JP4592614B2 - Tritium inspection apparatus and tritium inspection method - Google Patents

Description

  The present invention relates to a tritium inspection apparatus and a tritium inspection method, and is suitable for inspection of tritium contamination before and after dismantling of a nuclear reactor facility, a spent fuel reprocessing facility, a radioactive isotope facility, a particle beam facility, or such facility. The present invention relates to a tritium inspection apparatus and an inspection method.

In the conventional tritium inspection apparatus, contaminants are put in a sealed container and heated, water vapor containing tritium is evaporated into the cover gas, the cover gas containing water vapor is passed through a ventilated ionization chamber, and β emitted from tritium is emitted. The ionization current generated by ionizing the cover gas with a wire is collected on an electrode to which a high voltage is applied, and the radioactivity level of tritium is measured by measuring the ionization current output from the vented ionization chamber. The average energy of alpha rays emitted from the natural nuclides radon and thoron is as high as 5.5 MeV for radon and 6.3 MeV for thoron, whereas the radiation emitted from tritium is beta ray. Since the maximum energy is 18 keV and the average energy is 5.7 keV, the cover gas is supplied with radon and nitrogen gas not containing thoron from the nitrogen cylinder from the viewpoint of preventing troubles in tritium measurement. . In the future, if the amount of tritium contaminants generated during the dismantling of various facilities to be inspected for tritium increases, the above-mentioned sealed container will also become larger, and the consumption of nitrogen gas will increase, increasing the frequency of cylinder replacement. For this reason, labor improvement measures and maintenance cost reduction measures become issues. Further, when tritium is measured in the form of water vapor with a vent ionization chamber, there is a problem that the detection sensitivity is lower than that in the case of measuring with water in a liquid scintillation counter.

As the above countermeasure, the tritium collecting part and the tritium measuring part consist of a sampling pipe for drawing sampling air from the sampling place and one end of the sampling pipe connected to condense moisture in the sampling air. And a moisture collecting unit that thaws and obtains sampling water, a sampling water introduction pipe that collects sampling water from the moisture collecting unit, and a control unit that controls the operation of each part of the collecting unit, the tritium measuring unit includes a measuring container contacting a is connected to one end of the sampling water inlet pipe and a plastic scintillator or liquid scintillator and the sampling water directly, and tritium plastic scintillators or liquid scintillators and sampling water at the measurement container Luminescence due to the reaction of Introducing into the moisture collecting unit, the light detecting means for emitting, the counting means for counting the signal pulses output from the light detecting means, the water amount measuring means for measuring the amount of sampling water introduced into the measurement container, The tritium concentration is calculated using the air amount measuring means for measuring the amount of the sampled air, the count value of the counting means, the water amount measurement value of the water amount measuring means, and the air amount measurement value of the air amount measuring means. A tritium automatic measuring device including a data processing means is conventionally known from Patent Document 1 described later.

  Further, in the hygroscopic scintillator member suitable for selectively responding to tritiated water vapor or other hydrophilic tritiated nuclides in the gas, the scintillator is a solid scintillator material having a layer of hygroscopic material on the surface. As a method for producing the scintillator member made of the above-mentioned and the hygroscopic scintillator member, a method comprising a step of coating a solid scintillator material with a layer of a hygroscopic material is conventionally known from Patent Document 2 described later.

Since the conventional tritium contamination inspection apparatus is configured as described above, the sample water is attached to the path through which the sample water collected by the tritium collecting unit is introduced into the measurement container, and the sample water necessary for the measurement. In order to secure this amount, it is necessary to increase the sample water by supplying a large amount of water vapor with a water vapor generator, which causes a problem that the tritium measurement sensitivity is lowered. In addition, the plastic scintillator has a problem that it is contaminated with tritium by isotope exchange because it contains hydrogen atoms in its molecular structure. In addition, a solid scintillator having a hygroscopic material layer on the surface takes time to release the water vapor taken into the hygroscopic material so that the next measurement can be performed, and the residual water vapor becomes a measurement error. There was a problem.
JP-A-8-75863 JP-T-2001-517802

  In view of the above problems in the field, the present invention provides a tritium inspection apparatus and a tritium inspection method capable of accurately inspecting tritium containing a very small amount of tritium-containing specimen with high accuracy and in a short time. It is what.

