CN111880213A - Nuclear fuel rod based on D-D neutron source235U enrichment degree and uniformity detection method - Google Patents

Abstract

Translated fromChinese

本发明公开了一种基于D‑D中子源的核燃料棒²³⁵U富集度及均匀性检测方法，所用检测装置包括紧凑型D‑D中子源、中子慢化体、γ屏蔽体、核燃料棒传送孔道及γ探测器系统，紧凑型D‑D中子源外包裹含氢中子慢化体，中子慢化体外围包裹γ屏蔽体，紧凑型D‑D中子源上方中子慢化体中设置核燃料棒传送孔道，其末端安装γ探测器系统。中子慢化体将D‑D快中子慢化为热中子或超热中子，并在核燃料棒传送孔道内形成热中子场，利用热中子诱发核燃料中²³⁵U发生裂变反应，裂变产物退激发释放出大量γ射线，通过测量裂变退激γ射线强度实现对核燃料棒²³⁵U富集度及均匀性的检测。本发明能满足在线检测的要求，具有检测速度快、灵敏度高、样品无损伤等特点。

The invention discloses a D-D neutron source-based detection method for²³⁵ U enrichment and uniformity of nuclear fuel rods. The detection device used includes a compact D-D neutron source, a neutron moderator, a gamma shield, a Nuclear fuel rod transmission channel and gamma detector system, the compact D-D neutron source is surrounded by a hydrogen-containing neutron moderator, the neutron moderator is surrounded by a gamma shield, and the neutron above the compact D-D neutron source A nuclear fuel rod transfer channel is set in the moderator, and a gamma detector system is installed at the end of the channel. The neutron moderator moderates D-D fast neutrons into thermal neutrons or epithermal neutrons, and forms a thermal neutron field in the transmission channel of the nuclear fuel rod, and uses thermal neutrons to induce fission reaction of²³⁵ U in the nuclear fuel, The de-excitation of fission products releases a large amount of γ-rays, and the detection of²³⁵ U enrichment and uniformity of nuclear fuel rods is realized by measuring the intensity of fission-de-excited γ-rays. The invention can meet the requirements of on-line detection, and has the characteristics of fast detection speed, high sensitivity, no damage to samples, and the like.

Description

Translated fromChinese

基于D-D中子源的核燃料棒235U富集度及均匀性检测方法Detection method of 235U enrichment and uniformity of nuclear fuel rods based on D-D neutron source

技术领域technical field

本发明属于核工业无损检测技术领域，尤其涉及一种基于紧凑型D-D中子源的核燃料棒²³⁵U富集度及均匀性检测装置及其检测方法。The invention belongs to the technical field of non-destructive testing in the nuclear industry, and in particular relates to a²³⁵ U enrichment and uniformity detection device and a detection method for a nuclear fuel rod based on a compact DD neutron source.

背景技术Background technique

核装置和新型核能利用系统的研发中，对核燃料²³⁵U芯块富集度均匀性的要求很高，严格要求每一根核燃料棒中易裂变材料²³⁵U富集度保持高度一致，严格防控同一根核燃料棒中混入²³⁵U富集度不同的异常芯块。为确保核燃料在核装置系统和核电站反应堆中安全可靠运行，需对核燃料²³⁵U富集度及均匀性进行检测，避免由于核燃料²³⁵U芯块富集度在位置上的不均匀性产生局部分散热点，影响反应堆堆芯功率分布，导致功率波动甚至引起局部温度过高，影响反应堆安全运行，严重时，局部分散热点可能引起核燃料元件的静态自主破裂，发生重大的核安全事故。In the research and development of nuclear devices and new nuclear energy utilization systems, the requirements for the uniformity of the enrichment degree of nuclear fuel²³⁵ U pellets are very high^. Anomalous pellets with different²³⁵ U enrichment were mixed into the same nuclear fuel rod. In order to ensure the safe and reliable operation of nuclear fuel in nuclear installation systems and nuclear power plant reactors, it is necessary to test the²³⁵ U enrichment and uniformity of nuclear fuel to avoid local scattered hot spots due to the unevenness of nuclear fuel²³⁵ U pellet enrichment in position. , affecting the power distribution of the reactor core, causing power fluctuations and even causing local temperature to be too high, affecting the safe operation of the reactor. In severe cases, local scattered hot spots may cause static autonomous rupture of nuclear fuel elements, resulting in major nuclear safety accidents.

