Study of in-pile irradiation temperature monitoring device and method

Abstract

The application provides a research in-pile irradiation temperature monitoring device and method, and relates to the field of nuclear industry irradiation test. The irradiation temperature monitoring device comprises an isothermal expansion body and a deformation body, the isothermal expansion body and the deformation body are sealed into an irradiation container together with an irradiation sample; the isothermal expansion body is in contact with the irradiation sample, so that the isothermal expansion body is in contact with the irradiation sample in isothermal state, and the isothermal expansion body expands under the influence of the temperature of the irradiation sample; the deformation body is in contact with the isothermal expansion body, the expansion of the isothermal expansion body causes the deformation of the deformation body, the deformation of the deformation body can be fixed, and the maximum deformation amount of the deformation body is measured after the irradiation is completed, so that the highest temperature reached by the irradiation sample during the test is determined.

Description

Technical Field

[0001] This invention relates to the field of nuclear industry irradiation testing, and more particularly to a device and method for monitoring in-reactor irradiation temperature. Background Technology

[0002] High-flux neutron radiation damage to reactor materials can lead to shape changes, performance degradation, and ultimately, failure of reactor internals, fuel assemblies, and other components. Therefore, obtaining radiation performance data for the materials used in the reactor is essential for reactor design to ensure long-term safe operation.

[0003] Conducting irradiation tests on in-service materials using research reactors is an important means of obtaining data on the irradiation performance of materials over time, including dimensional changes and performance degradation. Irradiation temperature is a crucial control factor in material irradiation tests, but real-time temperature monitoring under research reactor irradiation conditions presents significant technical challenges.

[0004] Typically, temperature monitoring in irradiation tests can be achieved by either extending thermocouples onto the irradiated sample or placing low-melting-point alloy fuses close to the sample. Extending thermocouples onto the sample requires a temperature monitoring instrument located at the top of the irradiation device, i.e., the reactor core. However, due to reactor limitations, this method is often costly or impractical. While placing low-melting-point alloy fuses close to the sample provides a melting point within a range, rather than a precise single temperature point, this results in poor temperature measurement accuracy, failing to meet the high-precision temperature monitoring requirements of irradiation tests. Furthermore, once the alloy wire melts, it cannot automatically recover, making it a disposable component and offering no indication of material temperature changes after the wire's melting. In an irradiation test, fuses with different melting points are often required to effectively capture the approximate temperature range of the irradiated sample during the test. Summary of the Invention

[0005] The purpose of this invention is at least to provide a research reactor irradiation temperature monitoring device and method with high temperature measurement accuracy that does not require instruments to be placed inside the reactor during the irradiation process, and can reliably obtain the temperature parameters of the irradiated sample throughout the entire test cycle.

[0006] The following provides a brief overview of one or more aspects to offer a basic understanding of them. This overview is not an exhaustive summary of all conceived aspects, nor is it intended to identify key or decisive elements of all aspects, nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form to prepare for the more detailed descriptions that follow.

[0007] One embodiment of the present invention provides a device for monitoring the irradiation temperature inside a research reactor. The device includes an isothermal expansion body and a deformable body. The isothermal expansion body, the deformable body, and the irradiated sample are sealed inside an irradiation container. The isothermal expansion body is in contact with the irradiated sample, making the contact temperature between the isothermal expansion body and the irradiated sample is isothermal. The isothermal expansion body expands under the influence of the temperature of the irradiated sample. The deformable body is in contact with the isothermal expansion body. The expansion of the isothermal expansion body causes the deformation of the deformable body. The deformation of the deformable body can be fixed. By measuring the maximum deformation of the deformable body after irradiation, the highest temperature reached by the irradiated sample during the test can be determined.

[0008] In some embodiments, the deformable body is a shape extending along its own axis, and the deformable body undergoes buckling deformation under the expansion effect of the isothermal expansion body. The highest temperature reached by the irradiated specimen during the test is determined by measuring the deflection of the deformable body after irradiation.

[0009] In some embodiments, the deformable body abuts between the irradiation container and the isothermal expansion body, the first end of the deformable body is detachably connected to the irradiation container, and the second end of the deformable body abuts against the isothermal expansion body. The initial deflection of the deformable body is adjusted by adjusting the position of the first end of the deformable body relative to the irradiation container.

