>The plant was operated from Feb. l959 until Jan. 3, 1961 when a nuclear excursion rendered the plant inoperable, A summary of operations is presented for the period Feb. 1960 until the incident. Plant operational tinwe during the period was 78% of that available. Satisfactory operation of conventional plant equipment was observed during 196 startups and scrams. An inspection of fuel assemblies after 700 Mwd showed no damage except to the B-Al strips attached to these assemblies. A greater than predieted gain in core reactivity was attributed to boron loss. Control rod sticking occurred 53 times ln 2,730 cases of operation. Test results on a PL-type condenser showed that its performance meets design rating. Steam quality remained greater than 99% for power levels up to 4.7 Mw(t) and radiation in the main steam system continued to be satisfactorily low. Waste handling requirements were increased but posed no problem. (J.R.D.)

A total of 661 animals was exposed to sharp''-rising overpressures of 3 to 4 msec duration using a shock tube of novel design which produced a pressure pulse similar to that obtained with high explosives. The reflected shock overpressures associated with 50% lethality were 29.0, rabbit, respectively. Other observations included the time of death in mortally wounded animals and gross pathological lesions likely to contribute to mortality. Selected data from the literature bearing upon the influence of overpressure and pulse duration on lethality were reviewed. These included pulse durations ranging from less than 1 msec to 8 sec. The critical pulse duration, that duration shorter than which the overpressures required for mortality increases sharply, was noted to depend upon animal size and to be of the order of many hundreds of microseconds to very few milliseconds for smaller'' animals and a few to many tens of milliseconds for larger'' animals. (auth)

The monthly report for the Hanford Laboratories Operation, May 1961. Reactor fuels, chemistry, dosimetry, separation processes, reactor technology, financial activities, biology operation, and physics and instrumentation research, operations research and synthesis operation, programming, laboratory auxiliaries operation, and professional placement and relations practices are discussed.

For the purpose of evaluating the compatibility of graphite and INOR-8 in a dynamic fluoride fuel medium, INOR-8 Forced Convection Loop No. 9354-5 was operated 8850 hr. The loop operated at maximum temperature of 1300 deg F and circulated a fluoride fuel of the system LiF--BeF/sub 2/-- UF/sub 4/. Post-test examinations of the graphite and loop components revealed no apparent corrosion or carburization problems. (auth)

None

None

None

Work done on the EGCR graphite combustion problem that may follow from the maximum credible accident, that is the rapid loss of pressure from the primaryreactor coolant system is summarized. The solution to date is to protect the fuel support sleeves with a siliconized siliconcarbide coating and to allow the moderator surfaces to oxidize. The moderator surfaces have available only 6.5% of the total core flow which places an upper limit on the rate of oxidation. The rate of heat removal through the sleeve to the main coolant flow is sufficient to cause a decrease in temperature throughout the reactor and subsequent quenching of the oxidation. This method depends only on continued coolant flow from one blower. Problems attendant with this and other schemes of controlling the fire are discussed. (auth)

None

This document details activities of the irradiation processing department during the month of May, 1961. A general summary is included at the start of the report, after which the report is divided into the following sections: Research and Engineering Operations; production and Reactor Operations; Facilities Engineering Operation; Employee Relations Operation; and NPR Reactor.

General research and development on water-cooled and sodium-cooled reactors are reported along with specific developments on EBWR, BORAK-V, EBR-I, and EBR-H. Thermal and fast reactor safety studies are summarized in terms of fuel-coolant chemical reactions, kinetics of oxidation and ignition of reactor materials, core meltdown studies, and a sodium vapor pressure furnace. Evaluations were made of improved fast reactors for central station power and of a 50-Mwe Prototype Organic Power Reactor (POPR). Developments in instruments, reactcr fuels and materials, reactor components, heat engineering, separations processes, and advanced reactcrs are discussed. (M.C.G.)

Short-term corrosion tests with types 1100, 5154, 6061, and X8001 aluminum alloys were conducted in water at flow rates rsnging between 20 and 107 fps and at temperatures between 170 and 290 deg C. Corrosion of the alloys was less dependent on flow rate in the range of 20 to 67 fps than at higher velocities. At temperatures as high as 230 deg C no evidence of localized attack, except for random shallow pitting, was exhibited by these alloys, and all had comparable corrosion rates. At 260 and 290 deg C all alloys except X8001 showed extensive subsurface attack. At 260 deg C and at velocities up to 67 fps, the corrosion rate of X8001 aluminum was high during the early part of a run and then decreased to rates of between 5 and 15 mpy; at the highest velocity, the corrosion rate was constant at 200 mpy. Tests with X8001 aluminum at 260 deg C showed that mechanically polished specimens corroded at about the same rate as those with a machine finish. A significsnt improvement in corrosion resistsnce at 20 to 67 fps was accomplished, however, by exposing the specimens to water at 250 or 300 deg C in …