Development of the ZPPR-9 core benchmark problem

Iwai, Takehiko*; Sugino, Kazuteru; Ishikawa, Makoto

In the Reactor Physics Research Section, O-arai Engineering Center, a Standard Data Base for Nuclear Design is under development to improve the accuracy of FBR nuclear design calculations. The Reactor Integral Test Working Group of the Sigma committee is compiling data from TCA (Tank Type Critical Assembly), STACY (Static Experimental Critical Facility) and FCA (Fast Critical Assembly), for a set of nuclear data benchmark problems. An FBR benchmark problem from the Working Group has been added to the Data Base: the ZPPR-9 core, simplest of the JUPITER-I series, recommended for its ease of use. The compiled nuclear parameters are Criticality; Reaction rate data(Reaction rate ratio & Reaction rate distribution); Control rod worth; Sodium void reactivity and Sample Doppler reactivity. The benchmark problem definition is an idealization of the experimental geometly; we used detailed analytical methods to prepare correction factors, so that users of the benchmark can compare their results with the experiment. Wide use of the benchmark problem is anticipated. However, the calculation of correction factors is affected by the mesh size, the number of energy groups and the definition of cross sections, so it is necessary to use detailed analytical methods to produce modified correction factors when one uses a calculational model in which mesh size etc. are different.