Metamorphic testing of the NUIT code based on burnup time

Abstract

Traditional testing methods play an active role in nuclear design software testing. However, most of them belong to the direct comparison method, which judges whether the program is correct by comparing the actual result with the expected value. Because of the large number of nuclides and the existence of short half-life nuclides and closed-circle burnup chains, it is almost impossible to predict the production of the burnup program accurately. It makes the direct way inapplicable or even invalid. This issue that is hard to construct expected values is called the testing oracle problem. Metamorphic testing is one of the effective techniques to alleviate it. Metamorphic relation plays a crucial role in metamorphic testing. It describes the basic properties of mathematical equations and numerical solution algorithms, which is of considerable significance to deeply understand the nuclear design program's behavior. After analyzing the nature of the point-depletion calculation program, a set of metamorphic relations based on burnup time is identified and applied to the NUIT code. Specifically, the mutation operator is used to introduce artificial faults in the original code. Both metamorphic testing and the direct comparison method are all used to examine the mutant. The latter consists of transmutation trajectory analysis and the original program. Experiments show that the metamorphic relations proposed in this paper are real, and metamorphic testing has a similar failure detection ability to the direct comparison method. When the direct way is invalid, it can still work effectively, stably, and reliably without false positive. Finally, some useful suggestions on those metamorphic relations are given. Other burnup programs can directly apply them and learn from this example.