Ultrasonic Testing (UT) Requirements Under 10 CFR 50 Appendix B

Sensitivity setting is the auditable step: the reference block used must itself be in calibration and traceable, and its identity recorded on the report. 10 CFR 50 Appendix B, enforced by U.S. Nuclear Regulatory Commission: Appendix B is method-agnostic and names no certification scheme: Criterion IX simply requires qualified personnel and qualified procedures.

An auditor examining UT asks for instrument, probes, cables, couplant, and the calibration and reference blocks used to set sensitivity. Appendix B sets eighteen quality assurance criteria for activities affecting the safety-related functions of nuclear structures, systems and components. For an inspection service provider two criteria bite hardest. Criterion IX, Control of Special Processes, requires measures assuring that special processes 'including welding, heat treating, and nondestructive testing, are controlled and accomplished by qualified personnel using qualified procedures in accordance with applicable codes, standards, specifications, criteria, and other special requirements.' Criterion X, Inspection, requires inspection by individuals other than those who performed the activity being inspected. Criterion XVII requires records identifying the inspector or data recorder, the type of observation, the results, the acceptability and the action taken on any deficiency. Criterion XVIII requires planned periodic audits by trained personnel without direct responsibility in the area audited.

Source: Appendix B to 10 CFR Part 50, 'Quality Assurance Criteria for Nuclear Power Plants and Fuel Reprocessing Plants,' full text from the GPO govinfo CFR annual edition, Title 10 Volume 1, revised as of 1 January 2024 — Introduction and Criteria I through XVIII, quoting Criterion IX, X, XVII and XVIII verbatim. Cross-referenced against 10 CFR Part 21, 'Reporting of Defects and Noncompliance,' same edition, whose definition of 'basic component' at paragraph (4) expressly includes 'safety-related design, analysis, inspection, testing, fabrication, replacement of parts, or consulting services... whether these services are performed by the component supplier or others.' Accessed 21 Aug 2026.

Ultrasonic Testing under 10 CFR 50 Appendix B — procedure, personnel and evidence
Item	What applies	Why it matters
Regime	Appendix B to 10 CFR Part 50 — Quality Assurance Criteria for Nuclear Power Plants and Fuel Reprocessing Plants	Enforced by U.S. Nuclear Regulatory Commission
Method	Ultrasonic Testing (UT)	Needs its own procedure and its own qualified personnel
Procedure approval	The employer's Level III, qualified in this method	The signature an auditor traces
Other methods in scope	PAUT, RT, MT, PT, VT, ET	Each needs separate qualification
Renewal	Appendix B sets no expiry — it is a standing regulatory requirement, not a certificate. What recurs is verification. Criterion XVIII requires a comprehensive system of planned and periodic audits, and Criterion VII requires the licensee to assess the effectiveness of a supplier's quality control 'at intervals consistent with the importance, complexity, and quantity of the product or services.' For NDT service suppliers this normally lands on the joint utility audit cycle — NUPIC runs most vendors on a 33-month schedule — supplemented by annual internal audits.	Applies to the personnel certification behind this method

Does 10 CFR 50 Appendix B require a separate procedure for UT?

Yes. Every method in scope needs its own written procedure, approved by someone qualified in that method, describing technique, equipment, calibration, scanning or coverage, acceptance criteria and reporting. A single combined "NDT procedure" covering several methods is a finding under every regime that names procedures individually.

Who can approve a UT procedure under 10 CFR 50 Appendix B?

A Level III qualified in UT. Because 10 CFR 50 Appendix B accepts employer-based certification, that Level III may be contracted rather than employed — but their own qualification must cover UT, and an auditor will check that before accepting the signature.

What UT records does a 10 CFR 50 Appendix B audit sample?

The approved procedure, the technician's UT certification on the date of work, and the equipment evidence — instrument, probes, cables, couplant, and the calibration and reference blocks used to set sensitivity. The auditor works backwards from a finished job, so every item has to reconcile with the report and its stated acceptance criteria.

What is the most common UT finding at audit?

An in-calibration instrument used with an unidentified or out-of-calibration reference block. It is a records failure rather than a technique failure — the examination was performed correctly and the evidence supporting it cannot be produced, which under 10 CFR 50 Appendix B is recorded the same way as not having done the work.

Can a technician certified elsewhere perform UT under 10 CFR 50 Appendix B?

Not automatically. Employer-based certification ends when the holder leaves, so the new employer must certify them under its own written practice. Prior training and documented experience transfer as evidence; the certificate itself does not.

What equipment evidence does UT need under 10 CFR 50 Appendix B?

Calibration status traceable to the day of use, covering the instrument and its accessories — probes, cables, blocks and reference standards for ultrasonics; sources and densitometers for radiography. An in-calibration instrument with an out-of-calibration reference block fails the same way as an uncalibrated one.

How do UT requirements differ from the other methods in 10 CFR 50 Appendix B?

Scope, qualification and evidence are method-specific, so the differences are real rather than administrative. 10 CFR 50 Appendix B also covers PAUT, RT, MT, PT, VT, and each carries its own procedure, its own personnel qualification and its own equipment evidence.

Personnel certification for UT

Appendix B is method-agnostic and names no certification scheme: Criterion IX simply requires qualified personnel and qualified procedures 'in accordance with applicable codes, standards, specifications.' The scheme therefore comes from whatever code the licensee imposes — in practice ASME Section XI with ASNT SNT-TC-1A or ANSI/ASNT CP-189, or NQA-1. That makes certification employer-based: the supplier writes and owns the written practice and signs the certificates. An outsourced Level III can author and approve the written practice and the NDE procedures and can administer examinations, but Criterion I requires that whoever performs quality assurance verification have organisational freedom and sufficient independence, and the supplier's own management retains the responsibility.