A little bit of Rathlin O'Birne at Blackrock

The non-nuclear Blackrock lighthouse

Many lighthouse lovers in Ireland are aware that the tiny island of Rathlin O'Birne, just off the coast of Malin Beg in county Donegal, was the first and, so far, only Irish navigational light to be powered by nuclear energy, rather than the old, fuzzy sort. However, it was very nearly not so, as the original location was supposed to have been Blackrock (Mayo), our most distant light from the mainland, and the second-highest above sea level. (Kudos to anyone who knows the highest without looking it up. I made hen stumble over southern promontory (4,4))
In 1964, Irish Lights was contacted by the Atomic Energy Research Establishment in Harwell, Oxfordshire, about the possibility of converting one of its lights, Blackrock, to nuclear energy. Presumably, this was a pilot project; if it worked, others could have followed suit. Talks continued for a further six years. Several lighthouses were canvassed but the overwhelming favourite, Blackrock, messed up on the interview, letting slip that it was 86m above sea level. I can't say I understand the science but it appears that its elevation would have necessitated the light being tilted downwards to such a degree that the intensity of the beam would have been diffused considerably.
At around about the same time, automation was just starting to become commonplace and, with Rathlin O'Birne's vaporised paraffin burner now quite out of date, it was decided to kill two evil gannets with the one stone and upgrade the light and make that station automatic. AGA Navigation Aids Ltd were contracted to make the new optic, an acetylene gas light that both rotated the lens and fed the burner to fuel the light.

Rathlin O'Birne. Photo MyHome.ie

Blackrock also had the old vaporised paraffin burner and it too was going to be made automatic when the isotope generator known as RIPPLE X (Radio Isotope Powered Prolonged Life Equipment - Mark Ten) was installed. However, with Blackrock now out of the radioactive market, it was decided that Rathlin O'Birne, with a height above Mean High Water Springs of only 35m was a suitable candidate for the service to herald in the nuclear age. Rathlin O'Birne would get the RIPPLE-X; Blackrock would get the acetylene gas light originally intended for the Donegal light.
The upgrades on both lights started and finished in 1974. The RIPPLE-X was transported by road to Holyhead from Harwell, lifted aboard ILT Isolda, cleared customs at Dun Laoghaire and landed directly on Rathlin O'Birne on 7 June 1974. The whole journey from Harwell to Rathlin O'Birne took four days.
At Blackrock, a temporary light was installed on the balcony to allow for freedom of movement to dismantle the old optic and put in the new. Both lights were exhibited for the first time in the autumn of 1974. The keepers were superfluous now; attendants were appointed. Both sets of keepers were withdrawn and the respective stations reverted back to being uninhabited.

Frank Ryan was the PK at Blackrock. 35 years of service and a fifth-generation keeper, the powers-that-be had decided that he was no longer needed and he left the hostile rock by helicopter.
But not before he had pointed out that the new light was very fine and dandy, but it was a shame that it had the characteristics of the Rathlin O'Birne light. Apparently, nobody had thought to mention to AGA that the change of location would entail a change of rotation speed! 

Blackrock again, perched precariously on its rock