After July 1, 1992, no nuclear fission thermal power plant licensee may store or maintain in on-site spent fuel element pools or other on-site temporary storage facilities any spent nuclear fuel which was removed from the nuclear reactor core more than 3 years previously.
On-site storage of spent fuel assemblies; limitations
35-A M.R.S. § 4371, under NUCLEAR POWER GENERATING FACILITIES.
35-A M.R.S. § 4371