The Occupational Radiation Exposure (ORE) for the water primary cooling system (PCS) of the SEAFP (Safety and Environmental Assessment of Fusion Power) alternative plant model (APM) was assessed taking into account the first wall/ blanket section only.

All the potential radiological sources were considered and the analysis was restricted to the most important source at the PCS, the activated corrosion products (ACP). The neutrons have the capability to activate the materials under their flux and therefore also the inner surface of the in-vessel portion of the PCS undergo to such a process. Production, erosion/corrosion, transport and deposition of the ACP are the subject of a parallel work presented at the same meeting.

The ACP deposited on the inner surface of the PCS components are responsible for the personnel external irradiation. The relevant dose rate was evaluated by using the computer code MCNP and comparing the results with the respective values measured at the fission PWR plants. The comparison with the PWR made it possible to transfer the parameters relevant to the working activities to the SEAFP PCS. Maintenance and inspection were found to be the only working tasks applicable to the SEAFP circuit and the worker access was considered to be allowed 24 h after the plant shut down only.

The ORE figures are shown in the work for each working activity and are compared with those measured at the PWR similar circuit. The comparison showed a more acceptable result from the radiological safety point of view for the SEAFP staff.