An illustrative embodiment of a shaft seal assembly generally includes a first stator, a second stator, and a throttle member. In one illustrative embodiment, the second stator may be formed with a main body and an access plate positioned radially interior with respect to a portion of the first stator. The first stator and second stator may engage one another about a semi-spherical interface comprised of a convex surface on the second stator and a concave surface on the first stator. The second stator may include an internal channel in which a throttle member may be positioned, wherein a radially interior surface of the throttle member may be positioned a shaft.