Following a first issue relating to “chemistry matters”, issued in June, the regulator has said Hitachi’s arguments supporting its safety claims “do not meet the relevant expectations”, as they are “insufficient to provide a reasonable understanding” of the risk of using the reactor.
“The concerns identified by ONR in the regulatory issue will need to be addressed to our satisfaction before we would consider whether a design acceptance confirmation could be granted,” the regulator said.
In response to the ONR, Hitachi-GE said it “acknowledges” that its submissions, made in December 2014, “did not meet UK regulatory expectations”. “As a consequence Hitachi-GE must develop a revised approach in line with UK good practice, in order to build UK regulator’s confidence in our ability to deliver a suitable and sufficient full scope, modern standards, PSA by June 2016 as committed in generic design assessment step two,” it added.
“However the design process used in the development of the Japanese reference plant is rigorous and Hitachi-GE is confident that when we implement the revised PSA modelling approach this will demonstrate the proposed advanced boiling water reactor generic design is safe and will meet appropriate UK environmental and safety standards.”
The advanced boiling water reactor, designed by Hitachi-GE, generates electricity by using steam to power a turbine connected to a generator; the steam is boiled from water using heat generated by fission reactions within nuclear fuel.
The generic design assessment is the process by which the UK nuclear regulators assess the potential suitability of a nuclear reactor design for development at an unspecified location in the UK, considering safety and environmental impact considerations.
A spokesperson for Hitachi-GE told Utility Week: “Our resolution plan outlines how we’ll address the issue that has been raised. ONR has indicated this provides confidence the matters raised can be adequately resolved within GDA, and we’re focused on implementing that plan.
“ are a normal and important part of generic design assessment, addressing these types of issue early on in the new build process. This issue relates to the way we have presented information in our regulatory submissions, and does not indicate a problem with the design philosophy of the ABWR plant.”
The ABWR design is already licensed in Japan and the US, with four units having been built in Japan, and two currently under construction in Taiwan.