  A tritium inspection apparatus according to the present invention includes a specimen collection apparatus having an attachment surface for attaching tritium contained in a gas to be inspected supplied from a gas supply apparatus to be inspected, and tritium by cooling the adhesion surface. A cooling device for adhering a liquid or solid specimen layer containing a liquid, a beta ray emitted from the specimen layer installed opposite to the attachment surface and an amount corresponding to the detected beta dose A β-ray detection device for outputting a signal is provided.

  The tritium inspection method of the present invention includes an object sampling apparatus having an attachment surface for attaching tritium contained in a gas to be inspected supplied from a gas supply apparatus to be inspected, tritium by cooling the adhesion surface. A cooling device for adhering a liquid or solid specimen layer containing a liquid, a beta ray emitted from the specimen layer installed opposite to the attachment surface and an amount corresponding to the detected beta dose A first step of attaching the specimen layer having an average thickness of 0.05 mm to 0.5 mm to the attachment surface using a tritium inspection device provided with a β-ray detection device that outputs a signal, the β-ray detection device The method includes a second step of detecting β rays emitted from the subject layer and outputting a signal having an amount corresponding to the detected β dose.

  According to the present invention, since the thin specimen layer attached as a liquid or solid to the attachment surface of the specimen collection apparatus is a specimen containing tritium, the amount of the specimen is the same as that of Patent Document 1. Compared to the case, the amount is extremely small. Further, the formation of the analyte layer is performed simply and in a short time because the formation of the analyte layer is simple because the analyte gas is simply flowed along the attachment surface of the cooled specimen collection device. Since it is possible to detect tritium β-rays at the facing position of the attachment surface, there is very little possibility of contamination of foreign matters causing an error in the tritium inspection, and thus the sample collection device can be made simple. In addition, downsizing is possible, and tritium can be inspected with high sensitivity and high accuracy.

  Although the present invention does not exclude a cylinder-containing gas such as nitrogen supplied from a cylinder as a cover gas, even if a cylinder-containing gas is used, the amount used is compared with the case of the prior art for the reasons described above. The amount of cylinder change is also reduced because only a small amount is required.

  Still further, in the present invention, the specimen layer having a thin attachment surface can be evaporated and removed easily and in a short time by heating, so that the tritium content of the specimen containing tritium in the form of water vapor changes over time. It is suitable for measuring the above and for efficiently examining a large number of subjects.

  In the case of Patent Document 2, it is necessary to employ a scintillator with a hygroscopic material layer as a scintillator as a β-ray detection device. However, in the present invention, various conventionally known or well-known scintillators can be employed. Therefore, a desired scintillator can be adopted according to the inspection situation and conditions.

  In the following, the same symbols indicate the same parts.

Embodiment 1 FIG.
1 to 3 illustrate the first embodiment. FIG. 1 is a configuration diagram of a tritium inspection apparatus according to the first embodiment, and FIG. 2 is a detail of a part of FIG. FIG. 3 is a more detailed sectional view of a part of FIG.
1 to 3, the tritium inspection apparatus 1 includes, as main parts, a gas supply apparatus 2 to be inspected, a flat body 3 as an example of the specimen collection apparatus, a cooling apparatus 4, a β-ray detection apparatus 6, and The tritium detection device 7 is configured. The gas supply device 2 to be inspected includes a sealed container 21, a fan heater 22, a pump 23, a dust filter 24, a thermometer 25, and a hygrometer 26. Flat plate 3 is formed with a good metallic thermal conductivity such as aluminum, deposited surfaces 31 for attaching the object layer surface opposing the β ray detection device 6 contains tritium Thus, a specimen layer TL (see FIG. 3) containing tritium is formed on the adhesion surface 31 by the method described later.

  The cooling device 4 includes a cooling chamber 41, a cooling coil 42, and a refrigerator 43. In the cooling chamber 41, the flat plate 3 and the β-ray detection device 6 are installed facing each other as shown in the figure. ing. A refrigerant (not shown) is sent from the refrigerator 43 to the cooling coil 42, and the refrigerant circulates to cool the cooling coil 42. The cooling coil 42 is installed in a state where it is thermally coupled to the opposite side of the adhesion surface 31 of the flat plate 3, and the flat plate 3, that is, the adhesion surface 31 is cooled by the operation of the refrigerator 43. Function.