核燃料棒²³⁵U富集度及均匀性的检测方法有加速器质谱法、无源被动测量法等。加速器质谱法是基于加速器技术和离子探测的一种同位素质谱技术，将待测样品在加速器的离子源中电离，随后将离子束引出并加速，再借助电荷态、荷质比、能量和原子序数的选择，鉴别被加速的离子并加以记录，实现同位素比值的测定。加速器质谱法具有排除同量异位素本底和分子离子本底干扰的能力。无源被动测量法是基于核燃料中²³⁵U核素的自发α衰变伴随有能量为98keV和185.7keV的γ射线，其强度与²³⁵U富集度成正比关系，因此可以用γ射线能谱方法测量核燃料中²³⁵U自发衰变的放射性强度来确定其²³⁵U富集度的技术。当核燃料棒匀速通过检测装置，采用定时测量γ射线强度可得到燃料棒内每一块²³⁵U芯块的富集度分布图谱，对图谱数据进行分析处理后可得出²³⁵U芯块富集度值并判断出棒中是否混有异常芯块。需要注意的是，衰变产物²³⁴Pa再次衰变时会发生康普顿散射，在185.7keV能量处沉积能量，影响计数，称之为年龄效应，测量结果必须修正年龄效应的影响。The detection methods of²³⁵ U enrichment and uniformity in nuclear fuel rods include accelerator mass spectrometry, passive passive measurement, etc. Accelerator mass spectrometry is an isotope mass spectrometry technology based on accelerator technology and ion detection. The sample to be tested is ionized in the ion source of the accelerator, and then the ion beam is extracted and accelerated. selection, identification of accelerated ions and recording, to achieve the determination of isotope ratios. Accelerator mass spectrometry has the ability to exclude isobaric background and molecular ion background interference. The passive passive measurement method is based on the spontaneous α decay of²³⁵ U nuclide in nuclear fuel accompanied by γ rays with energies of 98 keV and 185.7 keV, the intensity of which is proportional to the enrichment of²³⁵ U, so it can be measured by γ ray energy spectroscopy. A technique for determining the enrichment of²³⁵ U from the radioactive intensity of spontaneous decay of²³⁵ U in nuclear fuel. When the nuclear fuel rod passes through the detection device at a uniform speed, the intensity distribution of each²³⁵ U pellet in the fuel rod can be obtained by measuring the intensity of γ-ray regularly. After analyzing the map data, the enrichment value of²³⁵ U pellet can be obtained And determine whether there are abnormal pellets mixed in the rod. It should be noted that when the decay product²³⁴ Pa decays again, Compton scattering will occur, depositing energy at the energy of 185.7keV, which affects the count, which is called the age effect, and the measurement results must be corrected for the influence of the age effect.

现有技术存在的问题是：加速器质谱法测量核燃料²³⁵U富集度的方法中，首先需要对样品(核燃料元件)进行预处理，该方法是一种破坏性分析方法，且检测过程繁杂，检测速度慢，无法满足核燃料元件在线、快速、无损检测的要求；无源法核燃料棒²³⁵U富集度检测系统的检测速度慢、单通道所需γ探测器数量多、系统采集数据统计涨落大、系统占地面积大等，无法满足核燃料元件快速检测的实际需求。The problem existing in the prior art is: in the method for measuring the²³⁵ U enrichment of nuclear fuel by accelerator mass spectrometry, the sample (nuclear fuel element) needs to be pretreated first. This method is a destructive analysis method, and the detection process is complicated and the detection process is complicated. The speed is slow and cannot meet the requirements of on-line, rapid and non-destructive testing of nuclear fuel elements; the detection speed of the passive method nuclear fuel rod²³⁵ U enrichment detection system is slow, the number of gamma detectors required for a single channel is large, and the statistical fluctuations of the data collected by the system are large. , the system occupies a large area, etc., which cannot meet the actual needs of rapid detection of nuclear fuel elements.

