Solitary Confinement Reform Act This bill amends the federal criminal code to establish standards for the use of solitary confinement at federal prisons. It limits the use of solitary confinement to situations that meet certain criteria, including that the confinement is limited to the briefest term and the least restrictive conditions practicable. It also prohibits, with limited exceptions, solitary confinement of inmates who are younger than 18 years of age, disabled, pregnant, or recently pregnant. The bill requires the Bureau of Prisons (BOP) to establish a transitional process for inmates in solitary confinement, requires inmates in solitary confinement to receive comprehensive mental health evaluations, and requires BOP employees to complete training on mental illness and the psychological effects of solitary confinement. It establishes, within the BOP, an Office of the Civil Rights Ombudsman. The office must be headed by a Civil Rights Ombudsman appointed by the Attorney General. The BOP must annually assess and report on the use of solitary confinement. The Department of Justice's Bureau of Justice Assistance must establish and administer a solitary confinement resource center.