The 6 nuclear stories that mattered this week

This week's nuclear news was about what makes a reactor bankable and what makes an operating plant stop. TerraPower bought construction certainty with guaranteed-price Korean EPC; Spain priced energy security above its phase-out calendar; Cernavoda lost its cooling margin to the Danube; and Aalo turned a test-reactor criticality into a factory bet. Startup continued apace in China and Russia's Bushehr program regained its specialists.

Key facts

• Six NNN stories from August 10–16 covered fleet financing, phase-out policy, cooling-water margins, microreactor manufacturing, commissioning and wartime staffing.
• TerraPower's HDEC agreement covers up to eight Natrium reactors with completion, price and performance guarantees — the financing unlock, not the concrete, is the news.
• Cernavoda's two 650 MWe CANDUs, roughly a fifth of Romania's power, are in safe shutdown below the Danube's 185 cm operating threshold.
• Spain's Almaraz renewal defers the largest early tranche of its 2019 phase-out schedule to June 2030.
• Aalo's July 4 milestone was a zero-power criticality of a full-scale core — not power production — now paired with a planned one-million-square-foot factory.

1. TerraPower bought the thing nuclear construction never had: guarantees

The week's most consequential deal happened in Seoul. TerraPower named Hyundai Engineering & Construction as EPC for up to eight future Natrium reactors with completion, price and performance guarantees, and signed a term sheet with SK Innovation for Korea's first commercial Natrium plant. The guarantees are the mechanism that turns offtake interest — Meta's eight-plant agreement from January — into projects banks can finance. Read the full analysis.

2. Cernavoda shut down because a river fell four centimetres short

Romania's only nuclear plant went dark in an orderly sequence: the Danube fell to 182 cm against a 185 cm operating threshold, and both CANDU units are now in safe shutdown. It was a cooling-margin problem, not a safety accident — but it cut a fifth of national supply during a heat wave, and Hungary is now preparing riverbed works to protect Paks from the same river. Full story.

3. Spain made its phase-out negotiable

A BOE order renewed Almaraz's licence to June 2030, superseding 2027/2028 shutdown dates while Madrid insists the 2035 fleet exit stands. The government's own rationale — consumer price exposure, imported-fuel dependence — applies to every reactor in the fleet, which is why industry is already talking about 60-year operation. What the extension really changes.

4. Aalo is trying to turn criticality into a factory

Aalo Atomics' CEO drove the week's loudest X conversation around its July 4 Critical Test Reactor milestone and a coming manufacturing announcement. The verified substance: a zero-power criticality of a full-scale core at INL — the fourth in DOE's Reactor Pilot Program — and a stated one-million-square-foot factory to mass-produce 50 MWe Aalo Pods. The claim, not yet the event. The PULSE on what's verified and what isn't.

5. Tianwan 7 loaded its first fuel

China's newest VVER-1200 began loading the first of 163 fuel assemblies at Tianwan — the irreversible step in commissioning, with first criticality and grid connection ahead, while sister unit Tianwan 8 completed cold functional tests and trails in the sequence. The commissioning picture.

6. Rosatom specialists returned to Bushehr

Russia's team at Iran's Bushehr site is back to 25 personnel as work on Units 2 and 3 continues — a small number with outsized significance for a program that has repeatedly paused on sanctions and security constraints. Details.

The through-line: capital and physics both showed up this week. TerraPower and Aalo are attacking the cost-of-building problem from opposite ends — EPC guarantees and factory mass production — while Cernavoda and Almaraz showed governments paying real money and political capital to keep operating atoms. Next week: whether TerraPower's framework becomes a signed unit order, and the Danube forecast.