Peringue/Goltz the French heavy-water specialist/scientist.

… the assassination of Peringue, the French heavy-water specialist who went over to the Communists through Berlin, added, thanks to the importance of his knowledge and the fact that we got him before he had talked, one billion francs from the Deuxième Bureau.

Fleming, Ian. Thunderball (James Bond) (p. 54).

Mathis admits now that Goltz, that French heavy-water scientist who went over last year, was assassinated by them, for big money, for big money, as a result of an offer he got out of the blue.

Fleming, Ian. Thunderball (James Bond) (p. 75).

Interesting passages here in Thunderball, about 20 pages apart. Are we to believe that S.P.E.C.T.R.E. assassinated two French heavy water specialists/scientists who had defected to the communists for Mathis, or are they the same person, and Fleming just got the name mixed up?

What even is a heavy-water specialist? What is Heavy Water? From PBS.org:

Heavy water is a form of water with a unique atomic structure and properties coveted for the production of nuclear power and weapons. Like ordinary water—H20—each molecule of heavy water contains two hydrogen atoms and one oxygen atom. The difference, though, lies in the hydrogen atoms. In ordinary water, each hydrogen atom has just a single proton in its nucleus. In heavy water, each hydrogen atom is indeed heavier, with a neutron as well as a proton in its nucleus. This isotope of hydrogen is called deuterium, and heavy water’s more scientific name is deuterium oxide, abbreviated as D20.

That same page notes:

To Norwegian Resistance fighters during World War II, heavy water was a mysterious substance considered so perilous that they were willing, under orders from the Special Operations Executive in London, to sacrifice the lives of their countrymen in order to keep it out of Nazi hands.

Heavy Water also called deuterium oxide, is used in some nuclear reactors to slow down the pace of neutrons as they split, allowing for a more consistent flow of energy.

As this page shows, (under Heavy Water in Europe) French scientists in the 1940s were front and center with the research into heavy water and its uses and also had to take steps to keep their research out of German hands. Nothing is said about any of them attempting to defect to the communists.

in 2016 there was a Norwegian limited run series called The Heavy Water War, which recounts “one of the most compelling stories of World War II: British intelligence and the Norwegian military’s heroic struggle to thwart Nazi Germany’s atomic bomb ambitions by sabotaging the heavy water plant in Rjukan, Norway.”

Spectre Before S.P.E.C.T.R.E.

Even before it became the name of perhaps the most famous criminal organization in fiction in the novel Thunderball, Ian Fleming liked the word “spectre”.

This interesting little word, according to Collins English Dictionary can be defined thusly:

spectre (ˈspɛktəor specter

n

1. (Alternative Belief Systems) a ghost; phantom; apparition
2. a mental image of something unpleasant or menacing: the spectre of redundancy.

The usage of the word had declined and actually reached its lowest point during the time that Fleming started using it:

As you can see, it has increased somewhat in use since that time.

Here are some instances in which Fleming used it prior to Thunderball, when it became the abbreviation for the SPecial Executive for Counter-intelligence, Terrorism, Revenge and Extortion. 

Here are some examples of its use:

Live and Let Die:

The great grey football of a head under the hurricane lamp looked like an elemental, a malignant spectre from the centre of the earth, as it hung in mid air, the golden eyes blazing steadily, the great body in shadow.

Diamonds Are Forever:

Spectreville. The Spectre Range. In total throughout the book there are 11 mentions of the two of these.

From Russia With Love:

Kronsteen…had sweated away a pound of weight in the last two hours and ten minutes, and the spectre of a false move still had one hand at his throat.

The decoding machine which is the MacGuffin of the novel is called a Spektor. (17 mentions)

Goldfinger:

Bond walked slowly up to the putt, knocking Goldfinger’s ball away. Come on, you bloody fool! But the spectre of the big swing – from an almost certain one up to a possible one down – made Bond wish the ball into the hole instead of tapping it in.

Despite the chart above, I don’t actually know how commonly this word was used in every day language. From here, it seems like a rather obscure word, which Fleming liked the sound, sight and meaning of, and enjoyed using it whenever he could, even a variation on the word in Spektor. He also used the variations Spectral and Spectrally on occasion. (also meaning ghostly)

Live and Let Die:

All through the centre of the state, the moss lent a dead, spectral feeling to the landscape.

Most of the tanks were dark, but in some a tiny strip of electric light glimmered spectrally and glinted on little fountains of bubbles…

…in the grey valleys they caught the light of the moon and waved spectrally

From Russia With Love:

The spectral eye of the nightlight cast its deep velvet sheen over the little room.

You Only Live Twice:

The poisons listed fall into six main categories: Deliriant. Symptoms: spectral illusions…

When the novel Thunderball came out, and all the controversy and eventual court case surrounding it, one of the items at issue was the criminal organization of S.P.E.C.T.R.E. and who actually came up with it. Kevin McClory claimed that he did and even later named his company Spectre Associates Inc.

From the outside, it would seem that Fleming had an affinity for the word, especially with his creation of the Spektor in From Russia With Love, and it would seem reasonable that it was a creation of Flemings. Eventually, McClory was awarded the film rights to all of Thunderball, including S.P.E.C.T.R.E and Ernst Stavro Blofeld while Fleming retained the literary rights to these.