It refers to the regularity or uniformity of the distribution of particles or radiation emitted from a source or generated in a reactor in all directions or angles. It is an important factor in nuclear engineering because it affects the performance, stability, and safety of the reactor.

A more concrete way of saying it

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Note added at 1 hr (2023-03-20 16:29:47 GMT)
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Set apart at regular intervals and at an anglr

The main difficulty I see with the ST: la partie de fixation comprend des dents réparties régulièrement angulairement, en particulier réparties uniformément angulairement, is that it offers two versions of the manner in which the teeth are réparties - first, régulièrement and then (supposedly more specific...) uniformément.
However régulièrement and uniformément are synonyms:
https://www.larousse.fr/dictionnaires/synonymes/uniformément...
uniformément. adverbe. De façon uniforme. Synonyme : constamment, régulièrement.

'with uniform angular spacing' is a straightforward 'plain English' translation of both the French phrases.

Although these webrefs are from different contexts, they refer to similar geometrical configurations (the first one is from a patent):

https://patentscope.wipo.int/search/en/detail.jsf?docId=WO19...
uniform angular spacing around the periphery of the tube and in longitudinally overlapping relation characterised by cutting said annular elements

https://www.mpirical.com/glossary/bpsk-binary-phase-shift-ke...
The constellation points chosen are usually positioned with uniform angular spacing around a circle.

https://www.researchgate.net/figure/Uniform-Spaced-Points-on...
the concept of star catalogs with near uniform angular spacing between stars arises

https://link.springer.com/chapter/10.1007/978-1-4684-5320-1_...
In usual practice, however, the object is insonified from angles separated from each other by a fixed interval thus giving a uniform angular spacing.

French term (edited): réparties régulièrement angulairement

> apart from the 'teeth', very similar in wording to the US 'nuclear reactor fuel assembly' patent spec. I quote.

Otherwise, I am still - after 20 years - waiting for my first Counsel's Opinion brief, as offered, from the AEA - Atomic Energy Agency in Vienna.

French term (edited): réparties régulièrement angulairement

The trouble is, we don't know what it really means. For angulairement I tend to think 'radially', but without more info and ideally a drawing we cannot say.

Given that there are at least two patents out there already with the same lingo, I'd be tempted to keep what you already have.

The support 112 is similar to the support 16, except that, in the example shown, the second magnetic element In this case, it is made in the form of four parts 122 distributed regularly angularly in corresponding cavities of the outer wall of the support
https://patents.google.com/patent/EP2934225A1/en

In this case, for the braking zone of each of the two screws 12 and 14, each thread has 5 identical notches, respectively 12C and 14C regularly distributed angularly. https://patents.google.com/patent/WO2013079887A1/en

Tony's 'distributed uniformly in an angular sense' is a tempting proposal, might I say, but 'sense' adds an extra dimension of interpretation and understanding that might quite possibly complicate matters (given that we don't know what is meant to start with).