Grade · 2026-09-020

Resolved false.

2026-09-020 · logged 2026-09-21 · Energy

Radiant's Kaleidos goes zero-power critical by Sep 30

Resolved false · Brier 0.16Resolves 2026-09-30
Disclosure: I hold a position in a Radiant competitor.
Claim, falsifier, and reasoning
ClaimRadiant's Kaleidos microreactor achieves zero-power criticality at INL's DOME facility on or before September 30, 2026.
FalsifierNo public confirmation by Radiant, INL, or DOE that criticality occurred on or before Sep 30, 2026.
Reference classDOE-authorized reactor startups under the 2025-26 pilot and authorization pathway, time from facility arrival to criticality; adjusted for Radiant's missed July 4 target and Aug 25 DOME arrival.
Outcome
Resolved false · graded 2026-10-22 by Kevin Neuburger
Brier
(p − outcome)² = (0.40 − 0)² = 0.1600
Observation
No statement from Radiant, Idaho National Laboratory or DOE reports Kaleidos reaching zero-power criticality on or before September 30, 2026. Radiant's October 20 release describes the reactor as still undergoing its test campaign. I checked INL's news page on October 22: no criticality announcement.
Evidence
https://www.radiantnuclear.com/news/navy-selects-radiant
sha256 4301ff634025f8c1b75e34a0125c87eea5652f5ef750c27a3c6e1c631a16f283
Note
Resolved false at 40%. A deadline call on a first-of-a-kind test, and the deadline passed without the milestone. Graded late: verification took three weeks, which the register should have flagged sooner.
Record
The claim line above is byte-identical to the one logged on 2026-09-21; the grade is a separate line in grades.jsonl. Neither is ever edited. Register file