Nuclear analysis of DEMO water-cooled blanket based on sub-critical water condition

For the water-cooled solid blanket of DEMO, the nuclear analysis was performed based on present cooling piping system. Especially, distributions of neutron load and temperature were calculated with Pn is 5 MW/m2. Furthermore, the local TBR was optimized by changing the material proportion for each Pn level (1–5 MW/m2). It was confirmed that the size of cooling loop for sub-critical water could be used as about 2000 × 450 mm and the cooling pipe diameter of D is 12 mm, d is 9 mm at v is 5.36 m/s. The pipe pitches would vary with Pn level which is related to the blanket structure design. Nuclear heat distribution is the base to decide the distribution of cooling pipe positions. It was found that the local TBR of blanket would be dropped down along with the Pn level rising which was mainly depended on the thickness of beryllium variation. Finally, the layout of cooling pipes for each level was obtained.

► For sub-critical water condition, the size of cooling loop would be more longer, for example, 2 m.
► Local TBR is related to the material fraction of breeders and multipliers, the beryllium is the dominant.
► Front area of blanket is dominant for blanket design and it would contribute the most of TBR comparing to the backside zones.