Mirion Technologies (MIR)

Radiation detection & measurement instruments (Mirion) — nuclear plant monitoring, medical dosimetry and defence detection

AI exposure 5% — derived from reported segment revenue, not asserted.

Where it sits

Connectivity → Test & Measurement Instruments · figures rebased to Q2 2026, reported 2026-07-28

Mirion makes radiation detection and measurement instruments — its largest business is nuclear power radiation detection and monitoring at 42% of revenue, with medical dosimetry at 35% and defence detection at 23%. It was previously placed in B4 Nuclear Power & Utilities, whose explainer describes the operators of nuclear plants and the merchant generators selling electricity; Mirion operates nothing and generates nothing. Placed here by what it makes under rule 1, alongside Keysight, Viavi and Anritsu. Its end market is the one thing that differs from the rest of the cohort — they instrument the electronics stack, Mirion instruments radiation.

Also tagged: secondary in Frontier & Emerging Bets → Healthcare AI & Medtech; secondary in Frontier & Emerging Bets → Defense & Government AI.

Reported segments

• Nuclear & Safety — 69.8% of revenue
• Medical — 30.2% of revenue

Mirion ($266.8M Q2 2026, +19.7% YoY). From the 10-Q segment note: Nuclear & Safety $186.2M = 69.8% (North America $106.0M, up from $66.1M; Europe $77.6M; Asia Pacific $2.6M) = primary B3 Test & Measurement Instruments; Medical $80.6M = 30.2% (North America $73.1M, Europe $7.5M). The nuclear half grew far faster than medical, taking its share from 65% to 69.8%. Radiation detection and measurement instruments — grouped by what Mirion makes rather than by the industries that buy it.

How the 5% is built

• Nuclear & Safety — 69.8% of revenue × 7% AI-driven (disclosed). Radiation detection for nuclear plants and defence; the AI build-out reaches it only indirectly, through new nuclear capacity built to power data centres
• Medical — 30.2% of revenue × 0% AI-driven (disclosed). Radiation oncology QA and dosimetry — no AI-infrastructure linkage

Investment read

Moat. Radiation-detection + nuclear-measurement niche (specialized instruments) serving nuclear, medical, and defense; qualification + installed-base moat.

Bottleneck / pricing power. Moderate pricing power (specialized, regulated niches with qualification barriers); benefits from the nuclear-renaissance + medical demand.

Role in the AI stack. The radiation/nuclear measurement + detection layer.

Connected companies

• Constellation Energy (CEG) — MIR supplies: radiation detection & safety monitoring for nuclear fleet
• Vistra (VST) — MIR supplies: radiation monitoring for nuclear power operations
• Cameco (CCJ) — MIR supplies: detection/measurement across nuclear fuel cycle
• Oklo (OKLO) — MIR supplies: reactor instrumentation & radiation monitoring for SMRs
• BWX Technologies (BWXT) — MIR supplies: radiation detection for nuclear components/defense

Others in Test & Measurement Instruments

• Keysight Technologies (KEYS)
• Viavi Solutions (VIAV)
• Anritsu (ANIRY)

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