KR100896988B1 - High-Cr Ferritic/Martensitic Steels having improved neutron irradiation stability containing an enriched boron-11 for the in-core component materials in the Gen-? fission reactor and the fusion reactor - Google Patents

Abstract

The present invention adds 30-200 ppm of boron-11 concentrated in high chromium ferrite / martensitic steel containing 8-12 wt% chromium to precipitates and matrix structures at a high neutron irradiation environment of 600 ° C. or higher and 200 dpa. A high chromium ferrite / martensitic steel with improved creep, swelling and mechanical strength in high temperature / high neutron reactors with improved thermal stability and neutron irradiation stability at the same time. It can be very useful for materials such as reactor pressure vessels and blankets.

High Chromium Ferrite / Martensitic Steels, Boron-11, 4th Generation Nuclear Fission Reactor, Nuclear Fusion Reactor, Core Components

Description

High-Cr Ferritic / Martensitic Steels having improved neutron irradiation stability containing an enriched boron-11 for the 4th generation nuclear fission reactor and fusion reactor core part material for the in-core component materials in the Gen-IV fission reactor and the fusion reactor}

The present invention relates to high chromium ferrite / martensitic steels containing concentrated boron-11 which simultaneously improves thermal stability and neutron irradiation stability.

Materials degradation is the beginning of safety degradation, and material development is the cornerstone of the development of new nuclear power systems. Heat transfer buffer plate breakout, steam generator heat pipe breakage, pipe breakage, and reactor penetration pipe corrosion problems, which have recently been a major safety issue in nuclear power plants, are not only related to the problems of soundness and reliability due to aging of components in life extension. It is the key. The importance of the field of nuclear materials cannot be overemphasized, considering that the development of high-temperature materials and radiation-resistant materials is essential for the development of fourth-generation and fusion nuclear systems.

Currently operating reactors were developed in the 1950s and 60s (particularly the materials used were selected and developed more than 40 years ago) and have been the core of power supply, but recently developed countries have high thermal efficiency, safety and reliability, We are accelerating the development of the Generation IV Reactor (G-IV) in consideration of the sustainability and economic feasibility, and 10 countries including the United States, the United Kingdom, France, and Japan, including Korea, aim for practical use after 2030. A joint effort is underway to develop a nuclear system. Candidate furnaces for the 4th generation nuclear power system are Gas Cooled Fast Reactor (GFR), Molten Salt Reactor (MSR), Lead-Alloy Cooled Fast Reactor (LFR), and Sodium. Sodium Cooled Fast Reactor (SFR), Supercritical Water Cooled Reactor (SCWR), and Very High Temperature Reactor (VHTR). Among them, Korea is interested in SFR, SCWR, and VHTR and participates in joint development. Especially, VHTR is the main target of hydrogen production reactor. The fourth generation reactor described above operates in harsher environments such as higher temperatures, higher neutron irradiation conditions, and various coolants in current light water reactors, and the like, and for the realization thereof, high temperature materials that can withstand high temperature coolants and high irradiation conditions, There is a need to develop a new material having excellent properties that can ensure compatibility with various coolants such as radiation resistant material, helium gas, liquid metal, and supercritical water.

Recently, high chromium-containing ferrite-martensitic steel (FMS) has attracted attention as a material having excellent high temperature characteristics as a candidate material for major components of the fourth generation reactor and fusion reactor.

High chromium ferritic / martensitic steels containing 8 to 12% by weight of chromium are fast neutrons since the 1970s because of their superior thermal properties and irradiation swelling resistance compared to austenitic stainless steels (eg SS316 and SS304). Nuclear fuel cladding, an important part of the core of fast breeder reactors, has been used as a material for wrappers or ducts surrounding it. The HT9 alloy (main component: 12% Cr-1% Mo-0.5% W-0.25% V), developed as a high-temperature heat-resistant material for thermal power plants in the 1960s, is the fuel cladding and duct of the US fast growth reactor (EBR-II). In addition to the materials selected and used in Europe and Japan, high-chromium ferritic / martensitic steels were selected as the cladding of the high-speed furnace, and the furnace investigation was performed. Recently, high-efficiency fourth-generation nuclear fission reactors have been considered in the design of high chromium ferrite / martensitic steels as core component materials for use at high temperatures above 600 ° C and high radiation ranges above 200 dpa.

