators is developing first fleet of experimental devices to be on the shelves for the start-up of the reactor (MADISON, ADELINE and MICA devices) also oriented on LWR support but also is preparing a second fleet of experimental devices (called devices under development or feasibility phase) also oriented on GENIV support. The slides linked give an overview of such developments.

JHR experimental capacities Fuel and material irridiation hosting systemps in the JHR reactor


Madison Device specificities Figure 1 : View of MADISON device implantation in JHR facility
The “Multi-rod Adaptable Device for Irradiations of experimental fuel Samples Operating in Normal conditions” will be installed in a reflector position of the JHR reactor on one of the displacement systems and will allow irradiating from 1 up to 8 experimental fuel rods (PWR or BWR). The experiments will investigate their behavior in normal working situations representative of power reactors that may not lead to an expected clad failure.

The in-pile part of the device, will house the experimental fuel samples and will be connected to a loop system providing the adequate thermal hydraulics (temperature, pressure, velocity) and chemical conditions representative of power reactors. Some heavy components of the loop system will be installed out-of-pile in an experimental bunker of the reactor building (see Figure 1).

The experiments targeted in the device will aim to investigate the evolution of the fuel properties (microstructure, fission gas release,…) in function of the burn-up or the Linear Heat Generation Rate (LHGR). Other experiments such as slow power variations representative of slow transient phenomena in power reactors or long-term irradiations (up to 3 years) are also targeted. They will allow investigate clad corrosion under irradiation or crack initiation.

The performances expected in the device are very ambitious :

The design of the water loop is jointly done by CEA and Engineering team from IFE-Halden (Norway) which has a massive experience on design, manufacturing and operation of such kind of loops. The general design of the loop is under finalization.

Once this phase completed, the device will enter a manufacturing phase in order to be available few months before JHR Start-Up.

Madison project leaflet


The first version of experimental ADELINE loop will be dedicated to power ramp testing. The experimental ADELINE loop will be able to reproduce various experimental irradiation scenarios with experimental new or pre-irradiated fuel rods, such as :
- Power ramp tests,
- Rod internal over-pressurization of fuel rod (“lift-off”),
- Rod internal free volumes gas sweeping in fuel rod,
- Fuel pellet centre melting conditions approach.

It will be a one rod experiment where clad failure will be allowed during the test protocol.

A first version will be mainly dedicated to power ramps testing. This will make it possible to continue the service offer and to operate with an experimental quality at least as good as the one already offered by ISABELLE1 loop whose ADELINE integrated many feedback.That means a good precision on qualified thermal balance and a good precision of the clad failure time and consequently a good knowledge of the Linear Heat Generation Rate (LHGR) of fuel rod inducing the failure. Moreover, some enhancements will be added in order to make a quantitative clad elongation measurement of fuel rod during the power transient and to carry out multiple experiences during a reactor cycle. The complete manufacturing of this device started in December 2014 (previous 3,5 years period).


ADELINE Device specificities


  • ADELINE typical experimental scenario and performances

The device will accept different fuel samples types :

  • PWR (including VVER type) and BWR fuel pellets from 5.5 mm up to 14 mm of diameter
  • UO2 fuels up to 12% enrichment of U5
  • MOX fuels up to 20% ratio of Pu/(U+Pu)
  • Rod length up to 600 mm
  • Fresh fuel as well as high burnup fuel up to 120 GWd/t

The experimental sequence is envisaged in the following way (see fig. 1):

  • A low power plateau that may last from one day to one week with the ability to maintain a clad temperature of 330°C (±10 °C).
  • A linear power ramp at a continuous velocity range between 100 W/cm/min and 700 W/cm/min.
    During this increase of power, the clad surface temperature is stabilized at Tsat+ΔTsat as soon as the sample reaches 300 W/cm at its peak level.
  • A high power plateau that may last 24 hours maximum at a linear power up to 620 W/cm at the sample peak level.
  • If a clad failure occurs during one of the last two phases, the stop of the experiment won’t be necessary.
    Indeed, the decision to end the experiment will be based on a certain level of contamination of the loop, not on clad failure detection.
  • Key features

  • Easy and fast recovery of the sample

An underwater equipment of transfer station has been designed in order to load and unload the fuel sample holder without disconnecting the ADELINE device ( In-pile and out-of-pile parts maintained connected).It will avoid unavailability periods of the experimental device ADELINE due to its transfer toward the hot cells. This new tool will make possible to carry out 3 to 4 ramp tests during a reactor cycle (about 25 days long).

