Earlier quoted context omitted.
The 1981 AG memo, which unfortunately seems not to be online anywhere (if you have access to Westlaw or LexisNexis the cite is 43 Op. Att’y Gen. 293) interprets the law as implicitly allowing shutdown costs after the budget authority is exhausted.
> The 1981 AG memo, which unfortunately seems not to be online anywhere (if you have access to Westlaw or LexisNexis the cite is 43 Op. Att’y Gen. 293) Well, I found it in the first page of Google results for the citation you provide: http://energy.gov/sites/prod/files/2013/10/f3/Shutdown.OLC_....
Thanks for finding that, not sure how I missed it. The language regarding orderly shutdown can be found in FN 12 on page 9.