# JHR Project, France irradiation devices “ ADELINE type ” preliminary qualification test

Stephane Gaillot, Francois Huet, Didier Tarabelli

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Stephane Gaillot, Francois Huet, Didier Tarabelli. JHR Project, France irradiation devices “ ADELINE type ” preliminary qualification test. AIEA IGORR conference, May 2021, Kazan, Russia. cea-05516030

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JHR Project, France

Irradiation Devices « ADELINE type »

Preliminary Qualification Tests

Authors: S.Gaillot (1), F.Huet (2), D.Tarabelli (3)

(1) CEA, DES, IRESNE, Nuclear Technology Department

(2) CEA, DES, DIMP, DPED (TechnicAtome)

(3) CEA, DES, IRESNE, Reactors Studies Department

CEA, French Alternative Energies and Atomic Energy Commission,
Division of Energies, CEA Cadarache.13108 Saint Paul lez Durance. France.
Technicatome, 1100, Rue Jean R. Guillibert Gauthier.13100 Aix en Provence. France

contact person : stephane.gaillot@cea.fr

**Abstract**

The Jules Horowitz Reactor (JHR) is under construction in the south of France at the CEA Cadarache. The JHR is a modern facility, MTR type (Material Testing Reactor), taking into account the last safety and regulation requirements. The JHR will meet the needs of operators in terms of materials and fuel irradiations for current nuclear reactors (Gen.2,3) and future reactors generations (Gen.IV, fusion support). It will also produce radioelements (mainly Mo99) for medical applications.

The JHR project is performed and will be operated within the framework of a consortium gathering countries or partners institutions including France (CEA, EDF, FRAMATOME, Technicatome), European Union (JRCs) as well as other contributing countries (Belgium, Spain, Finland, Sweden, Czech Republic, Israel, India, Japan, UK and China).

As part of the development of the irradiation devices fleet for the JHR reactor, technological qualification tests are necessary. They contribute to validate, from the experimental point of view, the proposed technological concepts. They allow verifying the associated experimental performances before manufacturing the final components.

This paper is proposed in this framework. It concerns irradiation devices fleet and "ADELINE type" components. Typically, this type of device will be devoted to perform in the JHR power ramps tests on an irradiated fuel rod.

After a reminder of the general context of the JHR project, the main characteristics of the reactor and the irradiation devices, a focus is made on the preliminary qualifications activities regarding critical components identified for "ADELINE type" device.

In this context, an overview of the qualification process provided on the device's cooling flow amplification component is described. Calibration tests of the cooling flowrate are also présented.

Finally, some concluding remarks will be given as to the contribution of the preliminary qualification tests in support to the development of experimental equipments for the JHR.
# 1. Introduction

In the process of the development of the irradiation device fleet for the JHR reactor operation, technological qualification phases are identified. These experimental support tests contribute to validate the concepts proposed during the design phase. It allows also checking the associated experimental performances.

This is in this framework and for the "ADELINE type" fuel irradiation device development phase that this paper is proposed.

After a recall of the context of the JHR project, the main characteristics of the reactor and the irradiation devices are given. Then, a focus is made on the critical component qualification tests identified for the "ADELINE type" irradiation device.

An overview of the qualification process provided on the device's cooling flow amplification system and calibration tests of the cooling flowmeter is presented and first elements are given.

# 2. Reminder of the context

The Jules Horowitz Reactor which is currently under construction at the CEA Cadarache centre (Bouches-du-Rhone department, France) is a material testing reactor (MTR). It will be used to perform irradiation tests on Fuel and Material samples as part of support Programmes for current nuclear power reactors (Gen II and III) and future reactors (Gen IV and fusion). This reactor will also be used to produce radioelements (mainly Mo-99) for medical purposes and will meet 50% of the European demand in this field.

<figure><img src="image_2.png" /><figcaption>Fig.1a: JHR support building. v07-2019</figcaption></figure>

<figure><img src="image_3.png" /><figcaption>Fig.1b: JHR reactor pool overview. v09.2019</figcaption></figure>

# 3. Main characteristics of the Reactor

## 3.1 Introduction

The main characteristics of the Jules Horowitz reactor are recalled below [R1]:

* ✓ the compact core is designed to generate a nominal power up to 100 $MW_{th}$,

* ✓ it is cylindrical in shape, with a diameter of 60 cm and a height of 60 cm,

* ✓ the reactor is immersed under 9.3 m of water (level with the mid-height plane) in a pool that is 12 m deep,

* ✓ the core is under-moderated in order to generate strong fast neutron fluxes, i.e. up to $5.10^{14} n.cm^2.s^{-1}$, $E > 1MeV$,

* ✓ the primary system is closed and slightly pressurised (12 bar upstream of the core),

* ✓ the cooling water in the core flows upwards at a velocity of about 10 m/s,

* ✓ gamma heating in the core is about 15 to 20 W/g (maximum local value),
* the beryllium reflector is 30 cm thick and surrounds the core vessel. Its role is to thermalize the neutrons produced in the core,

* the thermal neutron flux in the reflector is 3.10<sup>14</sup> n.cm<sup>-2</sup>.s<sup>-1</sup>.

