Frozen-Design Discipline
Once a design point is frozen, its numbers do not drift; every public figure traces to that fixed set, so the record cannot move under a reader.
What freezing a design means
A design under active study changes daily. A published record cannot. Kronos resolves the tension by freezing a design point: fixing the canonical numbers — the breeder's Q_sci 3.424, 88.7 MW, 9.86 MA, 16.84 T, delta −0.30; the burner's 26.49 T plug, 17 T throat, 5.44% neutron fraction — and requiring every public figure, page, and deposit to use exactly those values. A frozen set is the single source of truth for everything downstream.
Why discipline, not just a spreadsheet
- Consistency: a reader who sees 88.7 MW on one page and a different figure on another loses trust immediately; freezing forbids the mismatch.
- Traceability: because the numbers are fixed and versioned, any figure can be traced back to the frozen set that produced it.
- Honesty about change: when the design genuinely moves, a new freeze is issued as a new version rather than editing the old numbers in place.
How a change is handled
Freezing does not mean the design is final — these are design-and-simulation studies that will evolve. It means changes are deliberate and dated. When a result is revised, a new frozen set and a new deposit version capture it, exactly as the breeder paper's version two did. Nothing is quietly overwritten; see version control and provenance.
The tie to the gates
Freezing also fixes the honest gates. The four burner gates are stated against the frozen design bore and regime, so they cannot be softened by shifting the design under them. See the honest gates.
A frozen design point is a promise that the numbers you check today are the numbers we stand behind.