Neutron poison distribution in the central reflector to reduce the DLOFC temperature of a Th-LEU fueled OTTO PBMR DPP-400 core

The isotope Xe-135 has a large thermal neutron absorption cross section and is considered to be the most important fission product. A very small amount of such neutron poison may significantly affect the reactor reactivity since they will absorb the neutrons from chain reaction, therefore monitoring their atomic density variation during reactor operation is extremely important. In a molten reactor system, Xe-135 is entrained in the liquid fuel and continuously circulates through the core where the neutron irradiation functions and the external core where only nuclei decay occurs, at the same time, an off-gas removal system operates for online removing Xe-135 through helium bubbling. These unique features of MSR complicate the Xe-135 dynamic behaviors, and the calculation method applied in the solid fuel reactor system is not suitable. From this point, we firstly analytically deduce the nuclei evolution law of Xe-135 in the flowing salt with an off-gas removal system functioning. A study of Xe-135 dynamic behavior with the core power change, shutdown, helium bubbling failure and startup then is conducted, and several valuable conclusions are obtained for MSR design.

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Development of Gadolinium (neutron poison) monitoring system for fuel reprocessing facilities: Computational model and validation with experiments

Progress in Nuclear Energy ◽

10.1016/j.pnucene.2018.04.004 ◽

2018 ◽

Vol 107 ◽

pp. 57-60 ◽

Cited By ~ 3

Author(s):

S. Chandrasekaran ◽

Pew Basu ◽

H. Krishnan ◽

K. Sivasubramanian ◽

R. Baskaran ◽

...

Keyword(s):

Computational Model ◽

Monitoring System ◽

Neutron Poison ◽

Fuel Reprocessing

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A CFD Model for High Pressure Liquid Poison Injection for CANDU-6 Shutdown System No. 2

10th International Conference on Nuclear Engineering, Volume 3 ◽

10.1115/icone10-22168 ◽

2002 ◽

Cited By ~ 1

Author(s):

Bo Wook Rhee ◽

Chang Joon Jeong ◽

Hye Jeong Yun ◽

Dong Soon Jang

Keyword(s):

High Pressure ◽

Concentration Distribution ◽

Early Stage ◽

Neutron Cross Section ◽

Injection Rate ◽

Injection System ◽

Cfd Model ◽

Neutron Poison ◽

Tube Banks ◽

Hydrodynamic Code

In CANDU reactor one of the two reactor shutdown systems is the liquid poison injection system which injects the highly pressurized liquid neutron poison into the moderator tank via small holes on the nozzle pipes. To ensure the safe shutdown of a reactor it is necessary for the poison curtains generated by jets provide quick, and enough negative reactivity to the reactor during the early stage of the accident. In order to produce the neutron cross section necessary to perform this work, the poison concentration distribution during the transient is necessary. In this study, a set of models for analyzing the transient poison concentration induced by this high pressure poison injection jet activated upon the reactor trip in a CANDU-6 reactor moderator tank has been developed and used to generate the poison concentration distribution of the poison curtains induced by the high pressure jets injected into the vacant region between the pressure tube banks. The poison injection rate through the jet holes drilled on the nozzle pipes is obtained by a 1-D transient hydrodynamic code called, ALITRIG, and this injection rate is used to provide the inlet boundary condition to a 3-D CFD model of the moderator tank based on CFX4.3, a CFD code, to simulate the formation of the poison jet curtain inside the moderator tank. For validation, an attempt was made to validate this model against a poison injection experiment performed at BARC. As conclusion this set of models is judged to be appropriate.

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Neutronics Design Study on Ignition Zone of Travelling Wave Reactor

Volume 2: Plant Systems, Construction, Structures and Components; Next Generation Reactors and Advanced Reactors ◽

10.1115/icone21-16194 ◽

2013 ◽

Author(s):

Jian Zhang ◽

Hong Yu ◽

Zhi Gang ◽

Keyuan Zhou ◽

Yun Hu ◽

...

Keyword(s):

Traveling Wave ◽

Nuclear Reactor ◽

Travelling Wave ◽

Reactor Operation ◽

Geometry Model ◽

Nuclear Transmutation ◽

Neutron Poison ◽

Distribution Of Power ◽

Distribution Of Power Density ◽

Ignition Zone

Traveling wave reactor is a kind of nuclear reactor that can convert fertile material into fissile fuel as it runs using the process of nuclear transmutation. In the ignition stage of traveling wave reactor, the core performance is especially complex, since the fissile fuel and fertile material is put in different regions at the beginning. And the distribution of power density will change severely with burn-up during the reactor operation. It is an important part of the traveling wave reactor study to optimize the design of the ignition stage. In this paper, based on a two-dimensional RZ geometry model, some schemes with different sizes and compositions of the ignition zone, middle ignition zone position design and burnable neutron poison addition are simulated and analyzed. Finally, an optimized core design with multi-zone configuration and burnable neutron poison addition is shown. Some design outlines are introduced for further study.

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