In the mid-1980s, when the nuclear fusion reactor material development program began in earnest, the concept of reduced-activation steel was introduced, and research on low-emitting ferrite / martensite steel (RAFMS) was carried out in earnest. The starting material was ASTM Gr., Also known as modified 9Cr-1Mo steel. 91 alloy (main component: 9% Cr-1% Mo-0.20% V-0.08% Nb) ferritic / martensitic steel. Low-irradiation ferritic / martensitic steels have been followed by limitations of alloying elements to reduce the production of long-lived, high-level radioactive materials produced by neutron irradiation. In other words, the addition of molybdenum, niobium, nickel, copper and nitrogen was strictly restricted in low-emission ferritic / martensitic steels, and the addition of tungsten and tantalum was proposed instead of these elements. In addition, an alloy which reduces the chromium content to 7-9% was preferred as a method of suppressing the formation of the δ-ferrite phase which adversely affects the impact characteristics without increasing the amount of carbon or manganese, which is an α-phase stabilizing element. In this series of studies, in Japan, the F82H alloy (major component: 8% Cr-2.0% W-0.25% V-0.04% Ta) and JLF-1 alloy (major component: 9% Cr-2.0% W-0.25% V-0.05% Ta-0.02% Ti) has been newly developed and EUROFER-97 alloy (main component: 9% Cr-1.1% W-0.20% V-0.12% Ta-0.01% Ti) in Europe and ORNL 9Cr- in the US 2WVTa (main component: 9% Cr-2.0% W-0.25% V-0.07% Ta) was developed.

The high chromium ferritic / martensitic steels used in the core components of the fourth-generation nuclear fission reactors and fusion reactors mentioned above and considered in the design are not only major elements such as chromium, molybdenum, tungsten, vanadium and niobium, but also carbon, silicon, The alloys are configured to control manganese, nickel and nitrogen in an appropriate amount and to control phosphorus and sulfur for optimal properties.

In addition, some alloys (eg, ASTM Gr. 91, F82H, EROFER-97) attempted to increase mechanical strength by adding boron to improve thermal stability at high temperatures. More than about 30 ppm of boron added to the high chromium ferrite / martensitic steels coexists in M ₂₃ C ₆ precipitates or is dissolved in trace amounts in base metals to inhibit the growth of precipitates or the growth of pre-γ phase grains. The thermal stability is improved when deteriorated for a long time at a high temperature of more than 600 ℃, and the creep rupture strength and creep rupture time are increased or extended to improve the high temperature creep resistance. However, when the addition amount of boron exceeds 200 ppm, it is known that the workability is drastically reduced and the mechanical properties are also worsened. Therefore, the addition of an appropriate amount of boron (30 ~ 200 ppm) in high chromium ferrite / martensitic steel can improve the thermal resistance in the high temperature environment of more than 600 ℃ to improve the creep resistance.

However, since boron has a large absorption area for thermal neutrons (E = 0.025 eV), the use of boron in the nuclear field has been mainly used as a neutron absorber in control rods that absorb neutrons and control the number of neutrons. In particular, core components such as the fuel cladding of the fourth nuclear fission reactor core to be used in the energy region (200-400 keV) of the fast neutrons are exposed to a high neutron irradiation environment. The use of high chromium ferrite / martensitic steels containing boron in these very high neutron irradiation environments generates a significant amount of helium by the (n, α) reaction of boron, which swells due to the smooth coalescence and diffusion. Due to the volume expansion of the material caused by the helium bubbles along the grain boundaries cause helium embrittlement to deteriorate the mechanical properties of the parts, there is a problem that greatly reduces the neutron irradiation stability.

In order to solve the above problems, the inventors of the present invention have been researched to improve the neutron irradiation stability of boron-containing high chromium ferrite / martensitic steel, and mean concentrated boron-11 having a low neutron absorption cross section (boron having a mass number of 11). The neutron irradiation stability and thermal stability of the high chromium ferrite / martensitic steel were improved by adding boron-11).

It is an object of the present invention to provide a high chromium ferrite / martensitic steel containing concentrated boron-11 which simultaneously improves neutron irradiation stability and thermal stability.

In order to achieve the above object, the present invention provides a high chromium ferrite / martensite steel containing concentrated boron-11.

