Record of Decision: Darlington Small Modular Reactor
CNSC record of decision in OPG’s application for new nuclear at Darlington.
April 4, 2025
In November 2020, Ontario Power Generation (OPG) announced plans to build a prototype “small modular reactor” (SMR) at the Darlington Nuclear Generating Station, in addition to the existing reactors already in operation. Since then OPG has stated they may seek to build up to four such additional new reactors.
These prototype reactors have been sheltered by a decade-old environmental assessment in a decision made by the Canadian Nuclear Safety Commission (CNSC) in 2024.
As a result, OPG has applied for a licence to construct one new prototype reactor, a BWRX-300 reactor. A hearing was held in January 2025 and a decision was issued by the Commission granting the license to OPG in April 2025.
A copy of the decision provided to CELA by the Commission can be found here. The decision includes a number of comments relating to significant outstanding issues related to the design of the reactor (for a detailed discussion see pages 39-45 of the Decision). They are all deleaged to the CNSC staff for further review and acceptance.
In the decision, the Commission provided for “regulatory hold points” which require additional information including the following:
Despite the objections from many Intervenors that the design was insufficiently developed to grant this license, the Commission decided that in addition to delegating these questions of acceptability of design evolution to the Commission staff, certain issues would be considered in respect of the license to operate as opposed to the license to construct.
CNSC record of decision in OPG’s application for new nuclear at Darlington.
Oral submissions for the Darlington New Nuclear Project licence to construct hearing, scheduled for January 2025.
CELA’s presentation to the Canadian Nuclear Safety Commission hearing regarding whether a previous environmental assessment applies to a new nuclear project proposal.
CELA’s submission to the Canadian Nuclear Safety Commission in preparation for a hearing as to whether a previous environmental assessment applies to a new nuclear project proposal.
CELA has submitted a review of OPG’s Updated Plant Parameter Envelope and Environmental Impact Statement Review reports for the Darlington New Nuclear Project.
CELA, has submitted a letter in response to the Canadian Nuclear Safety Commission’s (CNSC) Revised Notice of Hearing in Writing dated May 4, 2021 requesting comments on an application from Ontario Power Generation Inc. (OPG) for a licence amendment to authorize activities related to the production and possession of Molybdenum-99 (Mo-99) at the Darlington Nuclear Generating Station (DNGS).
In 2008 Ontario Power Generation (OPG) sought environmental assessment (EA) approval to build up to four new nuclear reactors at the Darlington site. A Joint Review Panel (with members from the Canadian Environmental Assessment Agency and the Canadian Nuclear Safety Commission – CNSC) held public hearings in 2011. CELA and many other public interest organizations participated in the Joint Review and raised many concerns about:
The Joint Review Panel reported to the Federal Environment Minister in 2011 recommending acceptance of the EA. The federal government subsequently accepted the EA in May of 2012. The CNSC license issued in 2012 and valid until 2022 allows only for site preparation. In the meantime, the Ontario government had stated that it would not proceed with building new reactors in Ontario. In June of 2020, OPG applied to renew the site preparation licence beyond 2022; which was granted. Since then, as noted above, OPG has begun a process to seek approval to construct up to four new “small modular reactors” at the Darlington site. See the above section, ‘New Nuclear – Small Modular Reactors’ for more information.