According to an NRC press release, the six sites to be studied are:
Dresden Nuclear Power Station, Morris, Ill.
Millstone Power Station, Waterford, Conn.
Oyster Creek Nuclear Generating Station, Forked River, N.J.
Haddam Neck (decommissioned), Haddam Neck, Conn.
Big Rock Point Nuclear Power Plant (decommissioned), Charlevoix, Mich.
San Onofre Nuclear Generating Station, San Clemente, Calif.