Vahterus Plate & Shell Heat Exchanger Chosen for Nuclear-Fusion Power Plant

ITER is an international project that aims to build the world’s first full-size nuclear-fusion power plant. The power plant is under construction in the city of Cadarache in the South of France, at an estimated cost of around 15 billion euros. The objective of the plant is to produce more energy than is consumed, while the process is running.

Inside a Tokamak fusion reactor, magnetic-field reaction plasma will be heated up to 30 million degrees Centigrade. ITER Tokamak is supported by the largest cryogenic plant ever built. Large quantities of cryogenic helium are required in the plant.

In addition, a liquid-helium plant is already under construction and compressor stations will be delivered to the site. In the design phase, Vahterus Plate & Shell Heat Exchangers (PSHE) were chosen as a component part of the system to reclaim heat from the oil used in these compressor stations. The energy recovered will then be utilised in other parts of the plant.

When the aim of the project is to produce more energy than that consumed, maximum heat recovery from all heat resources at the ITER plant is critical. The heat from the compressor oil is transferred by the Vahterus PSHE into a water stream. To achieve a high rate of heat recovery the exchanger was designed with a low temperature approach between the hot oil and cold water (LMTD 4.4°C). Achieving such a tight approach in temperatures was made possible by using PSHE technology. Vahterus’ scope of supply included 12 large exchangers (PSHE Size 9HA-650), which were designed with a multi-pass construction (5/5) in order to reach the desired temperatures and recover the maximum amount of heat.

One more design requirement was that the heat exchanger solution must be compact. Vahterus PSHE technology is a thermally efficient and compact solution, which fitted well into the tight installation space within the compressor package. Since this plant is unique, it was important that all collaborators and technologies used were trustworthy and reliable. Vahterus was able to satisfy all the requirements of their partners in the project.

When helium is used in the plant, the integrity requirements for heat exchangers are very demanding. It was crucial for the client to choose a technology that could support this requirement. Vahterus developed a helium leak test with an exceptionally low leak rate requirement for the ITER compressor oil coolers. Firstly, the plate side of the unit was pulled under vacuum to a level of 10-2 mbar. After reaching an acceptable level of vacuum, the shell side was then pressurised with helium to 29.7 bar overpressure. The maximum allowable leakage rate was 10-8 mbar L/s. All 12 Vahterus PSHEs successfully fulfilled the requirements of the test.

We are proud and grateful to have been given the opportunity to participate in this unique and ground-breaking ITER project. Delivering PSHE oil coolers of the highest quality was our key objective.