A minor seepage of uranyl nitrate liquor from the containment surrounding a pump has occurred in the chemical separation area of the Thermal Oxide Reprocessing Plant (THORP) at Sellafield. The volume was approximately one litre, covering an area of about 30 cm squared. No person has been sujected to any radiological hazard from the seepage and there was no relase of radioactive material to the environmet. Air smaplers confirmed that there was no abnormal airborne radioactivity resulting from the seepage. The seepage was discovered during a routine inspection and occurred in a fully enclosed area.