Kemmerer Power Station

Kemmerer Power Station
Kemmerer Power Station under construction in November 2024
CountryUnited States
LocationKemmerer, WY
Coordinates41°42′21″N 110°33′38″W / 41.70583°N 110.56056°W / 41.70583; -110.56056
StatusUnder construction
Construction began10 June 2024
OwnersUS SFR Owner, LLC
Nuclear power station
Reactor typeUnit 1: SFR
Reactor supplierTerraPower
Power generation
Units under const.1 × 500 MWe Natrium SFR
External links
CommonsRelated media on Commons

The Kemmerer Power Station is an American nuclear power plant being built near Kemmerer, Wyoming by TerraPower. It will house one 345 MW Natrium reactor along with a thermal energy storage system able to vary its power output between 100 MW and 500 MW for load following.[1]

The power station is the first Natrium reactor to be constructed, and the first commercial sodium-cooled fast reactor in the United States since Fermi 1 was decommissioned in 1975. TerraPower submitted its construction permit application to the Nuclear Regulatory Commission (NRC) on 28 March 2024,[2] and construction of non-nuclear facilities began on 10 June 2024.[3] The NRC approved Kemmerer Power Station's Construction Permit Application on 4 March 2026, issuing the first construction permit for an advanced commercial nuclear power plant in over 40 years.[4]

Design

Kemmerer Power Station is divided into two distinct portions: the Nuclear Island and the Energy Island.[5]: 31–32  The Nuclear Island contains the Reactor Building, Reactor Aux Building, Fuel Handling Building, Fuel Aux Building, Nuclear Island Electric Modules, and Control Building. The Energy Island contains the Energy (Molten Salt) Storage Tanks, Steam Generation Building, Turbine Building, Cooling Towers, and Standby Diesel Generators.[5]: 53 

The power station utilizes a molten sodium, fast neutron spectrum reactor to generate heat. The initial fuel for the core is sodium-bonded uranium metal within a zirconium matrix clad in HT-9 steel.[5]: 32  The core is loaded in a hexagonal matrix consisting of fuel assemblies, reflector assemblies, shield assemblies, 13 control rod assemblies, and various other test and neutron source assemblies as needed for operation and testing.[5]: 33  Core outlet temperature at 100% power is 950 degrees Fahrenheit (510 degrees Celsius).[5]: 1208 

The reactor will produce a constant 840 MW of thermal power, while a molten-salt storage system similar to that of a concentrated solar power plant will vary its electric power.[6] Fission heat is transferred to the molten sodium coolant, which is circulated by two variable speed[5]: 1255  primary sodium pumps (PSP) to two intermediate sodium heat exchangers (IHX). The reactor, sodium coolant, PSPs, and IHXs are contained inside the reactor vessel.[5]: 33  To prevent the sodium reaction with air, an argon cover gas is maintained above the free surface of the sodium below the reactor vessel head.[5]: 34  All penetrations into the reactor vessel are above the free surface of the primary sodium coolant.[5]: 33  The reactor vessel is located inside a guard vessel with argon filling the annulus between the vessels and level instrumentation to detect sodium leakage from the reactor vessel.[5]: 34 

Two independent secondary sodium loops circulate a secondary liquid sodium through an IHX, a sodium-air heat exchanger (AHX) in the Intermediate Air Cooling System (IAC), a sodium-salt heat exchanger (SHX), and a variable speed[5]: 43  intermediate sodium pump (ISP).[5]: 34  Each loop is functionally identical and remains separate from the other for redundancy.[5]: 1102 

The IAC consists of an AHX, a chimney structure, air blowers, dampers, and an air heater. It has three modes of operation: Active Mode, Blower Mode, and Passive Mode. In Active Mode, the loop's ISP provides forced circulation of sodium coolant, and the blower provides forced airflow across the AHXs. In Blower Mode, the intermediate sodium circulates by natural convection with blowers operating. In Passive Mode, both the intermediate sodium and air circulate by natural convection.[5]: 35 

The intermediate sodium loop acquires heat from the primary coolant in the IHX. During normal shutdown and low power operations, heat is rejected to the environment by the IAC in Active Mode. As power rises, heat is transferred to the molten salt by the sodium-salt heat exchanger and heat rejection to the environment is reduced. Once heat is being removed from the intermediate sodium loop by only the sodium-salt heat exchanger, the plant is considered to be in High Power Operation.[5]: 1672 

Heat transferred from the SHX in the intermediate sodium loop is received by the Nuclear Island Salt System (NSS). This salt is circulated to the Hot Salt Tank at the Energy Island.[5]: 31  From there, the salt is circulated through Steam Generation to the Cold Salt Tank and then returned to the NSS to again be heated in the SHX.[5]: 41  The rate of transfer from the Hot Salt Tank through Steam Generation to the Cold Salt Tank does not need to match the rate of transfer from the Cold Salt Tank through the Nuclear Island to the Hot Salt Tank. This difference in flow rates enables the design to adjust electrical power while maintaining a constant reactor power.[5]: 40 

