SU1566233A1 - Method of determining radiation heat release - Google Patents

Abstract

The invention relates to calorimetric measurements of radiation heat generation in materials irradiated in the fields of ionizing radiation, and makes it possible to increase the reliability of heat emission measurements. In the method, the values of the background heat emission ratio for a pair of calorimeters are experimentally determined. Prior to loading a sample into one of them, both calorimeters are irradiated in the field of gamma quanta and the temperatures of the calorimeters and signals proportional to the radiation power of the calorimeters are recorded. The measured parameters determine the heat emission in the construction materials of this pair of empty calorimeters. The choice of gamma quanta as a factor that initiates background heat generation during the determination of a constant for a given pair of calorimeters is due to the fact that gamma-ray irradiation does not create induced radioactivity in the construction materials of calorimeters and does not create radiation-hazardous situations. The calorimeters are identical in design and alternately perform the functions of working and background, for which the sample is placed in one or the other calorimeter and irradiated with the same gamma-ray flux. Temperature measurements are carried out in the center and at the edge of the inner cavity of the irradiator. The method allows to reduce the error by 10-12% in comparison with the known ones.

Description

The invention relates to the field of calorimetric measurements of radiation heat generation in materials irradiated in the field of ionizing radiation, and can be used in nuclear power engineering, radiation materials science, in ionizing radiation-based technological processes, and the like.

The purpose of the invention is to increase the reliability of the determination and x-chromatization by eliminating the non-identity of the structural elements of the calorimeters.

In the method of exprm (a 1, the values of the ratio of lon thermal emissions of dt dcnon pari catorimetron are determined; the coefficient g.

this operation in the following sequence. This pair of structurally identical empty calorimeters, before being loaded into one of them (the working) sample, is irradiated in the same calibration field of y quanta. The following parameters are recorded: the temperature of the calorimeters Te and Ta, the signals of the calorimeters Efa (TV)

and la, the signals of calorimeters 9 and E (t5) (the hatched parameters characterize the calorimeter, which further functions as the background calorimeter, and the uncharted parameters refer to the calorimeter in which the sample is placed, i.e., the working calorimeter ). The heat dissipation of WA and wl in the materials of the construction of this pair of empty (without samples) calorimeters irradiated in the field of f-quanta is related to the measured parameters by the relations of the form Ef- (Ta) -Efa (Ta);

wJa-tfTjbB & Tj).

 E "RE CH E

where the sensitivity coefficients of the working - (Tj) and background - (Tj) calorimeters to the measured thermal effect are determined using known techniques with an electric heater. Hence the coefficient (Ta) -Efe (Te)

 ) The obtained true value of the SC coefficient is a constant for a given pair of calorimeters. The radiative heat release power W0 in the irradiated material is calculated by the formula;

w TVF (T) - SisililSi l

w.-j (T) in (t) .E () - (t $)

Ј $, (T)

where (T), T (TG) - coefficients

calorimeter intensity with and without a sample; H (T), E (TG) are signals proportional to the power of radiation heat D calorimeters (with and without a sample under operating conditions; T, T t are calorimeter temperatures under the same conditions. The choice of y-rays in quality factor

initiating background heat generation

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0

five

0

$

Jq

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in the process of determining the coefficient X., due to the fact that irradiation with v-quanta does not create induced radioactivity in the construction materials of calorimeters and, therefore, does not create radiation-hazardous situations in further manipulations with them.

Example. Two cylindrical calorimeters of integral heat flux of identical design (dimensions of each of the calorimeters used: length 39 mm, outer diameter 10 mm; dimensions of the internal cavity for placing the sample: length 20 mm, diameter 5 mm) with a sample from a solid steel cylinder (19.5 mm long with a diameter of 4.9 mm) are alternately performed as working and background calorimeters, for which the sample is transferred from one to another calorimeter, is irradiated with the same flux of t-quanta. The measurement is carried out at two different points — in the center and at the edge of the inner cavity of the irradiator.

The most accurate result of determining the amount of radiation power. heat generation is realized when the same calorimeter performs the functions of the working and background calorimeters. In this case, the coefficient Ж is exactly equal to one, since there are no systematic errors due to the technological imperfection of structural materials. In spite of sufficient accuracy, this option with sample overload in the same calorimeter has low practical value, is non-operational and in a number of practical important applications, for example, in reactor measurement fields, it is impossible or very technically difficult to overload samples.

The use of the proposed database allows obtaining reliable data on the energy release in structural, fissionable and absorbing materials used in nuclear power plants. The error in determining the heat release in materials can be reduced by 10-12% compared to known methods. In addition, the method can be used in systems of control reactors and installations that implement radiation technologies to increase efficiency and ensure safety during their operation.

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Claims (1)

Invention Formula The method of determining radiative heat in the irradiated material, including irradiation in the field of potentiating radiation of two calorimeters, one of which contains the material under study, measuring the electrical signals of their thermopiles and temperatures, calculating the desired value, which is designed to increase the reliability of determination and simplification by eliminating the influence of nonidentity of the structural elements of calorimeters, before irradiating the calorimeters in the field of ionizing radiation, empty calorimeters are placed in the y-radiation field, their electrical signals are measured battery and temperature, and the power W0 of radiation heat in the material is calculated by the formula and -wn РГТЛ- §А $ ШЈ-5Ш1, We-4CT) E (T) g 1 (tg t t t t FZ and "Ef (T1) (TG), d25 where (T) is the coefficient of sensitivity of the calorimeter with the sample; 0 five 0 E (TG) G (TT) is the sensitivity coefficient of a calorimeter without a sample; E (T) is the thermopile signal of the calorimeter with the test material; - signal thermocouple calorimeter without sample; -the temperature of the sample calorimeter; calorimeter temperature without sample; ETF (Te) is the signal of an empty calorimeter, into which the material under study is then placed, in the γ-radiation field; Ta is the temperature of an empty calorimeter in a field — TL - T1 five cheny; ) is the signal of a calorimeter without a sample in the y-radiation field; T- is the temperature of the calorimeter without a sample in the field, nz-ray.