[0010] In some embodiments, the irradiation temperature monitoring device includes a support frame disposed inside the irradiation container, an isothermal expansion body disposed on the support frame, and the support frame is detachably connected to the irradiation container. By adjusting the position of the support frame relative to the irradiation container, the isothermal expansion body is brought into contact with the irradiated sample.

[0011] In some embodiments, the irradiation temperature monitoring device includes a support frame disposed within an irradiation container. The support frame includes an adjusting member and a support base, with the adjusting member and support base being fixed relative to each other. An isothermal expansion body is disposed on the support base, and a deformable body abuts against the adjusting member and the isothermal expansion body. A first end of the deformable body is detachably connected to the adjusting member, and a second end of the deformable body abuts against the isothermal expansion body. The initial deflection of the deformable body is adjusted by adjusting the position of the first end of the deformable body relative to the adjusting member. The adjusting member is detachably connected to the irradiation container, and the isothermal expansion body contacts the irradiated sample by adjusting the position of the adjusting member relative to the irradiation container.

[0012] In some embodiments, an adjustment groove is provided on the top of the irradiation container, and an adjustment member can move along the adjustment groove to adjust the position of the adjustment member relative to the adjustment groove so that the isothermal expansion body comes into contact with the irradiated sample.

[0013] In some embodiments, an abutment groove is provided on the side of the isothermal expansion body facing the deformable body, and the deformable body is inserted into the abutment groove to abut against the isothermal expansion body.

[0014] In some embodiments, the thermal conductivity of the isothermal expansion body is higher than 200 W / (m·K), and the coefficient of thermal expansion is greater than 10.-5 ℃ -1 .

[0015] In some embodiments, the coefficient of thermal expansion of the deformable body is less than 10. -6 ℃ -1 .

[0016] In some embodiments, the coefficient of thermal expansion of the support frame is less than 10. -6 ℃ -1 .

[0017] One embodiment of the present invention provides a method for monitoring the irradiation temperature inside a research reactor. Using the above-mentioned irradiation temperature monitoring device inside the research reactor, the temperature monitoring method includes: irradiating an irradiation container containing an isothermal expansion body, a deformable body, and an irradiation sample into the reactor; stopping the reactor after reaching a predetermined dose; measuring the maximum deformation of the deformable body; determining the highest temperature reached by the irradiation sample during the test; and, in conjunction with the change in the reactor core power, back-calculating the temperature change of the irradiation sample throughout the entire irradiation cycle.

[0018] In some embodiments, the temperature monitoring method includes: adjusting the initial deformation of the deformable body, conducting several irradiation tests to determine several maximum temperatures, and taking the average of the several maximum temperatures as the final maximum temperature.

[0019] The temperature monitoring device of the present invention has the following technical effects: (1) The overall structure is simple. No measuring instruments need to be placed in the reactor during the irradiation test. No wiring is required. The implementation is easy and the cost is much lower than that of the thermocouple real-time temperature measurement scheme.

[0020] (2) High temperature measurement accuracy: relying on the thermal expansion correspondence and the buckling deformation amplification effect, the temperature measurement accuracy can reach 1℃, which is far superior to the traditional low melting point fuse temperature measurement scheme.

[0021] (3) The highest temperature in the entire irradiation cycle can be obtained with only one setup, without the need to set up multiple temperature measuring elements of different specifications, making the operation simpler, and the complete temperature history can be deduced by combining the core power. Attached Figure Description

[0022] The above-described features and advantages of the present invention will be better understood after reading the following detailed description of embodiments of the present disclosure in conjunction with the accompanying drawings. In the drawings, components are not necessarily drawn to scale, and components having similar related properties or features may have the same or similar reference numerals. Wherein: Figure 1 It is a pre-irradiation study reactor irradiation temperature monitoring device as shown in some embodiments.

[0023] Figure 2It is a post-irradiation study reactor irradiation temperature monitoring device as shown in some embodiments.

[0024] Figure 3 This is a schematic diagram of the adjustment groove according to some embodiments.

