Reactor Parameter Measurements

With the experimental lattice in the proper neutron environment and poisoned so that 1, homogeneous theory indicates that replacing a section of the cell with void will not alter the reactivity of the system. The effect of ceU inhomogeneities on this conclusion will be discussed. 

The conditions which must be satisfied to establish the proper neutron environmeid are that the flux shall be flat Le., constant parallel to the cell axis, over the test region) and that the spectrum shall be the same at corresponding points in the central cell and adjacent cells. The experimental criteria which have been enqtloyed in PLATR to insure that these condittons have been satisfied are in terms of the activation of bare and cadmium covered gold foils. 

After the establishment of the prtgier environment and the determination of tlie amount of thermal neutron absorber required to reduce to 1, the intraeell flux distribution Is determined to permit the determination of values for the thermal utilization, f, and the infinite multiplication factor, k , for the unpoisoned lattice. 

An extensive series of measurements has been made with clusters of j-in. diam. natural TJOk rods clad in aluminum. A major portion of the series dealt with a 37-rod cluster on an ll.l-ln. lattice pitch, the NDA-S L design. Among the parameters studied were lattice pitch, rod-rod pitch, cluster size, insulation gap between housing tubes, and clad material. The coolant void coefficient was also determined. A corresponding series of lattices has been evaluated using the ROCLAND-A code. The ai ee-ment between the calculations and measurements is satisfactory however, the calculations yielded are generally lower values than the measurements by 0.5-1.0% in ko,. 

Since August 1961 the experimental program has been concerned with tubular natural UOi elements which were fabricated at the Savannah River Laboratories of the USAEC. Lattices of single tube elements and coaxial tube 

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Development of Research Reactor Parameter Measuring System Based on PC... 

Development of research reactor parameter measuring system based on a personal computer was carried out at the Korea Atomic Research Institute. The work includes the interface constniction between a PC and reactor instruments, experimental logic development, programming and test. 

Nowadays, computerization is common trend in every field and many utilities are comnercially available at reasonable cost. For the case of research reactor experiments, however, a low cost and ready-made computerized system is not available yet since its demand is very limited, which means that reactor staffs should develop such system by themselves but majority of them are not specialists in the computer. From this point of view, it is considered that developing a reactor parameter measuring system based on the PC is worthwhile. 

Stability and Performance of Bound En me. The stability of the IME was determined by two methods. One measurement of bound activity was obtained using traditional cellulose hydrolysis experiments (described below). In the other method, direct kinetic parameter measurements were obtained using a recirculating differential (RDR) reactor system following the method of Ford et al. (46). 

Reaction kinetics may be determined for a fixed-bed reactor, provided measurements are performed under conditions comparable to those that prevail in the fluidized-bed reactor (for example the same solids composition and particle-size distribution, and the same activity state) [98] However, the kinetic parameters can also be determined directly by measurements in a bench-scale fluidized-bed apparatus [99]... 

Simultaneous measurements of the rate of change, temperature and composition of the reacting fluid can be reliably carried out only in a reactor where gradients of temperature and/or composition of the fluid phase are absent or vanish in the limit of suitable operating conditions. The determination of specific quantities such as catalytic activity from observations on a reactor system where composition and temperature depend on position in the reactor requires that the distribution of reaction rate, temperature and compositions in the reactor are measured or obtained from a mathematical model, representing the interaction of chemical reaction, mass-transfer and heat-transfer in the reactor. The model and its underlying assumptions should be specified when specific rate parameters are obtained in this way. 

Equations 10 - 15 are used in a later section to predict the performance of an isothermal trickle-bed reactor using measured values of all the model parameters except the mass transfer coefficients (and hence Biot numbers). The correlations of Goto and Smith (J35) and Turek and Lange (18) were used to obtain values of while the correlation... 

As noted above, the ECP is the key parameter in describing the susceptibility of reactor coolant components to corrosion damage. As experience has shown, the direct measurement of ECP in reactor coolant circuits has proved to be very difficult, notwithstanding the monumental efforts of Indig et al. at the General Electric Company-see [3], for example. The major challenge in in-reactor ECP measurements has been to devise a reference electrode that can withstand the harsh environmental conditions that exist within a reactor pressure vessel (RPV). 

The definition of reactivity inferred from measurements depends both on the type of integral parameter measured and on the procedure adopted for transforming the measured parameter into reactivity. Four definitions of reactivities have been presented in this section. As the reactor approaches criticality, the four reactivities approach the same value. The further the reactor is from criticality (or the larger the alteration of the system), the greater the difference in the value of the various reactivities. 

