U.S. APWR Mitsubishi

As a result of extensive verification and qualification testing, we have developed an Advanced Pressurized Water Reactor (APWR) design that is more efficient with greater output than any previous power plant. This design has been slightly modified to satisfy U.S. and international utility requirements as the US-APWR, and it will become the design that we sell around the globe. The US-APWR satisfies our customers’ requirements with the best performance for safety, economy, operation and maintenance.

The main specifications of the US-APWR are:

Electric Power                                      1700 MWe
Core Thermal Power                              4451 MWt
Reactor Fuel Assemblies                      257
Reactor Fuel                                        Advances 17 x 17, 14 ft
Active Core Length                               4.2 meters
Coolant Flow                                        2.75 x 10⁴ m³/h/loop
Coolant Pressure                                 15.5 MPa
Steam Generator Type                         90TT-1
Number if Steam Generators                 4
Reactor Coolant Pump Type                 100A
Number of Reactor Coolant Pumps        4
Reactor Coolant Pump Motor Output     6000 kW

Features of the US-APWR include:

Enhanced Safety:

A four-train safety system for enhanced redundancy.
An advanced accumulator.
An in-containment refueling water storage pit.

Enhanced Reliability

A steam generator with high corrosion resistance.
A neutron reflector with improved internals.
A 90% reduction in plant shutdowns compared to other four-loop PRWs.

Attractive Economy

A large core with a thermal efficiency of 39%.
Building volume per MWe that is four-fifths that of other four-loop PWRs.

More Environment Friendly

A 28% reduction in spent fuel assemblies per MWh compared to other four-loop PWRs.
Reduced occupational radiation exposure.
Capacity to use mixed oxide (MOX) fuels made from reprocessed nuclear fuel waste.

The US-APWR has several design features to improve plant economics. The core is surrounded by a steel neutron reflector which increases reactivity and saves ~0.1wt% U-235 enrichment. In addition, the US-APWR uses more advanced steam generators (compared to the APWR) which create drier steam allowing for the use of higher efficiency (and more delicate) turbines. This leads to a ~10% efficiency increase compared to the APWR.

Several safety improvements are also notable. The safety systems have enhanced redundancy, utilizing 4 trains each capable of supplying 50% of the needed makeup water instead of 2 trains capable of 100%. Also, more reliance is placed on the accumulators which have been redesigned and increased in size. The improvements in this passive system have led to the elimination of the Safety Injection system, an active system.