B&W mPower
Encyclopedia
The B&W mPower is a proposed 125 MW modular, advanced light water nuclear reactor. The reactor is to be built by Babcock & Wilcox Co. in North America, and shipped by rail to generating sites. The reactor's power output is approximately 125 MWe, or approximately 10% of a typical reactor. The reactor's design includes an underground containment facility that would store all of the spent fuel the reactor would use during its expected 60 year operating lifetime. Babcock & Wilcox is planning to apply to the Nuclear Regulatory Commission
for design certification by 2013, and plans to deploy the first unit by 2020 at the Tennessee Valley Authority
's Clinch River Site.
building. Current illustrations of mPower site concept drawings show that the reactor is to be installed at facilities of approximately four modules, representing a total of 500 MWe of generation capacity per site. Auxiliary buildings for steam turbines (for power generation) and dry cooling towers will also be on site.
According to Power Engineering, the mPower's design - the factory-built Integral Reactor Vessel and standardized containment design - is designed to provide cost and construction time certainty to a purchasing utility. This is unlike other reactor designs, which are often built on a cost-plus or cost-sharing basis and utilities may suffer delays or cost overruns in the event construction is held back.
In interviews, Babcock and Wilcox personnel have emphasized their track record of experience in the U.S. nuclear industry in comparison to the other firms that are engaged in development of small, modular reactors, as well as the engineering pedigree of the design of the mPower, in comparison to other, unnamed reactors which B&W personnel have referred to as "science projects".
(PWR) and the Boiling Water Reactor
(BWR). Like a BWR, the mPower's primary coolant and moderator is highly purified water (with no soluble neutron absorber - e.g. boric acid
- normally added to it); further, hookups for a Reactor Water Cleanup System are specified in the design to ensure that primary system water remains at the highest level of purity. Similar to the ABWR
, the mPower has numerous integral coolant recirculation pumps included inside the Integral Reactor Vessel (IRV). However, like the PWR, the mPower uses PWR fuel, uses a PWR-style entry from top of core control rod scheme, and like a PWR, retains nearly all of its coolant in liquid phase.
Though the mPower has certain similarities to light-water and advanced light-water reactors, it is designed with numerous major advances in the light water state of the art. The pressurizer and steam generator, along with all primary coolant loop piping and appurtenances, is omitted in favor of a wholly integral design for the primary loop inside a single Integral Reactor Vessel (IRV). Pressure is controlled by the drawing and maintenance of a steam bubble at the top of the IRV, and the integral steam generator is a highly advanced once-through steam generator with the advanced features that Babcock and Wilcox is noted for. Control rod drives are designed to not penetrate the IRV, as in the light water reactors of today, but instead be wholly enclosed within the IRV. Shims are omitted in favor of burnable neutron absorbers within the fuel.
The mPower is designed so as to produce steam with +50°F (+28°C) of superheat, allowing the steam turbogenerator to run in the superheated regime, and avoid the issue of having to deal with low-quality, efficiency-reducing moist steam of the saturated regime, as non-B&W light water reactors (such as the Westinghouse
AP1000 and the General Electric
ABWR and ESBWR) are known to produce.
Nuclear Regulatory Commission
The Nuclear Regulatory Commission is an independent agency of the United States government that was established by the Energy Reorganization Act of 1974 from the United States Atomic Energy Commission, and was first opened January 19, 1975...
for design certification by 2013, and plans to deploy the first unit by 2020 at the Tennessee Valley Authority
Tennessee Valley Authority
The Tennessee Valley Authority is a federally owned corporation in the United States created by congressional charter in May 1933 to provide navigation, flood control, electricity generation, fertilizer manufacturing, and economic development in the Tennessee Valley, a region particularly affected...
's Clinch River Site.
Overview
The mPower's Integral Reactor Vessel is designed to be prefabricated in a factory and sold to a buyer at a fixed price, shipped to a power plant site by rail, and installed in a pre-built underground containmentContainment building
A containment building, in its most common usage, is a steel or reinforced concrete structure enclosing a nuclear reactor. It is designed, in any emergency, to contain the escape of radiation to a maximum pressure in the range of 60 to 200 psi...
building. Current illustrations of mPower site concept drawings show that the reactor is to be installed at facilities of approximately four modules, representing a total of 500 MWe of generation capacity per site. Auxiliary buildings for steam turbines (for power generation) and dry cooling towers will also be on site.
According to Power Engineering, the mPower's design - the factory-built Integral Reactor Vessel and standardized containment design - is designed to provide cost and construction time certainty to a purchasing utility. This is unlike other reactor designs, which are often built on a cost-plus or cost-sharing basis and utilities may suffer delays or cost overruns in the event construction is held back.
In interviews, Babcock and Wilcox personnel have emphasized their track record of experience in the U.S. nuclear industry in comparison to the other firms that are engaged in development of small, modular reactors, as well as the engineering pedigree of the design of the mPower, in comparison to other, unnamed reactors which B&W personnel have referred to as "science projects".
