Nuclear Security Act of 2003

Nuclear Security Act of 2003 - Amends the Atomic Energy Act of 1954 to instruct the Nuclear Regulatory Commission (NRC) to: (1) establish a nuclear security force composed of NRC employees to provide for the security of all sensitive nuclear facilities against design basis threat; and (2) develop and implement a security plan containing specified elements for each sensitive nuclear facility to ensure the security of all sensitive nuclear facilities against such threat.

Authorizes a holder of a license for a sensitive nuclear facility to petition the Commission for additional requirements in the security plan for such facility.

Requires the NRC to establish a hiring and training program for the nuclear security force.

Establishes the Nuclear Security Fund for use by the Commission to administer the security programs for sensitive nuclear facilities.