A measuring device for measuring alpha radioactivity concentration in spent fuel wastewater on line

Abstract

The application relates to a kind of measuring device for measuring the alpha radioactivity activity concentration in spent fuel wastewater, comprising a support base, the top of the support base is provided with a liquid receiving tray, the outer side of one end of the liquid receiving tray is hung with a liquid inlet pump and a liquid outlet pump at intervals, and the outer side of the other end is hung with a sealed junction box; the liquid inlet pump is also connected with a constant liquid level pre-tank in communication through a pipeline; a support frame is arranged in the inner cavity of the liquid receiving tray, the top inner side of the support frame is fixedly connected with a liquid storage pool, the liquid storage pool is respectively connected with a first liquid level meter, a second liquid level meter and a third liquid level meter, and the bottom of the liquid storage pool is also connected with the liquid outlet pump in communication through a pipeline; the top outer side of the support frame is fixedly connected with a measuring pool, and the bottom of the measuring pool is connected with the top of the liquid storage pool in communication; the top of the measuring pool is provided with a film winding driving mechanism, a film is arranged on the film winding driving mechanism, and a detector is arranged on the top of the film winding driving mechanism. The application can effectively solve various problems of offline measurement, and realize online measurement of alpha activity concentration in high-concentration acidic liquid.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of radioactive waste water monitoring, and particularly relates to a measuring device for online measurement of alpha radioactivity activity concentration in spent fuel waste water. BACKGROUND

[0002] In the spent fuel treatment process, a large amount of alpha radioactive waste liquid containing high-concentration acidic liquid is generated. Since the alpha activity concentration in the waste liquid can directly or indirectly reflect the running state of the post-treatment process, it is necessary to monitor the alpha activity concentration of the radioactive waste liquid for the safety of personnel and the environment. The traditional measurement method usually adopts an offline analysis and detection method, that is, after the waste liquid is sampled, the sample is obtained through multiple repetitions of evaporation, conditioning, extraction and other chemical means, and then the sample is analyzed and measured to obtain the activity concentration. The offline measurement method has the disadvantages of being unable to measure the waste liquid in real time, being complicated, having poor timeliness, having a small sampling volume, and requiring personnel to periodically sample from the process pipeline, thereby increasing the risk of personnel exposure and environmental pollution. SUMMARY

[0003] In view of the deficiencies of the prior art, the present application provides a measuring device for online measurement of alpha radioactivity activity concentration in spent fuel waste water, which has the advantages of large measurement area, strong acid resistance, reasonable operation logic, simple operation steps and the like on the basis of meeting the measurement accuracy, and can effectively solve various problems of offline measurement and realize online measurement of the alpha activity concentration in high-concentration acidic liquid.

[0004] In order to achieve the above-mentioned purpose, the technical scheme of the present application is as follows:

[0005] A measuring device for online measurement of alpha radioactivity activity concentration in spent fuel waste water, comprising a support base, a liquid receiving disc is arranged on the top of the support base, a liquid inlet pump and a liquid outlet pump are arranged on the outer side of one end of the liquid receiving disc at intervals, and a sealed junction box is arranged on the outer side of the other end; the liquid inlet pump and the liquid outlet pump are electrically connected with the sealed junction box, and the liquid inlet pump is also connected in communication with a constant liquid level pre-tank through a pipeline;

[0006] A support frame is arranged in the inner cavity of the liquid receiving disc, a liquid storage pool is fixedly connected to the top inner side of the support frame, a first liquid level meter, a second liquid level meter and a third liquid level meter are respectively connected to the liquid storage pool, and the bottom of the liquid storage pool is also connected in communication with the liquid outlet pump through a pipeline; a measuring pool is fixedly connected to the top outer side of the support frame, and the bottom of the measuring pool is connected in communication with the top of the liquid storage pool;

[0007] The inner cavity of the measuring pool is provided with a water circuit partition plate spirally wound from the center to the outside, the center of the innermost circle of the water circuit partition plate is provided with a water outlet, the water outlet is connected with the top of the liquid storage pool; the outermost circle of the water circuit partition plate is provided with a water inlet, the water inlet is connected with the liquid inlet pump through a pipeline;

[0008] The top of the measuring pool is provided with a film winding driving mechanism, the film winding driving mechanism is provided with a film for blocking radioactive waste liquid, the top of the film winding driving mechanism is provided with a detector, and a gap is left between the bottom of the detector and the top of the film.

