Status of Experimental Programs and Research Projects

Regulatory History and Status of Nuclear Criticality Safety Research, R. H. Odegaarden. D.E.Solberg(NRC) 

The first efforts to confirm the adequacy of a calculation method for nuclear criticality safety were to use an empirical equation based on the density analog method originally proposed by H. C Paxton. This work was comideted in October 1965 and compared the specified density analog method with 58 critical experiments that were performed by A. D. Callihan et al., for metal and solution arrays. 

In January 1969, Regulatory sponsored a project at ORNL in which G. E. Whitesides made the ORNL cross-section processing codes and the KENO code operational at the National Bureau of Standards for Regulatory. Using the 16-group Knight-modified Hansen-Roach cross-section set and KENO, R. L Stevenson and R. H. Odegaarden published an ANS paper in November 1969 on an empirical relationship between criticality and surface density first proposed by R C. Paxton. 

The first AEC Regulatory-sponsored confirmatory research project was initiated in January 1973 with R D. Clayton, PNL. The purpose. of the work was to verify criticality data on the effectiveness of fixed neutron alv sorbets (copper and copper-cadmium plates) between fuel blocks consisting of a homogeneous mixture of PuOj-UOj-polystyrene at H to Pu U ratios of 30.6 and 2.8 (Ref. I). Other neutron absorbers [SS, SS-B, U(0.2), BoraL Cd, and Pb] were considered in 1976.  

Beginning in 1972, Regulatory began a series of efforts to improve and build on the nuclear criticality computer 

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