Fuel and Refueling
Power Engineering reports that the mPower is designed for a 5-year refueling cycle, and has a core that can be completely removed in a single evolution, and completely replaced in a second separate evolution, making the core nearly "plug and play", unlike the reactors of today, which require fuel handling and movement of individual fuel rods during a refueling outage. The entire used core, once removed, can be placed in storage in the conveniently located spent fuel pool next to the IRV in the containment, which is designed to hold an entire 60 years worth of used fuel, and is accessible by the convenient containment gantry crane located above the IRV within the containment.Thermal Hydraulics
According to sources, the mPower is designed to incorporate best of breed features from both the Pressurized Water ReactorPressurized water reactor
Pressurized water reactors constitute a large majority of all western nuclear power plants and are one of three types of light water reactor , the other types being boiling water reactors and supercritical water reactors...
(PWR) and the Boiling Water Reactor
Boiling water reactor
The boiling water reactor is a type of light water nuclear reactor used for the generation of electrical power. It is the second most common type of electricity-generating nuclear reactor after the pressurized water reactor , also a type of light water nuclear reactor...
(BWR). Like a BWR, the mPower's primary coolant and moderator is highly purified water (with no soluble neutron absorber - e.g. boric acid
Boric acid
Boric acid, also called hydrogen borate or boracic acid or orthoboric acid or acidum boricum, is a weak acid of boron often used as an antiseptic, insecticide, flame retardant, as a neutron absorber, and as a precursor of other chemical compounds. It exists in the form of colorless crystals or a...
- normally added to it); further, hookups for a Reactor Water Cleanup System are specified in the design to ensure that primary system water remains at the highest level of purity. Similar to the ABWR
Advanced Boiling Water Reactor
The Advanced Boiling Water Reactor is a Generation III boiling water reactor. The ABWR is currently offered by GE Hitachi Nuclear Energy and Toshiba...
, the mPower has numerous integral coolant recirculation pumps included inside the Integral Reactor Vessel (IRV). However, like the PWR, the mPower uses PWR fuel, uses a PWR-style entry from top of core control rod scheme, and like a PWR, retains nearly all of its coolant in liquid phase.
Though the mPower has certain similarities to light-water and advanced light-water reactors, it is designed with numerous major advances in the light water state of the art. The pressurizer and steam generator, along with all primary coolant loop piping and appurtenances, is omitted in favor of a wholly integral design for the primary loop inside a single Integral Reactor Vessel (IRV). Pressure is controlled by the drawing and maintenance of a steam bubble at the top of the IRV, and the integral steam generator is a highly advanced once-through steam generator with the advanced features that Babcock and Wilcox is noted for. Control rod drives are designed to not penetrate the IRV, as in the light water reactors of today, but instead be wholly enclosed within the IRV. Shims are omitted in favor of burnable neutron absorbers within the fuel.
The mPower is designed so as to produce steam with +50°F (+28°C) of superheat, allowing the steam turbogenerator to run in the superheated regime, and avoid the issue of having to deal with low-quality, efficiency-reducing moist steam of the saturated regime, as non-B&W light water reactors (such as the Westinghouse
Westinghouse Electric Company
Westinghouse Electric Company LLC is a nuclear power company, offering a wide range of nuclear products and services to utilities throughout the world, including nuclear fuel, service and maintenance, instrumentation and control and advanced nuclear plant designs...
AP1000 and the General Electric
General Electric
General Electric Company , or GE, is an American multinational conglomerate corporation incorporated in Schenectady, New York and headquartered in Fairfield, Connecticut, United States...
ABWR and ESBWR) are known to produce.
Safety
The mPower is designed so as to make loss of coolant accidents impossible due to the Integral Reactor Vessel which contains the entire primary coolant loop within the reactor pressure vessel. If secondary cooling is lost, creating an effective loss of standard heat removal, there are water supplies located above and within the containment that can be used to cool the IRV with gravity driven-cooling. Further advanced means of heat removal can be used in the event that these systems are exhausted, such as by flooding the containment and establishing natural circulation.See also
- Hyperion Power ModuleHyperion Power GenerationHyperion Power Generation, Inc. is a privately held corporation formed to construct and sell several designs of relatively small nuclear reactors, which they claim will be modular, inexpensive, inherently safe, and proliferation-resistant...
- NuScaleNuScaleNuScale Power LLC is a company formed to construct and sell dedicated design of relatively small nuclear reactors, which they claim will be modular, inexpensive, inherently safe, and proliferation-resistant.-History:The basic design is based on the MASLWR developed at Oregon...
MASLWR - Toshiba 4SToshiba 4S- General description :The plant design is offered by a partnership that includes Toshiba and the Central Research Institute of Electric Power Industry of Japan.The technical specifications of the 4S reactor are unique in the nuclear industry...