Tennessee Code Title 8. Public Officers and Employees § 8-36-203

(1) Any member eligible to retire may set the effective date of the member's retirement at any date within one hundred fifty (150) days before or after the date that the member's application is filed with the board; provided, that such effective date of retirement follows the date of the member's separation from service;

(2) A member may submit only one (1) retirement application even if the member has service credit in one (1) or more of the four (4) defined benefit plans administered by the retirement system pursuant to chapters 34-37 of this title. The retirement payment plan and beneficiary selected by the member on the retirement application shall be the same for all of the plans and may not be changed or revoked, except as provided in part 6 of this chapter. The retirement system shall pay benefits from each of the applicable plans on the member's effective date of retirement; provided, that the member has met the eligibility requirements of the particular plan for a retirement allowance. If on a member's effective date of retirement the member has not met the eligibility requirements for a retirement allowance from a particular plan, the retirement system shall commence payments from that plan once the member meets the eligibility requirements of the plan;

(3) Distribution of a member's benefit must begin by the required beginning date, which is April 1 of the calendar year following the calendar year in which the member attains age seventy and one-half (70 1/2 ) or age seventy-two (72) if the member was born on or after July 1, 1949, as such age is extended or otherwise modified by the Internal Revenue Code or the regulations promulgated thereunder, or April 1 of the calendar year following the calendar year in which the member terminates, whichever is later. If a member fails to apply for retirement benefits by the later of either of those dates, the board shall begin distribution of the monthly benefit as required by this section in the applicable form provided in § 8-36-206; and

(4) The amount of an annuity paid to a member's beneficiary may not exceed the maximum determined under the incidental death benefit requirement of § 401(a)(9)(G) of the Internal Revenue Code (26 U.S.C. § 401(a)(9)(G)), and the minimum distribution incidental benefit rule under Treasury Regulation § 1.401(a)(9)-6, Q&A-2.