Doosan Enerbility of South Korea and NAC International of the U.S. have designed a new metal cask for storing spent nuclear fuel that has received design certification from the U.S. Nuclear Regulatory Commission (NRC).
The new cask is called the Metal Storage Overpack (MSO)-37. It can hold thirty-seven pressurized water reactor (PWR) spent nuclear fuel assemblies. A ceremony was held to mark NRC approval at NAC’s corporate headquarters in Atlanta, Georgia. Changyeol Cho, Vice President of Doosan Enerbility's Nuclear Business Group, and Kent Cole, President and CEO of NAC International were among the attendees.
The MSO was conceptualized by the NAC and Doosan Enerbility for international applications. It is an alternative to concrete storage systems for the Korea Dry Cask Storage industry. The Doosan Enerbility and NAC teams cooperatively designed and engineered the new cask. In December 2019, NAC filed an amendment application with NRC for design certification. It is the world’s first metal storage cask to have obtained design certification from the NRC.
NAC said that the NRC approval is an MSO option of its Magnastor dry cask storage system technology. It is “the first and most widely deployed ultra-high-capacity canister system installed at US PWR commercial nuclear power plants”. To date, two hundred and eleven Magnastor systems have been loaded and are in service to safely store spent nuclear fuel at operating and shutdown sites.
NAC said, “Compared with conventional concrete storage casks, this newly-developed metal storage cask provides robust radiation shielding and structural integrity, significantly reduces the diameter of the cask, thereby optimizing the storage cask's footprint in dry storage facilities, which in turn allows storage of more casks in the same locality.”
Doosan Enerbility said that the MSO-37 was developed to take into account “the characteristics of spent nuclear fuel, facility operation environments, and public demand for rigorous safety and radiation protection standards in Korea”.
Jongdoo Kim is the Head of Doosan Energility’s Nuclear Business Group. He said, “With the technical capabilities recently acquired from the development and licensing experience of the metal storage cask, we plan to actively participate in spent nuclear fuel dry storage projects in the domestic market and to also contribute to the future development of casks designed for permanent disposal of spent nuclear fuel.”
Jongdoo added that “Based on our supply chain built with the leading local manufacturers, we are set to actively target the global nuclear cask market and will do our utmost to promote growth of the nuclear energy ecosystem and overseas exports.”
In October 2015, Doosan and NAC announced that they were signing a cooperation agreement for the joint development of a spent nuclear fuel storage system to be deployed in Korea.
In 2017, Doosan completed development of the DSS-21. It is a dry storage system that has the capacity to safely store as many as twenty one spent nuclear fuel assemblies. Since then, the DSS-24 and DSS-32 with larger storage capacities were developed. The DPC-24 was also developed. It is a cask that can be used for both storage and transportation of spent nuclear fuel.
In 2021, Doosan became the first Korean company to export spent nuclear fuel storage casks to the U.S. They supplied five sets of a vertical concrete cask to the Three Mile Island nuclear power plant in Pennsylvania.