Clinch River construction permit recommendation follows safety evaluation

Staff at the Nuclear Regulatory Commission have recommended the agency issue a construction permit to the Tennessee Valley Authority for its plans to construct a GE Vernova Hitachi Nuclear Energy (GVH) BWRX-300 reactor at the Clinch River site in Tennessee, according to the safety evaluation report published as part of the construction permit application process.

The recommendation to the commissioners is a boon for the project, which proposes constructing a 300-MWe boiling water reactor in Oak Ridge, Tenn. The June report-available in the NRC ADAMS library-presents the NRC staff's review of TVA's 2025 application and any additional information staff received through April of this year.

The findings: According to NRC staff, the application met five key criteria:

• It met applicable standards and requirements of the Atomic Energy Act of 1954, as amended, as well as commission regulations.
• It conforms to the applicable guidance for the construction permit applicant for a commercial light water reactor, with acceptable variances.
• TVA provides reasonable assurance that the final design will conform to the design basis with adequate margin for safety, based on the reactor's preliminary design.
• TVA provides reasonable assurance that the proposed facility can be constructed and conform with the permit, the Atomic Energy Act of 1954, as amended, and commission regulations.
• The financial information, technical analyses, programs, and organization shared and described by TVA demonstrated the applicant's financial and technical qualifications to engage in the construction of the SMR facility in accordance with commission regulations.

The Advisory Committee on Reactor Safeguards (ACRS) met in early June to complete its review of the safety aspects of the TVA application. Its conclusions and recommendations-published separately from the larger safety evaluation report-include the following:

• The application "describes an innovative, natural-circulation boiling water reactor (BWR) design with a simplified plant architecture, passive decay heat removal, and coolant retention based on reactor isolation. The design and the preliminary safety analysis report (PSAR) were sufficiently complete for the construction permit (CP) stage, leading to an efficient review."
• The safety methodology used by GVH is a "beneficial framework for ensuring the fundamental safety functions are met and the integrity of radionuclide release barriers is maintained given the explicit and traceable linkage of safety functions, classification of systems, structures and components (SSC), deterministic analyses, probabilistic risk assessment (PRA) insights, risk-informed special treatments, and defense-in-depth."

The report stated that the safety strategy used by GVH must demonstrate "timely reconciliation" with 10 CFR Part 50 to support the application's safety case. ACRS advised NRC staff to "capture lessons learned from this review for efficiently reconciling such defense-line type approaches with prescriptive light water reactor regulatory requirements for future applications."

ACRS did provide some "important concerns" that needed to be addressed at the operating license stage and at the initial startup. According to the report, this included "operational testing to confirm natural circulation stability especially at startup and low power, confirmation of isolation condenser system (ICS) performance and associated control and interlock functions, and design extension conditions and practical elimination claims (beyond design basis events)."

Ahead of schedule: The publishing of the safety evaluation report outpaced the original timeline, according to a letter NRC staff sent to TVA regarding the review status of the construction permit application. The agency originally informed TVA that the evaluation report would be complete by November. The expedited timeline is a result of "review efficiencies and frequent and productive engagements with TVA," according to the letter.

This has resulted in NRC staff projecting it will need about 16,500 staff hours to complete the review and issuance of the permit, a reduction from the estimate of 25,000 staff hours reported to TVA last year. The estimate of contractor costs to complete the review and issuance is approximately $1.4 million, which has not changed since last year, according to the letter.