Holtec highlights its used fuel assembly repairs at Angra

Holtec International said it repaired 125 damaged used fuel assemblies as part of the successful completion of its recent loading campaign of 480 used nuclear fuel assemblies into 15 HI-STORM FW dry storage casks at Angra unit 2 in Brazil.

Holtec said its team would return in early 2025 to load 75 damaged fuel containers from the Angra 1 site into 18 HI-STORM FW systems, also at the Complementary Dry Storage Unit for Spent Fuel (UAS).

Under a turnkey contract signed in 2017, Holtec of the USA supplied Eletronuclear with HI-STORM FW systems and related equipment for dry storage of used fuel from Angra units 1 and 2. Angra 1 is a Westinghouse-designed 609 MWe pressurised water reactor (PWR), while Angra 2 is a Siemens-designed 1275 MWe PWR. The units have different architectures and licensing bases, adding to the complexity of the project. Holtec modified their respective cask handling cranes and equipment for loading the fuel into the multi-purpose canisters and for moving the canisters to the dry storage facility.

PK Chaudhary, President of Holtec’s Nuclear Power Division with direct responsibility for Projects, Manufacturing & Supply Chain, said: "We thank Eletronuclear's team for their exemplary support for the Angra 2 used fuel storage campaign. We are gratified to see our innovative spent fuel storage solutions play a critical role at the Angra Nuclear Station. We look forward to a repeat success when our team returns to load used fuel at Angra 1 in early 2025."

The storage facility is designed to receive fuel elements after the cooling process in pools at the plants. They are stored in canisters made of steel and concrete to guarantee safety. It is a system which is used in the USA and is designed to withstand extreme events such as earthquakes and floods.

It includes physical security, radiation and temperature monitoring, an armoured access control centre and a storage warehouse with a technical workshop, designed and constructed by Holtec. The facility was constructed because the storage pools of both units were reaching full capacity. It is designed to hold up to 72 modules, with the capacity to receive used fuel until 2045.

Holtec said it used its Fuel Repair Device (FRD) to repair the damaged used fuel assemblies, technology which it used for the first time during refuelling at its Indian Point Nuclear plant in the USA last year. It says that its system renders a damaged fuel assembly that cannot be handled by normal means into one that can be handled in a normal manner using the plant’s existing fuel handling tooling and is "the only fuel repair technology available in the industry that involves no welding or introduction of any foreign material in the fuel pool".

Holtec says that in 2025 at Angra 1 it will load 18 HI-STORM FW systems with 75 damaged fuel containers and used fuel will be stored in MPC-37 canisters, each of which can contain 37 PWR used fuel assemblies.