A Three-Dimensional Depletion Analysis of the First Shippingport Pressurized Water Reactor

The first Shippingport seed-blanket core was operated for 5530 equivalent full power hours at equilibrium xenon and samarium conditions. The comparison of physics measurements and calculations presented are those applicable to the first core containing the initial seed material. A three-dimensional diffusion theory depletion analysis indicates that this calculational model describes with reasonable accuracy the directly observed and inferred reactor parameters examined over core lifetime. The reactor parameters compared include: criticality, reactivity lifetime, xenon transient behavior, temperature coefficients, and blanket power fraction. While the primary emphasis is on the three-dimensional calculational and experimental comparisons, the results of one and two-dimensional diffusion theory depletion calculations are included to indicate their relative merit. The results indicate that such reactor parameters as excess reactivity, temperature coefficients, and blanket power fraction, may be estimated to within approximately the same accuracy by one and two-dimensional depletion models as by this particular three-dimensional model. This conclusion must be qualified by noting the crudeness employed in the three-dimensional depletion model.