## 9-ZOOM--A ONE-DIMENSIONAL, MULTIGROUP, NEUTRON DIFFUSION THEORY REACTOR CODE FOR THE IBM 709. PART I. THEORY AND EQUATIONS. PART II. INPUT AND OPERATING INSTRUCTIONS. PART III. TEST PROBLEM

The UCRL IBM-704 Code, ZOOM, was programmed for the IBM-709. A number of changes was made in input format, power convergence scheme, technique of inner iteration, etc. 9-ZOOM is a memory-contained program requiring no working tapes and is between five and ten times as fast as 704 ZOOM. 9-ZOOM takes advantage of 709 features such as preferential order of multiply by zero, and for small problems approaches input-output limitations with excellent convergence properties. Features of 9ZOOM are detailed. Theory and equations, input and operating instructions, and a test problem are given. (W.D.M.)