  • Good accuracy of the thermal balance

The thermal balance will be based on a differential temperature measurement greater than 20°C allowing a 5.6% accuracy on the peak linear power value.

In the long term, a second version of this loop may be dedicated to the post-failure behavior coupled with a fission product laboratory.

For more information : conference IGORR15 presentation (English version)

MICA Irradiation Device

MICA is a capsule type experimental device whose objective is to study structural materials behavior under irradiation for LWR reactors (temperature : 300-450°C maximum). Although mainly inspired by the CHOUCA device used for decades in the OSIRIS reactor, the MICA device has been fully redesigned in order to fulfill the requirements and specificities of JHR.

MICA device has a long length (6,5 m) from which the in-pile part is made of external cladding (diameter 32 mm) and a sample-holder (useful volume : diameter 24 mm / length 600 mm).

The request temperature in the samples is mainly obtained by nuclear heating from the core and regulated through electrical elements axially inserted in the MICA structures.



Three MICA irradiation devices will be completed to be ready for the first loading in JHR.


Qualification of a NaK waste process treatment for JHR

The experimental devices CALIPSO and MICA who will be used for material studies in JHR will NaK as liquid coolant in order to homogenize the temperature within the samples. After use, the NaK has to be transformed, thanks to a safe process allowing to suppress chemical risks due do its high reactivity considering also a minimization of the production of effluents. To do so, a physic-chemical process of NaK transformation has been established at Cadarache.

The carbonatation has been identified as the best process : this one allow us to transform the sodium in carbonates, some chemical neutral components, thanks to the injection of water steam, dioxyde carbon and Nitrogen. Nevertheless, the specificity of NaK to become liquid at room temperature has necessitated an innovative adaptation of the process to avoid any of liquid NaK in the solid structure of the carbonates. Consequently, a safe and efficient treatment has been validated.

The mid-term objective is to perform the integration of the process in the NaK treatment facility of JHR called CARDENAK.

CLOE Device

Concerning the Long Term Operation of the NPP, the internal components composed of steel will see their irradiation dose increase leading to some sensitivity to local corrosion phenomena called IASCC (Induced Assistance Stress Corrosion Cracking). These complex phenomena require integral experiments in order to be fully representative of NPP operating conditions and thus dedicated experimental devices used in MTR. To answer this need and in collaboration with the India DAE-BARC Research Center (Mumbai), CEA has initiated the design of a loop-called CLOE- to study corrosion under irradiation for PWR and BWR  This loop will be located in the JHR reflector and will allow us to apply a mechanical strength on CT specimens during the irradiation.

MOLi Device

The MOLI device (for fission of MOLybdène 99) aimed to irradiate in JHR reflector target enriched in U235 in order to produce the Mo-99 isotope ( Fission product of U-235) for medical applications (*).
(*) using radioactive decay, Mo-99, gives Technetium Tc-99m (T1/2 ~ 6 h, g 140 keV). This Tc-99m is the most used tracer in nuclear medicine (80 % of performed scintigraphy in nuclear medicine use this isotope).

Four locations in JHR reflector are allocated to Mo99 production. The MOLI devices will be installed on displacement systems in order to allow the loading/unloading of the MOLI targets during reactor operation.

In support of the design, several scale1 mock-ups have been realized (Displacement system, irradiation device and associated tools, Safeguard cooling system…). The contract for manufacturing the in-pile part has been launched in 2015; those for the out-of-pile part and the tools will be launched in 2018.

The MOLI devices will allow to produce between 25 to 50 % of European needs (treatment of 2 to 4 million of patients) 18 months after JHR first criticality.


