Maintenance in the nuclear industry is the systematic set of activities performed to preserve, restore, and verify the performance of structures, systems, and components (SSCs) important to safety and reliability. It is one of the largest and most technically complex functions in a nuclear power plant, encompassing preventive maintenance, corrective maintenance, predictive maintenance, and surveillance testing across thousands of components with varying safety significance.
The regulatory basis for nuclear maintenance in most jurisdictions is extensive. In the United States, 10 CFR 50.65 — the Maintenance Rule — requires nuclear licensees to monitor the performance or condition of SSCs within scope, establish performance or condition goals, and take corrective action when goals are not met. The rule also requires assessment of the aggregate effect of maintenance activities on plant risk, and imposes special requirements for maintenance on risk-significant systems.
Maintenance work management — the process by which work is identified, prioritized, planned, scheduled, executed, and closed out — is a critical determinant of plant reliability and worker safety. Effective work management processes ensure that the right work is done at the right time with the right resources, that workers enter jobs with clear understanding of the hazards and required mitigations, and that as-found and as-left conditions are documented in a way that supports ongoing equipment health monitoring.
Human performance considerations are particularly important in maintenance work. Tasks performed in radiation fields, confined spaces, at elevation, or on energized equipment introduce layers of complexity and risk. Pre-job briefings, peer checks, independent verification of equipment restoration, and post-maintenance testing are standard practices that protect both workers and the plant.
The industry's maintenance programs increasingly incorporate risk-informed approaches — using probabilistic risk assessment (PRA) insights to focus resources on the components and systems whose failure would most significantly impact safety or reliability. This risk-informed, performance-based approach reflects the maturation of the industry's understanding of which maintenance activities deliver the most safety value.
Horizontal steam generators in VVER reactors require specialized inspection and maintenance strategies due to their unique geometry. Their layout improves sludge management and tube accessibility, but also introduces distinct inspection challenges.
Inspection TechniquesContamination control prevents the spread of radioactive material within the plant. Good housekeeping practices keep work areas clean, organized, and free of loose debris that could become contamination sources.
Key PracticesBottom Line: Clean work is safe work — strong contamination control keeps radioactive material exactly where it belongs.
Foreign Material Exclusion prevents debris, tools, fasteners, and other objects from entering plant systems where they could cause damage, flow restriction, or equipment failure. FME discipline protects both equipment and personnel.
Key ConceptsBottom Line: FME discipline keeps foreign objects out of critical systems — a small screw in the wrong place can become a major event.
Lockout/Tagout ensures that equipment is safely isolated from all hazardous energy sources before maintenance or testing begins. Proper LOTO protects workers from unexpected energization, movement, or release of stored energy.
Key ElementsBottom Line: LOTO is one of the most powerful safeguards in the plant — disciplined isolation keeps workers safe from hidden energy hazards.
Work control ensures that maintenance, testing, and modification activities are planned, authorized, executed, and documented in a safe and consistent manner. Strong work management keeps the plant aligned, predictable, and protected from inadvertent errors.
Key ElementsBottom Line: Work control is the gatekeeper of safe plant activity — disciplined planning, execution, and documentation keep every task aligned with the plant’s safety and reliability goals.
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