[0025] Explanation of reference numerals in the attached figures: 1-Adjusting bolt for deformable body; 2- Position adjusting bolt; 3-Deformable body; 4-Supporting frame; 41-Adjusting component; 42-Support base; 5-Isothermal expansion body; 6-Irradiated sample; 7-Irradiation container; 71-Adjustment groove. Detailed Implementation

[0026] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. It should be noted that the aspects described below with reference to the accompanying drawings and specific embodiments are merely exemplary and should not be construed as limiting the scope of protection of the present invention in any way.

[0027] It should be understood that the terms “system,” “device,” “unit,” and / or “module” used herein are one method of distinguishing different components, elements, parts, sections, or assemblies at different levels. However, if other words can achieve the same purpose, they may be replaced by other expressions.

[0028] It is understood that the technical terms that may be used in the description of this specification, such as “center,” “longitudinal,” “lateral,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” and “outer,” indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the implementation method and do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of the invention.

[0029] It should be noted that the use of terms such as "first" and "second" to define features in this document is merely for the purpose of distinguishing the corresponding features. Unless otherwise stated, these terms have no special meaning and should not be construed as limiting the scope of protection of this invention. As shown in this specification and claims, the terms "a," "an," "an," and / or "the" do not specifically refer to the singular and may also include the plural, unless the context clearly indicates otherwise. Generally, the terms "comprising" and "including" only indicate the inclusion of explicitly identified steps and elements, and these steps and elements do not constitute an exclusive list; the method or apparatus may also include other steps or elements.

[0030] In the description of this specification, it should also be noted that, unless otherwise expressly specified or limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, an integral connection, or a detachable connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium, or a connection within two components, etc. Those skilled in the art can understand the specific meaning of the above terms in this specification according to the specific circumstances.

[0031] This specification provides an embodiment of an in-research reactor irradiation temperature monitoring device. The research reactor serves as the experimental subject in irradiation tests of in-service materials. By conducting irradiation tests on in-service materials using the research reactor, irradiation performance data, such as dimensional changes and performance degradation of reactor in-service materials over time under irradiation conditions, can be obtained.

[0032] like Figure 1 As shown, the irradiation temperature monitoring device includes an isothermal expansion body 5 and a deformable body 3. The isothermal expansion body 5, the deformable body 3, and the irradiated sample 6 are sealed together inside the irradiation container 7. The isothermal expansion body 5 is in direct contact with the irradiated sample 6, ensuring that the temperatures of the isothermal expansion body 5 and the irradiated sample 6 are the same, i.e., isothermal. When the temperature of the irradiated sample 6 changes, the isothermal expansion body 5 changes synchronously with the temperature of the irradiated sample 6, resulting in volume expansion. The deformable body 3 is in contact with the isothermal expansion body 5. The expansion of the isothermal expansion body 5 will cause the deformable body 3 to deform, and this deformation can be permanently fixed. After the irradiation test is completed, by measuring the maximum deformation of the deformable body 3, the highest temperature reached by the irradiated sample 6 during the entire test can be determined.

[0033] In this embodiment, the temperature change is converted into a measurable physical deformation by utilizing the corresponding relationship of thermal expansion. There is no need to arrange any electronic testing instruments during the irradiation process, which avoids the problems of needing to install instruments in the reactor core and the high implementation difficulty and cost in the prior art. At the same time, it also solves the defects of poor accuracy and irreversibility of low melting point fuses. The overall structure is simple and reliable and is suitable for the installation space requirements of the research reactor irradiation container 7.

[0034] In some embodiments, the deformable body 3 is a rod-shaped or sheet-like structure extending along its own axial direction. For example... Figure 2 As shown, when the isothermal expander 5 expands due to heat, it applies pressure to the deformable body 3 along the axial direction, causing the deformable body 3 to buckle. After irradiation, the expansion amount of the isothermal expander 5 can be calculated by measuring the maximum deflection of the deformable body 3 after buckling, and the highest temperature reached by the irradiated sample 6 during the irradiation test can be determined.