  The β-ray detection device 6 is composed of, for example, a solid scintillator, and includes a tritium detection device 7 that receives a signal output from the β-ray detection device and detects tritium. The tritium detection device 7 includes a light guide 71, two photomultiplier tubes 72 and 73, two preamplifiers 74 and 75, a coincidence counting circuit 76, and a tritium measuring unit 77.

  1-3 and each subsequent figure, the symbol a is the gas outlet of the sealed container 21, the symbol b is the gas outlet of the dust filter 24, the symbol c is the gas inlet of the thermometer 25, and the symbol d is the gas in the cooling chamber 41. The inlet, symbol e indicates a gas outlet of the cooling chamber 41, and symbol f indicates a gas inlet of the gas supply device 2 to be inspected.

  Next, the operation of the tritium inspection apparatus 1 according to the first embodiment will be described. The hermetic container 21 includes a fan heater 22 therein, and the contaminant S, which is a kind of subject accommodated in the container 21, is heated by the fan heater 22, and at that time, the surface of the contaminant S or The water vapor adsorbed on the surface layer evaporates and is released into a gas (hereinafter referred to as a cover gas) present in the sealed container 21. The cover gas containing the water vapor in the sealed container 21 is introduced into the dust filter 24 by the pump 23, and the dust containing the particulate radionuclide in the cover gas is removed by the dust filter 24.

  The fan heater 22 can easily change the temperature of the hot air for heating the contaminant S by changing the voltage applied to drive it. Therefore, if the applied voltage is set by classifying and arranging the material and size of the contaminant S in advance, the fan heater 22 can be easily operated by a switch operation by selecting the optimum applied voltage. In addition, by providing a plurality of fan heaters 22 and changing the angle and the location where hot air is blown, or by fixing the fan heater 22 and rotating the contaminants S, the contaminants S can be efficiently heated and the heating time is increased. Can be shortened.

  The heating means for the contaminant S is not limited to the fan heater 22, but may be an infrared lamp or other heating means. Any heating method can be used as long as the contaminant S can be effectively heated. It may be. Further, as the above cover gas, air around the place where the tritium inspection apparatus of the present invention is installed is usually used. Such air is radon, thoron or other gaseous radionuclide, and radon or thoron. Particulate radionuclides such as progeny nuclides are included. In contrast, the dust filter 24 prevents the particulate radionuclide from being mixed into the specimen layer TL. The gaseous radionuclide is mainly a rare gas and has a low possibility of being mixed into the analyte layer TL because of its low affinity with many analyte gases such as water.

  The temperature and humidity of the cover gas from which the dust has been removed are measured by the thermometer 25 and the hygrometer 26, respectively, and then flowed through the cooling chamber 41 in the directions of d and e to be supplied to the adhesion surface 31. Is done. As described above, since the attachment surface 31 is cooled by the cooling coil 42, the water vapor in the cover gas is condensed or solidified and stuck to form the analyte layer TL. Excess cover gas that has passed through the cooling chamber 41 without being condensed or solidified is recirculated to the sealed container 21 by the pump 23 via the three-way solenoid valve 8 and circulated. Therefore, what contains the pump 23, the airtight container 21, the cooling chamber 41, the three-way solenoid valve 8, and the pipe line which connects them is an example of a circulation exhaust apparatus.

  Thus, β rays are generated from the tritium contained in the subject layer TL from the subject layer TL formed on the adhesion surface 31, and this is detected by the β ray detection device 6. 6 outputs a pulse signal of an amount corresponding to the detected β dose. The pulse signal is input to the tritium detection device 7 together with the temperature signal output from the thermometer 25 and the humidity signal output from the hygrometer 26.

As the β-ray detector 6, a solid scintillator conventionally known or well known in the art is exemplified. The β-ray energy radiated from the tritium is weak as the maximum energy is 18 keV and the average energy is 5.7 keV as described above. Therefore, the β-ray detector 6 formed of a solid scintillator directly touches the cover gas. It is preferable because the β-ray detection ability is improved. Therefore, the solid scintillator preferably has no deliquescence, corrosion resistance, high quantum efficiency, and no tritium contamination by isotope exchange. For example, CaF ₂ (Eu) scintillator and YAlO ₃ (Ce) scintillator are This is an example of a suitable scintillator that satisfies the above conditions. The scintillator has no isotope exchange reaction with tritium because the crystal does not contain a hydrogen atom. In addition, compared to plastic scintillators, it emits about twice as many photons as β-rays with the same energy, and has a high quantum efficiency.

