The last fuel-rod assembly has been removed from the reactor at the Pilgrim Nuclear Power Station.

PLYMOUTH - The last fuel-rod assembly has been removed from the reactor at the Pilgrim Nuclear Power Station. It is now contained in the spent-fuel pool with nearly 4,000 other assemblies for cooling, according to the Nuclear Regulatory Commission.

Phase I of the decommissioning is officially underway. Owner Entergy Inc. is beginning the process of cleaning up the site and dismantling equipment, buildings and other infrastructure at the power plant, which ceased producing power on May 31.

Earlier this week, the NRC stated it that Pilgrim had "certified cessation of power operations" and that future oversight will be led by its Division of Nuclear Materials Safety and Safeguards "in accordance with our decommissioning power reactor inspection program."

"The objectives of the decommissioning inspection program are to verify that decommissioning activities are being conducted safely, that spent fuel is safely being stored, and that site operations and license termination activities are in conformance with applicable regulatory requirements, license commitments, and management controls," the NRC wrote to Entergy.

Entergy, which bought Pilgrim from Boston Edison in 1999, plans to decommission and clean up Pilgrim over a 60-year period – the maximum time allowed by the NRC. However, Holtec International, a company that says it specializes in "accelerated decommissioning" of power plants, has agreed to purchase the site and restore it to NRC safety requirements in eight years. The NRC must approve the sale and license transfer before that can happen.

According to Holtec filings, all active fuel would be transferred from the site in two years and general cleanup would be completed by 2027, though activity would continue at the spent-fuel storage installation until 2062 or 2063.

Since earlier this year, Attorney General Maura Healey and the Executive Office of Energy and Environmental Affairs have been arguing to the NRC that Entergy Corp. and Holtec International have not demonstrated that the Decommissioning Trust Fund has a balance adequate to cover all the costs associated with decommissioning the plant and the long-term managing of spent fuel, which could lead to health and safety problems.

The Old Colony Memorial recently published a 3-part series on the past, present and future of the Pilgrim Nuclear Power Station. The articles examine the facility’s history from when it was first proposed to construction, operation and decommissioning, as well as what will happen to the site in the coming years.

Includes reports from the State House News Service