发明内容SUMMARY OF THE INVENTION

针对上述背景技术中指出的不足，本发明提供了一种基于紧凑型D-D中子源的核燃料棒²³⁵U富集度及均匀性检测装置及其检测方法，旨在解决现有核燃料²³⁵U芯块富集度均匀性检测过程繁杂、检测速度慢、灵敏度不高、辐射安全隐患大、检测过程中样品破坏性大、无法满足核燃料元件快速检测的实际需求的问题。In view of the deficiencies pointed out in the above background technology, the present invention provides a nuclear fuel rod²³⁵ U enrichment and uniformity detection device and a detection method based on a compact DD neutron source, aiming at solving the existing nuclear fuel²³⁵ U pellets The detection process of enrichment uniformity is complicated, the detection speed is slow, the sensitivity is not high, the hidden danger of radiation safety is great, the sample is destructive during the detection process, and it cannot meet the actual needs of rapid detection of nuclear fuel elements.

为实现上述目的，本发明采用的技术方案是：For achieving the above object, the technical scheme adopted in the present invention is:

一种基于紧凑型D-D中子源的核燃料棒²³⁵U富集度及均匀性检测装置，包括紧凑型D-D中子源、中子慢化体、γ屏蔽体、核燃料棒传送孔道及γ探测器系统，所以紧凑型D-D中子源外包裹一定厚度的含氢中子慢化体，所述中子慢化体的外围包裹γ屏蔽体，保证装置外围的辐射安全性能，屏蔽体外表面30cm处的环境辐射剂量当量率小于2.5μSv/h的国家安全标准。所述紧凑型D-D中子源上方一定距离处的中子慢化体上水平设置核燃料棒传送孔道，用于在线传送核燃料棒，所述核燃料棒传送孔道的末端安装高探测效率的γ探测器系统。A nuclear fuel rod²³⁵ U enrichment and uniformity detection device based on a compact DD neutron source, including a compact DD neutron source, a neutron moderator, a gamma shield, a nuclear fuel rod transmission channel and a gamma detector system , so the compact DD neutron source is wrapped with a hydrogen-containing neutron moderator with a certain thickness, and the neutron moderator is surrounded by a gamma shield to ensure the radiation safety performance of the device and shield the environment 30cm from the outer surface. The radiation dose equivalent rate is less than the national safety standard of 2.5μSv/h. A nuclear fuel rod transfer channel is horizontally arranged on the neutron moderator at a certain distance above the compact DD neutron source for online transfer of nuclear fuel rods, and a high detection efficiency gamma detector system is installed at the end of the nuclear fuel rod transfer channel .

优选地，所述γ探测器系统采用二单元BGO闪烁体γ探测器系统，γ探测器固有探测效率大于90％(200keV-2MeV)。Preferably, the γ detector system adopts a two-unit BGO scintillator γ detector system, and the inherent detection efficiency of the γ detector is greater than 90% (200keV-2MeV).

优选地，所述γ探测器系统包括BGO晶体、光电倍增管、钨材料和铅屏蔽层，所述核燃料棒传送孔道穿过BGO晶体，沿核燃料棒传送孔道的长度方向在所述BGO晶体的前后两侧设置钨材料做γ准直器，所述BGO晶体上方为光电倍增管，所述BGO晶体、光电倍增管和钨材料置于铅屏蔽层中。Preferably, the gamma detector system includes a BGO crystal, a photomultiplier tube, a tungsten material and a lead shielding layer, and the nuclear fuel rod conveying channel passes through the BGO crystal, and is before and after the BGO crystal along the length direction of the nuclear fuel rod conveying channel A tungsten material is arranged on both sides as a gamma collimator, a photomultiplier tube is placed above the BGO crystal, and the BGO crystal, the photomultiplier tube and the tungsten material are placed in a lead shielding layer.

