Numerical simulation and analysis of the pulsed neutron source method measuring the prompt neutron decay constant of a Godiva-like subcritical facility

During the operating of nuclear reactor, the applicable condition of point reactor neutron kinetics is changed by control rods bulk insertion and reactor lattice deviating from the critical state, The measurement of reactivity, with the increase of subcriticality, shows that the results impact on the kinetic distortion effect, along with prompt neutron flux strongly deteriorated. According to the diffusion theory about prompt neutron and delayed neutron, the theoretical analysis and application of point reactor neutron kinetics have been carried out to quantify the kinetic distortion correction factors in subcritical systems, and these indicate that prompt neutron distributions are strongly affected by kinetic distortion. With the self-developed Pulsed Neutron Source measurement system, subcriticality measurement in different configuration of control rods in the zero power reactor of Nuclear Power Institute of China was carried out. In this paper the reactivity of the deep subcritical system are obtained by experiment of Pulsed Neutron Source method, meanwhile, the bias between experiment results of the areas-ratio method and the characteristic decay constant method are analyzed by comparing the condition of the experiment and the theory model, the main factors inducing the bias are found, which supplies helpful reference for other similar design and experiment.

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The Use of Californium-252 as a Randomly Pulsed Neutron Source for Prompt-Neutron Decay Measurements

Nuclear Science and Engineering ◽

10.13182/nse74-5 ◽

1974 ◽

Vol 53 (4) ◽

pp. 393-414 ◽

Cited By ~ 15

Author(s):

J. T. Mihalczo

Keyword(s):

Neutron Source ◽

Prompt Neutron ◽

Neutron Decay ◽

Pulsed Neutron ◽

Pulsed Neutron Source

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Use of Californium-252 as a Randomly Pulsed Neutron Source for Prompt Neutron Decay Measurements

Nuclear Science and Engineering ◽

10.13182/nse70-a20716 ◽

1970 ◽

Vol 41 (2) ◽

pp. 296-298 ◽

Cited By ~ 16

Author(s):

John T. Mihalczo

Keyword(s):

Neutron Source ◽

Prompt Neutron ◽

Neutron Decay ◽

Pulsed Neutron ◽

Pulsed Neutron Source

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Measurement of Prompt Neutron Decay Constant of CFBR-II at Near Delayed Criticality Using Randomly Pulsed Neutron Method

Volume 5: Fuel Cycle, Radioactive Waste Management and Decommissioning; Reactor Physics and Transport Theory; Nuclear Education, Public Acceptance and Related Issues; Instrumentation and Controls; Fusion Engineering ◽

10.1115/icone21-16260 ◽

2013 ◽

Author(s):

Lingli Song ◽

Jiansheng Li ◽

Haojun Zhou ◽

Yu Jin

Keyword(s):

Liquid Scintillation ◽

Decay Constant ◽

Detection System ◽

Prompt Neutron ◽

Neutron Decay ◽

Timing Uncertainty ◽

Neutron Method ◽

Pulsed Neutron ◽

Liquid Scintillation Detector ◽

Good Agreement

Prompt neutron decay constant of CFBR-II (China’s Fast Burst Reactor) was measured by the randomly pulsed neutron method when the reactor was at the reactivity of −0.1$. A liquid scintillation detector was used to detect the leakage neutrons and the timing uncertainty of the detection system was less than 3ns. The detector and the Cf-252 fast ionization chamber were placed at several positions. Totally 5 prompt neutron timing distribution curves were obtained and the prompt neutron decay constant was 0.610us−1 in average with the uncertainty of 0.030us−1, which was in good agreement with the M.C. calculation.

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