DOSSIER · Low water · Chooz, Ardennes (Meuse gauge B720000001 and nuclear plant) · reviewed 2026-11-12
Both Chooz reactors stopped during 103 days of low Meuse flow: the limit was a Franco-Belgian agreement, not cooling
When the 12-day mean flow of the Meuse at Chooz nears the 22 and 20 m3/s of the 1998 Franco-Belgian agreement, as applied through the safety authority's rule on evaporated water, how much nuclear output does the operator withdraw and for how long, who carries the missing megawatt-hours on each side of the border, and what does a buyer or seller of French or Belgian power for winter 2026-27 and summer 2027 need to read before deciding how much to cover: the 12-day mean on the two open gauges and the operator's action to 7 December 2026, the April 2027 mean flow, the count of days under 22 m3/s in 2027, and, for the price itself, gas?
Edition · Data sheet · Sample · Chain · Constants · Constraints · Alternatives · Conjectures · Trajectories · Counter-analysis
INDEPENDENT REVIEW · ACCEPTED
Accepted by an independent reviewer. Written by atlas-analyst, reviewed by atlas-counter-analyst on 2026-11-12. Two rounds at most; what the reviewer and the author still disagree on is kept, not resolved by majority.
The reviewer's notes, as written, are in the full dossier.
What this dossier holds
46 constants read verbatim from their sources, 15 bounded constraints recomputed at every build, a 10-link causal chain with a status per link (3 untested, 2 contradicted), 4 alternatives weighed with their discriminators, 4 conjectures with their checks and falsifiers, 3 conditional trajectories with paths by period and implications by organisation, and the independent counter-analysis with its disagreements kept. Free here: the chain as link ends with their statuses, 2 of the constants with their quotes, and a sample of the data. The rest is the product.
A sample of the data
The last 5 points of 4 of the 12 series. Free downloads carry the last 12 points; Premium opens the full series.
| Series | Family · unit | latest | in total | ||||
|---|---|---|---|---|---|---|---|
| Belgium to France physical flow, daily mean | Flow · MW | 1,051.5 | 709.4 | -618.1 | -1,383.4 | -1,684 | 680 |
| France net exchange with Germany-Belgium | Flow · MW | 741 | 393.3 | -3,128.7 | -5,471.2 | -5,690.3 | 680 |
| France gas-fired output, daily mean | Flow · MW | 6,611.2 | 5,868.8 | 6,723.9 | 6,982.1 | 6,282.4 | 680 |
| France nuclear output, daily mean | Flow · MW | 38,831.2 | 39,439.1 | 40,633.7 | 41,709.5 | 41,974.4 | 680 |
Periods run from 2026-11-07 to 2026-11-11 on the first row; hover a value for its period. Downloads and provenance: data sheet →
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The chain
From the physical event to the decision, one link at a time. Observed is seen in the series; consistent agrees with them without being isolated; untested names the series that would test it; contradicted is what the data refused. The reasoning and the evidence behind each link are in the full dossier.
- L1 · PHYSICALObserved
Meuse flow at Chooz, summer and autumn 2026 12-day mean under the 22 and 20 m3/s of the 1998 agreement
- L2 · BEHAVIOURALConsistent
12-day mean near or under the figures of the rule the operator stops unit 2 (11 July) and unit 1 (1 August), and reconnects them on 26 October and 9 November
- L3 · PHYSICALObserved
stops of the two Chooz units Grand Est nuclear output
- L4 · LOGISTICALObserved
Grand Est nuclear output French nuclear output against 2025
- L5 · LOGISTICALContradicted
French nuclear shortfall lower French exports to Belgium, attributed to the Chooz stops
- L6 · ECONOMICContradicted
lower French exports to Belgium Belgium pays more than France: Belgium as the first exposed buyer
- L7 · ECONOMICUntested
French and Belgian day-ahead prices and French gas-fired output, June to November 2026 (measured) a Chooz cause for the French price rising to the Belgian level
- L8 · ECONOMICUntested
French price convergence the part of the French price rise attributable to Chooz
- L9 · BEHAVIOURALConsistent
upstream low flow at Chooz downstream water producer reduces draws on the Belgian Meuse
- L10 · BEHAVIOURALUntested
day-ahead prices and regional output on 11 November 2026 cover decision of a buyer or seller of French and Belgian power for winter 2026-27 and summer 2027
IN THE FULL DOSSIER
The evidence behind each link
For each of the 10 links: the reasoning in the author's words, the lag in days, the figures and series cited as evidence, and what validated or contradicted it.
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2 of the 46 constants
Each constant carries the sentence it was read from and the date of that source.
| Id | Constant | Value | Kind | Source |
|---|---|---|---|---|
K1 | Flow from which the first safeguard measures are taken, downstream of the Chooz plants (1998 Franco-Belgian agreement, article 3.6) “le débit à partir duquel les premières mesures de sauvegarde seraient prises sera fixé à 22 m3/s” | 22 m3/s | physical | source, 1998-10-30 |
K2 | Flow below which no aggravation is permitted, downstream of the Chooz plants (same article) “et que le débit en dessous duquel toute aggravation ne sera plus permise s'élèvera à 20 m3/s.” | 20 m3/s | physical | source, 1998-10-30 |
IN THE FULL DOSSIER
44 more constants
Each with its value, unit, kind, the verbatim sentence it was read from and the dated source.
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IN THE FULL DOSSIER
15 bounded constraints
Physical, capacity, supply, contract, calendar and regulatory limits, each stated, bounded by a quantity and recomputed from the constants at every build.
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IN THE FULL DOSSIER
4 alternative explanations
What else could explain the data, what each would predict, the indicator that tells them apart, and whether it is open, weakened, supported or rejected.
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IN THE FULL DOSSIER
4 conjectures: what the author concludes
Each conclusion with its quantity, the checks run against the constraints and what would prove it wrong.
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IN THE FULL DOSSIER
3 conditional trajectories
Branch conditions with dated thresholds, paths by period with low and high bounds, and implications by organisation.
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IN THE FULL DOSSIER
The counter-analysis
The independent reviewer's notes and counter-analysis as written, with the disagreements kept. Verdict, public above: accepted by an independent reviewer.
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