Retention properties in displacement damaged ultra-fine grain tungsten exposed to divertor plasma

•Ion-damaged ultra-fine grained tungsten (UFG W) and ITER-grade specimens were exposed to plasma in the DIII-D divertor.•For both microstructures, D release peaks were observed during thermal desorption spectrometry (TDS) at 200 °C and 750 °C.•In the pre-damaged UFG w specimens, the D release peak at 200 °C is enhanced.•A comparison between TDS and nuclear reaction analysis (NRA) profiles indicates that most of the trapped D in damaged UFG W is retained within a depth of 3 μm.