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The B&W mPower is a proposed small modular reactor designed by Babcock & Wilcox, and to be built by Generation mPower LLC, a joint venture of Babcock & Wilcox and Bechtel. It is a Generation III++ integral pressurized water reactor (light water reactor).

History

The reactor was unveiled by Babcock & Wilcox in June 2009.[1][2] In July 201, Generation mPower LLC, a joint venture of Babcock & Wilcox and Bechtel.[3] At the same time, Babcock & Wilcox announced that it will build a test facility for the mPower reactor design at the Center for Advanced Engineering and Research in Bedford County, Virginia.[4] In April 2011, Babcock & Wilcox has received a $5 million grant from the Virginia Tobacco Indemnification and Community Revitalisation Commission for this test facility.[5][6]

In June 2011 Generation mPower signed a letter of intent with the Tennessee Valley Authority for constructing up to six reactors at Clinch River Breeder Reactor site in Tennessee. The company also plans to deploy the first unit by 2020.[7]

Generation mPower is planning to apply to the Nuclear Regulatory Commission for design certification by 2013.[7]

Design

B&W mPower is a Generation III++ integral pressurized water reactor (light water reactor) with a modular design. The reactor and steam generator are located in a single reactor vessel located in an underground containment facility that would store all of the spent fuel.[2] The modular unit has diameter of 4.5 metres (15 ft) and it is 23 metres (75 ft) high. The reactor core is of 2 by 2 metres (6 ft 7 in by 6 ft 7 in). The steam generator, derived from naval designs, has 3.6 metres (12 ft) diameter and is 22 metres (72 ft) high. The unit has an air-cooled condenser giving 31% thermal efficiency, and passive safety systems.[8]

The reactor will have a rated electrical output of 125–180 MWe.[8] When originally announced, the reactor had planned capacity of 125 MWe.[2][8] Later the power was increased to 160 MWe and then to 160 MWe.[8] In its pre-application design certification interaction to the Nuclear Regulatory Commission, the reactor's rated capacity was described as 500 MWt of thermal power and 160 MWe of electrical power.[9]

The reactor has an expected lifetime of 60 year.[2][9][10][11]

Fuel and refueling

B&W 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 traditional reactors, 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 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 containment gantry crane located above the IRV within the containment.[10]

The core will not be a "plug and play cartridge" due to source term concerns [if dropped]; rather the traditional PWR fuel is off-loaded one assembly at a time as is typical of operating reactors. This evolution will not take long since the core comprises 69 fuel assemblies. Every feature of the fuel assembly is conventional and based on proven technology; the mPower reactor fuel is exceedingly similar to the fuel loaded in the AP-1000, EPR, and many other PWRs. Although the mPower reactor is advertised to operate for 4[not 5]-years between refueling, customers may operate this reactor with more frequent refueling outages if they so desire.[citation needed]

Thermal hydraulics

The mPower incorporates several features of the boiling water reactor (BWR). Like a BWR, the mPower reactor's primary coolant/moderator is highly purified water (with no boric acid). The Reactor Water Cleanup System ensures that primary system water remains pure. Similar to the ABWR, the mPower reactor has integral coolant recirculation pumps inside the Integral Reactor Vessel (IRV). The mPower reactor control rods are inserted from the top of the core and insert upon scram under gravity. All of the primary coolant is in the liquid phase during normal operation.[citation needed]

The mPower reactor is an advanced, generation 3++ light water reactor. The pressurizer, steam generator, primary coolant loop piping and reactivity control components are contained within a single Integral Reactor Vessel (IRV). The integral once-through steam generator is an advanced derivative of the steam generators used in older B&W designs (Davis Besse). Control rod drives do not penetrate the IRV, as in the light water reactors of today, but are instead wholly enclosed within the IRV. Burnable neutron absorbers within the fuel and control rod inventory is used to suppress hot excess reactivity. Cold shut-down is accomplished with control rod insertion (as in BWRs).[citation needed]

The mPower is designed to produce superheated steam and does not require steam separators and dryers prior to admitting steam into the high pressure turbine.[citation needed]

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.[citation needed]

See also

References

  1. ^ DiSavino, Scott; O'Grady, Eileen; Doggett, Tom (2009-06-10). "McDermott B&W unit unveils small nuclear reactor". Reuters. Retrieved 2012-02-17.
  2. ^ a b c d "B&W unveils modular nuclear power design". World Nuclear News. 2009-06-10. Retrieved 2012-02-17.
  3. ^ "B&W, Bechtel team up on mPower". World Nuclear News. 2010-07-14. Retrieved 2012-02-17.
  4. ^ "B&W to build mPower test facility". World Nuclear News. 2010-07-28. Retrieved 2012-02-17.
  5. ^ "B&W awarded grant for mPower development". World Nuclear News. 2011-04-13. Retrieved 2012-02-17.
  6. ^ "Babcock & Wilcox plans Virginia testing facility". Bloomberg Businessweek. Associated Press. 2010-07-27. Retrieved 2012-02-17.
  7. ^ a b "TVA progresses with mPower project". World Nuclear News. 2011-06-17. Retrieved 2012-02-17.
  8. ^ a b c d "Small Nuclear Power Reactors". World Nuclear Association. 2012. Retrieved 2012-02-17. {{cite web}}: Unknown parameter |month= ignored (help)
  9. ^ a b "B&W mPower". Nuclear Regulatory Commission. Retrieved 2012-02-16.
  10. ^ a b Spring, Nancy (2010-01-01). "B&W mPower". Power Engineering. Pennwell Corporation. Retrieved 2012-02-16.
  11. ^ Mansfield, Duncan (2009-06-10). "Babcock & Wilcox planning mini nuclear reactor". The Seattle Times. Associated Press. Retrieved 2012-02-17.
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