Ten experimental locations will be available in the core and another ten in the reflector, including six on the displacement systems, which are designed to modify the distance between the samples and the core in order to control the nuclear power in the fuel sample.

After the divergence phase of the reactor, the start-up phase of the experimental equipment's is planned over a one-trial period spanning 12 to 18 months. Once this stage is reached, the experimental loops will be operational and ready to meet the needs of future customers.

## 3.2 Experiments in the Core

In the core, various experiments are possible. The first possible configuration involves placing the irradiation device in the first crown of the core, and particularly in the center of a fuel element. This privileged position allows researchers to produce important fast neutron fluxes on the samples. These fluxes, translated into displacements per atom (dpa), are typically 15dpa/year with 100MW<sub>th</sub> reactor power. These conditions make it possible to carry out accelerated ageing campaigns on the samples. Other sites in the 2<sup>nd</sup> and 3<sup>rd</sup> crown presenting reduced fast neutron fluxes are considered. In addition, the devices can be located in the position of a fuel assembly to increase the embedded capacity of the samples.

<figure><img src="image_4.png" /></figure>

## 3.3 Experiments in the reflector

The Beryllium reflector has ten sites where it is possible to conduct experiments. Six sites are possible in fixed positions and four others are foreseen for mobile systems (SAD). The different positions available will enable researchers to obtain conditions of neutron fluxes compatible with the needs for fuel rod irradiation tests in LWR conditions (PWR, BWR,VVER).
# 4. The JHR Irradiation Loop for Fuel Power Ramps Tests.

## 4.1 Main features:

An experimental irradiation loop dedicated to rod irradiation functioning under LWR conditions in under detailed study (cf. fig.3). This loop is called ADELINE [R1, R2].

This fuel irradiation loop is composed of an in-core part located in the reactor pool and of another part located in the operation zone of the experiments (BUR, CEDE).

The in-core part includes the irradiation device equipped with a rod, the underwater lines and the fluid & electrical connections through the experimental penetrations of the pool.

The other part is made up of the fluid circuit, a tight bunker and connection of the circuit with the utilities of the JHR facility.

The fluid circuit is equipped with pressurization system and circulating pumps, making it possible to obtain the circulation of water-cooling towards the device and to reach the required thermal-hydraulic conditions at the bottom of the test channel (P=155 bar, T=270°C, Q=200 to 250g/s).

The experimental loop under study also takes into account the feedback of this kind of loop like the ISABELLE irradiation loop, which was used on the OSIRIS irradiation reactor located in SACLAY (FRANCE) and which was operated up to 2015.

<figure><img src="image_5.png" /></figure>

## 4.2 Expected Performances of the Loop:

The experimental rod is composed of a $UO_2$ type or MOx, irradiated or not.

The standard profile of power during the test is described hereafter:

* ✓ Conditioning phase with low power (100 W.cm⁻¹) ranging from a few hours to a few days,

* ✓ Power ramp test with kinetics going up to 700 W.cm⁻¹.min⁻¹,

* ✓ Power aimed at the high level of 620 W.cm⁻¹+/-10W.cm⁻¹ for one maximum duration of 24h,

* ✓ Withdrawal of the device according to the power decrease scenario.

The physical parameters around the rod correspond to the following PWR conditions:

P=155 bar, T=320°C with a fluid flow of Q=0.2 to 0.25 kg/s and P=73 bar, T=280°C for BWR conditions.
Regarding the displacement system (SAD), it can move to or from the core tank. It allows implementing linear power variations simply and quickly on the sample and reaching representative power level and fission products inventory during conditioning phase and before a soliciting test.

<figure><img src="image_6.png" /><figcaption>Fig.4a: Example of power evolution versus SAD displacement and fuel enrichment (analytical calculations)</figcaption></figure>

<figure><img src="image_7.png" /><figcaption>Fig.4b: Typical experimental scenario of a fuel power ramp test.</figcaption></figure>

Such a concept is convenient for operation (easy to handle, even during the operating cycle of the core) and for safety, the backward position and the off normal conditions of the device are not directly coupled to the core operations.

# 5. Qualification Phase

## 5.1 Introduction

In the process of technological development of a new experimental equipment, the preliminary qualification phase allow to validate certain design options. This step concerns, as a priority, the components defined to be functionally critical for the equipment.

