The objective of this Production Test Supplement is to evaluate at a K Reactor the operational aspects of a proposed method for reducing minimum downtime. The proposed method is to partially override the xenon transient with a block of enrichment in the central region of the reactor. The purpose of performing this test at a K reactor in addition to the original test at one of the older reactors, is to examine the operational aspects unique to a K reactor and to evaluate the feasibility of the method for reducing minimum downtime at a reactor of that type. It is expected that differences in operating techniques will be indicated at the K plant because of its greater size, of different speed of control restrictions and of the variation in the reactivity effectiveness of enrichment, rods, and poisons. The experience at B Reactor with the use of enriched core to reduce minimum downtime indicates the feasibility of proceeding with a similar test at one of the K reactors.

A program has been carried on at Hanford for a number of years to study the effect of neutron radiation on the dimensional changes in graphite. This program has been concerned with the changes measured on small graphite samples which have been exposed to various conditions of temperature and neutron flux. Theoretical studies have also been conducted to determine damage mechanisms. The prime purpose of this research program has been to develop, with the support of the carbon companies a radiation resistant graphite for use as a reactor moderator at high temperatures. In recent years it has been found that graphite contracts under prolonged neutron exposure at temperatures above approximately 300{degrees}C. This contraction is of concern because of the possible effects on reactor operation and life. For example, distortion of process tubes, vertical safety rods, and horizontal control rod channels can cause increased operating and maintenance problems. This report presents information on the actual depression of the graphite moderator at B, D, F, H, DR, and C Reactors.

This production test is designed to test the feasibility of controlling the amount of air entering a reactor, hence, the burnout of the graphite by monitoring the gas activity. Gas activity comes from the induced activity on argon, which is one of the constituents of air. This production test is basically a test to calibrate the gas activity instruments as a function of various amounts of argon in the reactors gas system. The first two parts of the test are calibration points with different amounts of argon. From these calibration points, extrapolation or interpolation can be used to determine expected activities for other amounts of argon. (GHH)

Localized tensile necking and splitting of the Zircaloy-2 clad on coextruded uranium cored fuel elements may represent an ultimate exposure limit. One way to increase the total energy capability of the fuel element is to corrugate the outside cladding so its perimeter is greater than that of a circle circumscribing the equivalent cross-sectional area. Thus swelling of the core will be accommodated by bending of the cladding rather than by large cladding tensile strains. The principal purpose of the irradiation in to demonstrate that fuel with a corrugated outer cladding accommodates more swelling than a fuel with circular outer cladding and, therefore, can be irradiated with the core in the high alpha uranium temperature range to exposures greater than 2000 MWD/T. This document details a proposal that GEH-10-62 be irradiated to a maximum exposure of 3000 MWD/T or to a volume increase of 5 percent as datermined by weight measurements.