Applying QMU to Nuclear Weapon Stewardship

Abstract

The academic bases of QMU are rooted in statistics and engineering reliability or design reliability methods. The following list of textbook references provides instruction on margin over variance ratios and how they relate to the probability of failure [3][4][5][6][7][8][9][10][11]. The earliest mention [12] of a probabilistic failure approach based on overlapping statistical distributions of loadings and strengths come from a publication by Sir Alfred Pugsley in 1939 [13]. He recognized that statistical variations in the strengths of aircraft when subjected to probabilistic variations in aircraft loadings could result in airframe failures.Descriptively, the QMU Confidence Factor (CF) is a metric defined as the performance margin divided by the performance uncertainties. The margin basis is dependent on a selected failure mode. The CF has similarities to other metrics with names, such as Safety Index, Safety Margin and Reliability Index. QMU can be related to other design metrics such as the engineering safety factor, the Sandia K-factor and first and second order reliability methods (see Appendix A).Aviation [14,15], space vehicles [7,16,17], and probabilistic mechanical design employ a variety of statistical methods, safety factors, and reliability/safety indexes to improve and optimize their designs. In particular, air and spacecraft designs use a reliability requirement and confidence limit specification.