Measurements of Reactor Parameters in Subcritical and Critical Assemblies Irving Kaplan... 

Data for validating pulverized coal combustion predictions requires accurate information for the reactor parameters shown in Table VI. Data measured in the combustion chamber typically include (1) locally measured values of the gaseous flow field velocity, temperature, and species composition, (2) coal particle burnout, number density, velocity, temperature, and composition, and (3) wall temperatures and heat fluxes. Evaluation should include comparisons with measurements from a wide variety of combustors and furnaces that range in scale from very small laboratory combustors (0.01-0.5 MW) and industrial furnaces (1-10 MW) to large utility boilers (up to 1000 MW). 

REVIEW OF OBTAINING AND ESTIMATION METHODS OF PHYSICO-CHEMICAL AND RELATED DATA PART 2 - GAS-LIQUID MASS TRANSFER PARAMETERS. MEASUREMENT AND SOME DATA IN SEVERAL TYPES OF REACTORS... 

Review of Obtaining and Estimation Methods of Physico-Chemical and Related Data Part 2 - Gas-Liquid Mass Transfer Parameters. Measurement and Some Data in Several Types of Reactors... 

A neutron zero power facility with only SOkg U-235 has been built up in 1970, then moved to the South-West center of Reactor Engineering in Sichuan P rovince. Basic zero power physics experiments have been done at diis facility including critical parameter measurements, fission rates, neutron flux distribution, neutron spectrum, material reactivity etc. in 1988, it was removed to ClAE again, and now it has been rebuilt and will be used for proving of the neutronics experiment medtods which will be served to CEFR first start-up and to primary test for die neutronic and other radiation detectors. It is considered also it will be valuable to the evaluation of some specimen nuclear cross section using its hard spectrum. 

A dynamic tubular reactor model, comprising a set of partial differential equations, has been used to test the computational efficiency and the data handling capabilities of the various software packages. Experimental data of three time-varying model inputs, i.e. the reactor temperature, the fluid velocity and the reactant inlet concentration, are used to estimate the model parameters fix)m experimental data of the reactor temperature measured at several fixed reactor locations as a function of time. This problem was originally published in 1992 [3]. 

Generic Safety Issue (GSI) I.D.5 (4) in NUREG-0933 (Reference 1), addresses the benefit to plant safety and operations of improved measurement of certain reactor parameters (e.g., reactor vessel water level and relief valve flow), and parameters outside of their normal operating range. 

Measurements of Reactor Parameters In Subcritical and Critical Assemblies a Re> view, /. Kaplan (MIT). 

Many the lattices which were investigated at BNL as subcritical assemblies were also studied in critical assemblies at Westinghouse (Bettis). b some cases the techniques at the two laboratories were similar, and in other cases the techniques were different. There were also a few critical e]q >eriments at BNL. The subcritical experiments at BNL fall. into two classes miniature lattice measurements and exponential measurements. Values of e, p, and f were obtained in small assemblies (miniature lattices) which have a neutron multq>lication of about 3, and in which the central neutron spectrum is characteristic of a critical assembly. Values of M and B were measured in larger assemblies (exponential assemblies) in which the neutron multiplication is between 3 and 50. Thus, there are considerable data to compare reactor parameters as measured in similar lattices by subcritical and critical techniques. 

In the case of some measurements, it is possible to interpret the data in several different ways. For instance, measurements of migration area may be interpreted by age-diffusion, age, one group, or multigroup theory. Numerical values of M as computed by the different methods will vary coMiderably, although each will form a con-slstent set of reactor parameters in its own critical equation, hi addition, there appears to be agreement in values of M as measured by subcritical and by critical. methods. Thus, it is necessary to make any comparison between critical and subcritical experiments with a common theoretical interpretation. 

As experimental techniques continue to improve, systematic errors in technique or interpretation of data will be revealed, but it appears that these systematic errors are also rapidly approaching a negligible limit. At the present time it appears that the reactor parameters of slightly enrlched-uranium water lattices, as measured in subcritical assemblies and in critical assemblies, are in agreement within the limits of experimenhtl errors. 

At the present time there exists an exceedingly large number of measurements of reactor parameters for graphite uranium systems. 

KAPLAN, I., Measurements of Reactor Parameters in Subcritical and Critical Assemblies A Review, MITNE-25 pp. 45 (1962). 

Reactor Parameters Critical Experiment Data Used Assemblies Used for Measurements Calculated Data t Measured Data Parameter Normalization Factors... 

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