[0009] Preferably, the detector comprises a detector shell, a planar cover plate is arranged in the detector shell, a photodetector is arranged on the top of the planar cover plate, a detector electronic unit connected with the photodetector, and a fiber optic collimating coupling body connected with one end of the photodetector;

[0010] The bottom of the planar cover plate is provided with a detector bottom frame, the detector bottom frame is provided with a light shielding film, the top of the detector bottom frame is provided with a scintillator, the top of the scintillator is provided with a fiber fixing frame, a plurality of scintillating fibers are arranged on the fiber fixing frame in a U-shaped and equidistant manner, and the ends of the scintillating fibers pass through the planar cover plate and are connected with the fiber optic collimating coupling body;

[0011] The top of the fiber fixing frame is provided with a light guide, the top of the light guide is provided with a light reflection layer, and the top surface of the light reflection layer is connected with the bottom surface of the planar cover plate;

[0012] The side surface of the detector shell is respectively provided with a detector waterproof power supply connector and a detector waterproof communication connector, the detector waterproof power supply connector and the detector waterproof communication connector are electrically connected with the detector electronic unit.

[0013] Preferably, the film winding driving mechanism comprises a driving support, rotating rods are arranged at the two ends of the driving support, and the two ends of the film are wound on the rotating rods at the two ends of the driving support; one end of each of the two rotating rods is connected with a rotating wheel, and the rotating wheel is exposed to one side of the driving support.

[0014] Preferably, the film is made of 2.4 μm thick polyester fiber film.

[0015] Preferably, the support base comprises a planar base and support shafts arranged at four positions on the top of the planar base, and the liquid receiving disc is arranged on the top of the support shafts.

[0016] Preferably, the bottom center of the liquid receiving disc is provided with a liquid outlet, and the inner cavity of the liquid receiving disc is further provided with a fourth liquid level meter for monitoring the liquid amount in the liquid receiving disc.

[0017] Preferably, one side of the lower part of the constant liquid level pre-tank is provided with a fifth liquid level gauge, and the top of the constant liquid level pre-tank is further connected with an overflow pipeline.

[0018] Preferably, the light shielding film is made of polished titanium foil, and the reflectivity of the light shielding film to light with a wavelength of 400-700 nm is greater than or equal to 70%.

[0019] Preferably, the scintillation fiber is a plastic wave shifting fiber.

[0020] The optical fiber fixing frame is made of acrylic material, and a plurality of optical fiber positioning holes for penetrating the scintillation fiber are formed at equal intervals at two ends of the optical fiber fixing frame, and two ends of the scintillation fiber are respectively penetrated into two adjacent optical fiber positioning holes at one end of the optical fiber fixing frame and penetrated out of two corresponding optical fiber positioning holes at the other end of the optical fiber fixing frame.

[0021] Preferably, the scintillator is a ZnS plastic scintillator, and the peak value of the light emission wavelength of the ZnS plastic scintillator is 423 nm.

[0022] The light reflection layer is made of an aluminum-coated film, and the light reflectivity of the light reflection layer to light with a wavelength of 400-500 nm is greater than or equal to 90%.

[0023] The technical effects and advantages of the present application are as follows:

[0024] 1. The present application provides a device for measuring the alpha radioactivity concentration in spent fuel wastewater, which is designed by combining a constant liquid level pre-tank, a liquid inlet pump, a liquid outlet pump, a support frame, a liquid storage pool, a measuring pool, a film and a detector, and has the advantages of large measuring area, strong acid resistance, reasonable operation logic, simple operation steps and the like, and can effectively solve various problems in offline measurement and realize online measurement of the alpha activity concentration in high-concentration acidic liquid.

[0025] The water circuit partition plate in the measuring pool has a spiral structure, which can ensure that the liquid quickly covers the measuring pool and at the same time avoid the problems of liquid overflow, uneven distribution and unstable flow rate as much as possible.

[0026] Since the detector uses multiple optical fibers to cover the measuring surface and has good uniformity, the detector uses an ultrathin titanium foil as a light shielding surface and a light reflection surface, which can ensure the detection efficiency and has strong acid resistance, and the alpha detection efficiency is high.

