The OP has been studying the Chopin for a year (first post). If the approach were correct and this were simply a question of endurance, his/her "fatigue" problems would have been gone a long time already.
This is exactly the point.
There are examples seen in the past by this forum where chopin etudes have seen some 5, or even 10+ years practice to still remain poorly executed and still cause tension and fatigue.
Cas70, I fully believe that you're experience was that the discomfort was relieved in a reasonable amount of time without the requirement to dig deeper. OP is not in that position, he/she has invested a full year and still can't play it.
And as Dima also pointed out was his experience, I see no reason that a well guided student should experience fatigue at all. However, students tend to either not get the right advice, or they get it and don't follow it. If the OP was genuinely prepared for 10/12 a year is way too long. Something is wrong, be it small (and requiring only a minor adjustment) or monumental (and requiring a major re-think of the entire approach), there is something that time and repetition has failed to fix. He needs a different answer. Simply being here asking the question is a pretty big clue that for this individual in this circumstance, time and repetition is not doing the trick.
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The "burn" which grows in intensity over time as you play through the work is the result of an ongoing technical concern that started at the VERY first note, and where the demands of the piece are significant enough to expose the flaw and lead to fatigue. This flaw will almost certainly exist as much in any piece that you can play comfortably as it does in the ones that leave you tired or strained, it just takes something hard to expose the problem.
At the beginning of the piece it is not significant, So much so that you are totally unaware of it. By the time you reach half way through the piece it has grown into something bit by bit that is now totally unmanageable.
You fix is at the base, individual key strokes and transitions. You develop an extreme sensitivity to the feeling of both correct playing and incorrect playing and can detect it within only 1 or 2 notes.
It is caused by a failure of one or more parts in the entire playing mechanism. The pieces all support each other. There is a sense of stability in correct technique caused by all parts working correctly as per their physiologically determined functions and no undue forces being applied to anatomy that wasn't built for it.
Such an example is burning in the forearm as a result of overuse of the flexors and extensors to move the fingers, rather than having the added support from the intrinsic hand muscles. As well as perhaps utilising a lessening of downward pressure by allowing the forearm to "float" over the keys instead of bearing down heavily and requiring the finger to over exert to hold the extra weight..
^which is a rough description of one possible variant of whats going wrong for the OP. Unfortunately though, OP has given no more information that "my hand and arm get tired". This is very non specific so the best possible advice is more or less just experiment with variations of movement until you find one that works better, breaking up the piece into fragments of 2 or 3 notes if necessary.
Correctly identifying what is wrong and changing it will remove the burn or tension
immediately - no time/repetition, immediately. The time and repetition will be used to make sure that the movement that works can be done at tempo and without thinking about it.
Your experience of a gradual dissipation of the sensation is most likely a result of a sub-conscious gradual changing of the movement patterns used until you settle in to a pattern that is sufficient for the demands of the given piece.
You're lucky you are able to find an adequate motion without too much thought, it doesn't work that way for everyone. Even so, you may be doing yourself a great disservice by assuming that you wouldn't improve faster by considering a different approach to resolving uncomfortable playing.