Hi Anteneh - your premise about 'destroying the product' is what the international community has been working to do to eliminate ivory stores. Generally, instead of irradiating, they burn them. There has been a big push in the past decade to convince owners of ivory stockpiles to burn them, and commit to burning any new amounts that they come across or seize.

As for your idea about replacing ivory with a similar replacement material - there has been some work to simply remove the horns of some animals in parks (rhinos mostly) so that they will not be targeted for the ivory. But, replacements are hard. Here are some constraints to consider: they would have to last in the wild; last over time as the elephant grows; function the same as a tusk; and each elephant would require a fitting. Plus, this approach would likely be very expensive. Human dentistry is expensive enough!

This is an important issue that needs new ideas like yours. Take a look at these two approaches for inspiration. 

Dyeing rhino horns

Pembient - biofabricated rhino horn

Thank you @Tom Quigley for the inspirational feedback, actually I am working on this replacement and honestly, I have considered the problems on replacement problems on some of the factors you mentioned and I am working on that design as we speak. 

I am sure this design of mine will be very useful but am not sure how I will manage to connet with other rearchers who are working on this particular probel and I will leave this task to this site. 

I worked on the Tracking Poached Elephant Ivory project through the Center for Conservation biology for 5 years and we were contacted regularly with inquiries like these. The biggest constraint isn't the engineering of the replacement, but the logistics of approaching the over 400,000 individual elephants across different countries, tranquilizing them and then performing field surgery. Most of these animals are shy or feel threatened by humans and in the case of forest elephants, you would be lucky to find them. 

Attempting something of this scale likely wouldn't be fast enough to prevent the extinction of the species. The solution likely lies in improving the socio-economic status of the people in these areas as well as educating the demand population. Poaching isn't done by a large assortment of independent people trying to make money - it's done through vast criminal networks, linked to other international crimes (drugs, human trafficking) as a way to launder money and involves corruption in law enforcement and governments. 

This is a tough one and I thank you for considering a solution. 

@Misa Winters thank you for the comment and yes I know this matter is a tough to solve and I understand is very hard when transitioning to implementation. Actually I consider this solution best especially for species facing extinction because no matter how you improve the socio economic status, no matter how you educate the society and so on, as long as the concept of "ivory equals money" is imprinted on some people mind they will find a way to illegally take and sell ivory or they will not believe the species are becoming extinct or choose not to believe and kill the last species if they have the chance, it is just the facts seen from past experience. 

The only way to stop this is just eliminate the product from the market no matter the challenge. This is the problem with peoples who work on conservation of species, they are afraid or hold back to take action while peoples who think only about money get things done no matter the cost.