The company said the HI-CUT technology used at Indian Point unit 3 has exceeded expectations and "revolutionises" segmentation of reactors undergoing decommissioning.

The gantry-operated HI-CUT device in use for the segmentation of upper reactor vessel internals at Indian Point 3 (Image: Holtec)

HI-CUT has been developed in a two-year programme to improve the efficacy of dismantling radiation-hardened and embrittled reactor internals and pressure vessels at retiring nuclear units with minimum personnel dose, assured control of spread of contamination and multi-layered protection to ensure personnel safety, the company said.

The system was first deployed in November, segmenting Indian Point 3's upper reactor vessel internals at more than double the projected severance rates.

The HI-CUT system has been tested on materials harder than severely irradiated reactor material under simulated conditions, with the test results informing the design, the company said. An operator training programme which included underwater testing of the system and a full-scale mockup of reactor vessel internals was completed before the system's deployment, and was instrumental in ensuring its success, it added. Special attention was paid to the development of a solid rigging and handling plan to handle parts, weighing over 50 tonnes, under water.

Holtec Decommissioning International (HDI) President Kelly Trice said the company hopes to bring its decommissioning technologies - including an innovation which can reduce the number of containers needed to package nuclear waste - to other countries facing decommissioning "in the coming years". Such innovations "enhance safety and environmental justice", he said.

Holtec claims its fleet approach to decommissioning means it can complete the physical work of decontamination and dismantlement decades sooner than if the current nuclear plant owner retains ownership of the plant. HDI, a wholly-owned subsidiary of Holtec International, is the licensed operator for Holtec-owned nuclear power plants and provides the licensee oversight of the decommissioning work that is performed.

Indian Point unit 3 ceased operations in April 2021 after 45 years in operation. It was the final unit at the site in New York state to close after unit 2 ceased operations April 2020. The site also includes the shut-down Indian Point 1, a 257 MWe (net) pressurised water reactor which operated between 1962 and 1974. Holtec completed its purchase of the Indian Point Energy Center from Entergy in June 2021.

As well as Indian Point, HDI is currently decommissioning Oyster Creek in New Jersey and Pilgrim in Massachusetts. The company has also purchased for decommissioning the Palisades plant in Michigan, but has said it intends to apply for federal funding to restart the single-unit plant which closed in May 2022 after over 50 years of operation.

Researched and written by World Nuclear News