[0035] The axial thermal expansion of the isothermal expansion body 5 is approximately 50 µm. The deformable body 3 converts the axial thermal expansion of the isothermal expansion body 5 into its own lateral (perpendicular to the axial direction) deflection change. The lateral buckling displacement δ of the deformable body 3 can reach the order of 1 mm, which greatly reduces the difficulty of subsequent measurements and significantly improves the temperature measurement accuracy. Experiments have shown that the temperature measurement accuracy can be controlled within 1℃, which is far superior to the scheme of monitoring irradiation temperature using a fused alloy wire.

[0036] In some embodiments, the deformable body 3 is clamped between the irradiation container 7 and the isothermal expansion body 5. The first end of the deformable body 3 is detachably connected to the irradiation container 7, and the second end of the deformable body 3 directly abuts against the surface of the isothermal expansion body 5. By adjusting the installation position of the first end of the deformable body 3 relative to the irradiation container 7, the initial deflection of the deformable body 3 can be adjusted to obtain different deflection changes and achieve more accurate temperature measurement.

[0037] In some embodiments, the isothermal expansion body 5 is provided with an abutment groove on the side facing the deformable body 3, and the second end of the deformable body 3 is inserted into the abutment groove and engages with the isothermal expansion body 5. The abutment groove can limit the end of the deformable body 3, prevent the deformable body 3 from slipping and misaligning due to compression during the test, ensure the reliability of deformation transmission, and improve the stability of temperature measurement results.

[0038] In some embodiments, the irradiation temperature monitoring device includes a support frame 4, which is integrally installed inside the irradiation container 7. An isothermal expansion body 5 is disposed on the support frame 4, and the support frame 4 is detachably connected to the irradiation container 7. By adjusting the installation position of the support frame 4 relative to the irradiation container 7, the position of the isothermal expansion body 5 can be adjusted to ensure that the isothermal expansion body 5 can reliably and tightly contact the irradiated sample 6, avoiding problems such as poor temperature synchronization and large temperature measurement errors due to poor contact.

[0039] In some embodiments, the support frame 4 includes an adjusting member 41 and a support base 42, with the adjusting member 41 fixed relative to the support base 42. An isothermal expansion body 5 is disposed on the support base 42, and a deformable body 3 abuts against the adjusting member 41 and the isothermal expansion body 5. The adjusting member 41 can be an adjusting rod or an adjusting plate. A first end of the deformable body 3 is detachably connected to the adjusting member 41, and a second end of the deformable body 3 abuts against the isothermal expansion body 5. The initial deflection of the deformable body 3 can be adjusted by adjusting the position of the first end of the deformable body 3 relative to the adjusting member 41.

[0040] Meanwhile, the adjusting component 41 is detachably connected to the irradiation container 7. By adjusting the position of the adjusting component 41 relative to the irradiation container 7, the entire support frame 4 and the isothermal expansion body 5 can be moved as a whole, ultimately ensuring that the isothermal expansion body 5 and the irradiated sample 6 are in reliable and tight contact.

[0041] In some embodiments, an adjustment groove 71 is provided on the top of the irradiation container 7, such as... Figure 3 As shown, the adjustment groove 71 is a strip groove, and the adjustment member 41 can move along the extension of the adjustment groove 71. After adjusting the position of the adjustment member 41 relative to the adjustment groove 71, it is fixed so that the isothermal expansion body 5 can reliably contact the irradiated sample 6.

[0042] Specifically, a position adjusting bolt 2 is connected and fixed to the adjusting component 41 via an adjusting groove 71. By moving the position adjusting bolt 2 within the adjusting groove 71, the position of the adjusting component 41, i.e., the support frame 4, relative to the irradiation container 7 can be adjusted, ensuring reliable contact between the isothermal expansion body 5 and the irradiated sample 6. After adjustment, the position adjusting bolt 2 is tightened. A deformable body adjusting bolt 1 is connected and fixed to the first end of the deformable body 3 via the adjusting groove 71 and the adjusting component 41. In this case, the adjusting component 41 is provided with a through groove adapted to the adjusting groove 71. By moving the deformable body adjusting bolt 1 within the adjusting groove 71 and the through groove, the position of the second end of the deformable body 3 relative to the adjusting component 41 can be adjusted, realizing the adjustment of the initial deflection of the deformable body 3. After adjustment, the deformable body adjusting bolt 1 is tightened.

