406
6 Applications: Two-Region Pebble Beds
Fig. 6.5 Preloaded stripes experiment in 1000 mm tall vessel
friction coefficient, etc. In the case of unchanging the main geometric design of the
reactor core, the modification of the design of the bottom of the reactor core maybe
the most efficient strategy to eliminate the stagnant zone, such as the increased base
cone angle and smooth transition from bases to sides.
The pebble flow is the principal issue for the design of the pebble-bed reactor.
For verifying the feasibility of a two-region designed pebble-bed reactor, the experimental installation with a taller vessel has been built, which is proportional to a real
pebble bed reactor. At first, the stable establishment and maintenance of the tworegion arrangement have been verified with the aid of the experimental installation.
At the same time, the applicability of the DEM program has also been validated. In
addition, it has been pointed out that the pebble’s bouncing on the free surface is an
essential factor for the mixing of the different colored pebbles. So the guide plates
have been proposed to be installed at the top of the pebble packing. The size of the
mixing zone has been reduced from 6–7 times to 3–4 times the pebble diameter. Second, the relationship between the width of the central region and the ratio of loading
6 Applications: Two-Region Pebble Beds
Fig. 6.5 Preloaded stripes experiment in 1000 mm tall vessel
friction coefficient, etc. In the case of unchanging the main geometric design of the
reactor core, the modification of the design of the bottom of the reactor core maybe
the most efficient strategy to eliminate the stagnant zone, such as the increased base
cone angle and smooth transition from bases to sides.
The pebble flow is the principal issue for the design of the pebble-bed reactor.
For verifying the feasibility of a two-region designed pebble-bed reactor, the experimental installation with a taller vessel has been built, which is proportional to a real
pebble bed reactor. At first, the stable establishment and maintenance of the tworegion arrangement have been verified with the aid of the experimental installation.
At the same time, the applicability of the DEM program has also been validated. In
addition, it has been pointed out that the pebble’s bouncing on the free surface is an
essential factor for the mixing of the different colored pebbles. So the guide plates
have been proposed to be installed at the top of the pebble packing. The size of the
mixing zone has been reduced from 6–7 times to 3–4 times the pebble diameter. Second, the relationship between the width of the central region and the ratio of loading