Hello, thank you for the question. It's been hanging around for a bit, and I didn't want to see it go unanswered. Sadly, I can't answer it and I doubt that anyone else here can either. If they could, they'd have taken the question already.
Here are the problems: the definition of an "operational requirement" might well be defined by the collective agreement itelf, or be made clear within the context of its use within that document. Clearly, it's beyond the purview of the experts here to review a collective agreement. This site isn't a law firm, and the lawyers on the Canada Law categories cannot and do not provide the level of legal advice specific to the customer which could allow the customer to make firm decisions about their legal matters. I give legal information all the time, recommendations, suggestions, and tell people what to expect when they go to court, or how to fill out a document, stuff like that.
If you're planning to make this an issue in your next round of collective bargaining, you need a better, firmer legal opinion from a lawyer who has spent some time on the issue and with you personally. You need a good and experienced labour lawyer. There aren't any of them on this website anyway.
Further, I assume that you're with a union with some size and some resources. Surely the union's top brass has access to good labour lawyers kept on retainer by the union for such purposes. You ought to run this one up the flagpole and see who salutes it.
I see that you aren't on a subscription, so you've paid a deposit to the site in order to ask the question. I assume you've paid that deposit yourself personally. You can leave that deposit with the site for a future question, or you can ask the site to refund your money. It's up to you.
Does that make sense? I just want you to know why you haven't got an answer yet.