  The relationship between the thickness of the specimen layer TL on the attachment surface 31 and the detection sensitivity of tritium generally has a characteristic that the detection sensitivity is saturated at a range corresponding to the maximum energy of β rays emitted from tritium. Therefore, the thickness of the specimen layer TL equal to or greater than the range does not contribute to detection sensitivity. The energy of β-rays radiated from tritium is weak. From the above, it is sufficient that the thickness T (see FIG. 3) of the specimen layer TL is 0.05 mm. Further, since the thickness of the specimen layer TL of 0.05 mm does not fall from the flat plate 3 due to surface tension even in the form of water, the specimen layer TL may be in the form of water or ice. Good. Since the water vapor density in the air is high in the summer and low in the winter, the temperature control of the refrigerant supplied from the refrigerator 43 to the cooling coil 42 has a wide range so that the summer automatically condenses and the winter solidifies. Thus, an appropriate amount of the specimen layer TL can be collected stably.

  In consideration of geometric efficiency and attenuation by the cover gas, the solid scintillator as the β-ray detection device 6 is desirably arranged as close as possible to the flat plate 3, and the object layer TL is formed on the flat plate 3. However, good tritium detection conditions can be realized by arranging the solid scintillator so as to face each other. In consideration of the above and considering the ease of manufacturing and operation of the actual apparatus and the inspection accuracy of tritium, the thickness T of the specimen layer TL is generally 0.01 mm to 1 mm, preferably The distance D1 between the adhesion surface 31 and the outer surface facing the adhesion surface 31 of the β-ray detector 6 is 0.05 mm to 0.5 mm, and is 0.5 mm to 5 mm, preferably 1 mm to 5 mm. The distance D2 between the layer TL and the outer surface of the β-ray detection device 6 is 0 to 5 mm, preferably 0.5 to 3 mm.

  When the inspection for one specimen layer TL is completed, the refrigerator 43 automatically switches from the cooling mode to the heating mode, a medium having a high temperature is supplied to the cooling coil 42, and the flat plate 3 is heated. The subject layer TL on the body 3 evaporates and is released into the cover gas, sucks ambient air from the electromagnetic valve 8 that is automatically switched when the heating mode is switched, and exhausts outside through the three-way electromagnetic valve 9. Is done.

  The β ray detector 6 emits fluorescence when β rays emitted from tritium are incident. The fluorescence is transmitted by the light guide 71 and is incident on the two photomultiplier tubes 72 and 73, which are converted into current pulses, respectively. Current pulses output from the photomultiplier tubes 72 and 73 are input to preamplifiers 74 and 75, respectively, and converted into voltage pulses. The voltage pulse is input to the coincidence counting circuit 76, and when a voltage pulse is input at the same time, a digital pulse is output assuming that tritium is detected. Since β-rays emitted from tritium have low energy, it is necessary to discriminate between the current pulses output from the photomultiplier tubes 72 and 73 and noise pulses due to thermal noise to remove the noise pulses. Since the probability of simultaneous occurrence of thermal noise in both the multipliers 72 and 73 is extremely low, the thermal noise can be eliminated by simultaneously counting the voltage pulses output from the preamplifiers 74 and 75 by the coincidence circuit 76.

In the tritium measuring unit 77, the digital pulse output from the coincidence counting circuit 76 and the temperature signal and humidity signal output from the thermometer 6 and the hygrometer 7 are input, and the digital pulse is counted and divided by the measurement time. The rate n is obtained, and the radioactivity amount C of tritium in the sample water is obtained by multiplying the count rate n by the k conversion constant of the tritium concentration per unit count rate obtained in advance in the calibration test. Further, from the temperature signal T (° C.) and humidity signal H (% RH), (g number of water contained per cover gas 1 cm ³⁾ water vapor density W of the cover gas by the following equation (1) is obtained. Therefore, the thermometer 6, the hygrometer 7, and the tritium measuring unit 77 function as a water vapor density measuring device.
W = (H / 100) × [0.000804 / (1 + 0.00366T)] × (e / P) (1)
Here, e is the saturated water vapor pressure at T ° C., and a table of saturated water vapor pressure corresponding to T ° C. is stored in the tritium metering unit 77. On the other hand, P is the pressure of the cover gas (the same unit as e) and is generally atmospheric pressure.

