IESET.
Hypotheses·energy·nuclear_revival_2023_2026_western_construction_starts

The 2022-2026 window saw rhetorical and policy-stated revival of Western large-scale nuclear power: France committed to EPR2 fleet (6 + 8 reactors by 2050) under loi accélération du nucléaire 2023; UK confirmed Sizewell C investment FID 2024 + Small Modular Reactor (SMR) competitive selection 2024-2025; US Vogtle Unit 4 commercial start July 2024 + several SMR / advanced-reactor licensing applications; Japan re-pivoted to nuclear restart + lifetime extension (2023 GX framework permits >60-year operation); Sweden, Finland, Netherlands, Belgium reversed phase-out policies.

The hypothesis tests whether this rhetorical revival translated into measurable concrete-pour construction starts and FIDs with full financing on 1+ Generation-III/III+ Western reactor by end- 2026, distinct from continued construction of pre-2022 commitments (Hinkley Point C, Olkiluoto-3 finished 2023). A weaker interpretation: rhetorical revival without construction starts is policy theatre, not industrial revival.

PARTIALengine/runs/nuclear_revival_2023_2026_western_construction_starts

PARTIAL — shape=panel_summary, |Δ_log|=0; claim direction ambiguous

confidence cueThe result is useful, but not decisive. Treat it as a clue, not a settled conclusion.

policy briefMixed or noisy

In ordinary language

In plain terms, this asks whether post 2022 nuclear revival dummy is actually linked to better or worse count western large reactor construction starts post 2022 from 2018 to 2027.

plain answer

The evidence is suggestive but not decisive. shape=panel_summary, |Δ_log|=0; claim direction ambiguous

why it matters

This matters because energy claims should change belief only when they survive a pre-declared empirical test.

how the test works

It compares 11 country or place units from 2018 to 2027, using a descriptive design.

what was measured
What changed
  • Post 2022 nuclear revival dummy
What we checked
  • Count western large reactor construction starts post 2022
  • Count smr first of a kind construction starts
  • Count reactor lifetime extensions
what this does not prove

A single test is not the whole truth. It narrows the claim under a specific sample, time period, and method. Strong policy conclusions need the pattern to survive nearby tests, alternative data, and serious objections.

verification

No evidence packet has been generated yet.

Results

engine/runs/nuclear_revival_2023_2026_western_construction_starts
1007550250201820232027USAFRAGBRJPNSWEFINNLD
illustrative sketch · run pending
No coefficients yet. When the model fires, this chart will show count_western_large_reactor_construction_starts_post_2022 across 11 sampled countries over 2018–2027.
The shapes above are stylised — none of the lines are real data.
Placeholder for nuclear_revival_2023_2026_western_construction_starts. Published chart will be generated from engine/runs/nuclear_revival_2023_2026_western_construction_starts/chart_data.json.

Pre-registration

registration ordering unverified
first-spec commit 4c8ce8e · 2026-07-18T22:11:21Z
run generated · 2026-04-30T13:38:24Z
Run timestamp predates this path's first git-add commit (rebase, rename, or pre-git local run). Spec hash is still the path's first-add commit — not repository HEAD — but ordering is not a clean pre-registration proof.

The 2022-2026 window saw rhetorical and policy-stated revival of Western large-scale nuclear power: France committed to EPR2 fleet (6 + 8 reactors by 2050) under loi accélération du nucléaire 2023; UK confirmed Sizewell C investment FID 2024 + Small Modular Reactor (SMR) competitive selection 2024-2025; US Vogtle Unit 4 commercial start July 2024 + several SMR / advanced-reactor licensing applications; Japan re-pivoted to nuclear restart + lifetime extension (2023 GX framework permits >60-year operation); Sweden, Finland, Netherlands, Belgium reversed phase-out policies. The hypothesis tests whether this rhetorical revival translated into measurable concrete-pour construction starts and FIDs with full financing on 1+ Generation-III/III+ Western reactor by end- 2026, distinct from continued construction of pre-2022 commitments (Hinkley Point C, Olkiluoto-3 finished 2023). A weaker interpretation: rhetorical revival without construction starts is policy theatre, not industrial revival.