[0027] The film of the present application is an ultrathin polyester fiber film, which has good tensile property and acid resistance and is a good material for preventing acidic liquid from contacting the detector.

[0028] The acid-proof liquid level gauge installed on the liquid storage tank realizes a highly feasible linkage type radioactive liquid on-line measuring method, which can effectively realize the flow balance of the measured liquid, and fully considers the occurrence of unexpected situations, and guarantees the normal operation of the equipment;

[0029] The liquid receiving disc is arranged to collect the overflow liquid due to unexpected situations and is connected with the liquid inlet pump and the liquid outlet pump, and the length and width of the liquid receiving disc are larger than those of the components thereon, so that the overflow liquid can be fully collected, and the liquid receiving disc is connected with the base and has good bearing capacity;

[0030] The liquid inlet pump and the liquid outlet pump of the present application use an acid-proof micro magnetic drive gear pump with adjustable rotating speed, the function of adjustable rotating speed of the pump meets the requirements of the linkage type radioactive liquid on-line measuring method, and the acid-proof micro characteristics are highly consistent with the use requirements of the post-processing process site;

[0031] The constant liquid level pre-tank is arranged to solve the problem of unstable liquid flow pressure in the process pipeline, the liquid in the process pipeline is collected by the constant liquid level pre-tank with appropriate size, and then the liquid is pumped into the measuring tank, so that the stable operation of the liquid inlet pump can be effectively guaranteed, and the influence of the process pipeline on the operation of the device is excluded. BRIEF DESCRIPTION OF DRAWINGS

[0032] Fig. 1 is a schematic diagram of the three-dimensional structure of the present application;

[0033] Fig. 2 is a schematic diagram of the partial structure explosion of the present application;

[0034] Fig. 3 is a schematic diagram of the internal structure explosion of the detector of the present application.

[0035] The drawings show that: 1, the support base; 2, the detector; 3, the support frame; 4, the film winding; 5, the measuring tank; 6, the liquid storage tank; 7, the first liquid level gauge; 8, the second liquid level gauge; 9, the third liquid level gauge; 10, the liquid receiving disc; 12, the liquid inlet pump; 13, the liquid outlet pump; 14, the sealing junction box; 15, the constant liquid level pre-tank; 16, the fifth liquid level gauge; 17, the liquid outlet; 18, the film winding driving mechanism; 19, the driving support; 20, the rotating wheel;

[0036] 21, the detector housing; 22, the plane cover plate; 23, the detector bottom frame; 24, the light shielding film; 25, the scintillation fiber; 26, the fiber fixing frame; 27, the scintillator; 28, the light guide; 29, the light reflection layer; 210, the photodetector; 211, the detector waterproof power supply connector; 212, the detector electronic unit; 213, the fiber collimation coupling body; 214, the detector waterproof communication connector. DETAILED DESCRIPTION

[0037] The application will be further described in detail in connection with the drawings of the embodiments.

[0038] Referring to Figs. 1-3 As shown in the drawings, a measuring device for measuring the alpha radioactivity activity concentration in the spent fuel wastewater in line, comprising a support base 1, the top of which is provided with a liquid receiving tray 10, one end of which is externally hung with an inlet pump 12 and a liquid discharge pump 13, and the other end is externally hung with a sealed junction box 14; the inlet pump 12 and the liquid discharge pump 13 are electrically connected with the sealed junction box 14 respectively, and the inlet pump 12 is further connected in communication with a constant liquid level pre-tank 15 through a pipeline;

[0039] A support frame 3 is arranged in the inner cavity of the liquid receiving tray 10, the top inner side of which is fixedly connected with a liquid storage pool 6, the top of which is connected with a first liquid level meter 7, a second liquid level meter 8 and a third liquid level meter 9 respectively, and the bottom of the liquid storage pool 6 is further connected in communication with the liquid discharge pump 13 through a pipeline; the top outer side of the support frame 3 is fixedly connected with a measuring pool 5, the bottom of which is connected in communication with the top of the liquid storage pool 6;

[0040] A water loop partition plate 51 is arranged in the inner cavity of the measuring pool 5, which is coiled from the center to the outer side, the center of the innermost circle of the water loop partition plate 51 is provided with a water outlet, which is connected in communication with the top of the liquid storage pool 6; the outermost circle of the water loop partition plate 51 is provided with a water inlet, which is connected in communication with the inlet pump 12 through a pipeline;

[0041] The top of the measuring pool 5 is provided with a film winding driving mechanism 18, the film winding driving mechanism 18 is provided with a film 4 for blocking radioactive waste liquid, the top of the film winding driving mechanism 18 is provided with a detector 2, and a gap is left between the bottom of the detector 2 and the top of the film 4.

