(a) An employee who is not a post-2011 employee and who has 5 years of credited service exclusive of service under § 5501(e)(4), (5) and (12) of this title shall have a vested right to a pension. A post-2011 employee who has 10 years of credited service exclusive of service under § 5501(d)(12) of this title shall have a vested right to a pension.
(b) A former employee's vested right shall be forfeited upon an application for a refund of the former employee's accumulated contributions.