Templates and records · UNE 73401

Nuclear independent design verification record

In nuclear design it is not enough for the author to check their own work. Someone who took no part in it confirms the design is correct, using a defined method and leaving a record.

In one sentence

The independent design verification record shows which design document was verified, by which method —design review, alternative calculation or qualification testing—, by whom, how independent that person was from the author, what was found and how it was resolved, because the design control criterion of nuclear quality assurance requires the design of safety-related items to be verified by people other than those who produced it, as CSN guide GS-10.6 explains.

Content reviewed on 17 October 2026

Type of information: Mandatory record Design control criterion; GS-10.6. Lifetime record for the licensee (IS-24)
Who fills it in: Independent verifier Competent in the subject and with no involvement in the design being verified; may belong to the same company
When: Before the design is released Or before the item is installed, if justified by schedule; never after it enters service
How long it is kept: Lifetime or at least 5 years IS-24 requires licensees to keep as lifetime records, for the whole life of the facility or component, those meeting any of its criteria, and to keep non-permanent records for at least five years. Suppliers apply whatever the licensee’s purchase order specifies.

What the standard requires

What UNE 73401 demands and what it leaves to your judgement

Design control in nuclear quality assurance requires design bases to be translated into specifications, drawings and procedures, and the adequacy of the design to be verified through reviews, alternative calculations or qualification tests. Verification is done by individuals or groups other than those who performed the original design, as also stated in 10 CFR 50 Appendix B, which GS-10.1 accepts as an alternative.

The method is chosen according to safety significance and design complexity. What must be written down is what was verified, how, by whom and what was decided on each comment.

Records documenting the facility’s design are lifetime records under Instruction IS-24.

Read it in context: Design and document control, in the UNE 73401 Academy

Structure

Fields the template should include

Document verified: code, revision and item it refers to
Safety class of the item
Design bases and requirements it is verified against
Method: design review, alternative calculation, qualification test
Verifier and justification of their independence
Comments or findings
Author’s resolution of each comment
Conclusion and acceptance date

Example

Example: verification of a support calculation

Company, people and figures are fictitious: the example only shows what a properly completed record looks like.

Field	Content
Document	Calculation CA-SP-114, revision 1 · support in the emergency cooling system
Class	Safety-related, per order PD-4471 (fictitious)
Bases	Licensee specification: deadweight, thermal and seismic loads
Method	Review of the calculation and a simplified alternative calculation of the seismic combination
Verifier	An engineer from another project team, with no involvement in the calculation
Finding 1	The seismic spectrum from the previous revision of the specification is used
Finding 2	Buckling of the section under the most unfavourable load combination has not been checked
Resolution	Calculation revised to revision 2 with the current spectrum and a buckling check · margin 1.4
Conclusion	Accepted on 12 February 2026

At the audit

Mistakes auditors commonly flag

The verifier is the author’s line manager and took part in the design.
Only a “verified” signature, with no method or comments.
Verifier comments with no documented response from the author.
Verification against a revision of the design bases that is no longer current.
Designs released to manufacturing before verification is closed.

In Kimobox

How this record is kept in Kimobox

1Design verification is recorded as an independent approval workflow, with the verifier identified.
2Technical documentation is versioned, with its revision and approval always traceable.
3The verifier’s comments and their resolution stay in the same record.
4The full history of verifications is kept for inspection.

Frequently asked questions

What people ask us before getting started

Can someone from the same company verify?

Yes, provided they took no part in the design and are competent. Independence is from the work being verified, not from the company.

What verification methods are there?

Design review, calculation by an alternative method and qualification testing. The choice depends on safety significance, complexity and previous experience with similar designs.

How long is it kept?

For the licensee, records documenting the design are lifetime records under IS-24: kept for the whole life of the facility. The supplier hands them over or keeps them as the order specifies.

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Sources

Where each figure comes from

References to the official text in force. If a standard is revised, this page is updated and the review date says so.

Guía de Seguridad GS-10.6 (Rev. 1) — Garantía de calidad en el diseño de instalaciones nucleares (Quality assurance in the design of nuclear facilities) Consejo de Seguridad Nuclear (Spanish Nuclear Safety Council) · April 2002
Instrucción IS-24, de 19 de mayo de 2010, del Consejo de Seguridad Nuclear, sobre el archivo y los periodos de retención de los documentos y registros de las instalaciones nucleares (CSN Instruction IS-24 on archiving and retention periods for nuclear facility documents and records) BOE-A-2010-8779 · BOE no. 133, 1 June 2010
10 CFR Part 50, Appendix B — Quality Assurance Criteria for Nuclear Power Plants and Fuel Reprocessing Plants (an alternative accepted by GS-10.1) U.S. Nuclear Regulatory Commission · Current text