摘要:

A novel approach for establishing acceptability of risk is presented and illustrated by an application to the case of the light water reactors. The advantage of the method is that it takes into consideration the shape of the probability distribution function over consequences, instead of simply using the expected value of this distribution. An individual’s attitude toward a certain consequence, such as loss of life, is described by a preference index under certainty, separately from his attitude toward uncertainty. The latter is quantified by the position of the individual in a risk space whose coordinates are related to the individual’s attitude toward gambling and his degree of dislike of improbable but serious consequences.

ISSN:0029-5639    

DOI:10.13182/NSE80-A19054

出版商:Taylor&Francis    

年代:1980

数据来源: Taylor

摘要:

A linearized formulation of the basic fluid conservation equations for describing the dynamic behavior of nuclear steam generators is presented. The model utilizes a movable boundary spatial discretization technique in one-dimensional geometry and is capable of representing the transient behavior of integral-economizer once-through steam generator (IEOTSG) units in the time and frequency domains. A generalized boundary treatment algorithm is developed to place and track boundaries between heat transfer regimes on the secondary side of a steam generator. An enthalpy transport model is incorporated in a manner consistent with the movable boundary formulation to reduce the nonphysical representation of the in-cell distribution of enthalpy with long axial regions and weighting functions. Results of transient calculations performed with the linearized model agree well with other computational results, as well as with the experimental data obtained at a 19-tube IEOTSG test facility.

ISSN:0029-5639    

DOI:10.13182/NSE80-A19055

出版商:Taylor&Francis    

年代:1980

数据来源: Taylor

摘要:

Magnetic confinement fusion programs are now entering the design phase for devices that will demonstrate the physics and engineering necessary for fusion reactors. One design area of significance that is receiving increased consideration is that of determining the characterization and potential consequences of plasma disruptions. The thermal energy and the magnetic energy stored in an engineering test facility type plasma will each be∼200 MJ.A thermal energy of 200 MJ will result in a very high heat flux if deposited on a tokamak wall in a short time. The consequences of such depositions as a function of disruption time, and of the spatial distribution of the plasma as it strikes the wall, are analyzed in this paper.

ISSN:0029-5639    

DOI:10.13182/NSE80-A19056

出版商:Taylor&Francis    

年代:1980

数据来源: Taylor

摘要:

A numerical model of the neutron noise field in boiling water reactors (BWRs), which can be readily implemented in existing deterministic computer codes, was formulated. The basis of the model is the assumption of separability of the noise field into local and global components. The application of this modeling was twofold: to determine the frequency range above which cross-correlation techniques can be used to measure steam velocities under normal operating conditions and to evaluate the validity of the point kinetics description of the global component of the neutron noise in BWRs. The model was implemented in the code LAPUR-3 and applied to the Hatch-1 BWR nuclear plant. Comparison with experimental results shows good agreement for frequencies above 6 Hz. At lower frequencies the global noise is overestimated, making apparent the limitation of the point kinetics formulation of the global noise component for this large reactor.

ISSN:0029-5639    

DOI:10.13182/NSE80-A19057

出版商:Taylor&Francis    

年代:1980

数据来源: Taylor

摘要:

The optimum235U enrichment of the uranium fuel for a once-through cycle for pressurized water reactors (PWRs) is∼20%. Such an enrichment leads to a core design having the following major advantages in safety, economy, and uranium utilization over present standard designs.1.There is a reduction in core volume by about a factor of 2, resulting in important savings in costs of core and pressure vessel.2.Safety will be enhanced as a result of utilization of metallic fuel elements with much greater strength and a factor of 10 better heat conduction and less stored energy than standard ceramic fuel elements. The maximum temperature is 700°F below melting, as compared with 300°F for ceramic fuel.3.Plutonium discharge is reduced by about a factor of 7.4.Need for a soluble neutron-absorber control is eliminated.5.While a detailed core design was beyond the scope of this work, a relatively simple fuel management scheme appears to be feasible which woulda.reduce initial uranium ore requirements by∼50% of that of standard PWRs and separative work by∼35%b.reduce annual usage of uranium ore by∼15% with a slight increase in separative work.

ISSN:0029-5639    

DOI:10.13182/NSE80-A19058

出版商:Taylor&Francis    

年代:1980

数据来源: Taylor

摘要:

AbstractTheoretical calculations and experimental measurements have been made to look for reported chemical dependence in the yield of delayed neutrons from thermal-neutron-induced fission in235U. Using an Einstein model of the lattice phonon distribution, calculations have been made that indicate no significant dependence of the fission cross section on the lattice phonon distribution. Two types of experimental measurements were made. The fission fragment yield was compared for thermal-neutron-induced fission in U3O8and UO2. The delayed neutron yields from U3O8and UO2were also compared. In neither measurement was there a significant difference in yield for the two chemical states of uranium.

ISSN:0029-5639    

DOI:10.13182/NSE80-A19059

出版商:Taylor&Francis    

年代:1980

数据来源: Taylor