Steam generated from the molten salt is provided to the main turbine generator, condensed from the turbine exhaust, and returned as feedwater to Steam Generation. Heat received by the circulating water in the condenser is rejected to the environment via cooling towers.[5]: 41 

Decay heat generated while the reactor is shutdown is circulated by the PSPs at minimum speed or via natural circulation if the PSPs are unavailable. Heat is removed from the reactor vessel by the IAC. During normal conditions, the IAC operates in Active Mode. During off-normal conditions, IAC Blower Mode will remove decay heat. IAC Passive Mode is used for Emergency operation. Both trains of IAC are required to remove decay heat in Passive Mode.[5]: 1296  When IAC is not available for decay heat removal, the Reactor Air Cooling (RAC) system provides decay heat removal through natural convection with air. RAC is the system designated as the safety-related decay heat removal method. RAC remains in service continuously, and no operator action or system configuration changes are required to initiate cooling. Natural circulation of the sodium coolant will heat the walls of the reactor vessel which will transfer heat to the RAC via radiative cooling.[5]: 34 

In the event of loss of power to the site, two Standby Diesel Generators automatically start to provide power to select plant loads for investment protection. There is no safety-related electrical distribution system for the plant. All safety-related functions are passive. While not required, IAC Active Mode is available with power from the Standby Diesel Generators.[5]: 1253 

Vendors

On 3 October 2024, TerraPower announced the selection of Premier Technology, Inc. to design, test, fabricate, and deliver the IAC's AHX and Air Stack Structures & Equipment.[7]

On 18 December 2024, TerraPower announced the vendors for key reactor components. Equipos Nucleares S.A., located in Spain, will construct the reactor head. Doosan Corporation, located in South Korea, will construct the core barrel, guard vessel and internal supports for the reactor. HD Hyundai, also in South Korea, will manufacture the reactor vessel. Marmen, a North American company, will construct the rotatable plug assembly.[8]

Milestones

TerraPower received the Wyoming state industrial siting permit for Kemmerer Power Station in January 2025.[9]

Kemmerer Training Center ground-breaking occurred in August 2025 to support training operators and maintenance technicians for site operation.[10]

After receiving its draft Environmental Impact Statement (EIS) from the NRC in June 2025, the NRC issued its final approved EIS in October 2025.[11]

References

  1. ^ Pequeño IV, Antonio (2024-03-19). "TerraPower: What We Know About Bill Gates's Nuclear Power Plant In Wyoming". Retrieved 2024-12-18.
  2. ^ Office of Nuclear Energy (2024-05-23). "NRC Dockets Construction Permit Application for TerraPower's Natrium Reactor". Washington, D.C. Retrieved 2024-09-22.
  3. ^ Walton, Rod (2024-06-12). "Next-Gen Nuclear: TerraPower Breaks Ground on 345-MW Natrium Reactor Project". Microgrid Knowledge. Retrieved 2024-09-22.
  4. ^ Timmer, John (March 4, 2026). "TerraPower gets OK to start construction of its first nuclear plant". Ars Technica. Retrieved March 5, 2026.
  5. ^ a b c d e f g h i j k l m n o p q r s t u v TerraPower (2024-03-28). Kemmerer Power Station Unit 1 Preliminary Safety Analysis Report (PDF) (Report). United States Nuclear Regulatory Commission. Retrieved 2024-10-04.
  6. ^ "TerraPower, LLC -- Kemmerer Unit 1 Application". United States Nuclear Regulatory Commission. Retrieved March 5, 2026.
  7. ^ "TerraPower Awards Natrium® Equipment Contract to Idaho-Based Premier Technology" (Press release). TerraPower. 2024-10-04. Retrieved 2026-03-06.
  8. ^ Grochowski, Garrett (2024-12-18). "TerraPower announces contract winners for Kemmerer nuclear plant". County 17. Retrieved 2024-12-18.
  9. ^ "TerraPower receives state permit for nuclear power plant". Oil City News. 2025-01-14. Retrieved 2026-01-13.
  10. ^ Raffetto, Caroline (2025-10-23). "TerraPower Builds Training Center at Kemmerer Nuclear Site". Construction Owners. Retrieved 2026-01-13.
  11. ^ "NRC issues final environmental approval for TerraPower's SMR". Nuclear Newswire. 2025-11-23. Retrieved 2026-01-13.
This article is issued from Wikipedia. The text is available under Creative Commons Attribution-Share Alike 4.0 unless otherwise noted. Additional terms may apply for the media files.