优选地，所述中子慢化体的厚度为15cm。Preferably, the thickness of the neutron moderator is 15 cm.

优选地，所述核燃料棒传送孔道设置于紧凑型D-D中子源上方距离紧凑型D-D中子源15-18cm处。Preferably, the nuclear fuel rod transfer channel is arranged above the compact D-D neutron source at a distance of 15-18 cm from the compact D-D neutron source.

本发明还提供了基于紧凑型D-D中子源的核燃料棒²³⁵U富集度及均匀性检测方法，采用紧凑型D-D中子源提供外源中子，在紧凑型D-D中子源外包裹含氢中子慢化体，在中子慢化体外围包裹γ屏蔽体，经中子慢化体慢化将2.45MeV的D-D快中子慢化为热中子或超热中子，并在紧凑型D-D中子源上方中子慢化体中设置的核燃料棒传送孔道内形成热中子场，利用热中子诱发核燃料中²³⁵U发生裂变反应，产生的高激发态裂变产物通过β-衰变的方式退激发，释放出大量γ射线，通过核燃料棒传送孔道末端设置的γ探测器系统测量裂变退激γ射线强度，实现对核燃料棒²³⁵U富集度的测量及均匀性的检测。The invention also provides a method for detecting the²³⁵ U enrichment and uniformity of nuclear fuel rods based on the compact DD neutron source. Neutron moderator, a gamma shield is wrapped around the neutron moderator, and the 2.45MeV DD fast neutron is moderated into thermal neutron or epithermal neutron by the neutron moderator. A thermal neutron field is formed in the transmission channel of the nuclear fuel rod set in the neutron moderator above the DD neutron source. The thermal neutron is used to induce²³⁵ U in the nuclear fuel to undergo a fission reaction, and the resulting highly excited fission products pass through β-decay. After de-excitation, a large amount of γ-rays are released, and the intensity of fission-de-excited γ-rays is measured by the γ detector system installed at the end of the nuclear fuel rod transmission channel, so as to realize the measurement of²³⁵ U enrichment and the detection of uniformity of nuclear fuel rods.

本发明进一步提供了上述基于紧凑型D-D中子源的核燃料棒²³⁵U富集度及均匀性检测装置在核燃料棒²³⁵U富集度及均匀性检测方面的应用。The present invention further provides the application of the above-mentioned compact DD neutron source-based detection device for²³⁵ U enrichment and uniformity in nuclear fuel rods in the detection of²³⁵ U enrichment and uniformity in nuclear fuel rods.

相比于现有技术的缺点和不足，本发明具有以下有益效果：Compared with the shortcomings and deficiencies of the prior art, the present invention has the following beneficial effects:

本发明提供一种基于紧凑型D-D中子源的核燃料棒²³⁵U富集度及均匀性检测装置及其检测方法，采用主动热中子诱发²³⁵U裂变的退激γ射线测量技术对核燃料棒²³⁵U芯块富集度及均匀性分布开展研究，实验测量核燃料棒²³⁵U富集度分布，并检测同一燃料棒中是否混入异常芯块。该检测装置能满足在线检测的要求，具有检测速度快、灵敏度高、样品无损伤等特点，具备检测出²³⁵U富集度±1％异常芯块的能力，保障我国核能安全、经济、高效、可靠发展。The invention provides a²³⁵ U enrichment and uniformity detection device and a detection method for a nuclear fuel rod based on a compact DD neutron source. The de-excited γ-ray measurement technology of active thermal neutron-induced²³⁵ U fission is used to measure the²³⁵ U of a nuclear fuel rod. Carry out research on the enrichment and uniformity distribution of U pellets, experimentally measure the distribution of²³⁵ U enrichment in nuclear fuel rods, and detect whether abnormal pellets are mixed in the same fuel rod. The detection device can meet the requirements of online detection, has the characteristics of fast detection speed, high sensitivity, no damage to samples, etc., and has the ability to detect abnormal pellets with a concentration of²³⁵ U ±1%, ensuring the safety, economy, efficiency, and safety of nuclear energy in China. Reliable development.

