NII Stali was among the world pioneers to start methodical investigation on effects of the ionizing radiation generated at nuclear burst on combat vehicles, vetronics and crew members, and to search for ways how to protect them.

As it's not always feasible to check potential technical solutions experimentally, our researchers developed a unique systematic and theoretical calculation mechanism to reliably simulate interaction of ionizing fields with different targets and vital human organs and to evaluate the consequences of such interaction. A number of simulators were created, in particular with the use of "Priz" (Prize) nuclear reactor and "Sneg" (Snow) neutron generator.

We have designed and are carrying our full-scale production of a range of new anti-radiation materials used in collective and local protection systems of combat vehicles as well as in personal protection equipment; these materials ensure reduction of the cumulative radiation dose by factors of 2-10. We have succeeded in finding ways to reduce the induced gamma-radiation from the running gear and other combat vehicle components.

Design models

For more than 40 years' experience NII Stali has created a wide range of methods, computational programs and theoretical models which have been proved both by model experiment and by actual nuclear attack.

Some of the products are described below.

PRIZ-F77 (HP) program system

The program complex is designed for approximate computation of dose characteristics of indirect ionizing radiation in sites of radiation sensible components in the objects of complex 3D geometry (vehicles) situated in the field of neutrons and gamma-photons of nuclear reactors or nuclear contaminated area.

The program system is used at the stage of vehicle radiation protection design.

The computation algorithm is based on the principle of superposition of equivalent sources with the regard for dose albedo from the internal components.

The advantage of the algorithm and the software is the relative simplicity of assigning the object geometry in the form of a wire-frame model and the use of predefined data on protective characteristics of plane elements forming the geometrical model faces, which considerably increases the computation speed and responsiveness at satisfactory accuracy.

A computer program called SKODIT was designed specially for dealing with a geometrical model; it greatly reduces the work content in preparation of the input data and interpretation of the computation results in the process of protection design.

ROZPRIZ-F77 (HP) program system

The program system is designed for computation of the gamma-neutron radiation field performance in different points of laminated targets in plane geometry.

The program system makes it possible to obtain the protective characteristics of plane assemblies, different functionals of the fields of neutrons and gamma-photons, and in the presence of multiplying medium the key parameters of the critical systems, such as the effective multiplication factor and the critical dimension can be evaluated.

The computation algorithm is based on a numerical solution in multienergy-group approximation of neutron and gamma-photon transport equation by descrete ordinate method. The system of one-group algebraic equations of the numerical model is solved either by the factorization method or by the iteration method depending on the layers parameters (optimization by the run-time).
A distinctive feature of the program system is a developed file system with nuclear design constants and radiation sources which ensures simple and convenient task formulation for interactive mode computation.

Program system for computation of gamma-neutron radiation field performance in three-dimensional geometry objects by Monte Carlo method

The program system is designed for computation of the gamma-neutron radiation field performance in complex three-dimensional geometry objects by Monte Carlo vector method. In the presence of multiplying medium the program system makes it possible to estimate the effective multiplication factor and the critical reactor parameters.

A distinctive feature of the program system is due regard to influence of the moving medium on the neutron transport process in the design model.

The program system is on the development stage.

Full-scale modeling, laboratory and ground testing

A neutron generator and a phantom simulating human bone and soft tissues and the internal; they are used for investigation of radiation effects on the human vital organs.

Laboratory testing of materials and protection systems is performed in the Test Center which has a specially conditioned hall with isotopic sources of neutron and gamma radiation as well as with neutron generator NG-150M and Roentgen-30 X-ray unit. In the Test Center such parameters can be evaluated as neutron, gamma and X-ray radiation attenuation factors, lead equivalent of different protective materials, compositions and protective structures.

A full scale test procedure

The Test Center is accredited by the Ministry of Standards of RF and is entitled to test and issue state certificates for protective materials and systems.

The main experimental data are obtained from ground tests. NII Stali has a testing ground equipped with a nuclear reactor, neutron generator and isotopic sources of gamma-radiation.

A full scale test procedure is shown in the figure.

In the process of ground tests such parameters are evaluated as neutron and gamma radiation attenuation factors, cumulative radiation doses of different vehicles under different irradiation conditions.