vatican.va/roman_curia/congregations/ccdds/documents/rc_con_ccdds_doc_20030317_ordinamento-messale_en.html
The Place for the Reservation of the Most Holy Eucharist
- In accordance with the structure of each church and legitimate local customs, the Most Blessed Sacrament should be reserved in a tabernacle in a part of the church that is** truly noble, prominent, readily visible, beautifully decorated, and suitable for prayer.**[125]
The one tabernacle should be immovable, be made of
solid and inviolable material that is
not transparent, and be locked in such a way that the danger of profanation is prevented** to the greatest extent possible**.[126] Moreover, it is appropriate that, before it is put into liturgical use, it
be blessed according to the rite described in the Roman Ritual.[127]
- It is more in keeping with the meaning of the sign that the tabernacle in which the Most Holy Eucharist is reserved not be on an altar on which Mass is celebrated.[128]
Consequently, it is preferable that the tabernacle be located,
according to the judgment of the diocesan Bishop,
Either in the sanctuary, apart from the altar of celebration, in a form and place more appropriate,** not excluding on an old altar** no longer used for celebration (cf. no. 303);
Or even in some chapel suitable for the faithful’s private adoration and prayer[129] and
organically connected to the church and readily visible to the Christian faithful.
- In accordance with traditional custom, near the tabernacle a special lamp, fueled by oil or wax, should be kept alight to indicate and honor the presence of Christ.[130]
- In no way should all the other things prescribed by law concerning the reservation of the Most Holy Eucharist be forgotten.[131]