Test method of materials in nuclear reactor

FIELD: power industry.

SUBSTANCE: specimen is made of two coaxially combined tubular elements; one of which is fully or partially located inside the other one; gas pressure is created in a cavity between elements, sealed, arranged in a nuclear reactor and irradiated.

EFFECT: increasing informativity and reliability of results of change of properties of reactor materials at irradiation in the reactor at various types of stress-and-strain state.

3 cl, 1 dwg

 

The invention relates to the field of reactor materials and can be used for reactor tests of structural materials for nuclear reactors.

There is a method of testing materials for long-term strength in the channel of a nuclear reactor: the patent for the invention №93013102 (1995.07.20, authors: Popov V.V. Potapov J.V.). The method applies to research the strength characteristics of materials, in particular tests of thin-walled tubular specimens loaded by internal pressure, and can be used to test fuel element cladding of nuclear reactor irradiation conditions. The method improves the accuracy of determining the time to failure of the sample in terms of exposure in reinstrumentation channel of the reactor. The inventive test piece, made in the form of thin-walled tubes, load gas under pressure, is placed in the insulated tube is installed in the reactor in such a way that part of the ampoule with the sample is placed in an active area, and some outside the active area, and is exposed to failure of the sample, and the time to failure of the sample is determined by comparison of the relative deformations of the non-irradiated part of the ampoule and the ampoule analogue tested outside of the reactor at identical parameters of loading. This method allows you to gain strength characteristics the specifications specifications of the investigated material through known properties of another material. The disadvantage of this method is the implementation of the stress-strain state of the test material under the action of stresses only one type of tensile stresses. This disadvantage is due to structural properties of the device for implementing this method.

The closest analogue, coinciding with the claimed invention by the greatest number of essential features, a method described in the literature: "Stress state dependence of in-reactor creep and swelling. Part 2: Experimental Results". M.M. Hall, Jr., J.E. Flinn // Journal of nuclear materials, 2010. V.396. 119-129. In this work the method of testing samples of steel 304 on in-reactor creep and swelling. The constructional schema devices used for sample loading and setting various types of stress-strain state of the material. This method of testing allows you to implement uniaxial tension, uniaxial compression, biaxial stretching, biaxial compression and circumferential stretching. However, the disadvantage of this method of testing is the inability to realize simultaneously the impact on the material as tensile and compressive stresses. This disadvantage is caused by the design of the devices developed to implement the described method of testing materials.

The aim of the invention is the higher is their informativeness and reliability of the results modify the properties of reactor materials under irradiation in the reactor under different types of stress-strain state.

This objective is achieved in that in the method of testing materials in a nuclear reactor, comprising loading the sample gas under pressure and placing it in a nuclear reactor, produce a sample of two coaxially aligned tubular elements, one of which is fully or partially inside the other, creating a gas pressure in the cavity between the elements, seal, place in a nuclear reactor and irradiated.

The minimum clearance between the elements is not less than 0.1 mm, it is Technologically difficult to provide a smaller gap, potential distortions that can lead to inaccurate results.

The wall thickness of the tubular elements does not exceed the size of the gap between the elements - the condition of tonkostennoy tubular sample.

Sealing compound tubular sample perform with end fittings, welding system, them to both ends of the inner and outer elements by way of argon-arc welding under pressure.

The internal volume of the composite sample between the inner and outer element is filled with an inert gas (argon, helium) under pressure, ensuring the required level of stresses in tubular structural elements.

The use of a composite sample consisting of two coaxially aligned tubular elements, internal, under esteem compressive stresses and external, under the action of tensile stresses, allows at the same temperature and dose under reactor irradiation simultaneously implement two completely different types of stress-strain state experienced a structural material.

After conducting reactor tests are really measuring the geometric dimensions of the tubular structural elements to determine the magnitude of their deformation.

New the essential feature of the proposed method is the production of such sample, which created the opportunity to implement in a single sample simultaneously two fundamentally different types of stress-strain state experienced a structural material under the action of tensile and compressive stresses at the same temperature and dose under reactor irradiation.

In the patent and technical literature, no information about the use of the same test method and devices with this significant feature, which allows to conclude that the claimed solution is not known from the prior art and novel and not obvious from the prior art, i.e. involves an inventive step.

The proposed method provides a technical effect, and may be implemented using known what technology means. Therefore, it has industrial applicability.

The inventive method is technically implemented using the fabricated device is shown on the accompanying drawing, where:

1 - the inner tubular element;

2 - external tubular element;

3 is a bottom annular tube;

4 - upper annular tube;

5 - technological stub.

The invention is illustrated by the following example. For implementing the inventive method test material in a nuclear reactor BOR-60 were manufactured composite tubular samples. Material used pipe from steel 18CR10NITI in austeniana condition with a diameter of 10.2 mm with wall thickness of 0.5 mm Pipe for the inner part of the samples was tied up at the rolling machine from the source pipe 10,2×0.5 mm in size 6,03×0,55. After tightening the pipe held joint heat treatment of pipes of large and small diameters: the austenization at a temperature of 1050°C for 30 minutes with cooling with the furnace. Thus, achieved similar structural state of the metal pipes.

Made 8 samples, two for each pressure level - 0, 25, 70 and 100 ATM. The samples were filled with argon and germetizirovany using argon-arc welding under conditions of excessive pressure with subsequent testing for tightness. All the fabricated samples were hermeti is low.

The samples were placed in a reactor and tested at temperatures (420-450°C to damaging doses of 15 and 30 sleep. After conducting reactor tests were conducted measuring the geometric dimensions of the tubular structural elements to determine the magnitude of their deformation.

1. The method of testing materials in a nuclear reactor, in which the test sample is used for gas under pressure and place it in a nuclear reactor, characterized in that the manufactured sample of two coaxially aligned tubular elements, one of which is fully or partially inside the other, creating a gas pressure in the cavity between the elements, seal, place in a nuclear reactor and irradiated.

2. The method according to claim 1, characterized in that the minimum gap between the elements is not less than 0.1 mm

3. The method according to claim 1, characterized in that the thickness of the walls of the tubular elements does not exceed the magnitude of the gap between the elements.



 

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