Regarding the "ADELINE type" irradiation device, the defined critical components, requiring a qualification phase, concern, in priority, the flow amplifier block located in the upper part of the in pile part of the device. This injection block has a role of amplifier (accelerator) fluid flow into the device. This fluid flow is necessary to ensure proper cooling of the fuel rod in the test section.

The second qualification test concerns the calibration of a flow meter located in the test section downstream of the fuel rod. The planned flowmeter is a VCône type (compact VENTURI type). It will provide a measure of the cooling flow in the test channel. This measurement occurs in the thermal balance of the experimental rod. The cooling flow require high accuracy (objective dQ/Q < 1%).

## 5.2 Flow amplifier block Qualification Test

### 5.2.1 Introduction

The flow amplifier block, object of this qualification, is composed of a metallic body equipped with two injectors associated with two nozzles. With this configuration, it make possible to create a dynamic movement of the fluid inside the test device (flow recirculation using the pressure energy of injected flow throw the amplifier block). The advantage of implementing this type of component is to limit the injected flow rate (inductor) in the device by a factor of about 2 to 4.
This type of injectors-nozzle system had been already implemented in the past on the ISABELLE irradiation device used on the OSIRIS reactor (Saclay-France) [R3] or on the Jet pump device used on the SILOE reactor (Grenoble-France).

<figure><img src="image_8.png" /><figcaption>Fig.5a : "ADELINE type" device
Overview of the flow amplifier system</figcaption></figure>

<figure><img src="image_9.png" /><figcaption>Fig.5b : view of the amplifier
prototype module</figcaption></figure>

## 5.2.2 Qualification objective

In the context of development of the first fleet of irradiation devices for the JHR, it is identified necessary to qualify the operating principle of the Injectors-nozzles system. These operations permit to validate the hydraulic behaviour as well as the manufacturing operation (in particular, the control of the machining of the injectors (reproducibility aspect) as well as the operation of assembling of the injector-nozzle pair (effect of the distance between the components).

## 5.2.3 Input data

For an inducing flow (thermal hydraulic support circuit) of Q=50 g/s at the pressure of P=170 bars approximately, the objective for the "ADELINE type" loop is to create an induced flow (cooling flow) of Q=200g/s at P=155 bars in the test section. The injector-nozzle system leads to a flow amplification of a factor of approximately four. This system thus allows to reduce the flow rate of the out of core part and to limit the size of the components (pumps, valves, etc.).

<figure><img src="image_10.png" /><figcaption>Fig.6a: "ADELINE type" device.
TH input data in front of
the amplifier system</figcaption></figure>

<figure><img src="image_11.png" /><figcaption>Fig.6b: "ADELINE type" device.
TH parameters objective
in the test section
(downstream the amplifier system)</figcaption></figure>
Thermal hydraulics calculations have been carried out on the amplifier system. The results are given in fig.7.

It should be noticed that the performance of the injector-nozzle system is highly dependent on pressure losses in the outlet part of the circuit. It can have a significant impact on the amplification factor and the final thermal hydraulics performances of the system.

<figure><img src="image_12.png" /><figcaption>Fig.7a: ADELINE type.
TH preliminary calculation
of fluid amplification factor
(configuration with 2 injectors)</figcaption></figure>

<figure><img src="image_13.png" /><figcaption>Fig.7b: ADELINE type.
Preliminary losses of pressure calculation
through the flow amplification system
depending of injectors used (1 to 4)</figcaption></figure>

The results obtained specify the data to be taken into account for the tests according to the desired performances: The configuration, which will be considered for these tests, is given hereafter:

- Two injectors-nozzles of the ISABELLE type (PE-1, ISA-4)

- Inductive flow rate of Q=50 g/s, Induced flow rate of 250 g / s, Amplification factor of 4,4.

### 5.2.3 The test section and the experimental loop

The support test section, which is under study for this qualification test reproduces partially the design of the final "ADELINE type" test device where will be used the flow amplifier system.

The test section consists of a pressure metallic box containing in the upper part the flow amplifier unit to be tested, a down corner part and the test section equipped with the VCone flowmeter as it's illustrated in the following figures:
<figure><img src="image_14.png" /><figcaption>Fig.8a : simplified scheme
of the injectors qualification test section</figcaption></figure>

<figure><img src="image_15.png" /><figcaption>Fig.8a : overview of
the overall test section CAD design.</figcaption></figure>

An inert rod with different geometries will be used in the qualification test section in order to create different pressure losses in the circuit and to determine the thermal hydraulic impact on the system.

The instrumentation will be used in the test section will permit to measure on-line the pressure losses of different components in the device (centering pieces, rod, instrumentation, etc.).

