Recent investigations have shown that the Charpy-V test is an unreliable indicator of the true irradiation embrittlement. This has increased the need for a direct measurement of the fracture toughness. In the case of surveillance testing, where the specimen size is typically small, especially two types of tests are attractive, static testing based on the J-integral and dynamic testing performed by the instrumented impact hammer. Many factors speak in favor for the dynamic test. However, it is not clear whether the irradiation embrittlement is depicted similarly by static and dynamic tests. In this work the the effect of loading rate upon irradiation embrittlement measured by fracture mechanical properties is investigated. It is shown that the shift in the fracture toughness transition temperature is smaller for dynamic loading than for static loading and a theoretical explanation for the effect is proposed.