There has been no information whatsoever forthcoming from EDF or from yourselves as to exactly what caused the loud banging noises from Heysham Nuclear Plant on the 15th August.
If this information has to be asked for under FOI then consider this question also a FOI request (although this information which caused panic amongst residents as far away as Ulverston in Cumbria should be immediately open and transparent).
It is our understanding that the loud banging noises you refer to on 15 August 2019 were in relation to the start-up of EDF Energy’s Heysham 2 nuclear power station, Reactor 8.
The noise was caused by the opening and closing (cycling) of pressure relief valves during the reactor start-up activities. This occurred in response to changes in steam pressure. Quick opening and closing of these heavy valves can often make a loud banging noise.
On this occasion, these noises continued for a period of about twelve minutes. This combined with the timing (on a relatively silent night) of the activity resulted in the sound being heard in the vicinity of the power station.
We can confirm that we have no nuclear safety concerns as a result of these events and there was no risk to the public.
A statement on this from EDF Energy can be found on their website at the following link: Update on noises heard at Heysham 2 Power Station - https://www.edfenergy.com/media-centre/news-releases/statement-noise-heysham-2-power-station.
We hope this addresses any concerns you may have had.