[0042] In this embodiment, the water sample flows along the loop of the measuring pool 5 and finally falls freely into the liquid storage pool 6 below the measuring pool 5, when the liquid level in the liquid storage pool 6 is only at the position of the first liquid level meter 7, the system starts the liquid discharge pump 13 to avoid the water sample overflowing the liquid storage pool 6, when the liquid level in the liquid storage pool 6 is at the position of the second liquid level meter 8 or between the second liquid level meter 8 and the first liquid level meter 7, the inlet pump 12 and the liquid discharge pump 13 are started simultaneously to keep the liquid in and out at the same time, when the liquid level in the liquid storage pool 6 is at the position of the third liquid level meter 9 or between the third liquid level meter 9 and the second liquid level meter 8, only the inlet pump 12 is started to avoid the liquid level in the measuring pool 5 and the liquid storage pool 6 being too low.

[0043] In this embodiment, the first liquid level meter 7, the second liquid level meter 8 and the third liquid level meter 9 are all acid-proof liquid level meters.

[0044] In this embodiment, the liquid inlet pump 12 and the liquid outlet pump 13 are the same kind of acid-proof micro magnetic force driving gear pump, both of which can be automatically started and stopped according to the device working logic or manually started and stopped in the manual mode.

[0045] In this embodiment, the film winding driving mechanism 18 comprises a driving support 19, both ends of the driving support 19 are respectively provided with rotating rods, both ends of the film 4 are respectively wound on the rotating rods at both ends of the driving support 19, one end of each of the rotating rods is connected with a rotating wheel 20, and the rotating wheel 20 is exposed to one side of the driving support 19.

[0046] In this embodiment, the film 4 is made of 2.4 μm thick polyester fiber film.

[0047] In the implementation, the polyester fiber film is used to block the radioactive waste liquid pollution detector surface, when the polyester fiber film is used for a long time or is contaminated, the film winding mechanism can be manually adjusted through the rotating wheel 20 to drive the film to move, so as to restore the background measurement value of the detector.

[0048] In this embodiment, the support base 1 comprises a plane base and support shafts respectively arranged at four positions on the top of the plane base, and the liquid receiving disc 10 is arranged on the top of the support shafts to stably support the whole measuring device.

[0049] In this embodiment, the liquid receiving disc 10 is provided with a liquid outlet 17 at the center of the bottom, and the inner cavity of the liquid receiving disc 10 is further provided with a fourth liquid level meter for monitoring the liquid amount in the liquid receiving disc 10.

[0050] In the implementation, the liquid receiving disc 10 is made of stainless steel, and is used to collect the liquid overflowing due to accidental conditions and connect the liquid inlet pump 12, the liquid outlet pump 13 and the sealed junction box 14, when there is liquid in the liquid receiving disc 10, the liquid can flow out through the liquid outlet 17 at the center of the liquid receiving disc 10 to the waste liquid collection process pipeline, and the fourth liquid level meter is used as the insurance of the measuring device, if the liquid level in the liquid receiving disc 10 is at or exceeds the position of the fourth liquid level meter, the system alarms and stops the liquid inlet pump 12 and the liquid outlet pump 13.

[0051] In this embodiment, the fifth liquid level meter 16 is arranged on one side of the lower part of the constant liquid level pre-tank (15), and the top of the constant liquid level pre-tank (15) is further connected with an overflow pipeline.

[0052] In the implementation, the process liquid inlet pipeline continuously feeds liquid into the constant liquid level pre-tank 15, to avoid empty pumping, when the liquid level reaches or exceeds the position of the liquid level meter 16, the liquid inlet pump 12 is started (note: the starting logic priority of the liquid inlet pump 12 is higher than that of the liquid level meter in the liquid storage pool 6).

