COGEMA Engineering Corporation (COGEMA), under a contract from CH2M Hill Hanford Group (CH2M Hill), has performed an ultrasonic examination of the knuckle region of Double-Shell Tank 241-AP-101 utilizing the Remotely Operated Nondestructive Examination (RONDE) system (also known as the SAFT/TSAFT system) (Pardini et al. 2001). The purpose of this examination was to provide information that could be used to evaluate the integrity of the knuckle region of the primary tank. The requirements for the ultrasonic examination of Tank 241-AP-101 were to detect, characterize (identify, size, and locate), and record measurements made of any circumferentially oriented cracks that might be present in the knuckle area of the primary tank. Any measurements that exceed the requirements set forth in the Engineering Task Plan (ETP), RPP-11832 (Jensen 2002), are reported to CH2M Hill and the Pacific Northwest National Laboratory (PNNL) for further evaluation. Under the contract with CH2M Hill, all data is to be recorded on disk and paper copies of all measurements are provided to PNNL for third-party evaluation. PNNL is responsible for preparing a report(s) that describes the results of the COGEMA ultrasonic examinations. Examination Results The results of the ultrasonic examination of the knuckle region of Tank 241-AP-101 provided by COGEMA have been evaluated by PNNL personnel. The results of the examination of Tank 241-AP-101 indicated no circumferential crack-like indications were present anywhere in the knuckle region between the upper knuckle weld and the lower knuckle weld over the approximately 240 circumferential inches scanned. v