Production Test IP-546-A. consisting of 20 charges for the purpose of irradiating the first hot die sized fuel elements was charged in C-Reactor July 27, 1963. A second tests PT-IP-616-A containing a total of 19 charges had been charged on two separate outages; 13 land 6 tubes on September 28, 1963 and October 30, 1963, respectively. Fabrication of test quantities was becoming more routine and additional irradiation tests were planned. This report summarizes the fabrication of hot die sized fuel elements originally intended for Production Test IP-630-A, but changed to ``Supplement ``A`` to Production Test IP-546-A, Irradiation of Diffusion Bonded Fuel Elements,`` HW-75465 E. The production test was changed due to unexpected growth behavior of hot die sized fuel during irradiation.

A program for the irradiation of samples-of N-Reactor graphite has been in progress since November 30 1961, in the General Electric Test Reactor (GETR). The basic purpose of the program is to achieve an exposure to the samples equivalent to 20 years of operation of N-Reactor and to relate the physical distortion of the samples to the expected behavior of the N-Reactor moderator stack. Theoretical studies to relate sample exposure in the GETR to exposure in N-Reactor have been underway since the program began. The conversion of exposure depends on three main items: the flux and exposure in the GETR test position; the flux and exposure in the N-Reactor stack; and the relationship of the amount of carbon damage per unit flux in N-Reactor to that in the GETR. To date all three items of the conversion have been based strictly on computer calculations. The first item (the GETR flux) has been calculated as group one, E > 0.18 MeV, of the three-group computation made every reactor cycle by the GETR physics group, This computation is normalized to reactor conditions by comparison of group three, E < 0.17 ev, with measured cobalt-alloy monitors. No direct comparison of group one with …

Metallic thorium uranium fuel elements continue to show excellent irradiation performance in high temperature pressurized water coolant. Volume expansion measurements made after 2.1{times}10{sup 20} fissions/cm{sup 3} (6200 MWD/T) at fuel temperatures above 500 C shows no indication of fission gas-in-duced swelling. Analysis of fuel swelling data from tubular elements shows apparent effect of geometry (restraint) on both low temperature volume expansion and the temperature at which accelerated volume expansion initiates. Evidence of grain boundary tearing has been observed in tubular metallic uranium fuels irradiated in 1600 pos water coolant. Volume expansion due to two types of structural damage have ben observed uranium - 2 w/o zirconium alloy irradiated to 0.25 a/o burnup at temperatures up to 550 C.

Purpose of this supplement is to increase the maximum allowable liquid level in the near downcomer for single downcomer operation. The required clearance between the downcomer lid and liquid level is reduced from 24 inches to 18 inches in the near downcomer, providing bulk outlet temperature is maintained less than 93 C.

With recent concern for downcomer capacity at most areas, it seems appropriate that a survey be made to determine what instrumentation and data are available. The following is a brief description of the available instrumentation and data for KE, KW, H, F, DR, D, C, and B reactors.

This document provides the Hanford Production Reactors operating histories from January 1, 1961 through November 30, 1969. The raw log sheets are provided.

Early in December 1963 eighteen natural uranium columns were discharged from C Reactor. Fifteen (15) of these columns contained alternately charged HDS (test) and AlSi (control) fuel elements in the downstream half (positions 1--16); two columns were charged full length with HDS material; and one column was charged full length with AlSi material. All canned pieces were nominally C5NS dimensions except that the HDS pieces were slightly longer than the standard AlSi pieces. Uranium fabrication history, through heat treatment, was controlled ad equivalent for both test (HDS) and control (AlSi) material. For these eighteen columns average exposure was {approximately}960 Mwd/ton, average tube power was {approximately}1125 kw, and average tube outlet temperature was {approximately}100 C. Two striped charges were discharged in September 1963 @ 370 Mwd/ton. This report presents results of the post-irradiation measurements that have been completed and analyzed as of this date. A second set of measurements for a portion of the material is being programmed.

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Because of the unexpected growth behavior of hot die size fuel elements during irradiation, it was necessary to re-evaluate the plans for hot die size irradiation testing and redirect the development effort. Tests were initiated to determine the cause of the growth, and plans were made to incorporate findings into subsequent irradiation tests. This report summarizes work done to determine the cause of the unexpected growth and the status of irradiation tests designed to measure improvements in the growth behavior of irradiated hot die size fuel.