Falsification criterion — what would disprove this

set before the run · honoured after

This hypothesis is considered falsified if:

Descriptive — falsified by counter-fact. Falsified if 2022-2026 sees ZERO new Western large-reactor construction starts (other than pre- 2022 commitments) AND ZERO SMR first-of-a-kind construction starts AND fewer than 3 phase-out reversals AND fewer than 5 lifetime extensions. Each metric counted independently. Verdict tiers: "supported" = 4 of 5 metrics hit thresholds; "partial" = 3 of 5; "refuted (revival is rhetoric)" = ≤ 2 of 5.

formal test & threshold
test:      nuclear_revival_inventory
threshold: Western large-reactor construction starts ≥ 2 (Hinkley C-2 / Sizewell C / EPR2 site work counts if FID + concrete by 2026) AND SMR FOAK construction starts ≥ 1 AND Phase-out reversals ≥ 3 AND Lifetime extensions ≥ 5 AND Vogtle-4 LCOE < $180/MWh

Method

Template
descriptive
Sample
11 countries · 2018 – 2027
Evidence type
descriptive

Descriptive inventory: count construction starts + FIDs + lifetime extensions + phase-out reversals 2022-2026 by country, compared to 2010-2021 baseline. Cross-check IAEA PRIS records. Key tests: (a) Western large-reactor construction starts 2022-2026: count ≥ 2 = supported (excludes pre-2022 commitments still in construction). (b) SMR first-of-a-kind construction starts: count ≥ 1 = supported (NuScale Carbon-Free Power Project was cancelled Nov 2023, so the bar is whether any SMR actually breaks ground in West). (c) Phase-out reversals: count ≥ 3 of (BEL, NLD, SWE, ITA, ESP, CHE) formally reversing. (d) Lifetime extensions: count ≥ 5 reactors approved for 60+ year operation in OECD 2022-2026. (e) Vogtle-4 levelised cost: report unconditionally; if it is below $130/MWh the project's economics are tractable, if above $180/MWh the comparative-effectiveness picture is poor. Known limitations: (1) SMR landscape is in flux; cancellations (NuScale CFPP Nov 2023) outweigh starts in 2023-2024. (2) "Construction start" definition (concrete pour vs site preparation) varies; use IAEA PRIS first-concrete-for-base-mat. (3) Vogtle-4 is the FIRST Western large reactor to start commercial ops post-2018 (Olkiluoto-3 in 2023 in Europe was the prior case); both finished 5-10 years late and 2-3x over budget. Whether this represents end-of-bad-streak or warning-of-future cost is contested. (4) Asian nuclear (CHN, KOR) is excluded by scope definition (this is "Western" revival); CHN nuclear is on a different institutional trajectory.

Data

VariableSourceTransform
count_western_large_reactor_construction_starts_post_2022
outcome
constructed:IAEA PRIS (Power Reactor Information System) construction-start records, filtered to OECD + UK + KOR + JPN, ≥1000 MWe Getier 5
level
count_smr_first_of_a_kind_construction_starts
outcome
constructed:IAEA PRIS + ARIS (Advanced Reactor Information System) for SMR designs (NuScale, BWRX-300, X-energy Xe-100, Rolls-Royce tier 5
level
count_reactor_lifetime_extensions
outcome
constructed:IAEA PRIS lifetime-extension licensing decisions (US NRC subsequent license renewal SLR; French ASN/IRSN visite décennaltier 5
level
log_total_announced_nuclear_capex_usd
outcome
constructed:country-program announced + FID-confirmed capex: France EPR2 cost estimates (RTE / EDF + Cour des Comptes), UK Sizewell tier 5
log
vogtle_4_levelised_cost_usd_per_mwh
outcome
constructed:Georgia Power / Southern Company project costs / 60-year lifetime / capacity factor. Cross-check fred:CES2023700001 (US tier 5
level
phase_out_reversal_policy_count
outcome
constructed:count of formal phase-out reversals 2022-2026 (Sweden 2023 abandons phase-out target; Belgium 2023 lifetime extension; Ntier 5
level
post_2022_nuclear_revival_dummy
treatment
constructed:indicator = 1 from 2022-08 onwards (post-energy-crisis policy framing window).tier 5
indicator
log_eu_ets_price
control
eea:eu_ets_verified_emissionstier 2
log
log_natural_gas_ttf
control
constructed:TTF EUR/MWh, monthly. eex fetcher pending.tier 5
log
nuclear_share_existing_generation
control
constructed:IEA / IRENA share of nuclear in country generation mix, 2021. Pre-existing reliance moderates revival probability.tier 5
level
post_fukushima_residual_phaseout_status
control
constructed:indicator = 1 if country had a formal phase-out policy at 2021 baseline (DEU, BEL, ITA, ESP, CHE, TWN). Used to identifytier 5
indicator

