ISSN:0550-3043    

DOI:10.13182/NT70-A28660

出版商:Taylor&Francis    

年代:1970

数据来源: Taylor

摘要:

Under the joint ENEL-EURATOM program for the utilization of plutonium in thermal reactors, the power distribution calculation methods used by ENEL were subjected to extensive investigation aimed at ascertaining their adequacy in handling the various aspects of UO2and PuO2cores.Two categories of codes were verified by comparison with experimental data:Codes that permit the determination of the macroscopic power distribution of the whole core as a function of irradiation; namely, FLARE and CONDOR. The calculated data were found to compare favorably with the experimental observations.Codes that permit the assessment of the effect of local nonuniformities on power distribution over the fuel lifetime, namely, the BURNY code in the two-group, in the four-group (1 thermal and 3 fast), and in the five-group (2 thermal and 3 fast) versions gave a satisfactory agreement with the actual power distribution while the239Pu and235U fission rate ratios were evaluated better by the two-thermal-group version. Since allowance was made for the spectrum softening due to the water gap, the GAM-THERMOS-SQUID system achieved the same accuracy as the two-thermal-group BURNY, but it was much more time consuming. However, the two-thermal-group version of the BURNY code tended to overestimate the effect of the water gap on the corner rod slightly, and the one-group version rather undere stimated it.

ISSN:0550-3043    

DOI:10.13182/NT70-A28661

出版商:Taylor&Francis    

年代:1970

数据来源: Taylor

摘要:

In this paper, we discuss the feasibility of the application of the gaseous-core reactor to electric-power-generation systems. An analysis of the radiation-heat-transfer process in the gaseous core is presented. The results of this analysis are then combined with an estimate of the quantity of uranium required for criticality to determine the core pressure and temperature for various values of power generation and core diameters. This analysis indicated that attractive power levels in reactors of practical size can be obtained with gas pressures and wall temperatures within the potential capability of known structural materials. As an example, it is estimated that a spherical gaseous-core reactor with a radius of 152.4 cm would generate ~4000 MW(th) with a gas pressure of ~11 atm. Several configurations of the gaseous-core reactor employing thermionic converters and heat pipes are described.

ISSN:0550-3043    

DOI:10.13182/NT70-A28662

出版商:Taylor&Francis    

年代:1970

数据来源: Taylor

摘要:

Four slugs containing a sum total of 20.950 g of plutonium as Al-Pu 10% alloy have been irradiated in the EL-3 reactor to an integrated flux of 5×1021n/cm2. After 2.5 years of cooling, the processing has been carried out in the hot cell“Petrus.”It consisted of (a) an alkaline and/or nitric dissolution of the“napkin-rings,”(b) a plutonium separation by two extraction cycles with trilaurylamine (5 vol%), each consisting of a plutonium extraction from a nitric medium and stripping by a solution containing sulfuric and nitric acids, (c) a transplutonium element separation by two HDEHP (8 vol %) extraction cycles, each consisting of an actinide-lanthanide extraction from an aluminum and lithium nitrate solution and a selective stripping of the transplutonium elements by a lithium nitrate solution containing diethylenetriaminopentaacetic ions (DTPA), and (d) an americium/curium separation by anion exchange resin using a nitric solution containing a complexing agent as eluent.From these runs 2.6 g of plutonium, 150 mg of americium, and 15 mg of curium have been recovered. The overall yields of plutonium and transplutonium elements were>97 and 98%, respectively, and theβ—γdecontamination factors>105.In general, these results show clearly the effectiveness of solvent extraction in actinide reprocessing.

ISSN:0550-3043    

DOI:10.13182/NT70-A28663

出版商:Taylor&Francis    

年代:1970

数据来源: Taylor

摘要:

A chemical etchant for UO2consisting of three parts concentrated HCl and one part concentrated HNO3is reported. This etchant, when used for ten minutes at 60°C on cleaved {111} surfaces, produces distinctive pits at dislocations intersecting the surface and at low-angle grain boundaries. The fact that the etch pits mark the sites of dislocations was shown by comparing the enlargement of pits with etching time and the etch pits on matching cleavage faces. Comparison of etch rates at various temperatures gave an activation energy of 15.1 kcal/mole.

ISSN:0550-3043    

DOI:10.13182/NT70-A28664

出版商:Taylor&Francis    

年代:1970

数据来源: Taylor

摘要:

Optimized schedules for the expansion of fabrication capacity for nuclear fuels can result in substantial savings to the electrical economy. This is evident when the fabrication costs for optimized schedules are compared with conservative schedules based only on near-term demand. A method is presented by which such optimization is achieved through mathematical simulation of numerous logically selected expansion schedules which are all based on the same time-dependent demand data. The schedules are generated by assuming different plant utilization policies and planning horizons, and are compared on a levelized unit cost basis. The schedule yielding the lowest cost over the time period studied is defined as optimum. A parametric analysis is included to show the variation of optimum expansion schedules and unit costs with changes in the various economic parameters.

ISSN:0550-3043    

DOI:10.13182/NT70-A28665

出版商:Taylor&Francis    

年代:1970

数据来源: Taylor