The high chromium ferritic / martensitic steels containing the concentrated boron-11 according to the present invention have higher thermal stability and neutron irradiation stability in high temperature and high neutron environments than conventional high chromium ferritic / martensitic steels containing natural boron. It can be usefully used as a material for core parts of fourth-generation nuclear fission reactors and fusion reactors that require such properties to be improved.

The high chromium ferrite / martensitic steels used in the present invention may be commonly used or alloys developed in the present invention, and the composition may be chromium, carbon, silicon, manganese, vanadium, phosphorus, sulfur, nitrogen, boron-11 ( Refers to boron having a mass number of 11, hereinafter referred to as boron-11), including balance iron, specifically, 8-12 wt% of chromium, 0.09-0.2 wt% of carbon, 0.04-0.4 wt% of silicon, and 0.1 manganese ˜0.6 wt%, vanadium 0.20 to 0.25 wt%, phosphorus 0.002 to 0.02 wt%, sulfur 0.0015 to 0.01 wt%, nitrogen 0.005 to 0.1 wt%, boron-11 30 to 200 ppm, balance iron.

In addition, the high chromium ferrite / martensitic steel according to the present invention may further include one or more selected from the group consisting of nickel, molybdenum, tungsten, niobium, tantalum, neodymium, titanium and copper. Specifically, nickel 0.3-0.5% by weight, molybdenum 0.4-1.0% by weight, tungsten 0.5-3.0% by weight, niobium 0.05-0.08% by weight, tantalum 0.04-0.12% by weight, neodymium 0.03-0.05% by weight, titanium 0.01-0.02 It may include one or more selected from the group consisting of 0.5% to 1.5% by weight and copper.

In the high chromium ferrite / martensitic steel containing the concentrated boron-11 according to the present invention, the boron affecting the neutron irradiation stability in the boron is a phenomenon caused by Boron-10 having a mass number of 10. Boron in the natural world contains boron-10 having a mass number of 10 and 11 (hereinafter, boron-10 means boron having a mass number of 10) and boron-11 having about 20%: 80%. And the boron that actively participates in the (n, α) reaction is boron-10. In fact, when comparing the neutron absorption cross section of boron and boron -10 -11 -10 The boron in the entire energy region than that of boron than -11 ^{10 5} ~ 10 10 barn indicates a very large value (see Fig. 1).

On the other hand, boron-11 is negligible because the neutron absorption cross section for the (n, α) reaction is nearly zero at 8 MeV or less, including 200-400 keV, which is the high-speed neutron energy region used in the fast reactor. In other words, the addition of boron-11 enriched boron-11 to high-chromium ferrite / martensitic steels to limit the addition of boron-10 with high neutron absorption cross-section results in thermal stability without compromising neutron irradiation stability even at high doses of fast neutrons. Can be maintained.

At this time, the content of the concentrated boron-11 in the high chromium ferrite / martensite steel is preferably 30 ~ 200 ppm. If the boron-11 content is less than 30 ppm, the role of inhibiting the growth of M ₂₃ C ₆ precipitates or inhibiting the growth of pre-γ-phase grains is reduced. There is a problem of deterioration, and if the boron-11 content exceeds 200 ppm, there is a result that the workability is sharply lowered and the mechanical properties are also lowered.

Therefore, the high chromium ferrite / martensitic steel containing the concentrated boron-11 according to the present invention is precipitated at high temperature of 600 ° C. or higher and high neutron irradiation environment of 200 dpa or higher than conventional high chromium ferrite / martensite steel. Because of its excellent thermal stability and neutron irradiation stability, the fourth-generation nuclear fission reactors (eg, sodium cooling fast reactors, supercritical pressurized water cooling reactors, hot gas cooling reactors) and nuclear fuel cladding and reactors, which are the main core components of fusion reactors It can be very usefully used for materials such as pressure vessels and blankets.

After addition of boron-11 concentrated by a conventional concentration method on high chromium ferrite / martensite containing 8-12% by weight of chromium of the present invention, an ingot was prepared using a vacuum induction dissolution (VIM) method. After the hot working at 1000 ~ 1200 ℃ and heat treatment at 600 ~ 800 ℃ it can be prepared according to the conventional steel production method.

