Utilisation Limits of 1¼Cr½Mo (SA387-11-2) Steel in High Plate Thickness

Technical requirements for petrochemical reactor steels have proliferated in the last decade. The need to increase economic benefits together with higher operating temperatures and pressures are leading to the construction of higher capacity reactors with thicker walls. Also, more and more severe and sometimes conflicting requirements in these specifications make it difficult, to derivate a steel design, e.g. in terms of chemical composition and processing parameters, for an optimized balance between quality demands and economical aspects. The design of pressure vessel for petrochemical industry is based on mechanical properties and the design method, which are given by the construction code.

On models for estimating the post-radiation defect state of the -phase

Processes that take place in the precipitates of -phase under irradiation with fast neutrons are topical and draw attention when one searches for ways of improving radiation resistance of structural reactor steels. A special feature of these processes is that the formation of vacancies and interstices proceeds at the background of a disordering of the initial crystal lattice, which mani-fests itself in the formation of antisite defects. X-ray and neutron diffraction techniques are efficient tools of studying changes that occur in the post-radiation structural state of such systems. However, interpretation of the experimental results calls for more complicated models for the description of structural effects exerted by accumulation of radiation defects in the material than those developed before for elementary metals. Several models are proposed in this paper.

Industry Experience Fabricating Hydroprocessing Reactors Using 2¼ Cr-1 Mo-V Steel

Starting in the 1980’s, the process conditions for hydroprocessing reactors became increasingly more severe and started to exceed the economic and technically-feasible ranges for 2¼Cr-1Mo steel. Hence, new grades of reactor steels were developed to meet these demands. Reactor fabricators, steel producers, the Materials Properties Council and some refiners cautiously developed their initial applications of the new materials, with extensive testing of both the materials and fabrication methods, and restrictions to use only the most experienced, highly technical fabrication shops. The data and experience has grown exponentially since then and today, the most commonly-specified material for thick wall reactors is 2¼Cr-1Mo-¼V steel. The list of qualified fabricators worldwide has also grown, but is still limited. The purpose of this paper is to show how the industry has climbed the “learning curve,” by giving the statistics on the overall numbers of fabricated reactors (which is now over 1150), and the locations of the fabricators by country, that have been produced. Trends on the use of forgings versus plates are also included, along with the major changes over the years in the applicable ASME Codes and API standards affecting these reactors. Some of the lessons learned from past fabrication problems are also discussed along with the subsequent safeguards initiated within the industry standards.

Influence of irradiation on the dynamics of changes in the mechanical properties of the nuclear reactor vessel

Nuclear power plants are important generating units of the energy system worldwide. In the normal mode, nuclear power plants are absolutely safe, but emergency systems with radiation emissions have a devastating impact on the environment and public health. Despite the introduction of technologies and automatic monitoring systems, the threat of a potentially dangerous situation remains. The reactor vessel is the main object of activities to ensure the safety of nuclear power plants. One of the problems of ensuring the safety of nuclear power plant reactor vessels is the prediction of the level of crack resistance of reactor steels. The paper shows the possibility of estimating the neutron irradiation level on the nature of the temperature dependence of KIC. The prediction of the influence of radiation damage on the fracture toughness of the reactor steel can be obtained on the basis of the results of tests of small cylindrical samples with annular notches.

Dynamic properties of reactor steels Kh16N15M3T1 and Kh13V2 under shock-wave loading of submicrosecond scale

Kh16N15M3T1 and Kh13V2 reactor steels were investigated. The study was carried out using a light-gas gun with the deformation velocities ranging from 4·104 to 3·106 s-1 and shock-loading pulses in 0.05-1 μs duration range. Dependences of the spallation strength and dynamic elastic limit in a wide temperature range are obtained. The recovered specimens were used to carry out the metallography analysis.