[0043] In some embodiments, the isothermal expansion body 5 has a thermal conductivity higher than 200 W / (m·K) and a coefficient of thermal expansion greater than 10. -5 ℃ -1 Made of high thermal conductivity, the isothermal expansion body 5 and the irradiated sample 6 can quickly reach thermal equilibrium, ensuring good temperature synchronization and avoiding temperature measurement errors caused by temperature lag due to high thermal resistance. The high coefficient of thermal expansion amplifies the expansion under the same temperature change, and combined with the buckling amplification effect of the deformable body 3, further improves temperature measurement accuracy. Typical materials include pure copper and pure aluminum.

[0044] In some embodiments, the coefficients of thermal expansion of the deformable body 3 and the support frame 4 are less than 10. -6 ℃-1 A low coefficient of thermal expansion ensures that the thermal expansion of the deformable body 3 and the supporting frame 4 is minimal and negligible, thus avoiding interference from their thermal expansion on the measurement results and guaranteeing the accuracy of the final temperature measurement. Typical materials that can be selected include Invar alloy.

[0045] Based on the research reactor irradiation temperature monitoring device described in the above embodiments, this specification also proposes a research reactor irradiation temperature monitoring method, which includes the following:

[0046] S1: Assemble the temperature monitoring device, adjust the isothermal expansion body 5 and deformable body 3 into position, and seal them together with the irradiated sample 6 into the irradiation container 7. Send the irradiation container 7 into the core of the research reactor to carry out the irradiation test.

[0047] S2: After the irradiation reaches the predetermined dose, the reactor is stopped, the irradiation container 7 is removed, the maximum deformation (i.e., lateral deflection) of the deformable body 3 is measured, and the highest temperature reached by the irradiated sample 6 during the test is determined.

[0048] In some embodiments, determining the maximum deformation (i.e., lateral deflection) of the deformable body 3 allows for the deduction of the maximum expansion of the isothermal expander 5 during irradiation. The highest temperature reached by the irradiated specimen 6 throughout the entire test can be determined based on a pre-defined expansion-temperature correlation.

[0049] S3: By combining the historical variation data of the reactor core power, the complete temperature change of irradiated sample 6 during the entire irradiation cycle was further deduced, providing more comprehensive temperature data for irradiation performance analysis.

[0050] In some embodiments, the initial deformation of the deformable body 3 is adjusted, and several irradiation tests are conducted to determine several maximum temperatures. The average of these maximum temperatures is taken as the final maximum temperature. Based on the final maximum temperature and combined with historical data on the core power variation of the reactor, the complete temperature variation data of the irradiated sample 6 throughout the entire irradiation cycle is further derived to eliminate temperature measurement deviations caused by single-test errors, further improve the accuracy of the final temperature measurement results, and meet the requirements of high-precision irradiation tests.

[0051] The research method for monitoring in-reactor irradiation temperature relies on an in-reactor irradiation temperature monitoring device. It does not require real-time monitoring during irradiation; the highest temperature can be obtained simply by measuring the deformation after irradiation. It is simple to operate, low in cost, and far more accurate than the traditional fusible wire method.

[0052] The basic concepts have been described above. It is clear that the detailed disclosure above is merely illustrative and does not constitute a limitation of this specification, especially for those skilled in the art. Furthermore, unless expressly stated in the claims, the order of elements and sequences, the use of numbers and letters, or other names in this specification are not intended to limit the order of the processes and methods described herein. Although various examples of currently considered useful embodiments of the invention have been discussed in the foregoing disclosure, it should be understood that such details are for illustrative purposes only, and the appended claims are not limited to the disclosed embodiments. Rather, the claims are intended to cover all modifications and equivalent combinations that conform to the substance and scope of the embodiments described herein.

Claims

1. A device for monitoring in-reactor irradiation temperature, characterized in that, The irradiation temperature monitoring device includes an isothermal expansion body and a deformable body, wherein the isothermal expansion body and the deformable body can be sealed together with the irradiated sample into the irradiation container. The isothermal expansion body can come into contact with the irradiated sample, making the contact temperature between the isothermal expansion body and the irradiated sample is isothermal, and the isothermal expansion body can expand under the influence of the temperature of the irradiated sample. The deformable body is in contact with the isothermal expansion body, the expansion of the isothermal expansion body can cause deformation of the deformable body, and the deformable body is configured to determine the highest temperature reached by the irradiated sample during the test by measuring the maximum deformation of the deformable body after irradiation.

