; and (2) $500,000,000 in the Multilateral Telecommunications Security Fund established under subsection (c) of this section. (b) Public Wireless Supply Chain Innovation Fund (1) Establishment (A) In general There is established in the Treasury of the United States a trust fund to be known as the Public Wireless Supply Chain Innovation Fund (referred to in this subsection as the R&D Fund ). (B) Availability (i) In general Amounts deposited in the R&D Fund shall remain available through the end of the tenth fiscal year beginning after the date of enactment of this Act. (ii) Remainder to Treasury Any amounts remaining in the R&D Fund after the end of the tenth fiscal year beginning after the date of enactment of this Act shall be deposited in the general fund of the Treasury. (2) Borrowing authority (A) In general The NTIA Administrator may borrow from the Treasury of the United States an amount not to exceed $750,000,000 to use for grants under this subsection. (B) Deposit of funds Any amounts borrowed under subparagraph (A) shall be deposited in the R&D Fund. (3) Use of fund (A) Grants (i) In general Except as provided in subparagraph (B), amounts deposited in the R&D Fund shall be available to the NTIA Administrator to make grants under this subsection in such amounts as the NTIA Administrator determines appropriate, subject to clause (ii) of this subparagraph. (ii) Limitation on grant amounts The amount of a grant awarded under this subsection to a recipient for a specific research focus area may not exceed $20,000,000. (B) Reimbursement of Treasury As proceeds are deposited in the R&D Fund under subsection (a)(1), the Commission shall first use those proceeds to reimburse the general fund of the Treasury for any amounts borrowed under paragraph (2)(A) of this subsection. (4) Administration of fund The NTIA Administrator, in consultation with the Commission, the Director of the National Institute of Standards and Technology, the Secretary of Homeland Security, the Director of the Defense Advanced Research