[0053] In this embodiment, referring to Fig. 3 As shown in the figure, the detector 2 comprises a detector housing 21, a planar cover plate 22 is arranged in the detector housing 21, a photoelectric detector 210 is arranged on the top of the planar cover plate 22, a detector electronic unit 212 connected with the photoelectric detector 210, and a fiber collimating coupling body 213 is connected to one end of the photoelectric detector 210.

[0054] A detector bottom frame 23 is arranged on the bottom of the planar cover plate 22, a light shielding film 24 is arranged in the detector bottom frame 23, a scintillator 27 is arranged on the top of the detector bottom frame 23, a fiber fixing frame 26 is arranged on the top of the scintillator 27, a plurality of scintillating optical fibers 25 are arranged on the fiber fixing frame 26 in a U-shaped and equidistant manner, and the end of the scintillating optical fiber 25 passes through the planar cover plate 22 and is connected with the fiber collimating coupling body 213.

[0055] A light guide 28 is arranged on the top of the fiber fixing frame 26, a light reflecting layer 29 is arranged on the top of the light guide 28, and the top surface of the light reflecting layer 29 is connected with the bottom surface of the planar cover plate 22.

[0056] The side of the detector housing 21 is respectively provided with a detector waterproof power supply connector 211 and a detector waterproof communication connector 214, the detector waterproof power supply connector 211 and the detector waterproof communication connector 14, and a sealing junction box 14 are all electrically connected with the detector electronic unit 212.

[0057] In this embodiment, the light shielding film 24 is made of polished titanium foil, the thickness of the titanium foil is 5 μm, the metal titanium has excellent oxidation resistance and acid resistance, especially has very good corrosion resistance to nitric acid which often exists in the field of nuclear detection; when the acid gas / liquid contacts the light shielding film 24, the light shielding film 24 can block the acid gas / liquid for a long time without being corroded and penetrated, and has good light reflecting ability, the reflectivity of the light of 400 nm-700 nm wavelength is ≥70%, and the scintillating light emitted by the plastic scintillator 27 can be reflected, further improving the efficiency of the detector.

[0058] In this embodiment, the scintillating optical fiber 25 is a plastic wave shifting optical fiber, which has the characteristics of high absorption rate of the light entering from the side of the optical fiber and the scintillating light emitted by the plastic scintillator 27, and can change the wavelength of the outgoing light, so that the outgoing light is more suitable for being detected by the photoelectric detector 210.

[0059] In the embodiment, the optical fiber fixing frame 26 is made of acrylic material, and a plurality of optical fiber positioning holes for penetrating the scintillating optical fibers 25 are equidistantly formed at two ends of the optical fiber fixing frame 26. Two ends of the scintillating optical fibers 25 are respectively penetrated into two adjacent optical fiber positioning holes at one end of the optical fiber fixing frame 26 and are respectively penetrated out of two corresponding optical fiber positioning holes at the other end of the optical fiber fixing frame 26. The ends of all the scintillating optical fibers 25 are gathered into a bundle at the outlet, and then are bent into the optical fiber collimation coupling body 213 with a proper bending radius, and are in contact with the photodetector 210 and transmit light into the photodetector 210.

[0060] In the embodiment, the scintillator 27 is made of ZnS plastic scintillator, and the peak value of the light emitting wavelength is 423 nm.

[0061] In the embodiment, the light reflecting layer 29 is made of an aluminized film, and the light reflectivity of the aluminized film in the wavelength range of 400 nm to 500 nm is greater than or equal to 90%.

