A bulkhead penetrator assembly and stress reduction apparatus for use in subsea environments, the penetrator assembly comprising: a central element having a first end and second end and having a substantially cylindrical body comprising an enlarged central portion, the enlarged central portion being ceramic and having first and second shoulders (214, 216) that gradually transition down respectively to the first and second ends; a first fixture having an opening adapted to receive the first end of the central element and a metallic seal surface comprising an annular pocket; a second fixture having an opening adapted to receive the second end of the central element and a metallic seal surface geometrically configured to abut the second shoulder of the central element; a deformable translatable seat disposed within the pocket of the first fixture and adjacent to the first shoulder of the central element, the deformable translatable seat comprising a deformable material geometrically configured in cooperation with adjoining surfaces of the first fixture and the first shoulder to abut the first shoulder of the central element; wherein the annular pocket forms a recessed space in the metallic seal surface of the first fixture for receiving the deformable translatable seat; and wherein the annular pocket in which the deformable translatable seat is disposed is relatively larger than the deformable translatable seat and is adapted to provide for deformation of the deformable translatable seat, and is further adapted to provide for translation of the deformable translatable seat by movement of the deformable translatable seat within the relatively larger annular pocket. a central element having a first end and second end and having a substantially cylindrical body comprising an enlarged central portion, the enlarged central portion being ceramic and having first and second shoulders (214, 216) that gradually transition down respectively to the first and second ends; a first fixture having an opening adapted to receive the first end of the central element and a metallic seal surface comprising an annular pocket; a second fixture having an opening adapted to receive the second end of the central element and a metallic seal surface geometrically configured to abut the second shoulder of the central element; a deformable translatable seat disposed within the pocket of the first fixture and adjacent to the first shoulder of the central element, the deformable translatable seat comprising a deformable material geometrically configured in cooperation with adjoining surfaces of the first fixture and the first shoulder to abut the first shoulder of the central element; wherein the annular pocket forms a recessed space in the metallic seal surface of the first fixture for receiving the deformable translatable seat; and wherein the annular pocket in which the deformable translatable seat is disposed is relatively larger than the deformable translatable seat and is adapted to provide for deformation of the deformable translatable seat, and is further adapted to provide for translation of the deformable translatable seat by movement of the deformable translatable seat within the relatively larger annular pocket.