Verification, Validation, Certification

Three separate gates: solving the equations right, choosing the right equations, and satisfying an external authority that both were done.

Three Distinct Gates

Verification asks whether the code solves its governing equations correctly. Validation asks whether those equations describe reality well enough for the intended use. Certification asks whether an external authority accepts the evidence for a regulated purpose. They are answered by different people, with different evidence, in that order.

Verification

Verification is mathematics and software engineering. Its evidence is the observed order of accuracy under mesh refinement, comparison to exact or manufactured solutions, and bounded iterative residuals. It says nothing about whether the physics is right; a perfectly verified code can faithfully solve a wrong model.

Validation

Validation is physics. Its evidence is quantitative comparison between simulation and measurement, with uncertainty on both sides, in a defined regime. Validation must follow verification: comparing an unverified code to experiment mixes numerical error with model-form error, and apparent agreement may be coincidental cancellation.

Certification

Certification is a governance act. A regulator or standards body reviews the verification and validation record and decides whether it supports a claim for a regulated use. Certification does not add physical truth; it adds accountability and an audit trail. A model can be verified and validated yet uncertified, or certified for one use and not another.

At Kronos

The breeder and burner designs are simulation and design work, not built hardware. Published claims rest on verification first; physical validation against operating devices is a separate, ongoing obligation; and any future licensing certification is a further, external gate. The record keeps the three distinct so a reader can see which claims are mathematical, which are physical, and which are authorized.