Specifically

Mixing and dissolving the concentrated boron-11 and the alloying element to produce an ingot (step 1);

Hot working the ingot prepared in step 1 (step 2);

It can be prepared by a method comprising the step (step 3) of producing a high chromium ferrite / martensite steel by heat-treating the ingot hot worked in step 2.

In addition, further intermediate heat treatment and cold working after the heat treatment in step 3 to produce the high chromium ferrite / martensitic steel according to the present invention into structural parts of the required type (e.g., nuclear fuel sheaths or ducts of fourth-generation reactors). It may further include a step (step 4) of the final heat treatment after performing several times.

Hereinafter, the manufacturing method of the present invention will be described in detail step by step.

First, step 1 is a step of preparing an ingot by mixing and dissolving the concentrated boron-11 and the alloying element.

The boron-11 can be concentrated by conventional methods.

As the alloy composition element, chromium, carbon, silicon, manganese, vanadium, phosphorus, sulfur, nitrogen, boron-11, balance iron may be used. Specifically, chromium 8-12 wt%, carbon 0.09-0.2 wt%, 0.04 to 0.4 wt% of silicon, 0.1 to 0.6 wt% of manganese, 0.20 to 0.25 wt% of vanadium, 0.002 to 0.02 wt% of phosphorus, 0.0015 to 0.01 wt% of sulfur, 0.005 to 0.1 wt% of nitrogen, boron-11 30 to 200 ppm, Contains balance iron.

Further, the alloy composition element may further include one or more selected from the group consisting of nickel, molybdenum, tungsten, niobium, tantalum, neodymium, titanium, and copper. Specifically, nickel 0.3-0.5% by weight, molybdenum 0.4-1.0% by weight, tungsten 0.5-3.0% by weight, niobium 0.05-0.08% by weight, tantalum 0.04-0.12% by weight, neodymium 0.03-0.05% by weight, titanium 0.01-0.02 It can be used including one or more types selected from the group consisting of% by weight and 0.5 to 1.5% by weight of copper.

The ingot may use a vacuum induction (VIM) method.

Specifically, an induction current is applied to the melting chamber in a high vacuum (1 × 10 ⁻⁵ to 0.5 torr) atmosphere to first dissolve the alloying element, and then a deoxidizer such as aluminum or silicon is added thereto. Trace elements, especially nitrogen, are charged to the molten metal at the point when dissolution is almost complete, and then a sample for component analysis is collected. After dissolution is completed, the molten metal is poured into a cuboid at 1500 ° C. to perform tapping, and an oxide layer on the surface is subjected to mechanical processing to prepare an ingot.

Next, step 2 is a step of hot working the ingot prepared in step 1.

Through the hot working (hot working) to produce a hot workpiece suitable for hot processing. At this time, the hot working is preferably carried out for 0.5 to 2 hours at a temperature of 1000 ~ 1200 ℃. If it is out of the above range, that is, below 1000 ° C., the purpose of solution annealing cannot be sufficiently achieved, and if it exceeds 1200 ° C., the size of the prior-γ phase grain is increased so as to increase the mechanical properties of the final product. Can cause deterioration problems.

Next, step 3 is a step of manufacturing a high chromium ferrite / martensitic steel by heat-treating the product hot worked in the step 2.

Preferably, the heat treatment is performed by performing annealing heat treatment at 900 to 1200 ° C. for 0.5 to 2 hours, and secondly at 600 to 800 ° C. for 1 to 3 hours. The reason for performing the first heat treatment in the γ-phase temperature range of 900-1200 ° C. is to re-dissolve undesired precipitates in the hot processed product and to control the size and amount of precipitates by adjusting the cooling temperature. . In addition, the reason for performing the second heat treatment at 600 ~ 800 ℃ is to produce the desired precipitated phase and to control the size of the crystal grains.

By this method it is possible to produce a high chromium ferrite / martensitic steel comprising the concentrated boron-11 according to the present invention.

In addition, in order to manufacture the strength of the high chromium ferrite / martensitic steel according to the present invention in the form of a structural component of another type, after the heat treatment of step 3 after the additional intermediate heat treatment and cold processing several times repeated after the final heat treatment (step It may further include 4).

Specifically, the additional intermediate heat treatment is performed for 1 to 3 hours at 600 to 800 ° C., and the cold working is continuously performed for 2 to 4 times, and the final heat treatment is performed at 600 to 800 ° C. for 1 to 3 hours. Can be performed to produce high chromium ferrite / martenside steels of improved strength.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are only examples of the present invention, and the scope of the present invention is not limited to the following examples.

