26 U.S.C. § 2016

If any tax claimed as a credit under section 2014 is recovered from any foreign country, the executor, or any other person or persons recovering such amount, shall give notice of such recovery to the Secretary at such time and in such manner as may be required by regulations prescribed by him, and the Secretary shall (despite the provisions of section 6501) redetermine the amount of the tax under this chapter and the amount, if any, of the tax due on such redetermination, shall be paid by the executor or such person or persons, as the case may be, on notice and demand. No interest shall be assessed or collected on any amount of tax due on any redetermination by the Secretary resulting from a refund to the executor of tax claimed as a credit under section 2014, for any period before the receipt of such refund, except to the extent interest was paid by the foreign country on such refund.