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IN VESSEL

OPE-0849 F4E Market Survey TECHNICAL NOTE

Testing of Prototype Supports for the Blanket Cooling Manifold System and of Pads of the First Wall Panels

Lot 1: Thermal tests on a pipe support

The purpose is to quantify the Thermal Contact Conductance (TCC) between the pipe and its support.

The conceptual design of the support selected for the testing is shown in Figure 1. The support is for 6 pipes. It includes profiled strap, packer and support structure pressed onto the pipes by means of preloaded threaded rods. The threaded rods are of high strength material (Alloy 718 ASTM B637) to maximize the preload and to withstand the expected high temperatures. The pipes are coated with alumina (in yellow on the sketch). The purpose of the alumina is to provide electrical insulation between the pipes and the support. The support is fastened onto the Vacuum Vessel by means of legs that are long and flexible to accommodate the thermal expansion of the pipes during operation.

The principle of the test will be to create heat waves in the support or in the water and to measure the resulting temperature gradients at selected locations. Several thermo-couples (temperature sensors) will be placed at adequate locations to measure temperature variations. The TCC is determined based on the measurement performed.

The water circuit can be established though one or several pipes. The water flow, pressure and temperature in the cooling circuit during the test are parameters to be selected and justified by the Supplier.

Then the TCC between pipes and straps is determined for the given conditions (pretension in the bolts, and outside diameter of the pipes).

The support will successively be tested in ambient conditions and in vacuum conditions. It will be adiabatically restrained at convenient locations to be agreed with F4E.

The test shall first be performed in ambient conditions in order to validate all selected parameters and operating conditions. Once the test conditions are found acceptable, the test willbe repeated in vacuum conditions. A comparison of the results in ambient and vacuum conditions will be provided.

The test will be repeated for three different values of the bolt preload. A preliminary calibration will be performed to establish the relationship between the torque and the pretension in the bolt.

The pipes will be provided with three different outside diameter. The tests will be performed with all three pipe sizes and the effect of the pipe size variation on the TCC will be determined.

Figure 1: Outboard Support (Conceptual Design)

Figure 2: Schematic View of Thermal Test Conditions

Lot 2: Mechanical tests on a pipe support

The conceptual design of the support selected for the mechanical testing is shown in Figure 3.Two different processes have been used to apply the alumina coating on the pipes: the High Velocity Oxygen Fuel (HVOF) process and the Detonation Gun (DG).

The support will be restrained at the legs by the provided fastening bolts. The tie-rods are preloaded to the agreed values.

The support and pipes will be submitted to two types of test: a static test and a cycle test.

The purpose is twofold: to determine the force needed to have the pipe slide inside the clamps and to compare the behaviour of the different coating processes used.

The test will be repeated for three different values of the bolt preload. A preliminary calibration will be performed to establish the relationship between the torque and the pretension in the bolt.

The pipes will be provided with three different outside diameter. The tests will be performed with all three pipe sizes and the effect of the pipe size variation will be determined.

In the static tests, the pipes are submitted one by one to the axial forces. The axial force is incremented by steps of 5kN up to 25kN. The electrical resistance between pipe and support is monitored during the test in order to verify the integrity of the alumina coating.

If the pipe slides inside the support, the value which made the pipe to slide is recorded and the test continues with the next pipe until all have been tested.

The support is then dismounted and a visual examination of the alumina takes place.

Figure 3:Mechanical / Test Conditions

The cyclic test is similar to the static test. An axial force is applied on one pipe a time with the tie-rods successively preloaded to three different values. The axial force is applied sinusoidally varying from zero to 25kN (or to any other agreed value once the static test has been implemented). A limitation shall be put in place ensuring that in case of sliding; the displacement of the pipe is limited to 4mm. The number of cycles is limited to 30,000.

When the 30,000 cycles are completed for all the prescribed preloads, the supportis dismantled and a visual examination of the alumina takes place. If possible the wearing of the surfaces in contact is measured.

Lot 3: Impact tests on alumina coated pads

Lot 3 concerns the performance of impact tests on stainless steel pads coated with alumina. Ten pads coated with the High Velocity Oxygen Fuel process (HVOF) and ten pads coated with the Detonation Gun (DG) process will be tested in total.

The main objective of the impact tests is to check the integrity of the coating of the pads under a cycling dynamic loading of 500J and 400 KN during 500 Cycles.

The applied alumina coating will be considered qualified if no short circuit between the pad and the first wall occurs during the 500 cycles. After the test is completed, the pad will be examined carefully to see if wear has resulted in production of alumina powder. The state of the metal to metal contact surface will also be examined and reported.

The proposed test scenario consists in dropping a mass from a certain height onto the pad.

Upon impact, the potential energy will transform into kinetic energy. In order to obtain the right energy and the right force at the impact, the Supplier shall determine the mass to be dropped, its height, and the characteristics of the energy absorbing layer underneath the pad holder. The Supplier shall submit the Test Procedure to F4E for approval before the implementation.

Figure 7: Schematic View of Pad Test Conditions

For any question, contact us on , specifying “ÖPE-0849 survey” in title.

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