On December 10, 2010, the NRC issued a Notice of Violation to Sanford Medical Center for a Severity Level III violation involving the failure to secure the high dose-rate remote (HDR) afterloader brachytherapy unit in accordance with License Condition 19.A and Section 3.3.1.1 of Standard Operating Procedure, NM-X2, "Radiation Safety Procedures for the Nucletron Microselectron HDR, Version 2." Specifically, on June 15 through July 29, 2010, the licensee failed to secure the HDR afterloader unit from unauthorized removal or access from its storage area when the unit was not in use because a mechanical locking mechanism failed to function as designed, leaving the unit unsecured.