(a) Prohibition.—Except as otherwise provided in this section, the Secretary of a military department may not carry out a modification of an aircraft, weapon, vessel, or other item of equipment that the Secretary plans to retire or otherwise dispose of within five years after the date on which the modification, if carried out, would be completed.

(b) Exceptions.—

(1) Exception for below-threshold modifications.—The prohibition in subsection (a) does not apply to a modification for which the cost is less than $100,000.

(2) Exception for transfer of reusable items of value.—The prohibition in subsection (a) does not apply to a modification in a case in which—

(A) the reusable items of value, as determined by the Secretary, installed on the item of equipment as part of such modification will, upon the retirement or disposal of the item to be modified, be removed from such item of equipment, refurbished, and installed on another item of equipment; and

(B) the cost of such modification (including the cost of the removal and refurbishment of reusable items of value under subparagraph (A)) is less than $1,000,000.

(3) Exception for safety modifications.—The prohibition in subsection (a) does not apply to a safety modification.

(c) Waiver Authority.—The Secretary concerned may waive the prohibition in subsection (a) in the case of any modification otherwise subject to that subsection if the Secretary determines that carrying out the modification is in the national security interest of the United States. Whenever the Secretary issues such a waiver, the Secretary shall notify the congressional defense committees in writing.