Introduction to the ALMR/PRISM

Brought to you by that marvelous trio: Darren Bleuel, John Scott, Larry Sevigny

The acronym ALMR stands for Advanced Liquid Metal Reactor. Substantial work has been done by General Electric, with the help of Argonne National Laboratory, in designing a reactor of this type. Their design is called the PRISM. PRISM stands for Power Reactor Innovative Small Module. The ALMR (or PRISM) is a fast reactor but, unlike most fast reactors, it is not designed to breed significant amounts of Plutonium (though the core could be modified to optimize this).

Each plant site contains three power blocks. A power block consists of three of these modular reactors, thus the use of the word Module in PRISM. Therefore, each reactor site contains nine reactors. Each reactor produces 160 MWe of power. A reactor producing this amount of power is considered to be small thus, the use of the word Small in PRISM. Each power block produces 480 MWe of power. The steam generated by the three reactors in a power block passes to a common steam turbine to generate electricity. Thus, the total plant produces 1440 MWe of power from three steam turbines.

A utility can choose to have less than three power blocks on a plant site or they can start with one and add-on power blocks as their demand increases. Even more significant to the economics of the utility is the fact that each reactor is liscenced separately and that reactors on a power block can start producing electric power before the other reactors are even built.

The last PRISM innovation is the idea of the reactor components being built in a factory and shipped to the plant site; even the large reactor vessel. Currently, components are constructed at the plant site but, with this new approach, factory standards can be assured before the components are shipped.

At the present time, funding on the PRISM reactor has been discontinued, with no definite plan to resume research in the near future.

• Problems and Benefits of the ALMR
• Core and Reactor Vessel
• ALMR Fuel Assemblies
• ALMR Gas Expansion Modules
• Ultimate Shutdown System
• Control Rods
• Reflectors and Blankets
• In-Vessel Transfer Machine and Storage
• ALMR Cooling System
• EM Pump and Orificing
• Intermediate Heat Exchanger and Steam Generators
• Reactor Housing
• Reactor Vessel Auxilary Cooling System (RVACS)
• Containment and Seismic Isolation

Or browse through all the topics using the handy directional arrows below:

References:

1. "The New Reactors," Nuclear News, September 1992/Vol.35/No. 12, pages 88-90
2. "1992 ALMR Plant Design Summary," DOE Publications, January 1992

gav@nuc.berkeley.edu