FUSION INTEGRAL EXPERIMENTS AND ANALYSIS AND THE DETERMINATION OF DESIGN SAFETY FACTORS .1. METHODOLOGY

The role of the neutronics experimentation and analysis in fusion neut ronics research and development programs a discussed. A new methodolog y was developed to arrive at estimates to design safety factors based on the experimental and analytical results from design-oriented integr al experiments. In this methodology, and for a particular nuclear resp onse, R, a normalized density function (NDF) is constructed from the p rediction uncertainties, u(i)'s, and their associated standard deviati ons, +/- sigma(i)'s, as found in the various integral experiments wher e that response, R, is measured. Important statistical parameters are derived from the NDF, such as the global mean prediction uncertainty, ($) over bar u, and the possible spread, +/- sigma(u), around it. The method of deriving safety factors from many possible NDFs based on var ious calculational and measuring methods (among other variants) is als o described. Associated with each safety factor is a confidence level, designers may choose to have, that the calculated response, R, will n ot exceed (or will not fall below) the actual measured value. An illus trative example is given on how to construct the NDFs. The methodology is applied in two areas, namely the line-integrated tritium productio n rate and bulk shielding integral experiments. Conditions under which these factors could be derived and the validity of the method are dis cussed. The described methodology could be applied to the integral exp eriments proposed for the International Thermonuclear Experimental Rea ctor (ITER) neutronics research and development, particularly, in deri ving the required safety factors for ITER shielding.