< Example  1> Containing Boron-11 High chrome  ferrite/ Martensite  Steel manufacturing 1

As the test materials used in the examples, chromium 12% by weight, carbon 0.2% by weight, silicon 0.4% by weight, manganese 0.6% by weight, vanadium 0.2% by weight, phosphorus 0.02% by weight, sulfur 0.01% by weight, nitrogen 0.04% by weight, nickel 0.5 wt%, molybdenum 1.0 wt%, tungsten 0.5 wt%, boron-11 30-200 ppm and the balance iron were prepared in a 30 kg ingot in a vacuum induction melting furnace. The ingot was hot worked at 1100 ° C. to a final thickness of 15 mm.

Since the following heat treatment was performed.

Specifically, the alloy was quenched (Normalizing) at 1050 ° C for 1 hour and then air cooled.

Thereafter, a tempering treatment consisting of one or two steps was performed. Specifically, the so-called alloy is air cooled by performing a tempering treatment at 750 ° C. for 2 hours, or first cooled at 700 ° C. for 2 hours, followed by air cooling, and then again at 1 ° C. at 750 ° C. High chromium ferrite / martensitic steels were prepared by air cooling with a 2nd Tempering treatment for hours.

The tempering product is additionally repeated 2-4 times of the intermediate heat treatment and cold processing for 1 to 3 hours at 600 ~ 800 ℃ continuously, the final heat treatment is performed for 1 to 3 hours at 600 ~ 800 ℃ of the final product High chromium ferrite / martensitic steels were made.

< Example  2> Containing Boron-11 High chrome  ferrite/ Martensite  Steel manufacturing 2

The alloy composition is chromium 9%, carbon 0.10%, silicon 0.4%, manganese 0.4%, vanadium 0.20%, phosphorus 0.02%, sulfur 0.01%, nitrogen 0.05%, nickel 0.4%, molybdenum 1.0 A high chromium ferritic / martensitic steel was prepared in the same manner as in Example 1 except for the weight percent, 0.08 weight percent niobium, 30-200 ppm boron-11, and the balance iron.

< Example  3> Containing Boron-11 High chrome  ferrite/ Martensite  Steel manufacturing 3

The alloy composition is 9% by weight of chromium, 0.09% by carbon, 0.05% by weight of silicon, 0.45% by weight of manganese, 0.20% by weight of vanadium, 0.02% by weight of sulfur, 0.01% by weight of sulfur, 0.07% by weight of nitrogen, 0.5% by weight of molybdenum, tungsten 1.8 A high chromium ferritic / martensitic steel was prepared in the same manner as in Example 1 except for the weight percent, 0.05 weight percent niobium, 30 to 200 ppm boron-11, and the balance iron.

< Example  4> Containing Boron-11 High chrome  ferrite/ Martensite  Steel manufacturing 4

The alloy composition is chromium 9% by weight, carbon 0.11% by weight, silicon 0.04% by weight, manganese 0.4% by weight, vanadium 0.20% by weight, phosphorus 0.02% by weight, sulfur 0.01% by weight, nitrogen 0.06% by weight, nickel 0.4% by weight, molybdenum 1.0 A high chromium ferritic / martensitic steel was prepared in the same manner as in Example 1 except for the weight percent, 1.0 weight percent tungsten, 0.08 weight percent niobium, 30-200 ppm boron-11, and the balance iron.

< Example  5> Containing Boron-11 High chrome  ferrite/ Martensite  Steel manufacturing 5

The alloy composition is 12% by weight chromium, 0.11% carbon, 0.1% silicon, 0.6% manganese, 0.25% vanadium, 0.02% phosphorus, 0.01% sulfur, 0.06% nitrogen, 0.3% nickel, molybdenum 0.4 A high chromium ferritic / martensitic steel was prepared in the same manner as in Example 1, except that 2.0 wt% tungsten, 0.05 wt% niobium, 1.0 wt% copper, 30-200 ppm boron-11, and the balance iron were used. .

