(1) Subject to the limitations of this chapter and ORS chapter 238A, the Public Employees Retirement Board shall, from time to time, establish rules for transacting its business and administering the system in accordance with the requirements of ORS chapter 183.
(2) All rules adopted by the board become part of the written plan document of the Public Employees Retirement System for the purpose of the status of the system and the Public Employees Retirement Fund as a qualified governmental retirement plan and trust under the Internal Revenue Code and under regulations adopted pursuant to the Internal Revenue Code.