2. The in-reactor irradiation temperature monitoring device according to claim 1, characterized in that, The deformable body has a shape that extends along its own axis. The deformable body is capable of buckling deformation under the expansion effect of the isothermal expansion body. The deformable body is configured to determine the highest temperature reached by the irradiated sample during the test by measuring the deflection of the deformable body after irradiation.

3. The reactor-in-research irradiation temperature monitoring device according to claim 2, characterized in that, The deformable body abuts between the irradiation container and the isothermal expansion body. The first end of the deformable body is detachably connected to the irradiation container, and the second end of the deformable body abuts against the isothermal expansion body. The deformable body is configured to adjust the initial deflection of the deformable body by adjusting the position of the first end of the deformable body relative to the irradiation container.

4. The in-reactor irradiation temperature monitoring device according to claim 1, characterized in that, The irradiation temperature monitoring device includes a support frame disposed inside the irradiation container, and an isothermal expansion body disposed on the support frame. The support frame is detachably connected to the irradiation container. The support frame is configured such that the isothermal expansion body can contact the irradiated sample by adjusting the position of the support frame relative to the irradiation container.

5. The reactor-in-research irradiation temperature monitoring device according to claim 2, characterized in that, The irradiation temperature monitoring device includes a support frame, which is disposed inside the irradiation container. The support frame includes an adjusting component and a support base, and the adjusting component is fixed relative to the support base. The isothermal expansion body is disposed on the support base, the deformable body abuts against the adjustment member and the isothermal expansion body, the first end of the deformable body is detachably connected to the adjustment member, the second end of the deformable body abuts against the isothermal expansion body, and the deformable body is configured to adjust the initial deflection of the deformable body by adjusting the position of the first end of the deformable body relative to the adjustment member. The adjusting member is detachably connected to the irradiation container. By adjusting the position of the adjusting member relative to the irradiation container, the isothermal expansion body is brought into contact with the irradiated sample.

6. The reactor-in-research irradiation temperature monitoring device according to claim 5, characterized in that, An adjustment groove is provided on the top of the irradiation container, and the adjustment member can move along the adjustment groove. The adjustment member is configured to allow the isothermal expansion body to contact the irradiated sample by adjusting the position of the adjustment member relative to the adjustment groove.

7. The reactor-in-research irradiation temperature monitoring device according to any one of claims 1 to 6, characterized in that, The isothermal expansion body has an abutment groove on the side facing the deformable body, and the deformable body is inserted into the abutment groove to abut against the isothermal expansion body.

8. The reactor-in-research irradiation temperature monitoring device according to any one of claims 1 to 6, characterized in that, The thermal conductivity of the isothermal expansion body is higher than 200 W / (m·K), and the coefficient of thermal expansion is greater than 10. -5 ℃ -1 .

9. The research reactor irradiation temperature monitoring device according to any one of claims 1 to 6, characterized in that, The coefficient of thermal expansion of the deformable body is less than 10. -6 ℃ -1 .

10. The reactor-in-research irradiation temperature monitoring device according to claim 5, characterized in that, The coefficient of thermal expansion of the support frame is less than 10. -6 ℃ -1 .

11. A method for monitoring in-reactor irradiation temperature, characterized in that, Using the reactor-in-research irradiation temperature monitoring device according to any one of claims 1 to 10, the temperature monitoring method includes: The irradiation container containing the isothermal expansion body, the deformable body and the irradiated sample is placed into a pile for irradiation. After reaching the predetermined dose, the reactor was stopped, and the maximum deformation of the deformable body was measured to obtain the highest temperature reached by the irradiated sample during the test. By combining the study of core power variation, the temperature variation of the irradiated sample throughout the entire irradiation cycle was obtained.

12. The method for monitoring in-reactor irradiation temperature according to claim 11, characterized in that, The temperature monitoring method includes: The initial deformation of the deformable body is adjusted, and several irradiation tests are conducted to determine several maximum temperatures. The average of these maximum temperatures is taken as the final maximum temperature.

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