[0062] In specific use of the present application, the pump and the liquid level meter are powered through the probe waterproof power supply joint 211 and the probe waterproof communication joint 214, 12V power is supplied to the probe 2 and RS485 communication is conducted, the probe 2 can detect the alpha dose rate in the measuring pool 5 below in real time after being powered on, the liquid with a mass concentration of 7 mol / L of uranium nitrate is continuously input into the constant liquid level pre-tank 15 through the liquid inlet pipeline, if the liquid level of the constant liquid level pre-tank 15 is too high, the liquid can be discharged through the overflow pipe of the constant liquid level pre-tank 15, when the liquid level reaches or exceeds the position of the liquid level meter 16, the liquid inlet pump 12 is started to make the liquid flow into the measuring pool 5, the running speed of the liquid inlet pump 12 is adjustable (the speed of 0 r / min-6000 r / min corresponds to the power supply voltage of 0 V-24 V, the corresponding relationship is linear), in order to avoid liquid overflow caused by too fast liquid inlet, the liquid inlet pump 12 of the embodiment adopts 5V power supply, corresponding to the speed of 1,250 r / min, a polyester fiber film with a thickness of 2.4 μm which does not contact the probe surface is arranged between the measuring pool 5 and the probe 3, the film is manually moved by the film winding mechanism 18 after being used for a specific time or being contaminated, so as to restore the background measurement value of the probe 2, at this time, the liquid flows along the water circuit of the measuring pool 5 in a spiral manner, finally covers the entire measuring pool 5 and continuously flows into the liquid storage pool 6, ensuring that the liquid level of the measuring pool 5 is high (the alpha ray attenuation degree is related to the distance height) while there is no overflow, when the liquid in the liquid storage pool 6 gradually accumulates to reach the position of the liquid level meter 7, in order to protect the liquid storage pool 6 from liquid overflow, the liquid discharge pump 13 is started, the liquid discharge pump 13 adopts an acid-proof micro magnetic drive gear pump consistent with the liquid inlet pump 12, adopts 24V power supply, corresponding to the speed of 6000 r / min, when the liquid level is drawn to the position of the liquid level meter 8 or between the position of the liquid level meter 8 and the position of the liquid level meter 7, the power supply of the liquid discharge pump 13 is changed to 5V power supply, corresponding to the speed of 1250 r / min, that is, the same as the speed of the liquid inlet pump 12, realizing the balance of liquid inlet and outlet. Because of some reasons (such as the equipment is not used for a long time, the pump is started and stopped in the middle or manually operated), when the liquid level in the liquid storage pool 6 is between the position of the liquid level meter 9 and the position of the liquid level meter 8, only the liquid inlet pump 12 is started, the liquid inlet pump 12 adopts 5V power supply, corresponding to the speed of 1,250 r / min, ensuring that the liquid flows quickly into the linkage working state, so that the equipment returns to normal measurement work. In addition, when the liquid overflows due to unexpected circumstances, the liquid receiving disc 10 is also used to collect the overflow liquid and quickly discharge the liquid through the liquid outlet 17.

[0063] The above only describes the preferred embodiments of the present application, it should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, several modifications and improvements can be made, which all belong to the protection scope of the present application.

Claims

1. A measuring device for measuring the alpha radioactivity activity concentration in spent fuel wastewater on-line, characterized in that: The utility model provides a support base (1) top is equipped with the liquid receiving tray (10), and the liquid receiving tray (10) one end outside interval is equipped with the liquid inlet pump (12) and liquid outlet pump (13), and the other end outside is equipped with sealed terminal box (14), and the liquid inlet pump (12) and liquid outlet pump (13) are electrically connected with sealed terminal box (14) respectively, and the liquid inlet pump (12) is also connected with constant liquid level pre-tank (15) through pipeline, The liquid receiving tray (10) inner chamber is equipped with support frame (3), and the top inside of support frame (3) is fixedly connected with liquid storage pool (6), and the first liquid level meter (7), second liquid level meter (8) and third liquid level meter (9) are connected on the liquid storage pool (6) respectively, and the bottom of liquid storage pool (6) is also communicated with liquid outlet pump (13) through pipeline, and the top outside of support frame (3) is fixedly connected with measuring pool (5), and the bottom of measuring pool (5) is communicated with the top of liquid storage pool (6), The inner chamber of measuring pool (5) is equipped with water circuit baffle (51) that is coiled from center to outside, and the center of the innermost circle of water circuit baffle (51) is equipped with water outlet, and the water outlet is communicated with the top of liquid storage pool (6), and the outermost circle of water circuit baffle (51) is equipped with water inlet, and the water inlet is communicated with liquid inlet pump (12) through pipeline, The top of measuring pool (5) is equipped with film winding drive mechanism (18), and the film winding drive mechanism (18) is equipped with film (4) for blocking radioactive waste liquid, and the top of film winding drive mechanism (18) is equipped with detector (2), and the gap is left between the bottom of detector (2) and the top of film (4).

