; and (v) modifications to the projects for which such applications are filed, including changes in size, location, or technology. (e) Department of defense determination of unacceptable risk (1) The Secretary of Defense may not object to an energy project filed with the Secretary of Transportation pursuant to section 44718 of title 49, except in a case in which the Secretary of Defense determines, after giving full consideration to mitigation actions identified pursuant to this section, that such project would result in an unacceptable risk to the national security of the United States. Such a determination shall constitute a finding pursuant to section 44718(f) of title 49. (2) Not later than 30 days after making a determination of unacceptable risk under paragraph (1), the Secretary of Defense shall submit to the congressional defense committees a report on such determination and the basis for such determination. Such report shall include an explanation of the operational impact that led to the determination, a discussion of the mitigation options considered, and an explanation of why the mitigation options were not feasible or did not resolve the conflict. The Secretary of Defense may provide public notice through the Federal Register of the determination. (3) The Secretary of Defense may only delegate the responsibility for making a determination of unacceptable risk under paragraph (1) to the Deputy Secretary of Defense, an under secretary of defense, or a principal deputy under secretary of defense. (f) Authority To accept contributions of funds The Secretary of Defense is authorized to request and accept a voluntary contribution of funds from an applicant for a project filed with the Secretary of Transportation pursuant to section 44718 of title 49. Amounts so accepted shall remain available until expended for the purpose of offsetting the cost of measures undertaken by the Secretary of Defense to mitigate adverse impacts of such a project on military operations and readiness or to conduct studies of