Today several nuclear power plants that were shut down for decommissioning are planning to restart – Three Mile Island Unit 1, Palisades, and Duane Arnold.  

Holtec, owner and operator for Palisades Nuclear Power Plant, is planning for restart in 2027 and their initial construction permit application (Part 1) is scheduled for submission to the Nuclear Regulatory Commission by December 2025.  

In October 2023, Holtec submitted a filing with the NRC (Nuclear Regulatory Commission) to formally begin the process of seeking federal reauthorization of power operations at the plant. However, it’s important to note that the broader effort to restart the plant began earlier with Holtec’s acquisition of the plant in June 2022 and subsequent application for federal loan funding in early 2023.  

The plant was approved for restart and the DOE (Department of Energy) has provided a conditional commitment for a loan guarantee (up to $1.52 billion), but the NRC is still in the process of reviewing licensing and regulatory requests from Holtec, the plant’s owner, and is expected to issue a final decision by July 31.  

Although the DOE loan guarantee was the final financial hurdle, other milestones in support of a Palisades restart were the critical starting blocks. On July 31, 2023, Michigan Governor Gretchen Whitmer signed into law the State of Michigan’s Fiscal Year 2024 budget, which provides $150 million in funding for the plant’s restart. And on September 12, 2023, Holtec jointly announced a multi-decade power purchase agreement (PPA) with two not-for-profit rural electric cooperatives – Michigan’s Wolverine Power Cooperative and business partner Hoosier Energy – for the sale of Palisades’ power output, which would underpin the plant’s long-term economic viability and debt service.  

However, Holtec envisioned the Palisades Nuclear Power Plant site as an opportunity to showcase their SMR-300 design – a small modular reactor with a 300 MWe output – and increase the site’s output capability from 800 MWe to 1,400 MWe. Holtec plans to start construction on one of the two SMR-300 units in mid-to-late 2027.  

This small modular reactor design is a two-loop PWR (Pressurized Water Reactor) that utilizes a unique design feature – an integral Pressurizer stacked on top of a Once-Through Steam Generator (OTSG). The Holtec SMR-300 will utilize 69 Framatome’s 17 x 17 GAIA fuel assemblies (up to 5% enrichment) and 29 HARMONI rod cluster control assemblies (RCCAs).  

The OTSG generates super-heated steam, which in turn drives the turbine more efficiently and reliably, and contributes to the plant’s overall performance and economic viability. Super-heated steam has a higher enthalpy (energy content) than saturated steam at the same pressure, leading to a higher thermal efficiency in the steam cycle and thus greater electrical output. The super-heated steam also reduces the risk of water droplets forming within the turbine, which can cause erosion and damage the turbine blades. This coupled with a well-optimized secondary plant, and modern equipment and controls results in high thermal efficiency (37%, compared to the typical 33% for US nuclear plants).    

Its integral design significantly streamlines the Reactor Coolant System (RCS) by combining key components, contributing to the overall simplification and enhancement of its safety characteristics by eliminating unnecessary redundant systems, and additional automated features which in turn, lowers operation and maintenance costs. Each major reactor component is 12 feet in diameter or less. This allows for fabrication and pre-assembly of components in a factory (Krishna P. Singh Technology Campus in Camden, NJ) that can be paired with flexible and affordable shipping options. Overall, the SMR-300 is expected to be less expensive to build and maintain than traditional nuclear plants ($2,902/kw versus $6,936/kw in construction costs).   

Another advantage of the SMR-300 is that it uses the same fuel as our current nuclear power plants (LEU or Low Enrichment Uranium – 5% enrichment or less), taking advantage of an existing nuclear fuel supply chain and infrastructure, removing the cost and time delay currently needed to develop HALEU (High Assay Low Enrichment Uranium – less than 20% enrichment but more than 5%) fuel.  This also allows for new fuel types that are currently under development to further improve fuel cycle economics, withstand extreme conditions, and/or catastrophic events, such as Accident Tolerant Fuels (ATFs) new fuel claddings.