Tenn. Code § 8-3514
Upon the death of a member after retirement, any balance of his accumulated contributions, at the time of his retirement, remaining after deductions of the total retirement benefits received by him shall be paid to his designated beneficiary, or, if no beneficiary is specified, to the executor or administrator of his estate. Provided, however, that if the amount payable shall be two hundred fifty dollars ($250) or less, it may be paid to the next of kin in the absence of designation of a beneficiary.
Provided further, however, should the board find in the case of a member who retired due to disability prior to October 1, 1957, and who died before September 30, 1964, the amount of his pension payable to him prior to his death shall be payable thereafter to his widow during her unremarried lifetime, provided the widow is not receiving widow's benefits payable under the Social Security Act.
T.C.A. § 8-3514