Calculations of heat inside active lattice

1 Calculations. Of Heat Inside Active Lattice. The assembly plates will.contain a. concentration of of about 20.4 mg/cm. At a power output of 10 kw per gram, which corresponds to a slow flux of about 2 10, the heat taken out of each side of an assembly plate is about- 24 cal/chi /sec. With a flow velocity of 30 ft/sec in the reactor-core and a plate separation of 0.117 in., the heat transfer- coefficient, with no scale formation, should be about 0.9 cal/cm /sec/ C, or 6300 Btu/hr/ft / F. The film temperature drop is therefore 27°C. 

2 Calcaiations of Heat la Berjlliam and in Porelga Haterlals Near Active Lattice. Outside the core, heat is produced primarily from absorption of y rays. Some of these come from the reactor itself, and some arise from neutron capture in beryllium, and in graphite. 

The calculation of the heat distribution in the reflector mas based oh the neutron distribution for the very thin slab reactor eithout any thorium (Fig. 4.2.F) since in this case the heat load in the reflector is heaviest. The results are given in Fig. 4.5.A. To simplify the computation of the y- ray absorption, the core and reflector were assumed to be infinite slabs this, leads to an overestimate of the heat load since.the neutron flux was assumed to be uniform over the-whole core and equal to 2, 10.  

added heat fluX per. experimental hole is about 0./03A /A bw, where A is the cross-sectionaT area of the hole, and A is the.distance from the core surface to the. face, of.the hole opposite the core surface, provided A is much smaller than A. For the 6-ih. hole A 40 cm, the total heat flux is about 0.6 kw or 3.5 watts/cm. Tbe pile y-ray heat flux at 40 cm in the absence of a hole is 3.5 watts/cm hence the hole increases the load due to the y-ray heqt by a factor of 2, or the total heat flux increases from 4.6 watts/cm (see Fig. 4.5.A) to 4.6 + 3.5 8.1 watts/cm -. -- 

The greatest heat load outside the core occurs in the mid-plane of the beryllium reflector at the interface between beryllium and core. This maximum 

---