  The internal volume of the apparatus according to the first embodiment (that is, the total internal volume in the container and the gas conveyance pipe included in the period from the symbol a to the symbol a to the symbol a in FIG. The same applies to the exhaust system.) When V is V, the amount of water vapor in the cover gas is V × W. The amount of the specimen layer TL is the product of the area and the thickness of the specimen layer TL, and the area is the area of the attachment surface 31 of the flat plate 3, and the thickness is the maximum energy of β rays emitted from tritium. In this case, the necessary amount of the analyte layer TL, that is, the necessary sample water is uniquely determined.

The tritium metering unit 77 automatically sets the target water vapor density W2 with respect to the initial water vapor density W1 of the cover gas so that V × (W1-W2) is the amount of the sample water, and the water vapor density is the target value. If the sample water is reduced to W2, it is assumed that the necessary sample water has been secured, and the β-ray detector 6 automatically switches to the tritium test, and the tritium radioactivity C of the specimen layer TL is obtained as described above, and the radioactivity C Is multiplied by the ratio of W1 and (W1-W2), and the radioactivity amount Cs of tritium adsorbed on the surface of the contaminant S or the surface layer is obtained and output by the following equation (2).
Cs = C × W1 / (W1-W2) (2)

When the ambient air of the tritium contamination inspection device is used as the cover gas, the sample layer TL as the background sample is collected from the water vapor in the air before the contamination S is inspected. When the background count rate of the subject layer TL is at a level that does not interfere with the tritium test, for example, when the statistical fluctuation of the background count rate is σ, the unit count is set to a count rate equivalent to 3σ. Confirm that the radioactivity amount of tritium multiplied by the conversion constant of tritium concentration per rate is lower than the target measurement level. The background count rate n _b is stored in the tritium measuring unit 77, and the net count rate n _N is obtained by subtracting the background count rate n _b from the count rate n as the measurement result of the above-mentioned contaminant. By multiplying the count rate n _N by the conversion constant k of the tritium concentration per unit count rate and calculating the net radioactivity C _N as shown in the following formula (3), the radioactivity of tritium can be measured with high accuracy. .
C _N = k × n _N = k × (n−n _b ) (3)

  As described above, in the first embodiment, the contamination S to be inspected is put in the sealed container 21 and heated by the fan heater 22 to efficiently evaporate the water vapor adsorbed on the surface or the surface layer of the contamination S and cover it. The specimen layer TL is collected by condensing or coagulating the water vapor containing the released tritium on the flat plate 3 in a planar shape by discharging into the gas, and β of tritium emitted from the planar specimen layer TL. The detection is performed by a β-ray detection device 6 such as a bare solid scintillator that is placed close to the opposite surface, and the amount of sample water used for the measurement is minimized. Since the β-ray energy loss until detection is reduced and β-rays of tritium are detected at a suitable geometric condition at a short distance, the tritium contamination is highly sensitive even if the amount of water vapor released from the contaminant S is small. Can be inspected, the apparatus can be downsized with it.

In addition, as a solid scintillator, it is possible to use it by exposing the scintillator directly to the cover gas by using CaF ₂ (Eu) scintillator and YAlO ₃ (Ce) scintillator that have no deliquescence and have corrosion resistance. Since there is no β-ray energy loss due to the film and the quantum efficiency is higher than that of the plastic scintillator, tritium contamination is not caused by isotope exchange, so that tritium contamination can be inspected with high sensitivity. Moreover, since the contaminant S is heated using the fan heater 22, even if the shape of the contaminant S is complex, by blowing hot air, heat is transmitted to the shaded area, and water vapor is reliably transmitted from the contaminant S. Since it can be evaporated and heated uniformly and efficiently, tritium contamination can be inspected with high accuracy. In addition, paying attention to the fact that both the photomultiplier tubes 72 and 73 are very unlikely to generate thermal noise at the same time, the coincidence circuit 76 simultaneously counts the voltage pulses output from the preamplifiers 74 and 75, respectively. Since the thermal noise of the double tubes 72 and 73 can be eliminated, tritium contamination can be inspected with high sensitivity and high accuracy.

