Safe keeping facilities are available with the major Banks, you will need to have an account and you will have to sign a receipt part of which will include a waiver that you are responsible for any loss, these are in some ways like an uncomplicated version of the safety deposit boxes you see in the movies, you provide the box ( or probably a large envelope ) and the cost varies, I suggest about €25+ annually will cover this .
Nothing is risk free, you are not safe from a devaluation, if the Bank goes bust then your cash is sitting in their vault, try convincing a Liquidator on that one,
IMO not a good idea, spread your risk using IriSh Govt and other European Govt depositor guarantees and perhaps if brave buy some currency dollar or sterling or other... good luck