Experimental studies of 6000-litre LMFBR cores at ZPPR

The ZPPR-10 program has provided basic physics data for large two-zone conventional LMFBR cores. The early assemblies, 10A and 10B, had core volumes of 4600 litres. The assemblies reported here have core volumes of 6000 litres and represent 900 MW(e) reactors. The measurements emphasized the spatial variation of reaction rate distribution and control rod worths for configurations having 19 and 31 control rod positions. Two configurations with rods inserted were made critical by fuel additions in the later phases. A number of sodium void reactivities were measured. Analysis was made with ENDF/B-IV data.