In the framework of collaborative agreement between UK-NNL and CEA on JHR, the JHR section is welcoming visiting scientists (called Secondee) from the UKAEA – CCFE, Culham Centre for Fusion Energy. This research Centre from Oxford is notably taking care of the operation of the JET Tokamak. This collaboration has already given fruitful results by doing a feasibility study of several irradiation devices which could be load in the JHR (called FUSERO) for specific needs of the Fusion community working on material. For example one can quote:

  • Study of mechanical and optical behavior of functional ceramics under irradiation,
  • Study of samples irradiation at very low temperature,
  • Study of metallic material behavior under thermos-mechanic fatigue.



Non-Destructive Exams Benches

The NDE benches of JHR (supply by the Finnish Research organization VTT) aim to examine irradiated fuel & Material samples in the various experimental devices used in JHR. These Exams can be done either before, during or after the experimental process for control or for scientific objectives.

These benches are located in the hot cells and in the pools (reactor and storage pools) and will be used according the irradiation level of the object to examine.

The UGXR (Underwater Gamma X-Ray bench) Bench

This bench has the advantage to directly perform exams on the experimental devices (even sometimes without any disconnection). It allows:
- The measurement before and after the experiment of the spatial distribution of the gamma emitters in an experimental fuel pin (gamma spectrometry)
- The exam of the experimental sample by X rays radiography and tomography and of the internal structures of the experimental device.

It is important to quote that a second similar bench will be installed  in the interim storage of the reactor building and will particularly be used for long time acquisition measurements.

The SIN (Système d’Imagerie Neutronique) neutronography bench

The neutronography bench is a complementary tool to the UGXR benches. It cannot host full experimental devices but samples holder or pin holder which have been before unload from the experimental devices in the hot cells and eventually repackaged in a dedicated container.

Its uses lead to the constraint of using as a « light source » the neutron flux coming the core compared to the UGXR bench which uses gamma and X rays.

Its justification is linked to the fact that neutron interact in a different way with matter compared to photons. Neutron, contrary to X rays can make the difference between fissile isotopes and not and are very sensitive to water traces, this allowing to detect pins with minor waterproofness default. Accordingly, the neutronography bench is compulsory for the power ramps process in conjunction with the ADELINE device.


Training of the JHR International partners to French Rules regarding design and manufacturing of Mechanical components of Research Reactors

How to share good Industrial practices on experimental devices and NDE equipments between partners ? CEA with AREVA and EDF worked on this topic and has published a code validated by the French Safety Authority (English version published by AFCEN).

CEA continue to regularly propose such training session with INSTN. For example :

  • From design to realization of experimental devices in an MTR
  • First elements of the French Mechanical code RCC-MRx

More to know about INSTN training

Other devices studies

The Jules Horowitz Reactor Research Project: A New High Performance Material Testing Reactor Working as an International User Facility – First Developments to Address R&D on Material (Gilles Bignan , Christian Colin, Jocelyn Pierre, Christophe Blandin, Christian Gonnier, Michel Auclair, Franck Rozenblum)

See presentation at MINOS 2015

Fuel and material irradiation hosting systems in the Jules Horowitz Reactor (J. Pierre, P. Jaecki, P. Roux, C. Colin, T. Dousson, L. Ferry, J. Estrade, C. Gonnier, C. Blandin*)

See presentation at EHPG Meeting 2014

Test devices in Jules Horowitz Reactor dedicated to the material studies in support to the current and future Nuclear Power Plants (C. Colin, J. Pierre, C. Blandin*, C. Gonnier, M. Auclair, F. Rozenblum)

See presentation at FONTEVRAUD 2014

The LORELEI Test Device for LOCA Experiments in the Jules Horowitz Reactor (L. Ferry, D. Parrat, C. Gonnier, C. Blandin*, Y. Weiss, A. Sasson, & al)

See presentation at TOP FUEL 2014

* Corresponding author : marie-pierre.ferroud-plattet@cea.fr Page up

Revision : 2018-03
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