A commercial graphite useful in nuclear reactor construction is described. A survey of all currently available sources on chemical and physical properties was made and the information listed. Some data on cost and available sizes are also included. (auth)

None

This report addresses the control design review of P&W quarterly for July to September 1960.

In connection with the ORR Hastelloy-N irradiation experiments, a limited number of tensile tests and uniaxial and biaxial stress-rupture tests on S8DR Hastelloy-N heats were conducted at AI to determine the effect of some of the ORNL test conditions. The tests performed at AI were in parallel to the ORNL control tests. The results showed that the effect of the test condition variations between the two tests were generally insignificant. The effect of the test conditions is discussed.

None

None

Nickel plated aluminum was considered as a jacketing material for nuclear fuel elements as early as 1954, and both static and dynamic corrosion tests were carried out by Argonne National Laboratories and by Atomic Energy of Canada Ltd., employing demineralized water at temperatures of from 260 to 316{degree}C. Results generally indicated that the nickel had excellent corrosion resistance; however, difficulties were experienced in achieving satisfactory continuity and adhesion of the plate; subsequent work emphasized Ni-Aluminum alloy development. At Hanford, our earliest experience employed Ni plate on aluminum-jacketed fuel elements primarily to minimize mechanical damage to the jacket surface during an irradiation test. The appearance of these fuel elements after discharge suggested that the nickel plate might also be a highly satisfactory coating for corrosion and abrasion resistance. Incentives were manifold, including reducing the incidence of in-reactor fuel element failures and permitting reduction of the aluminum jacket thickness with a concomitant increase in space available for uranium or for cooling water passage. A program has been carried out for the past three years aimed at determining various methods of employing nickel plated aluminum jacket material and testing the capabilities of high quality commercially adequate plate. Almost exclusively chemically deposited plate has …

In 1955 the Fuels Development Operation began irradiation testing of fuel elements in high temperature water. It was assumed that if a new reactor were built at Hanford, it would be cooled by high-temperature, pressurized water. Corrosion tests showed that aluminum-clad production fuel elements could not be used in high-temperature water. Therefore, while work to improve the resistance of aluminum to high-temperature water proceeded, the Fuel Design Operation began irradiation of stainless steel- and Zircaloy-2-clad fuel elements. During 1956 and 1957, stainless steel-clad elements were tested in the Materials Testing Reactor (MTR), Hanford H Reactor Loop, and the KE Reactor Recirculating (KER) Loops. During 1957, a coextrusion method for cladding uranium rods with Zircaloy-2 was developed. The first irradiation of Zircaloy-2-clad fuel from an off-site supplier began in late 1958. The objective of the irradiation was to study the dimensional stability of the fuel rods and a seven-rod fuel assembly. Two coextruded, seven-rod elements were irradiated in KER Loop l.

None

In Hanford reactors the reactivity gain upon loss of coolant water is an important factor in the speed of control requirements. The reactivity gain in the cold, clean reactor is determined from experiments, but additional effects must be taken into account if the gain in the operating reactors is to be obtained. One of these effects is the change in Xenon and Samarium poisoning with neutron temperature, which is discussed here. Earlier work on the relationship of operating limits to the reactivity gain upon loss of coolant is given in Reference 1. Work on this problem is continuing by Reactor Physics, IPD, but the newer work is not yet documented. In earlier calculations, the neutron temperature could only be guessed. Recent measurements of neutron temperatures have indicated the magnitude of the neutron temperature change upon loss of water. This document interprets the data of Reference 2 in terms of the change in Xenon and Samarium poison to be expected on water loss under typical operating conditions.

IP-401-A authorized the irradiation of 18-inch UO{sub 2} elements and IP-363-A authorized 18-inch KSE-3 elements. This document provides specific loading and operating conditions for a charge of one UO{sub 2} element and two KSE-3 elements in KER-1.

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.

Under simplifying assumptions, an expression is obtained relating the integrated kinetic energy transferred to moderator atoms to the thermal neutron exposure in adjacent fuel. Reactor-dependent factors are explicit in the expression which make it possible to compare graphite contraction data from different reactors or to estimate graphite damage in a new reactor based oil observed damage in existent reactors. Graphite temperature, which may be an important factor in graphite contraction, is not considered as one of the variables in this report. Also, the damage dependency on neutron energy is not dealt with in great detail because of the relatively unknown facts in this regard. A particular application of concern at the present is to determine the pertinent factors relating to fast neutron exposure in the NPR to assist in determining the integrated damage over the life of the pile.

This report covers progress on the Projection Welded Brazed Closure following work of Ard and Steinkamp (HW-69592). In order to continue the investigation of the closure on NPR inner fuel, a 600 KVA machine was acquired. Weld tests were conducted; the heat balance problem was addressed.

The nuclear heat generation rate in the first capsule irradiated was higher by a factor of two than was calculated. The original capsule was irradiated in a dry bore with cooling water in the annulus only. The new capsule will be irradiated in a water-cooled bore facility with additional cooling coils around the lithium containing tube. This will keep the inner capsule temperature below 150 C during the initial tritium buildup period prior to outgassing. This Supplement authorizes the irradiation of an additional capsule and the removal of the present facility and installation of a single tube general purpose facility. All remaining provisions of the original development test are in force except for minor exceptions due to the water flow in the bore which have been changed in the following writeup.

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.

The oxidation of graphite in the Hanford reactors is of consequence since graphite burnout affects the strength of the moderator. As a means for indication of any highly oxidizing condition within the stack, containers or boats of small weighed samples of reactor-grade graphite are positioned along the length of an empty process channel in each reactor. The rate of oxidation of the monitoring samples, referred to as the burnout rate, is reported as percent weight lose per 1000 operating days (%/KOD). Currently the burnout rate limit is 2%/KOD. This document presents recent burnout data at the C-reactor.

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.

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.

None

During the 0000--0800 shift on August 21, 1960, the delayed neutron monitor on KER Loop 1 indicated a high coolant activity level. Sympathetic responses were also recorded on the Loop 2, 3 and 4 monitors indicating a possible fuel element failure in Loop 1. The KER Reactor began shutdown operations immediately thereafter. The purpose of this report is to summarize the events pertinent to this reactor outage and to discuss the results obtained from coolant and coupon samples taken from Loop 1.

This report to the FEDC Working Committee details activities in N-Reactor fuel element fabrication and materials testing for the time period of September 1965 to January 1966.