<figure><img src="image_16.png" /><figcaption>Fig. 9a: Test section CAD drawing</figcaption></figure>

<figure><img src="image_17.png" /><figcaption>Fig.9b : Test section
& Flow regulation module</figcaption></figure>

The qualification test section will be coupled to a flow regulator module (fig.9) allowing to drive a range of flows from Qmin to Q=100g/s (induced flows).

The test section will be equipped in the lower part with a VCône or a Venturi flowmeter (induced flowrate).This instrumentation will be also calibrated in LWR conditions (PWR & BWR).

The calibration of the flowmeter will consist of a comparison of experimental value given by the VCône or Venturi & compared with values given by a reference flowmeter located on the loop (CORIOLIS type).

Note: the interest of the use of VCône flowmeter comparing to a Venturi is its compact geometry.
<figure><img src="image_18.png" /><figcaption>Fig.10a : Design of the test section
Equipped with flow meter.</figcaption></figure>

<figure><img src="image_19.png" /><figcaption>Fig.10b : Pressure losses characteristics
for different flowmeters (VCône, Venturi, CORIOLIS)</figcaption></figure>

The fluid supply for the qualification test section will be obtained by an experimental loop called CORAIL which reproduces the thermal-hydraulic conditions at the PWR or BWR conditions for a variable flow rate of Q=1 to 5m³/h in each of 6 channels stack.

<figure><img src="image_20.png" /><figcaption>Fig.11a : CORAIL experimental loop.
CAD scheme</figcaption></figure>

<figure><img src="image_21.png" /><figcaption>Fig.11b : Overview
of the experimental CORAIL loop</figcaption></figure>

Hereafter are given the main TH characteristics of the CORAIL test loop:

Fluid: demineralised water

Pressurisation: 155-190 bar

Inlet temperature: 250-350°C, Outlet Temperature = 250-362°C. Void fraction <40%

Total Flow rate (6 channels) : 30m³/h,

Chemical skid: B (0-1000ppm), Li (0-350ppm), O₂, H₂

### 5.2.4 Experimental test grid proposal:

The tests, which will be performed with the test section dedicated to the qualification of the amplifier flow system, are foreseen on the CORAIL experimental loop. The objective of these tests are to check the thermal-hydraulic performances of the nozzle injector's block on the following operating range:
<table><caption>Table 2: Experimental test grid proposal</caption><thead><tr><th>Location</th><th>Thermal Hydraulics conditions</th><th>Temperature</th><th>Flowrate</th></tr></thead><tbody><tr><td>amplifier system inlet</td><td>P = 1 to 190 bar (ou P. max operating pressure)</td><td>T = 20 to 350°C</td><td>Injection flow Q = 0 to 100 g/s</td></tr><tr><td>amplifier system outlet</td><td>P = 1 to 169 bar. Nominal conditions PWR: 155 bar, T = 320°C. BWR: 80 bar, T = 280°C.</td><td>T = 20 to 350°C</td><td>Amplified flow Q = 0 to 300 g/s (PWR) Q = 0 to 350 g/s (BWR)</td></tr></tbody></table>

## 6. Conclusion

In the process of the development of experimental devices for the JHR project, qualification tests of critical components are necessary.

The tests presented in this paper concern preliminary qualifications tests such as the validation of a fluid flow amplifier system for the "ADELINE type" device, which is under development for the fleet of JHR experimental devices.

The system to be tested consists of a set of two injectors and nozzles.

The flow rate obtained by the amplifier system permit to cool correctly the test rod.

Its performance and reliability have to be guaranteed.

This is the objective of these preliminary thermal hydraulics qualification tests.

The out-of-pile qualification test section will make it possible to reach the conditions necessary to verify the thermal-hydraulics of the system. The results, which will obtained will depend strongly of the manufacturing precision of the components (injectors geometries in particular).

In parallel of this qualification, calibration tests of cooling flowmeter are also identified in order to increase the accuracy of the thermal balance of the fuel rod during the power ramp tests.

## 7. Références

[R1] IGORR 2009
JHR. The ADELINE irradiation loop in the Jules Horowitz MTR.
Testing a LWR fuel rod up to the limits with a high quality level. Experimental process.
S.GAILLOT, D.PARRAT, G.LAFFONT, C.GONNIER, C.GARNIER
CEA, DEN, CEA CADARACHE, F-13108 Saint-Paul-lez-Durance, France.

[R2] PHYSOR 2014
Jules Horowitz Reactor, France.
Development of an experimental loop INTEGRATING AN optimized irradiation process.
S.GAILLOT, S.VITRY & T.DOUSSON
CEA, DEN, CEA CADARACHE, F-13108 Saint-Paul-lez-Durance, France.

[R3] NUCLEAR ENGINEERING & DESIGN 168
Techniques for Power ramps tests in the ISABELLE1 loop of the OSIRIS Reactor.
A. ALBERMAN & AL.

<figure><img src="image_22.png" /></figure>