< Example  6> Containing Boron-11 High chrome  ferrite/ Martensite  Steel manufacturing 6

The alloy composition is 11 wt% chromium, 0.10 wt% carbon, 0.3 wt% silicon, 0.2 wt% manganese, 0.20 wt% vanadium, 0.02 wt% phosphorus, 0.01 wt% sulfur, 0.04 wt% nitrogen, tungsten 3.0 wt%, niobium 0.07 A high chromium ferritic / martensitic steel was prepared in the same manner as in Example 1 except that the wt%, 0.07 wt% tantalum, 0.04 wt% neodymium, 30-200 ppm boron-11, and the balance iron were used.

< Example  7> Containing Boron-11 High chrome  ferrite/ Martensite  Steel manufacturing 7

The alloy composition is chromium 8% by weight, carbon 0.10% by weight, silicon 0.2% by weight, manganese 0.5% by weight, vanadium 0.20% by weight, phosphorus 0.005% by weight, sulfur 0.002% by weight, nitrogen 0.005% by weight, tungsten 2.0% by weight, tantalum A high chromium ferrite / martensitic steel was prepared in the same manner as in Example 1 except that 0.04 wt%, boron-11 30-200 ppm and the balance iron were used.

< Example  8> Containing Boron-11 High chrome  ferrite/ Martensite  Steel manufacturing 8

The alloy composition was 9% chromium, 0.11% carbon, 0.05% silicon, 0.4% manganese, 0.20% vanadium, 0.005% phosphorus, 0.005% sulfur, 0.03% nitrogen, 1.1% tungsten, tantalum A high chromium ferritic / martensitic steel was prepared in the same manner as in Example 1 except that 0.12 wt%, 0.01 wt% titanium, 30-200 ppm boron-11, and balance iron were used.

< Example  9> Containing Boron-11 High chrome  ferrite/ Martensite  Steel manufacturing 9

The alloy composition is 9% by weight of chromium, 0.10% by weight of carbon, 0.08% by weight of silicon, 0.5% by weight of manganese, 0.20% by weight of vanadium, 0.002% by weight of sulfur, 0.0015% by weight of sulfur, 0.05% by weight of nitrogen, 2.0% by weight of tungsten, tantalum High chromium ferritic / martensitic steels were prepared in the same manner as in Example 1, except that 0.07 wt%, 0.02 wt% titanium, 30-200 ppm boron-11, and balance iron were used.

Table 1 below shows the composition of the high chromium ferrite / martensitic steel with improved neutron irradiation stability, including boron-11 of Examples 1 to 9.

Furtherance Example (% by weight) One 2 3 4 5 6 7 8 9 Cr 12.0 9.0 9.0 9.0 12.0 11.0 8.0 9.0 9.0 C 0.2 0.10 0.09 0.11 0.11 0.10 0.10 0.11 0.10 Si 0.4 0.4 0.05 0.04 0.1 0.3 0.2 0.05 0.08 Mn 0.6 0.4 0.45 0.40 0.6 0.2 0.5 0.4 0.5 Ni 0.5 0.4 0.4 0.3 Mo 1.0 1.0 0.5 1.0 0.4 W 0.5 1.8 1.0 2.0 3.0 2.0 1.1 2.0 V 0.20 0.20 0.20 0.20 0.25 0.20 0.20 0.20 0.20 Nb 0.08 0.05 0.08 0.05 0.07 P 0.02 0.02 0.02 0.02 0.02 0.02 0.005 0.005 0.002 S 0.01 0.01 0.01 0.01 0.01 0.01 0.002 0.005 0.0015 N 0.04 0.05 0.07 0.06 0.06 0.04 0.05 0.03 0.05 Cu 1.0 Ta 0.07 0.04 0.12 0.07 Nd 0.04 Ti 0.01 0.02 B-11 0.003 ~ 0.02 0.003 ~ 0.02 0.003 ~ 0.02 0.003 ~ 0.02 0.003 ~ 0.02 0.003 ~ 0.02 0.003 ~ 0.02 0.003 ~ 0.02 0.003 ~ 0.02 Fe Balance Balance Balance Balance Balance Balance Balance Balance Balance

1 is a graph showing the (n, α) reaction neutron absorption cross-sectional area of boron (boron-10, boron-11).