  When the inspection is completed, the refrigerator 43 automatically switches from the cooling mode to the heating mode, and supplies a high-temperature refrigerant to the cooling coil 42 to forcibly evaporate the specimen layer TL on the flat plate 3. Preparation time for the next tritium test is shortened. Furthermore, the temperature signal and the humidity signal output from the thermometer 25 and the hygrometer 26 are input to the tritium measuring unit 77, and the water vapor density contained in the cover gas is obtained from the temperature signal and the humidity signal, and based on the water vapor density. Since the time required to collect the specimen layer TL is calculated and incorporated in the time schedule for automatic operation, the time utilization is not wasted and the utilization rate of the apparatus is improved.

Embodiment 2. FIG.
FIG. 4 is a cross-sectional view illustrating the second embodiment and illustrating another example of the sealed container 21 of the gas supply device 2 to be inspected . In FIG. 4, an infrared lamp 27 and a mirror 28 are employed instead of the fan heater 22 employed in the first embodiment. In addition, although it omits between code | symbol a and code | symbol f, it is the same as that of the said FIG. The infrared radiation emitted from the infrared lamp 27 is squeezed by the mirror 28 and irradiated to the concrete crushed powder as an example of the contaminant S and heated at 500 ° C. or higher. Since the water vapor generated by the decomposition of calcium hydroxide is released into the cover gas, tritium inside the concrete can be easily inspected, and the conventional tritium contamination inspection device for concrete, which is large and expensive, is provided at a low cost. it can.

Embodiment 3 FIG.
FIG. 5 is a cross-sectional view illustrating the third embodiment and illustrating another example of the sealed container 21 of the gas supply device 2 to be inspected . The third embodiment is different from the first embodiment only in that a drum can is employed as the sealed container 21 and the fan heater 22 used in the first embodiment is omitted. The same. 1 to 3, the cover gas in the drum can 21 is sucked by the pump 23, the water vapor containing tritium is cooled by the cooling device 4, and condensed or solidified on the flat plate 3. The specimen layer TL is collected, and β rays emitted from tritium are detected by the β ray detector 6. As a result, as in the first embodiment, tritium is concentrated by changing the water vapor into the form of water or frost, so that the tritium contamination is reliably inspected even if the amount of water vapor released from the contaminants in the drum can 21 is small. can do.

Embodiment 4 FIG.
FIG. 6 is a diagram illustrating the fourth embodiment, and is another configuration diagram including a partial cross-sectional view of the tritium inspection apparatus. In the first embodiment, the pollutant S to be measured is placed in the sealed container 21 and heated by the fan heater 22 to evaporate the water vapor adsorbed on the surface or surface layer of the pollutant S and release it into the cover gas. The cover gas is sucked by the pump 23. In the fourth embodiment, as shown in FIG. 6, an inhaler 211 is employed instead of the sealed container 21 employed in the first embodiment, and the fan heater 22 is used. Instead of this, an infrared lamp 27 and a mirror 28 similar to those in the second embodiment are provided. The inhaler 211 is like a heel facing downward, and the lower end is in an open state, and the contaminant S in the open state is spot-like when the infrared ray radiated from the infrared lamp 27 is squeezed by the mirror 28. The water vapor heated and evaporated from the surface or surface layer of the heated portion is sucked by the pump 23 together with the air around the contaminant S by the suction device 211, and the suction gas is tritium as in the first embodiment. Inspected. The infrared lamp 27 and the mirror 28 spot-heat the spot where the contaminant S is to be heated, and can efficiently recover the evaporated water vapor without disturbing the air flow unlike the fan heater 22 in the first embodiment. It becomes. For this reason, a small and inexpensive portable tritium inspection apparatus can be provided. Note that the heating temperature of the infrared lamp 27 can be easily adjusted according to the material of the contaminant by changing the applied voltage for operating the infrared lamp 27. This also applies to the second and third embodiments and the embodiments described later.
In the fourth embodiment, an inhaler 211 opened to the atmosphere is employed instead of the sealed container 21 employed in the first embodiment, and the internal volume V of the apparatus described in the first embodiment is thus determined. However, it is difficult to determine the amount of tritium.

