Tennessee Code Title 8. Public Officers and Employees § 8-37-212

(a) Upon the death of a retired member after the retired member's retirement allowance payments have commenced (provided, that the retired member has not elected an optional allowance that has become effective), any excess of the amount of the retired member's accumulated contributions at retirement over the sum of the retirement allowance payments received shall be paid in one (1) sum to the person nominated by the member, if living, otherwise to the member's estate in accordance with § 8-36-120.

(b) Upon the death of a retired member and the beneficiary nominated by the retired member under the terms of an option, if an option was elected and had become effective, any excess of the retired member's accumulated contributions at retirement over the sum of the retirement allowance payments received by the retired member and such beneficiary shall be paid to the estate of the last to survive of the member and such beneficiary in accordance with § 8-36-120.