Reactor subcritical

Render reactor lubcrilical Reactor protection system Render reactor subcritical Reactor protection system Standby liquid control sy.stein... 

The asymptotic period and the prompt mode decay constant can be related more naturally to reactivities other than the static reactivity. The natural reactivities are related to real flux distributions in the subcritical reactor and to the importance function in the reference critical reactor. 

Consider a subcritical reactor with a steady-state source. The neutron flux established asymptotically in this reactor is the solution of the inhomogeneous Boltzmann equation... 

The first consequence of the above results is that the equations satisfied by the expected values N and C are exactly those which arise by considering N and C to be ordinary continuous functions of time and by considering all processes to occur at average rates. Other consequences concern the fluctuations. It is seen, for example, that equilibrium values exist for all quantities in the case of a subcritical reactor, Ic < I, or kp Icd < 1. For no delayed neutrons, these are... 

N. G. Sjostrand, Measurements on a subcritical reactor with a pulsed neutron source. Proceedings of the International Conference on the Peaceful Uses of Atomic Energy, vol. 5, 1956. 

DENSE PLASMA AS A NEUTRON SOURCE FOR THE SUBCRITICAL REACTOR... 

The energy gain of the subcritical reactor > 100 may be enough to close the energy cycle at the efficiency of thermonuclear systems y]f 0.1... 

At a frequency operating regime with / — 1 Hz the plasma heating power is equal to Wp 14 MW, the thermal power of the blanket (in a subcritical reactor) is about Wb = 100 MW, and the neutron power is 1 MW, The first wall neutron flux was chosen sufficiently small 100 wattlcm-. ... 

If a source is placed in a subcritical reactor such that the flux is in the fundamental mode, then the count rate at a detector near the core can be written as ... 

Which of the following best describes a subcritical reactor s neutron population response to a small insertion of positive reactivity ... 

A subcritical reactor has an initial of 0.8. Positive reactivity is added until the subcritical count rate is doubled. What reactivity addition caused the count rate to double ... 

As a subcritical reactor approaches criticality, for equal positive reactivity additions ... 

In a subcritical reactor, is increased from 0.861 to 0.946. Which ONE of the following is the amount of reactivity that was added to the reactor core ... 

Which ONE of the following describes the response of the subcritical reactor to equal insertions of positive reactivity as the reactor approaches criticality ... 

In a subcritical reactor, the longer lived precursors do not decay as rapidly as the shorter... 

The multiplication of source neutrons in a subcritical reactor by positive reactivity additions. 

This code was used to calculate the thickness of the oxide layer formed on the surface of different components such as steam generators or heat exchangers of ADS concepts like the EFIT subcritical reactor which is a lead-cooled reactor. 

Accelerator-Based Reactor Concepts. A subcritical reactor concept triggered by an accelerator has been proposed by Los Alamos National Laboratory. The technology associated with this concept is not mature, and its feasibility has not been established. This concept is not viable in the next few decades and, thus, cannot achieve the mission requirements. 

The exponential assembly, which is supplied with neutrons from an external source, is perhaps the simplest of these facilities. The exponential facilities include the Sigma Pile, which is used for cross-section measurements and for the evaluation of diffusion parameters the Standard Pile, which is used as a basic standard of flux in the determination of counter efficiencies, one type of reactor power measurement, and the determination of cross sections, is also a device in this class. A third type of exponential equipment is the Subcritical Reactor in which a fissionable isotope is added to an assembly and in which neutron multiplication is made to occur. The a,cis made up of a sample volume of the reactor under consideration. 

When a neutron source is placed near a subcritical reactor, the fissions induced in the fuel multiply the source neutrons entering the core. The multiplication is defined as the ratio of the total thermal-neutron flux due to source neutrons and fission neutrons to the flux due to the source alone. The degree of multiplication is dependent upon the magnitude of the -eproduction factor of the assembly. The equation relating kgff and multi-nation is readily derived from the sketch below, in which it is assumed Q neutrons are introduced each second. 

Since this expression has been derived for a subcritical reactor, k ff < 1, the expression for M may be rewritten after cancelling out Q as... 

If we have a subcritical reactor containing a neutron source, what will its response be to a small positive step insertion of reactivity which makes the reactor less subcritical Critical Supercritical ... 

The initial viewpoint in this section will be to give a qualitative explanation of what occurs in a subcritical reactor when fast neutrons are injected. A simple derivation of the relationship between the decay of the resulting thermal-neutron population and the reactivity of the system will be made purely from physical considerations. Finally, consideration will be made regarding two-group diffusion theory to describe the proposed experiment. 

Fast neutrons are injected into the subcritical reactor from a position of symmetry outside the reactor core. The total number of neutrons in the burst will be emitted over a period of a few microseconds. The fast neutrons diffuse into the core and are slowed down primarily by making elastic collisions with the atoms in their flight paths. The amount of time it takes the neutrons to be slowed down to the thermal region will depend on the energy of the neutrons in question and on the slowing-down power of the reactor. 

The apparatus for the experiment is set up according to Fig. 5.8. The following procedure will be used to measure the negative reactivity associated with a subcritical reactor condition. This procedure can be used for each of the following measurements ... 

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