Embodiment 5 FIG.
FIG. 7 illustrates the fifth embodiment, and is an explanatory diagram including a partial cross-sectional view of another example of the subject sampling apparatus 2 which is a part of the tritium test apparatus. In the fourth embodiment, the contaminant S released to the atmosphere is spot-heated by squeezing the infrared ray radiated from the infrared lamp 27 with the mirror 28, and the water vapor evaporated from the surface or the surface layer of the heating location is Although the suction device 211 sucks the air around the contaminant S together with the inhaler 211, in the fifth embodiment, as shown in FIG. 7, the suction device 211 has a ring-shaped rubber sucker around the entire periphery thereof. 212, and the suction cup 212 is pressed against the inspection target surface of the contaminant S to capture and seal the inspection target surface. In this way, when the contaminant S has a spread like a concrete surface, for example, the water vapor evaporated from the surface to be inspected can be reliably collected. As a result, the flat plate 3 and the β-ray detector 6 described in the first embodiment. And other devices can be used to test for tritium contamination with high accuracy. Further, in the case of inspecting the inside of the concrete surface, it is possible to increase the applied voltage of the infrared lamp 27 to raise the heating temperature to release water vapor inside the concrete surface, and to reliably collect the water without scattering it. it can.

Embodiment 6 FIG.
FIG. 8 illustrates the sixth embodiment. The sixth embodiment is different from the first embodiment in that a water vapor supply device 29 is additionally installed between the gas outlet b of the dust filter 24 and the gas inlet c of the thermometer 25. Structure. The water vapor supply device 29 includes a water supply tank 291 containing pure water, a glass fiber 292, a heating container 293, a heater 294 provided outside the heating container 293 and heating the container, and an electromagnetic valve 295. is there. The water vapor supply device 29 is hermetically connected to a pipe line connecting the dust filter 24 and the thermometer 25 via an electromagnetic valve 295, and one end of the glass fiber 292 is immersed in pure water in the water supply tank 291. However, the other end reaches the inside of the heating container 293. When the heating vessel 293 is heated by the heater 294 and the electromagnetic valve 295 is opened, the pure water rises between the glass fibers 292 by capillary action and reaches the heating vessel 293 where it is heated and vaporized, and the pipe line It is supplied to the cover gas that passes through. Therefore, Embodiment 6 can perform a tritium contamination test even under conditions where it is difficult to collect water vapor from the contaminant S (not shown), and can supply a tritium contamination test apparatus with a high utilization rate.

Embodiment 7 FIG.
FIG. 9 illustrates the seventh embodiment. The seventh embodiment is different from the first embodiment in that the cooling device 4 includes a Peltier element 5 instead of the cooling coil 42 and the refrigerator 43, and the other structure is the same. In FIG. 9, the cooling device 4 includes a Peltier element 5, a heat radiation fin 51, a blower fan 52, and a DC power source (not shown) that operates the Peltier element 5. The cooling surface of the Peltier element 5 is thermally bonded to the flat plate 3, and the heat dissipation surface of the Peltier element 5 is thermally bonded to the heat dissipation fins 51. When a current flows in one direction from the DC power source to the Peltier element 5, the cooling surface of the Peltier element 5 is cooled to cool the flat plate 3, and the specimen layer TL is collected on the adhesion surface 31. On the other hand, the heat generating surface of the Peltier element 5 is thermally joined to the heat radiating fins 51 and radiates heat by the wind sent from the blower fan 52. On the other hand, when an electric current is applied to the Peltier element 5 in the opposite direction, the cooling surface is reversed to become a heat radiating surface, the flat plate 3 2 is heated, and the specimen layer TL is forcibly evaporated. The Peltier element 5 is suitable for spot-like cooling, and can easily reverse the flow of heat by reversing the current. Therefore, the tritium inspection device 1 of the present invention can be downsized and further inexpensive. A portable device can be provided.

  INDUSTRIAL APPLICABILITY The present invention is useful for inspecting tritium contamination for various materials and substances that may be contaminated with tritium, such as concrete.

1 is a configuration diagram of a tritium inspection apparatus in Embodiment 1. FIG. FIG. 2 is a detailed view of a part of FIG. FIG. 3 is a detailed sectional view of a part of FIG. 2. FIG. 5 is a cross-sectional view of a sealed container in a second embodiment. FIG. 6 is a cross-sectional view of a sealed container in a third embodiment. It is a block diagram including the partial cross section figure of the lithium test | inspection apparatus in Embodiment 4. FIG. It is explanatory drawing including the partial cross section figure of the tritium test | inspection apparatus in Embodiment 5. FIG. FIG. 10 is an explanatory diagram of a water vapor supply device in a sixth embodiment. FIG. 10 is an explanatory diagram of a tritium inspection device in a seventh embodiment.

