I don’t understand the concept of being Orthodox and being allowed to recieve in the Catholic Church. How can the Catholic Church allow someone who is not Catholic and does not profess communion with Rome to recieve the Eucharist? How can you have Eucharistic communion when you don’t have physical communion? It makes no sense.
From the Code of Canon Law, see the underlined portion.
Can. 844 §1 Catholic ministers may lawfully administer the sacraments only to catholic members of Christ’s faithful, who equally may lawfully receive them only from catholic ministers, except as provided in §§2, 3 and 4 of this canon and in can. 861 §2.
§2 Whenever necessity requires or a genuine spiritual advantage commends it, and provided the danger of error or indifferentism is avoided, Christ’s faithful for whom it is physically or morally impossible to approach a catholic minister, may lawfully receive the sacraments of penance, the Eucharist and anointing of the sick from non-catholic ministers in whose Churches these sacraments are valid.
§3 Catholic ministers may lawfully administer the sacraments of penance, the Eucharist and anointing of the sick to members of the eastern Churches not in full communion with the catholic Church, if they spontaneously ask for them and are properly disposed. The same applies to members of other Churches which the Apostolic See judges to be in the same position as the aforesaid eastern Churches so far as the sacraments are concerned.
§4 If there is a danger of death or if, in the judgement of the diocesan Bishop or of the Episcopal Conference, there is some other grave and pressing need, catholic ministers may lawfully administer these same sacraments to other christians not in full communion with the catholic Church, who cannot approach a minister of their own community and who spontaneously ask for them, provided that they demonstrate the catholic faith in respect of these sacraments and are properly disposed.
§5 In respect of the cases dealt with in §§2, 3 and 4, the diocesan Bishop or the Episcopal Conference is not to issue general norms except after consultation with the competent authority, at least at the local level, of the non-catholic Church or community concerned.
This covers the Orthodox and the Polish National Catholic Church (PNCC). Most missalites that you find in the pews has this on either the back of the front cover or the front of the back cover stating who may receive the Eucharist.