● ready  · ● pending  · ● reconstruct-needed

Detailed result card

Result card — nuclear_revival_2023_2026_western_construction_starts

Verdict: PARTIAL — shape=panel_summary, |Δ_log|=0; claim direction ambiguous

Pre-registration

  • Claim: The 2022-2026 window saw rhetorical and policy-stated revival of Western large-scale nuclear power: France committed to EPR2 fleet (6 + 8 reactors by 2050) under loi accélération du nucléaire 2023; UK confirmed Sizewell C investment FID 2024 + Small Modular Reactor (SMR) competitive selection 2024-2025; US Vogtle Unit 4 commercial start July 2024 + several SMR / advanced-reactor licensing applications; Japan re-pivoted to nuclear restart + lifetime extension (2023 GX framework permits >60-year operation); Sweden, Finland, Netherlands, Belgium reversed phase-out policies. The hypothesis tests whether this rhetorical revival translated into measurable concrete-pour construction starts and FIDs with full financing on 1+ Generation-III/III+ Western reactor by end- 2026, distinct from continued construction of pre-2022 commitments (Hinkley Point C, Olkiluoto-3 finished 2023). A weaker interpretation: rhetorical revival without construction starts is policy theatre, not industrial revival.
  • Falsification rule: Descriptive — falsified by counter-fact. Falsified if 2022-2026 sees ZERO new Western large-reactor construction starts (other than pre- 2022 commitments) AND ZERO SMR first-of-a-kind construction starts AND fewer than 3 phase-out reversals AND fewer than 5 lifetime extensions. Each metric counted independently. Verdict tiers: "supported" = 4 of 5 metrics hit thresholds; "partial" = 3 of 5; "refuted (revival is rhetoric)" = ≤ 2 of 5.
  • Falsification test: nuclear_revival_inventory

Comparison

  • shape: panel_summary
  • treatment_country: USA
  • treatment_value: 0.0
  • donor_pool_median: 0.0
  • ratio: None
  • log_diff: None
  • n_donor_countries: 10
  • end_year_window: [2022, 2027]

Variables resolved

  • constructed: IAEA PRIS (Power Reactor Information System) construction-start records, filtered to OECD + UK + KOR + JPN, ≥1000 MWe Generation-III/III+. Manual-drop pending under data/manual/derived/. → count_western_large_reactor_construction_starts_post_2022 (outcome, publisher=constructed, n=110)
  • constructed: IAEA PRIS lifetime-extension licensing decisions (US NRC subsequent license renewal SLR; French ASN/IRSN visite décennale; Japan NRA 60+ extension). Manual-drop pending. → count_reactor_lifetime_extensions (outcome, publisher=constructed, n=110)
  • constructed: country-program announced + FID-confirmed capex: France EPR2 cost estimates (RTE / EDF + Cour des Comptes), UK Sizewell C strike-price + RAB-finance details, Vogtle 3+4 final cost, etc. Manual-drop pending. → log_total_announced_nuclear_capex_usd (outcome, publisher=constructed, n=110)
  • constructed: Georgia Power / Southern Company project costs / 60-year lifetime / capacity factor. Cross-check fred:CES2023700001 (US power gen employment). Manual-drop pending. → vogtle_4_levelised_cost_usd_per_mwh (outcome, publisher=constructed, n=110)
  • constructed: indicator = 1 from 2022-08 onwards (post-energy-crisis policy framing window). → post_2022_nuclear_revival_dummy (treatment, publisher=constructed, n=110)
  • constructed: indicator = 1 if country had a formal phase-out policy at 2021 baseline (DEU, BEL, ITA, ESP, CHE, TWN). Used to identify which countries had the most policy-distance to revival. → post_fukushima_residual_phaseout_status (controls, publisher=constructed, n=110)

Variables missing data

  • constructed: IAEA PRIS + ARIS (Advanced Reactor Information System) for SMR designs (NuScale, BWRX-300, X-energy Xe-100, Rolls-Royce SMR, etc.), construction-start records 2022-2026. Manual-drop pending. (outcome, name=count_smr_first_of_a_kind_construction_starts)
  • constructed: count of formal phase-out reversals 2022-2026 (Sweden 2023 abandons phase-out target; Belgium 2023 lifetime extension; Netherlands 2024 new-build commitment; Italy 2024 lifting ban; Switzerland 2024 lifting ban). Manual-drop pending. (outcome, name=phase_out_reversal_policy_count)
  • eea:eu_ets_verified_emissions (controls, name=log_eu_ets_price)
  • constructed: TTF EUR/MWh, monthly. eex fetcher pending. (controls, name=log_natural_gas_ttf)
  • constructed: IEA / IRENA share of nuclear in country generation mix, 2021. Pre-existing reliance moderates revival probability. (controls, name=nuclear_share_existing_generation)

Generated by scripts/run_descriptive.py at 2026-04-30T13:38:24+00:00

Strongest opposing argument

Every hypothesis ships with its charitable opposing argument. The framework earns credibility by handling objections at their strongest, not weakest.

Notes

Data readiness: - IAEA PRIS / ARIS: manual-drop pending under data/manual/derived/ (PRIS data is publicly downloadable from iaea.org but not via API) - EU ETS price: eea ready - TTF gas: eex fetcher pending or manual-drop - Country phase-out policy timeline: hand-curated, manual-drop pending - Vogtle-4 cost: Georgia Power filings, manual-drop Run when IAEA PRIS / ARIS manual-drop is populated through end-2025.

Authored framework. Read the transparency note.