Preface; Subsequent to the analysis in the body of this report metallurgical developments indicated that it would not be feasible to build the APPR-1 Core II with the increased boron loading specified herein. At the time of the issuance of this report the Core II boron loading is to be the same as that for Core I. At the time of procurement of the core in the fall, if metallurgical developments warrant, the increased boron loading will be employed. The loading discussed in the body of the report and the first three appendices is that designed to meet the specifications outlined in the introduction. Appendix IV discusses changes in the loading to account for the various methods of employing boron.