Spent fuel for five minutes like a CAT scan: no supporting calculation or correction found on Valar's site as of late September 2026

claim not supportedsafety

What was said

Isaiah Taylor (Valar's NRC-lawsuit post, still online) (2025-04-07): "Our analysis indicates" that "holding the spent fuel from this system for five minutes" gives the radiation exposure of a CAT scan.
Valar Atomics is Suing the NRC (Isaiah Taylor) (Valar Atomics, 2025-04-07)

What the record shows

Valar's own safety paper treats shielding as a safety function ('inherent shielding that cannot be inadvertently defeated').
Ward250 Nuclear Safety Design Agreement, No. 100403, Rev 02 (status: Draft), pages 14-15 (Valar Atomics, 2025-10)
DOE's review has the spent core leave the site in dry storage casks.
NEPA Determination DOE-ID-26-005: Valar Ward250 Research Reactor (categorical exclusion B5.26) (U.S. Department of Energy, Office of Nuclear Energy, 2026-04-22)
In late September 2026 the post still carries the sentence, unchanged in every archived copy, and a robots tag, 'noindex, nofollow', asking search engines not to list it; archive copies show the tag appeared between 23 March and 22 July 2026 (orig-061). No correction has been posted.
Valar Atomics is Suing the NRC (Isaiah Taylor) (Valar Atomics, 2025-04-07)
Context of the sentence: it concerns Ward One, 'a 100kWt High Temperature Gas Reactor' whose 'planned operational lifetime is less than a month', and it states no cooling time before the fuel is held.
Valar Atomics is Suing the NRC (Isaiah Taylor) (Valar Atomics, 2025-04-07)
EIA explains that used fuel keeps giving off heat from the decay of radioactive elements 'created when the uranium atoms were split apart'.
The nuclear fuel cycle (Nuclear explained) (U.S. Energy Information Administration, 2023-10-26)

The gap: Valar's public claim that holding its spent fuel for five minutes equals a CT scan concerned Ward One, a planned 100 kWt reactor with a planned lifetime under a month, and gave no cooling time. No supporting calculation and no correction were found on Valar's site as of late September 2026, where the post stands unchanged; since sometime between 23 March and 22 July 2026 the page has carried a tag asking search engines not to list it, and who added it and why is not in the record. For scale: a CT scan is about 1 to 10 millisieverts (FDA), so five minutes would need 12 to 120 millisieverts an hour; the post gives no amount of fuel, cooling time, distance or shielding.

In plain termsUsed reactor fuel, including the TRISO fuel beads Valar uses, is radioactive after it comes out of a reactor, because the split uranium atoms leave behind radioactive fragments; how radioactive depends on the reactor's power, how long it ran and how long the fuel has cooled. In April 2025 Valar's founder wrote that holding the spent fuel from his planned small reactor for five minutes would give about the same radiation as a CT scan, a routine hospital scan. No calculation supporting it has been found on Valar's site. The original sentence is still on Valar's site, unchanged, and since sometime between March and July 2026 the page has carried a tag asking search engines not to list it; who added it and why is not in the record. For Ward 250, Valar's own safety paper treats radiation shielding as a safety function, and DOE's review has the used fuel leave the site in dry storage casks.

Why it matters: A founder's public statement about holding used fuel remains on the company's site; no supporting calculation or correction was found there as of late September 2026.

What would settle it: Valar publishing its calculation or a correction; any later change to the post would show against archived copies.

facts orig-017, orig-061, safe-026 · checked 2026-10-02: Checked in late September 2026: re-read Valar's 7 April 2025 NRC-lawsuit post on the live site (the sentence concerns Ward One, 100 kWt, planned life under a month, and states no cooling time; the robots tag 'noindex, nofollow' confirmed in the page code), Internet Archive copies of 23 March 2026 (no tag) and 22 July 2026 (tag present), the Ward250 Nuclear Safety Design Agreement and DOE's categorical exclusion. No Valar correction or supporting calculation was found on its site. Corrected in late September 2026: added the CT-scan dose-rate scale (12 to 120 millisieverts an hour over five minutes); title and wording restated as 'no correction found'. Updated 30 Sept 2026: news and commentary citations removed so the entry rests on Valar's own words and government records; now also cites the U.S. Energy Information Administration.