ASME XI is the ASME code for nuclear in-service inspection (ISI) of operating reactors. This guide decodes inspection scope, NDE methods, weld acceptance, and code-specific gotchas.
\nASME XI covers nuclear in-service inspection (ISI) of operating reactors. Boundaries: defined start/end conditions per the code's scope section. Excluded: items covered by other codes (e.g. ASME VIII for pressure vessels).
\nASME XI specifies acceptance criteria for indications: linear/rounded limits, cluster rules, length × thickness ratios. Code-specific tables differ from generic ASME V. Inspectors must reference the correct code section.
\nPer ASME Section IX — WPS / PQR / welder qualification. Essential variables per the specific process (SMAW, GMAW, GTAW, FCAW, SAW). Continuity log per ASME XI-specific requirements.
\n| Service / Concern | Recommended Method | Code Reference |
|---|---|---|
| Original construction welds | RT or UT | ASME XI + ASME V Article 2/4 |
| Surface cracks (ferro) | MT | ASME V Article 7 |
| Surface cracks (non-ferro) | PT | ASME V Article 6 |
| In-service thickness monitoring | UT-T | ASME V Article 5 |
| Crack-like subsurface | PAUT or TOFD | ASME V Article 4 + Mandatory Appendices |
ASME XI sets construction + initial inspection requirements. In-service inspection follows API 510 / 570 / 653 + state jurisdictional rules.
\nA: ASME Section V Article 1 + API 510/570/653 + ISO 17635 acceptance pathway: Procedure qualified + Level III approved, inspector trained per applicable scheme, acquisition equipment calibrated + traceable. Atlantis delivers the full code-acceptance package.
\nA: Methods (UT/RT/MT/PT/VT) are the same; ACCEPTANCE CRITERIA differ. Reference the specific code's acceptance section.
\nA: Yes — global delivery, ASNT NDT Level III + ASME XI-qualified inspectors. Free consultation + tailored quote.
\nA: Per-asset 3D model with inspection-data overlay, weld register, repair history, NDT signatures. Pressure-equipment register integrated.
\nA: ASNT NDT Level II + nuclear-specific Code Qualifications.
\nA: ASME XI-specified retention, typically life-of-equipment. Atlantis NDT ERP stores all records SHA-256 hashed.
\nA: Inspector + welder qualification typically 3-6 months. Atlantis NDT 5-day cohorts accelerate the path.
\nA: Yes — ASNT NDT Level III led discovery + scope sizing + tailored quote. request a free consultation.
\n\n\nRecommended practices and guides inform an inspection programme; binding requirements come from the in-service codes (API 510, API 570, API 653), the construction codes and the regulations that apply to the asset. NDE personnel are qualified under the employer's written practice (commonly ASNT SNT-TC-1A, ANSI/ASNT CP-189 or ISO 9712), and NDE procedures are approved by the employer's NDT Level III. Acceptance of indications follows the governing code; damage beyond its rules may be referred for an engineering fitness-for-service assessment (API 579-1/ASME FFS-1), which Atlantis NDT does not perform. Keep procedure revisions, calibration records and personnel certifications traceable; Atlantis ERP can hold these records.
\n\nAPI RP 571 enumerates damage mechanisms in refining + petrochem service. For power generation, the dominant mechanisms include: sulfidation (API 571 §4.4.2), naphthenic-acid corrosion (§4.4.6), high-temp H2 attack / HTHA (§4.5.1), amine-stress corrosion (§4.5.4), sour-water cracking (§5.1.3), CUI / corrosion-under-insulation (§4.3.4), MIC / microbiologically-influenced corrosion (§4.3.8), erosion-corrosion (§4.2.14), and chloride stress corrosion of austenitic SS (§4.5.1.4). Atlantis NDT Level III consulting (consult here) maps each circuit to its dominant mechanism + recommends method.
\nRBI per API RP 581 decomposes consequence + likelihood for power generation equipment: (1) Generic Failure Frequency (gff) by component class; (2) Damage Factor (DF) per active mechanism; (3) Inspection Effectiveness Factor (A-E) based on prior inspection thoroughness; (4) Consequence — Financial + Safety + Environmental.
\nWhere findings require engineering assessment, the responsible integrity team must define the assessment scope, necessary measurements and applicable methodology. Atlantis NDT can discuss examination evidence; it does not provide an engineering fitness-for-service assessment.
\nAtlantis NDT delivers integrated stack for power generation operators: Atlantis ERP (NDT reports, technician certificates, crew dispatch and equipment calibration), Digital Twin platform (3D asset model with overlaid damage-mechanism heat-map), Reporting Software (offline mobile capture with code-aligned templates), and Atlantis NDT LMS (continuous inspector cert refresh per power generation-specific scope). Affordable, accessible, fully customizable.
\nUse the edition required by the contract, governing requirements and applicable jurisdiction. Record that edition in the procedure and evaluate changes before adopting a later publication.
\nA: 4-20 weeks depending on team size + scope. SMB: 4 weeks. Mid-size: 8-12 weeks. Enterprise multi-region: 12-20 weeks. Atlantis NDT delivers phased rollout with clear milestone gates.
\nA: Atlantis ERP has an open REST API, so it connects to SAP, Maximo, NetSuite or any other system that accepts API connections; each integration is scoped with you during implementation. Free integration scoping consultation.
\nA: Request a free 30-min consultation at /contact. We reply within one business day. We scope your asset class + damage mechanisms + code requirements + delivery model preference + integration needs in a single call.
\nAtlantis NDT — led by Anoop Rayavarapu (ASNT NDT Level III in UT, RT, MT, PT and VT). Free consultation. request a free consultation. Pricing varies by region and scope.
","order":0,"createdAt":"2026-06-24","updatedAt":"2026-10-18","quickAnswer":{"question":"What does ASME XI cover and how is inspection done in 2026?","answer":"ASME XI governs nuclear in-service inspection (ISI) of operating reactors. Inspection scope includes UT + RT + MT + PT + VT per ASME Section V Articles 2 / 4 / 5 / 6 / 7. Code-specific acceptance criteria + welder qualification per ASME Section IX. ASNT NDT Level III led.","bullets":["ASME XI = nuclear in-service inspection (ISI) of operating reactors","References ASME Section V (NDE) + IX (welding)","Free Atlantis NDT consultation"]}}