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Letter to Ontario Power Generation regarding Regulatory Hold Point 3 – Darlington Unit 3

Regulatory Operations Branch

June 19, 2023

Mr. Richard Geofroy
Senior Vice President, Nuclear
Ontario Power Generation Inc.
1 Holt Road South, P.O. Box 4000
Bowmanville, ON L1C 3Z8

Ms. Subo Sinnathamby
Senior Vice President, Refurbishment
Ontario Power Generation Inc.
1855 Energy Drive, 3C14
Courtice, ON L1E 0E7

SUBJECT: Darlington NGS - Unit 3 Return to Service: Request for CNSC Consent to Remove the Regulatory Hold Point for Prior To Exceeding 1 % Full Power

Dear Mr. Geofroy and Ms. Sinnathamby:

The purpose of this letter is to respond to Ontario Power Generation’s (OPG) submission [1], which requests removal of Regulatory Hold Point-3 (RHP-3), allowing operation above 1 % full power for the refurbished Darlington Unit 3 reactor, and provides the associated Completion Assurance Document.

Canadian Nuclear Safety Commission (CNSC) staff’s assessment [2] of OPG’s submission [1], as well as all supporting documentation, concluded that OPG has met all the pre-requisites established by the Commission to remove RHP-3. Therefore, as the person authorized by the Commission and pursuant to Licence Condition 15.4 of the Darlington Nuclear Generating Station (DNGS) Power Reactor Operating Licence 13.03/2025, consent to remove RHP-3 is hereby granted and may now allow operation above 1% full power for the Unit 3 reactor.

Yours sincerely,

Ramzi Jammal
Executive Vice-President and
Chief Regulatory Operations Officer
Regulatory Operations Branch

c.c: A. Viktorov, A. Mathai, M. Rickard, C. Loreti, N. Abonasara, A. El-Merhi, B. Lin, A. Oussoren, C. Badal, C. Brown, C. Chan, Darlington Site Office


  1. OPG Letter, R. Geofroy and S. Sinnathamby to R. Jammal, “Darlington NGS Refurbishment: Unit 3 Return to Service: Request for CNSC Consent Prior to Exceeding 1% Full Power (RHP3)”, NK38-CORR-00531-24130, dated June 15 2023.
  2. CNSC staff document entitled: “Request by Ontario Power Generation Inc. to Remove Regulatory Hold Point for Reactor Power Increases Prior to Exceeding 1% Full Power for Unit 3”, dated June 18, 2023.

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