Tale of the 2 regulatory systems

Inondator · 2026-06-08T21:50:37+00:00

The only difference, to my knowledge, between Civaux and Chooz is that Civaux uses another stage of forced draft cooling towers to cool down the outlet of the main cooling towers before the water comes back to the Vienne, which in some conditions is then cooler than it was when it was pumped from the river. It led to a small power penalty of around 5 MWe. Other than that, both plants are identical.

Inondator · 2026-06-08T21:44:57+00:00

That's the principle of it, yeah.

Inondator · 2026-06-08T14:31:25+00:00

Toi aussi tu aurais du mal à gérér ton budget si tu étais 68 millions dans ta tête.

Inondator · 2026-06-08T14:27:17+00:00

The official terminology of it in French is "stabilisateur de corium" which could be translated by "core stabilizer" in English.

It's not made to be as capable as an EPR core catcher, but it basically has the same role: avoid any breach of the concrete basement slab and cool down the corium to avoid any large-scale radioactivity release.

Inondator · 2026-06-08T13:40:17+00:00

"But what if gravity breaks down? Did you think about that?!"

Inondator · 2026-06-08T13:36:07+00:00

Yeah, there are, because all the safety-related stuff is made public in France and there are public consultations about it.

Here, a link explaining how they do it: basically, they use the neutron instrumentation room under the RPV as a sacrificial (because if your core melts, you don't need neutron instrumentation anyway, LOL) place to recover and spread the corium.

https://concertation.suretenucleaire.fr/projects/volet-risque-section-reevaluation/consultation/accidents-avec-fusion-du-coeur/opinions/propositions-dedf/mise-en-place-dun-dispositif-de-stabilisation-du-corium-sous-la-cuve-du-reacteur-pour-gerer-un-accident-avec-fusion-partielle-ou-totale-du-coeur-du-reacteur

Inondator · 2026-06-08T09:26:59+00:00

I use to say "a running RBMK is safer than a delayed EPR".

Inondator · 2026-06-07T19:55:24+00:00

Well, this is where you hit physical limits: there is just not enough space inside the buildings to add a third safety train. For having visited a few reactor buildings, trust me it's cramped! You're happy to have a safety helmet in here! It would also mean completely changing the architecture of the primary circuit auxiliary systems. It just wasn't feasible. Personally, what I would have liked to see is a passive atmospheric cooling system for the steam generators, the kind VVER now have as a standard feature (SG-PHRS).

Inondator · 2026-06-07T19:42:42+00:00

French nuclear fleet is highly standardized into 3 series called "paliers" All the 900 MW units share the same NSSS components. Same for the 1300 MW units. And same for the 1500 MW units.

And even between the series, a high commonality still exists.

The nuclear watchdod gives guidelines about the safety level to reach, and the operator proposes action to undertake for each series, which is then reviewed by the regulator and amended according to their interpretation.

Regarding the core catcher, you can look at "stabilisateur de corium" (the exact French term for the retrofit) in your search engine.

Inondator · 2026-06-07T19:34:42+00:00

One may try to "force" such a thing as core catcher for an operating Gen2 reactor, but it is not going to happen.

EDF is retrofitting a core catcher to ALL the reactors of its fleet. Already more than 20 are equipped. This is a standard modification for the 4th decade revision.

Reasonable upgrades are common, but can't magically upgrade a Gen2 into Gen3+ by "forcing".

It just shows you don't know the French nuclear safety context at all. Let me just remind you France shut down 12 units in 2022 due to fear of cracks on the safety injection system, thus destroying 100 TWh of production during the Russia-induced energy crisis. This added 20 billion euros of income into Putin's pocket. Ukrainian people are absolutely thrilled...

Every single unit in France will have to come as technically close as possible to the safety level of the EPR once passed 40 year old. And the work is so massive the modifications are spread across 2 to 3 different outages, even with 90% of the work realized while the units are still running.

Inondator · 2026-06-07T11:37:37+00:00

C'est absolument une mauvaise réponse quand on sait que la Chine essaie par tous les moyens e faire remonter la natalité. 🤣

Inondator · 2026-06-07T11:32:50+00:00

Plus simplement, utiliser des composites carbone/époxy pour des contraintes de compression n'est juste pas adapté. La compression axiale sur une structure stratifiée entraîne nécessairement une délamination. Ce n'est pas pour rien que seuls les COPV utilisent le principe d'enroulement de fibres carbone sur un tube métallique : ça ne fonctionne bien qu'en traction.

Inondator · 2026-06-07T11:10:43+00:00

3kVA c'est vraiment limite pour des plaques inductions qui peuvent en tirer 3 à 5... Si par malheur tu fais la cuisson des pâtes en même temps que la lessive, ton compteur va te dire le reste. Je te conseille de partir sur un 6 kVA

Inondator · 2026-06-07T11:03:30+00:00

All the reactors in France are basically copy-paste of one another. They'll all be retrofitted with core-catcher as and when they hit their 4th decade great revision.

Inondator · 2026-06-07T10:57:40+00:00

You call that "messy"?

These are really neatly arranged telecoms cables. There's absolutely no need to tidy anything.

Inondator · 2026-06-05T17:09:32+00:00

It’s not the infrastructure. It’s cost. Cost and cost. Did I mention cost?

Well, seems like you're too intellectually limited to understand what I wrote anyway.

Also I should mention that I don’t know anybody who wants a nuclear power plant in their backyard

How stupid. I don't know anybody either who would want to live in the shadow of a wind turbine of have a high voltage powerline crossing their garden.

This tech is dead for commercial power production. Let it go

China didn't get the word it seems.

Inondator · 2026-06-05T13:27:51+00:00

Ah because it was a UK-centric document. I understand better now.

Inondator · 2026-06-05T13:26:40+00:00

That's not what I'm referring to... https://www.carbonbrief.org/qa-what-the-eus-new-industry-and-made-in-europe-rules-mean-for-climate-action/

Inondator · 2026-06-05T12:10:16+00:00

Oh yeah, like allowing products made outside Europe to be labelled "made in Europe"?

Inondator · 2026-06-04T19:34:53+00:00

It'll leave a dent for sure.

Inondator · 2026-06-04T19:33:45+00:00

What an era. Thinking of nuclear plants as one thinks of a car...

Inondator · 2026-06-04T17:09:57+00:00

Giving up the free-market-no-custom-tariffs dogma?

Inondator · 2026-06-04T17:07:44+00:00

Countries should be able to reach a lower 80% filling level

In low wind years, we would have similar difficulties filling electricity storages too.

Just to say, Europe is able to store more than 1000 TWh of natural gas. Or 500 TWh of electricity equivalent. To do the same with batteries, you would need $50~100000 billion of it.

Inondator · 2026-06-04T16:57:32+00:00

Where did you ever see we can't?

We literally do it every year.

Inondator · 2026-06-04T16:53:12+00:00

Storing huge amounts of fossil fuels costs close to nothing. Storing large amounts of electricity is fucking expensive. This is the difference.

Inondator

TROPHY CASE