革新軽水炉iBR

iBR was developed through the evolution of Toshiba’s proven ABWR which has a large capacity electricity output (1,350MWe). In addition to providing large capacity electrical output that is ideal as a baseload power source, it is a next-generation nuclear power plant capable of flexibly responding to the need to adjust the power supply and demand to facilitate coexistence with renewable energy.

Furthermore, Toshiba considers safe operation to be the most important factor for nuclear power plants to supply energy in a stable manner. In addition to complying with new regulatory requirements, iBR’s safety systems provide the world’s highest level of safety in a light-water reactor. The iBR achieves no need for emergency evacuation, no long-term relocation and a 7-day grace period without any external support, incorporating a defense-in-depth design for the possibility of a large-scale natural disaster and other events.

The iBR is a next-generation innovative reactor that features unprecedented safety based on the proven high-capacity power supply track record of the ABWR combined with innovative safety design using the latest technology.

In addition to the known high-capacity performance of the ABWR, the ability to respond to load fluctuation provides more than adequate performance as a baseload power source.

The BWR integrated the steam generation system inside the Reactor Pressure Vessel (RPV), and the ABWR eliminated the need for external recirculation piping by adopting reactor internal pumps, removing the large-diameter piping below the reactor core, providing a high level of safety that reduces impact in the event of a LOCA (Loss-of-Coolant Accident).

The provision of an innovative Passive Containment Cooling System (iPCCS) that does not need pumps or other devices, Ultra Condenser (UC), In-containment Filtered Venting System (IFVS) that minimizes the release of fission products (FP) eliminates the necessity of emergency evacuation in the event of any accidents, a safety concept that prevents soil contamination.

The iBR is designed to enable cooling of the nuclear reactor and Primary Containment Vessel (PCV) in the event of any accidents without actuating pumps or other devices. The highest level of safety in a light water is achieved by means of an Ultra Condenser (UC), innovative Core Catcher (iCC), an In-containment Filtered Venting System (IFVS) that minimizes the release of fission products (FP), as well as the introduction of a double cylinder containment vessel. In the event of a Severe Accident (SA) like the Fukushima Daiichi Nuclear Power Plant accident, emergency evacuation of surrounding residents and long-term relocation are not necessary.

The iBR adopts a double cylinder containment vessel. The configuration of the double cylinder portion (Outer Well = O/W) provides nearly double the capacity of the existing ABWR for the Pressure Containment Vessel (PCV). The provision of the same level of pressure resistance and airtightness in the Dry Well (D/W) and Wet Well (W/W) contain noble gases and hydrogen gases in the event of a severe accident, and prevent overpressure damage of the PCV. In addition, the adoption of the double cylinder structure enhances seismic resistance.

The innovative Core Catcher (iCC) is installed on the floor of the Dry Well (D/W) in the lower part of the Pressure Containment Vessel (PCV). Water in the Suppression Pool (S/P) is continually supplied to the cooling channel, automatically and passively cooling molten core debris in the unlikely event of a reactor core meltdown.

Robust steel-reinforced concrete (SC) structure dome capable of withstanding Air Plane Crash (APC)

The passive safety systems are contained in the building which is rigorously protected by a steel-reinforced concrete (SC) structure dome. This protects the safety systems from an Air Plane Crash (APC) or various natural disasters.

A complicated configuration incorporating various technologies is required in order to create a power plant with high safety performance that contributes to the realization of a carbon neutral society. Toshiba has reduced uncertainties by designing the iBR based on the proven ABWR system configuration. Utilizing its know‐how accumulated over many years, Toshiba proposes a feasible next‐generation nuclear plant.  

Lessons learned from the Fukushima Daiichi Nuclear Power Plant accident indicated that countermeasure facilities needed to be added to provide for the possibility of a Severe Accident (SA). The structure in which these countermeasure facilities were added to the existing main control room entailed many operation related issues, and increased the maintenance load.

The iBR achieves a unified operation environment for normal operation, as well as during outage and in the event of a severe accident, by means of expanding the target plant status as a consideration for the design of the main control room from the initial design stage.

The compact easy to use main control room provides support for operation and maintenance personnel during normal operation, outage and even severe accidents. The system is designed using the latest technology to ensure it continues to function in a sound and seamless manner during both normal operation and in the event of an emergency.

A wealth of experience has been garnered over many years since starting operation in 1966, and various types of basic development and research have been conducted, accumulating a wide range of results. This extensive experience and knowledge ensure dependable and economic plant construction

In the field (construction site), there are many civil engineering, construction and electrical, mechanical and other companies that perform work in a complex manner. Toshiba closely coordinates with these diverse members from the design and planning stages to ensure work proceeds smoothly.

Field work is efficiently executed by means of performing work in parallel, reducing on-site work, boosting on-site work efficiency and other such specific measures and policies that facilitate coordination between related members, collaborative concepts, proposals and execution.

The BWR integrated the steam generation system into the Reactor Pressure Vessel (RPV), and the adoption of a Reactor Internal Pump (RIP) with the ABWR eliminated the need for external recirculation piping, providing a simple design.

Provision of the performance to coexist with renewable energy which has been increasing in recent years is an important factor, as well as high electrical power output, when evaluating the economic efficiency of nuclear power plant operation. In addition to enabling control with the control rod position, the iBR facilitates flexible output control by means of recirculation flow control. This recirculation flow control method consists of adjusting the void fraction by changing the recirculation flow rate, keeping the core output distribution nearly constant, enabling major changes to the reactor output to be quickly made.