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Critical Assembly Training Simulator


Development of a Full-Scale Critical Assembly Test Bench Training Simulator

Tech Area / Field

  • FIR-NSS/Nuclear Safety and Safeguarding/Fission Reactors

8 Project completed

Registration date

Completion date

Senior Project Manager
Tocheny L V

Leading Institute
VNIIEF, Russia, N. Novgorod reg., Sarov


  • Oak Ridge National Laboratory / Instrumentation and Controls Division, USA, TN, Oak Ridge\nLos Alamos National Laboratory, USA, NM, Los-Alamos

Project summary

The principal objective of the Project is development of a full-scale simulator to train operational personnel actions corresponding to normal (standard) operation during assembling of the training (inert) multiplying system mockup. This work will allow involvement of weapons experts in solution of the problem of safety ensuring at nuclear dangerous installations. When developing the simulator solution of the following problems should be ensured:

– simulation of physical processes that occur in multiplying systems (MS);

– development of a computer data bank on physical characteristics of a large number of multiplying systems (density of leakage neutron flux from the system, N; multiplication factor, Q; reactivity, r) previously obtained in the experiments on FKBN-2M test bench or by computations;
– development of a firmware complex ensuring an adequate response of the FKBN-2M control and safety system (CSS) at changing of MS model geometry;
– operation of FKBN-2M test bench in real-time scale according to information output by the simulating computer and CSS;
– imitation of deviations and errors in operation of separate test bench devices;
– imitation of physical process evolution in the multiplying system during abnormal situations and emergencies;
– development of a software allowing simulation of the assembly of various MSs on display as the experiment designing and output of the data on the current values of N, Q, r;
– fabrication of mockups for several typical MSs made of inert materials;
– development of a hardware complex and training methods for establishment of Training Center for training and improvement of professional skills of experts working in the area of nuclear technologies.

All the Project works will be conducted on the FKBN-2M critical assembly test bench (abbreviation of Russian “Fizicheskiy Kotel na Bystrykh Nejtronakh” translated as “Fast Physical Boiler”, model 2, Modernized). The Project involves experts in physics from RFNC-VNIIEF.

Presently, the nuclear safety in operation of critical systems is determined by operating regulations and experts’ skills. Analysis of abnormal situations shows that accidents on critical assemblies test benches are mainly caused by violation of the established operating regulations. Thus, the measure set ensuring nuclear safety, based solely on the human factor is insufficient and a measure set based on automated control over multiplying system assembly process should be introduced. These measures in combination determine the system of safety assurance during nuclear dangerous operations.

The method for the works consists in the following. Data banks on critical assemblies’s components will be developed. Computer codes using the Monte Carlo method will be adapted for computer simulation of the physical processes proceeding in MS. This will ensure monitoring of the MS during the assembly. At the experiment setting-up phase, the MS will be assembled on display using a special program package, in this manner the regulations of the future operations will be verified. The current configuration of the MS being simulated will be bound by the program to appropriate values of the leakage neutron flux from the system, neutron multiplication factor, and reactivity. These parameters are correspondent with readings of CSS design devices, which will be displayed.

The MS assembly techniques will be verified directly on the test bench in the training regime using training mockups made of inert materials (marked with bar codes for linking with FM parts being imitated), with the control program tracking the degree of correspondence of the operations performed to the established operating regulations. The work in the training regime will involve manipulation of all mechanisms and controls of the test bench from the control board and using CSS, like in the normal operations. A change in the assembly neutron physical parameters will be mapped in readings of the design devices. Thus, complete imitation of the real MS assembly on the FKBN-2M test bench is ensured.

The expected results are the following:

– developed working program for computation of physical processes in multiplying systems on the basis of previously developed methods, including the Monte Carlo method;

– developed computer data bank on the multiplying system parameters obtained previously on the FKBN-2M test bench;
– developed program allowing simulation of the assembly of various MSs on display as the experiment designing and displaying the data on the current status of the MS being imitated;
– fabricated training mockups of typical MSs made of inert materials;
– developed hardware complex and training methods for establishment of Center for training and improvement of professional skill of experts working in the area of nuclear technologies.


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