Thread by @EnergieDevlpmt

Due to the current #heatwave, a lot has been happening this week for the French #nuclear power production.

In this thread, I will recap the situation as we know it on this Saturday morning.

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First, let's take a tour of the French #nuclear power plants experiencing or soon to experience disruptions due to #heat.

1/ Golfech on the Garonne river
The plant has reduced its production by 1000MW since July 13 at 17:30. According to EDF, this should last until the 24th.

2/ Tricastin on the Rhône river
The power plant has reduced its production by 735MW since this morning, July 16, at 2:30 am.
According to EDF's last assessment, this derating should last at least until the 18th.

3/ St Alban upstream on the Rhône
The water temperature limit should be reached tomorrow, July 17.

4/ Bugey also on the Rhône
Temperature limit should be reached from the 19th.

5/ Blayais on the Gironde estuary
The maximum temperature at discharge should be reached from July 17

In total, the operation of 5 of the 18 French #nuclear power plants is affected or is expected to be affected soon by the #heatwave.

This is not uncommon: all of these plants have already experienced outages caused by heat and/or drought over the past 5 years.

However, given the already tense situation on the #electricity market, EDF wants to avoid shutting down these plants.
The levels of production it intends to maintain:
- 300MW at Golfech
- 1800MW at Tricastin
- 1300MW at St Alban
- 900MW at Bugey
- 1800MW at Blayais

And there, 3 cases:
1/ For Bugey, it will probably be possible to maintain production at 900MW (out of the 3600 installed and 1800 currently in service) while respecting the regulations applicable to the plant, namely the maximum temperature allowed downstream. So no problem.

2/ For some power plants, like Golfech, the regulation of thermal discharges includes a possibility of derogation in "exceptional climatic situations", if RTE, the French TSO, requests it or if necessary to ensure "the balance between consumption and production of electricity".

3/ For others, such as Blayais, the regulation does not allow any derogation and the production target announced by EDF is physically incompatible with the operating limits applicable to the plant.

This is why EDF has requested a temporary modification of the regulations applicable to 3 #nuclear plants: Blayais, Golfech and St Alban.
This request was accepted by the French Nuclear Safety Authority on July 13 and approved by the government yesterday.
asn.fr/l-asn-informe/…

In concrete terms, this decision suspends the downstream temperature limits for St Alban and Golfech and the discharge temperature limits for Blayais until July 24.
The warming limits (upstream-downstream difference) are not suspended.

So, what to make of this situation?

First of all, it should not come as a surprise.
It has been obvious at least since 2019 (when the July #heatwave led to the shutdown of 10% of the installed #nuclear capacity in France) that the climate hazard is significant...

... perhaps not critical alone but enough to be problematic if it is combined with another source of tension on the supply-demand balance.
I would have bet on the growth of air-conditioning but corrosion or a geopolitical crisis, that works too.

It was equally easy to imagine that the environmental regulation of #nuclear power plants would not hold for a second in the face of a serious risk to the balance of the grid.
The suspension of thermal discharge limitations is a pragmatic and unsurprising decision.

I think this episode signals the failure of the current regulation, put in place after the 2003 heatwave.
Its great innovation was to provide for limited derogation possibilities at the request of the TSO but apparently this flexibility is insufficient even before being used.

To state the obvious, it also highlights the vulnerability of #nuclear power to climate change, in particular the vulnerability of "French-style" nuclear power, with its large reactors, large power plants and therefore large cooling needs.

Climate change has to be factored in nuclear projects.

Especially as France is preparing to renew its fleet, it would be unimaginable to build reactors if we cannot demonstrate that they will be able to operate with the #climate they will experience throughout their lifetime

Finally, similar thermal discharge limits apply to many activites in France and Europe (as they derive from an EU directive) and most industries cannot expect to benefit from the same arrangement as #nuclear plants.

They must urgently adapt to increasingly severe heatwaves.