If there is no surviving spouse or survivor of a member covered by Code Section 47-23-105 or if a member not covered by such Code section dies before retirement, the amount of accumulated contributions made by such member, with regular interest on such amount, shall be paid to his or her named beneficiary, if any, or to the living person, if any, nominated by written designation of the member duly executed and filed with the board, otherwise to the member's estate.