The members of the Committee shall not receive compensation for the performance of services for the Committee, but shall be allowed reasonable travel expenses, including per diem in lieu of subsistence, at rates authorized for employees of agencies under subchapter I of chapter 57 of title 5, while away from their homes or regular places of business in the performance of services for the Committee. Notwithstanding section 1342 of title 31, the Secretary may accept the voluntary and uncompensated services of members of the Committee.