Provides that, if a member had thirty years of service credit at the time of death, but had not retired, his or her accumulated contributions plus interest and the employer's accumulated contributions plus interest, less any amount identified as owing to an obligee upon withdrawal of accumulated contributions pursuant to a court order filed under RCW 41.50.670, and any other benefits payable upon his or her death shall be paid to his or her estate or to such persons, trust, or organization as he or she has nominated by written designation duly executed and filed with the department. Interest on accumulated contributions shall be determined by the director.