2. The device for measuring the concentration of alpha radioactivity in the wastewater from spent fuel according to claim 1, characterized in that: The detector (2) includes a detector housing (21), the detector housing (21) is provided with a planar cover plate (22), the planar cover plate (22) is provided with a photodetector (210) on the top, and a detector electronic unit (212) connected with the photodetector (210), one end of the photodetector (210) is connected with a fiber optic collimating coupling body (213); The bottom of the planar cover plate (22) is provided with a detector bottom frame (23), the detector bottom frame (23) is provided with a light shielding film (24), the top of the detector bottom frame (23) is provided with a scintillator (27), the top of the scintillator (27) is provided with a fiber optic fixing frame (26), a plurality of scintillating fibers (25) are arranged in a U-shaped and equidistant manner on the fiber optic fixing frame (26), and the ends of the scintillating fibers (25) pass through the planar cover plate (22) and are connected with the fiber optic collimating coupling body (213); The top of the fiber optic fixing frame (26) is provided with a light guide (28), the top of the light guide (28) is provided with a light reflection layer (29), and the top surface of the light reflection layer (29) is connected with the bottom surface of the planar cover plate (22). The detector shell (21) is respectively provided with a detector waterproof power supply connector (211) and a detector waterproof communication connector (214), the detector waterproof power supply connector (211) and the detector waterproof communication connector (214) are electrically connected with the detector electronic unit (212), and the sealing terminal box (14) is also electrically connected with the detector electronic unit (212).

3. The device for measuring the concentration of alpha radioactivity in the spent fuel wastewater according to claim 1, wherein: The film winding driving mechanism (18) comprises a driving support (19), both ends of the driving support (19) are respectively provided with rotating rods, both ends of the film (4) are wound on the rotating rods at both ends of the driving support (19), one end of each of the two rotating rods is connected with a rotating wheel (20), and the rotating wheel (20) is exposed to one side of the driving support (19).

4. The device for measuring the concentration of alpha radioactivity in the spent fuel wastewater according to claim 3, wherein: The film (4) is prepared by using a 2.4 μm thick polyester fiber film.

5. The device for measuring the concentration of alpha radioactivity in the wastewater from spent fuel according to claim 1, characterized in that: The support base (1) comprises a plane base and support shafts arranged at four positions on the top of the plane base, and the liquid receiving disc (10) is arranged on the top of the support shafts.

6. The device for measuring the concentration of alpha radioactivity in the spent fuel wastewater according to claim 5, wherein: The liquid receiving disc (10) is provided with a liquid discharge port (17) at the center of the bottom, and the inner cavity of the liquid receiving disc (10) is further provided with a fourth liquid level meter for monitoring the liquid amount in the liquid receiving disc (10).

7. The device for measuring the concentration of alpha radioactivity in the spent fuel wastewater according to claim 1, wherein: The constant liquid level pre-tank (15) is provided with a fifth liquid level meter (16) on one side of the middle lower part, and the top of the constant liquid level pre-tank (15) is further connected with an overflow pipeline.

8. The device for measuring the concentration of alpha radioactivity in the spent fuel wastewater according to claim 2, wherein: The light shielding film (24) is prepared by using a polished titanium foil, and the reflectivity of the light shielding film (24) to the wavelength of 400 nm to 700 nm is greater than or equal to 70%.

9. The device for measuring the concentration of alpha radioactivity in the aqueous solution of spent fuel according to claim 8, characterized in that: The scintillating optical fiber (25) is a plastic wave shifting optical fiber. The optical fiber fixing frame (26) is prepared by using an acrylic material, a plurality of optical fiber positioning holes for penetrating the scintillating optical fiber (25) are arranged at equal intervals at both ends of the optical fiber fixing frame (26), and two ends of the scintillating optical fiber (25) are respectively penetrated into two adjacent optical fiber positioning holes at one end of the optical fiber fixing frame (26) and penetrated out of two corresponding optical fiber positioning holes at the other end of the optical fiber fixing frame (26).

10. The device for measuring the concentration of alpha radioactivity in the wastewater from spent nuclear fuel according to claim 8, characterized in that: The scintillator (27) is a ZnS plastic scintillator, and the light emitting wavelength peak value of the scintillator (27) is 423 nm. The light reflecting layer (29) is prepared by using an aluminum-coated film, and the light reflectivity of the light reflecting layer (29) in the wavelength range of 400 nm to 500 nm is greater than or equal to 90%.

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