Letter to Ontario Power Generation regarding Regulatory Hold Point 1 – DNNP Unit 1

Regulatory Operations Branch

March 30, 2026

Mr. Mark Knutsen
Senior Vice President, Enterprise Engineering and Chief Nuclear Engineer
Ontario Power Generation Inc.
1908 Colonel Sam Drive
Oshawa, Ontario  L1H 8W8

Subject: DNNP LTC – Request for CNSC consent to remove the regulatory hold point prior to installation of reactor building foundation

Dear Mr. Knutsen,

The purpose of this letter is to respond to the Ontario Power Generation (OPG) submission [1], which requests removal of the first regulatory hold point (RHP-1) to allow construction associated with the installation of the Reactor Building (RB) foundation, and provides the associated completion assurance document as per the Ontario Power Generation – Canadian Nuclear Safety Commission (CNSC) Staff Protocol for the Management of Regulatory Hold Points (RHP) [2].

The Canadian Nuclear Safety Commission (CNSC) staff assessment [3] of OPG’s submission, as well as all supporting documentation, concludes that OPG has met all the pre-requisites established by the Commission to remove RHP-1. Therefore, as the person authorized by the Commission and pursuant to Licence Condition 15.3 of the Darlington New Nuclear Power Reactor Construction Licence 32.01/2035, I consent to remove RHP-1. OPG may now allow construction associated with the installation of the RB foundation.

Yours sincerely,

Ramzi Jammal
Executive Vice-President and Chief Regulatory Operations Officer
Regulatory Operations Branch
Canadian Nuclear Safety Commission

cc: M. Ferry, S. Irvine, D. Tyndall, K. Bramma, K. Simerson (OPG)

S. Eaton, B. Vary, B. Rzentkowski, M. Rickard, M. Broeders, A. Viktorov, K. Cormier, J. Leblanc, A. Oussoren, W. Chung, A. Baig, N. Simon, DNNP mailbox (CNSC)

References

1. OPG letter, M. Knutsen to R. Jammal, “DNNP LTC - Request for CNSC Release of Regulatory Hold Point-1 (RHP-1) Prior to Installation of Reactor Building Basemat”, March 25, 2026.
2. DNNP Protocol, “Ontario Power Generation – Canadian Nuclear Safety Commission Staff Protocol for the Management of Regulatory Hold Points (RHP) in the Darlington New Nuclear Project Licence to Construct Phase”, September 2025.
3. CNSC staff document: “Request by Ontario Power Generation Inc. to Remove Regulatory Hold Point for Installation of the Reactor Building Foundation”, March 27, 2026.