Claims (11)

Concentrating boron-11 and mixing with the alloying elements and then dissolving to prepare an ingot (step 1); Hot working the ingot prepared in step 1 for 0.5 to 2 hours at 1000 to 1200 ° C. (step 2); Heat treatment step of performing the heat treatment for the ingot hot worked in the step 2 primarily at 900 ~ 1200 ℃ for 0.5 to 2 hours, and then secondly at 600 ~ 800 ℃ for 1 to 3 hours (step 3) ; And After the heat treatment of step 3, the additional intermediate heat treatment is performed for 1 to 3 hours at 600 ~ 800 ℃ and performing the cold working successively two to four times, the final heat treatment at 600 ~ 800 ℃ 1 Prepared by a method comprising the step of performing for ˜3 hours (step 4), Chromium 8-12 wt%, carbon 0.09-0.2 wt%, silicon 0.04-0.4 wt%, manganese 0.1-0.6 wt%, vanadium 0.20-0.25 wt%, phosphorus 0.002-0.02 wt%, sulfur 0.0015-0.01 wt%, nitrogen High chromium ferrite / martensitic steel with improved neutron irradiation stability containing 0.005 to 0.1% by weight, boron-11 30 to 200 ppm and boron-11 including balance iron. The method of claim 1, wherein the high chromium ferrite / martensitic steel is 0.3 to 0.5% by weight of nickel, 0.4 to 1.0% by weight of molybdenum, 0.5 to 3.0% by weight tungsten, 0.05 to 0.08% by weight of niobium, 0.04 to 0.12% by weight of tantalum Highly improved neutron irradiation stability containing boron-11, characterized in that it further comprises at least one selected from the group consisting of 0.03 to 0.05% by weight of neodymium, 0.01 to 0.02% by weight of titanium and 0.5 to 1.5% by weight of copper. Chromium Ferrite / Martensitic Steel. Concentrating boron-11 and mixing with the alloying elements and then dissolving to prepare an ingot (step 1); Hot working the ingot prepared in step 1 for 0.5 to 2 hours at 1000 to 1200 ° C. (step 2); And Heat treatment step of performing the heat treatment for the ingot hot worked in the step 2 primarily at 900 ~ 1200 ℃ for 0.5 to 2 hours, and then secondly at 600 ~ 800 ℃ for 1 to 3 hours (step 3) ; And After the heat treatment of step 3, the additional intermediate heat treatment is performed for 1 to 3 hours at 600 ~ 800 ℃ and performing the cold working successively two to four times, the final heat treatment at 600 ~ 800 ℃ 1 Comprising the step (step 4) of performing for ˜3 hours, A method for producing a high chromium ferrite / martensitic steel having improved neutron irradiation stability containing boron-11 according to claim 1. The high chromium ferrite / martensitic steel of claim 1, wherein the ingot of step 1 is prepared by a vacuum induction melting method. 4. The method of claim 3, wherein the ingot of step 1 is manufactured by a vacuum induction melting method. The method of manufacturing high chromium ferrite / martensitic steel with improved neutron irradiation stability containing boron-11. 4. The high chromium ferrite / containing chromium ferrite having improved neutron irradiation stability according to claim 3, wherein the high chromium ferrite / martensitic steel containing boron-11 is used for core parts of a fourth generation reactor. Method for producing martensitic steels. 7. The high chromium ferrite neutron irradiation stability of claim 6, wherein the reactor is a sodium cooling reactor, a supercritical water cooling reactor or a nuclear fission reactor of a hot gas cooling reactor, or a fusion reactor. Method of making martensitic steels. The method of claim 6, wherein the core component is any one selected from the group consisting of a nuclear fuel cladding tube, a reactor pressure vessel and a blanket, the production of high chromium ferrite / martensitic steel with improved neutron irradiation stability containing boron-11. Way. 2. The high chromium ferrite / containing chromium ferrite having improved neutron irradiation stability according to claim 1, wherein the high chromium ferrite / martensitic steel containing boron-11 is used for core parts of a fourth generation reactor. Martensite River. 10. The high chromium ferrite of claim 9, wherein the reactor is a sodium cooling reactor, a supercritical water cooling reactor or a nuclear fission reactor of a hot gas cooling reactor, or a fusion reactor. Martensite River. 10. The high chromium ferrite / martensitic steel according to claim 9, wherein the core component is any one selected from the group consisting of a nuclear fuel cladding tube, a reactor pressure vessel, and a blanket.

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