; or (ii) occurred in connection with any act of nonconsensual sex; or (B) an escape, attempted escape, or conspiracy to escape from within a security perimeter or custody, or both; or (C) possession of weapons, possession of illegal narcotics with intent to distribute, or other similar, severe threats to the safety of the inmate, other inmates, staff, or the public. (13) Solitary confinement The term solitary confinement means confinement characterized by substantial isolation in a cell, alone or with other inmates, including administrative segregation, disciplinary segregation, and confinement in any facility designated by the Bureau of Prisons as a special housing unit, special management unit, or administrative maximum facility. (14) Special administrative measures The term special administrative measures means reasonably necessary measures used to— (A) prevent disclosure of classified information upon written certification to the Attorney General by the head of an element of the intelligence community (as specified or designated under section 3(4) of the National Security Act of 1947 ( 50 U.S.C. 3003(4) )) that the unauthorized disclosure of such information would pose a threat to the national security and that there is a danger that the inmate will disclose such information, as described by section 501.2 of title 28, Code of Federal Regulations, or any successor thereto