Scheduled nuclear outages are built on precision, coordination, and trust. Every work scope is planned months, and often years, in advance to ensure facilities return to service safely and on schedule. When underwater inspections, repairs, or debris removal are part of that scope, the same level of preparation must extend below the waterline.
Underwater work cannot be treated as a last-minute task during a refueling outage. It should be integrated into outage planning early, aligned with plant milestones and executed by teams that understand the pace, expectations, and discipline of nuclear work.
At J.F. Brennan Company (Brennan), our nuclear divers help energy producers execute scheduled outages with confidence by bringing outage-ready planning, nuclear-qualified training, and dependable underwater execution to some of the most schedule-sensitive work at the plant.
Scheduled refueling and maintenance outages are carefully sequenced to minimize downtime and maintain generation reliability. Within those compressed windows, underwater work often supports systems that are critical to plant restart.
This can include:
These scopes often sit directly on the critical path to restart. If underwater findings are discovered late, or if work is not properly planned, outage schedules can be affected.
Scheduled outages reward preparation, not improvisation.
Underwater work during a nuclear outage requires more than commercial diving expertise.
Brennan prepares for these environments long before outage execution begins.
Our divers complete nuclear-specific training tailored to plant requirements, including mock contaminated diving exercises, visual inspection qualifications, and specialized welding certifications when required. Teams are trained to understand outage critical path concepts and the operational impacts of delays.
This preparation allows our crews to operate as an integrated extension of the station’s team.
The most successful outage support begins well before mobilization.
Brennan often engages months in advance to participate in scope development, schedule coordination, and contingency planning. This early involvement allows our project managers to align staffing, equipment, and execution strategies with plant outage expectations.
Planning includes:
Collaboratively planning and coordinating underwater scope around outage milestones, plant equipment, and access restrictions.
Preparing alternate staffing plans, night-shift support, and follow-on work options if conditions change.
Flagging schedule overlaps or access limitations that could create delays.
Establishing inspection reporting workflows that support engineering review and outage closeout.
Early engagement reduces uncertainty and helps outage managers maintain schedule certainty.
During a scheduled outage at a two-reactor nuclear generating station, Brennan supported planned circulating water plug installation, intake bay inspections, and system cleaning activities necessary to facilitate cooling system maintenance.
Returning the circulating water system to service depended on successful completion of this work.
Because cooling system readiness directly affected plant restart, outage planning began six months before execution. Brennan worked closely with plant personnel and other work groups to refine task sequencing, identify contingencies, and establish around-the-clock dive support if required.
When schedule setbacks emerged elsewhere in the outage, that contingency planning allowed dive operations to expand immediately without affecting overall outage milestones.
Real-time dive video and immediate file transfer to system engineers supported rapid evaluation of findings, allowing decisions to be made without delay.
At another nuclear facility, Brennan supported a planned outage involving remotely operated vehicle inspections and dive support for circulating water system assessments.
During execution, inspection findings identified macrofouling conditions that required immediate expansion of dive cleaning scope.
Because Brennan had been integrated into planning early, staffing and equipment resources were already structured to adapt.
This flexibility is one of the most important advantages of early contractor involvement.
Underwater scope should be included in long-range outage planning.
Early engagement allows nuclear dive contractors to align personnel loading, qualifications, and execution strategies to outage requirements.
Ask:
These questions reduce risk before execution begins.
Nuclear outage support requires rigorous documentation.
Dive contractors should demonstrate:
Even planned outages can reveal unexpected conditions. The right dive partner can rapidly assess findings, communicate clearly with outage leadership, and execute follow-on work without resetting schedules.
Scheduled nuclear outages succeed when every scope is planned with discipline and executed with precision. Underwater work is no exception.
We support our clients, so nuclear power plants can execute refueling and maintenance outages with confidence by bringing our nuclear-qualified training, outage-aligned planning, and dependable execution to all underwater work.
Brennan is approved to perform safety-related work in accordance with ASME NQA-1 (2022), 10 CFR 50 Appendix B, and 10 CFR Part 21, and is certified to ISO 9001 (Quality Management), ISO 14001 (Environmental Management), and ISO 45001 (Occupational Health and Safety Management) standards.
About J.F. Brennan Company
J.F. Brennan Company, Inc. (Brennan) is a family-owned marine construction firm specializing in environmental remediation, dam construction, commercial diving, harbor management, and submarine cable services. Working closely with public and private owners of water-based infrastructure since 1919, Brennan operates throughout waterways across the United States and Canada.