Advanced light water reactor “SRZ-1200”

Tokyo, September 29, 2022 – Mitsubishi Heavy Industries, Ltd. (MHI) in collaboration with four Japanese PWR utilities(Note), has developed the conceptual design of an advanced light water reactor “SRZ-1200”. This reactor has additional safety features when compared to conventional pressurized light water reactors. It is in the intention of MHI to take the SRZ-1200 conceptual design and proceed with basic design efforts. These efforts will ensure new innovative nuclear technologies are available toward a stable energy supply for Japan.

The SRZ-1200 is a 1,200MWe class advanced light water reactor designed based on enhanced Japanese regulatory safety standards which incorporates lessons learned from the Fukushima Daiichi accident. Development of the SRZ-1200 is in progress which will ensure the regulatory requirements of “strengthening safety equipment” and “resistance to natural disaster and security against terrorism and unforeseen event” are fulfilled. The cumulation of this development will ensure safety and reliability of the SRZ-1200.

Relative to new safety mechanisms, even though the SRZ-1200 accounts for global lesson learned, low-probability postulated events are still accounted for in the design to ensure plant and public safety. These safety mechanisms include, but are not limited to, an advanced accumulator design, and systems which effectively reduce the probability of radioactivity release in the event of a postulated accident. Efforts of this nature and the resultant SRZ-1200 design features will limit any impact to the public and plant site.
Furthermore, the SRZ-1200 design is intended to enhance operational flexibility which will effectively allow for improved electrical power delivery alongside variable electric power sources such as renewables. The ability to adapt the SRZ-1200 for hydrogen production will also be studied to ensure that all potential uses of energy generated from this plant are efficiently and proactively applied for all of societal needs.

MHI has been involved in the construction and maintenance of all of the 24 PWRs in Japan and has led the efforts to restart and ensure the safe operation of the existing nuclear power plants. These efforts will continue as we bring the SRZ-1200 to market as early as possible to realize a carbon-neutral society for Japan.

The name of SRZ has the following meaning:

S: supreme safety, sustainability
R: resilient light water reactor
Z: ultimate type (Z) contributing to society by Zero Carbon emission.
(In Japan, “Z” also has a meaning of “ultimate type”)
1200: represents the electrical power output of 1200MWe class

Taking into account the Fukushima Daiichi accident, MHI Group strives to continuously enhance safety through the restart of existing nuclear power plants as well as the safe and stable operation upon restart. This is part of our contribution to society and we intend to continue this contribution through the development of advanced light water reactors which achieve the world’s highest level of safety.

• Four PWR utilities: Hokkaido Electric Power Co., Inc., The Kansai Electric Power Co., Inc., Shikoku Electric Power Co., Inc., and Kyushu Electric Power Co., Inc.