Explanation of symbols

1 Tritium inspection device, 2 Inspected gas supply device, 21 Airtight container,
211 Inhaler, 212 Suction cup, 22 Fan heater, 23 Pump,
24 dust filter, 25 thermometer, 26 hygrometer, 27 infrared lamp,
28 mirror, 29 water vapor supply device, 291 water supply tank, 292 glass fiber,
293 Heating vessel, 294 heater, 295 solenoid valve, 3 flat plate, 31 adhesion surface,
4 cooling device, 41 cooling chamber, 42 cooling coil, 43 refrigerator, 5 Peltier element,
51 radiating fins, 52 blower fans, 6 β-ray detector, 7 tritium detector,
71 light guide, 72 photomultiplier tube, 73 photomultiplier tube, 74 preamplifier,
75 preamplifier, 76 coincidence counting circuit, 77 tritium metering section, 8 solenoid valve,
9 Three-way solenoid valve, S contaminant, TL Sample layer.

Claims (13)

  A specimen collecting device having an attachment surface for attaching tritium contained in the inspection gas supplied from the inspection gas supply device, and a liquid or solid object containing tritium by cooling the attachment surface. A cooling device for adhering a specimen layer, a β-ray detection apparatus that is installed opposite to the attachment surface and detects β-rays radiated from the specimen layer and outputs a signal in an amount corresponding to the detected β-dose A tritium inspection device characterized by comprising:   The gas supply device to be inspected includes a heating device that heats tritium contaminants as necessary to release water vapor containing tritium into a cover gas that covers the tritium contaminants, and particulates contained in the gas to be inspected. A particulate matter removing device for removing a substance, wherein the cooling device is a cooling and heating device having a heating function for heating and evaporating the specimen layer, and the β-ray detection device outputs from the β-ray detection device 2. The tritium inspection device according to claim 1, further comprising a tritium detection device that inputs a signal to detect tritium.   3. A circulation exhaust device for circulating the cover gas through the inspection gas supply device and the specimen collection device and exhausting the cover gas to the outside after the tritium inspection. Tritium inspection equipment.   4. The tritium inspection apparatus according to claim 3, wherein the inspection gas supply apparatus includes a drum can containing the tritium contaminant.   The tritium inspection device according to any one of claims 1 to 3, wherein the gas supply device to be inspected includes a tritium capture container with a sucker that hermetically surrounds the tritium contaminant.   The said to-be-inspected gas supply apparatus was equipped with the infrared lamp which radiates | emits the infrared rays for heating the said tritium contaminant, and the mirror which condenses infrared rays, The any one of Claims 1-3 characterized by the above-mentioned. The tritium inspection device described. 2. The specimen collection device according to claim 1, wherein the specimen collection device is a flat plate made of aluminum , and the β-ray detection device is a CaF ₂ (Eu) scintillator or a YAlO ₃ (Ce) scintillator. 2. The tritium inspection device according to 2.   The tritium detection device includes a plurality of photoelectric conversion elements that receive the signal emitted from the β-ray detection device, and a coincidence counting device that receives signals from the plurality of photoelectric conversion elements and simultaneously counts the signals. The tritium inspection device according to claim 2.   The tritium inspection device according to claim 2, wherein the cooling and heating device includes one or both of a refrigerator and a Peltier element.   The tritium inspection device according to claim 2, further comprising a water vapor density measuring device for measuring a water vapor density in the cover gas.   The tritium inspection device according to claim 2 or 10, further comprising a water vapor supply device for supplying water vapor into the cover gas.   The tritium inspection device according to claim 1 or 2, wherein a distance between the adhesion surface and an outer surface of the β-ray detection device facing the adhesion surface is 1 mm to 5 mm.   A specimen collecting device having an attachment surface for attaching tritium contained in the inspection gas supplied from the inspection gas supply device, and a liquid or solid object containing tritium by cooling the attachment surface. A cooling device for adhering a specimen layer, a β-ray detection apparatus that is installed opposite to the attachment surface and detects β-rays radiated from the specimen layer and outputs a signal in an amount corresponding to the detected β-dose A first step of attaching the specimen layer having an average thickness of 0.05 mm to 0.5 mm to the attachment surface using a tritium inspection apparatus comprising: a radiation from the specimen layer by the β-ray detector A tritium inspection method characterized by including a second step of detecting a β ray and outputting a signal of an amount corresponding to the detected β dose.

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