INDUSTRY · NUCLEAR

Nuclear

The industry where safety overrides everything else. Here instrumentation and control is not a productivity tool but a safety barrier — classified, redundant, diverse and qualified. Three major accidents shaped an entire discipline: defense in depth, safety culture, severe-accident management.

The main domains

Reactors

PWR, BWR, SMR

Pressurized or boiling water reactors, and emerging small modular reactors (SMR). Reaction control, cooling, containment.

I&C

Safety-classified systems

Classified architecture (IEC 61226), redundant and diverse protection systems, equipment qualification, independence of defense lines.

Fuel cycle

Enrichment to reprocessing

Fuel fabrication, in-reactor management, storage and reprocessing. Criticality, radiation protection, material traceability.

Key challenges

Defense in depth — multiple independent barriers; no single failure may lead to a release. Redundancy and diversity at every level.
Classified I&C — safety classification (IEC 61226), critical software (IEC 60880), protection systems separated from control systems.
Qualification & ageing — equipment qualified to accident conditions (temperature, radiation, seismic), lifetime management and major refurbishment.
Cybersecurity — dedicated IEC 62645 framework, strict isolation of safety systems, specific human-factors treatment.
Human factors — control-room ergonomics, procedures, simulator training — a direct legacy of Three Mile Island.

Key technologies

Functional Safety Safety PLC Cybersecurity OT DCS PLC

Standards & references

Nuclear I&C derives from IEC 61508 but is mainly governed by dedicated standards: IEC 61513 (I&C architecture), IEC 60880 (safety-system software), IEC 61226 (classification), IEC 62645 (cybersecurity), and IAEA safety standards.

Major players

Operators

EDF, Rosatom, KEPCO, CGN, TVA, Vattenfall.

Reactor vendors

Framatome, Westinghouse, GE Hitachi, Rosatom, KHNP.

SMR

NuScale, Rolls-Royce SMR, GE Hitachi (BWRX-300), TerraPower.

I&C

Framatome (Teleperm XS), Westinghouse, Mitsubishi, Rolls-Royce.

Landmark accidents

Three accidents defined modern nuclear safety — each transformed design, operation or regulation.

Event	Year	Location	Lesson
Three Mile Island	1979	USA	Partial core meltdown, no casualties. Caused by misreading control-room indications. Founded human-factors study and interface ergonomics.
Tchernobyl	1986	USSR (Ukraine)	RBMK reactor explosion during a test. The worst civil nuclear accident. Imposed the concept of safety culture (INSAG) and international cooperation.
Fukushima Daiichi	2011	Japan	Earthquake then tsunami: total loss of power, several core meltdowns. Generalized stress tests and the hardening of heat sinks and backup power.