Efforts have been made to experimentally evaluate and to calculate the effect of reactor environment on splines. This report follows some of these efforts and relates them to operational experience. The use of splines in the Hanford Reactors has improved the efficiency and ease of operating the reactors. With the widespread use of splines, it is important to know the effect of reactor exposure to safely and efficiently use the splines in reactor operation.

The N-Reactor Hazard Summary Report examines the hazard from operating the N-Reactor with a uniform fuel loading enriched to 0.947% U{sup 235}. Incentives have been developed for reactor testing of a block of 49 tubes loaded with co-producer elements, i.e. elements capable of producing both weapons grade plutonium and tritium. The element utilizes an outer fuel tube enriched to 1.25% U{sup 235} with an inner target lithium-aluminum rod. Criteria have been developed to guide the evaluation of safety aspects of such tests. It is the purpose of this document to review the hazards associated with the proposed test and to set forth special precautions which will be necessary to maintain a high level of safety.