附图说明Description of drawings

图1是本发明实施例提供的基于紧凑型D-D中子源的核燃料棒²³⁵U富集度及均匀性检测装置的结构示意图。FIG. 1 is a schematic structural diagram of a device for detecting²³⁵ U enrichment and uniformity of nuclear fuel rods based on a compact DD neutron source provided by an embodiment of the present invention.

图2是本发明实施例提供的γ探测器系统的结构示意图。FIG. 2 is a schematic structural diagram of a gamma detector system provided by an embodiment of the present invention.

图中：1-紧凑型D-D中子源；2-中子慢化体；3-γ屏蔽体；4-核燃料棒传送孔道；5-γ探测器系统；501-BGO晶体；502-光电倍增管；503-钨材料；504-铅屏蔽层。In the figure: 1-compact D-D neutron source; 2-neutron moderator; 3-gamma shield; 4-nuclear fuel rod transmission channel; 5-gamma detector system; 501-BGO crystal; 502-photomultiplier tube ; 503-tungsten material; 504-lead shielding layer.

具体实施方式Detailed ways

为了使本发明的目的、技术方案及优点更加清楚明白，以下结合附图及实施例，对本发明进行进一步详细说明。应当理解，此处所描述的具体实施例仅仅用以解释本发明，并不用于限定本发明。In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

参照图1，基于紧凑型D-D中子源的核燃料棒²³⁵U富集度及均匀性检测装置，包括紧凑型D-D中子源1、中子慢化体2、γ屏蔽体3、核燃料棒传送孔道4及γ探测器系统5，采用辐射安全性能好、可移动式、紧凑型D-D中子源1提供外源中子，D-D中子产额大于10⁹n/s，中子输出稳定度高于99％，紧凑型D-D中子源1外包裹15cm厚的含氢中子慢化体2(含硼聚乙烯)，能有效地将2.45MeV的D-D快中子慢化为热中子，热中子占比大于85％，紧凑型D-D中子源1置于含氢中子慢化体2的中间位置，紧凑型D-D中子源1上方15-18cm高处的中子慢化体2中设置核燃料棒传送孔道4，用于在线传送核燃料棒，核燃料棒传送孔道4的末端安装高探测效率的γ探测器系统5，中子慢化体2的外围包裹γ屏蔽体3，保证装置外围的辐射安全性能。整套装置长为1.8m，直径为

Referring to Figure 1, the²³⁵ U enrichment and uniformity detection device for nuclear fuel rods based on a compact DD neutron source includes a compactDD neutron source 1, aneutron moderator 2, a gamma shield 3, and a nuclear fuelrod transmission channel 4 andγ detector system 5, adopting the portable and compactDD neutron source 1 with good radiation safety performance to provide external neutrons, the DD neutron yield is greater than 10⁹ n/s, and the neutron output stability is higher than 99%, the compactDD neutron source 1 is wrapped with a 15cm thick hydrogen-containing neutron moderator 2 (boron-containing polyethylene), which can effectively moderate 2.45MeV DD fast neutrons into thermal neutrons. The proportion of neutrons is greater than 85%, the compactDD neutron source 1 is placed in the middle position of the hydrogen-containingneutron moderator 2, and the compactDD neutron source 1 is placed in theneutron moderator 2 at a height of 15-18cm. The nuclear fuelrod transfer channel 4 is used for online transfer of nuclear fuel rods. A high detection efficiencygamma detector system 5 is installed at the end of the nuclear fuelrod transfer channel 4. Theneutron moderator 2 is surrounded by a gamma shielding body 3 to ensure the radiation outside the device. safety performance. The whole device is 1.8m long and has a diameter of

中子慢化体2将2.45MeV的D-D快中子慢化为热中子或超热中子，慢化后传送孔道内平均中子通量大于10⁵n/(cm²·s)，热中子-超热中子占比大于85％；中子慢化体2中设置的核燃料棒传送孔道4内形成热中子场；燃料棒以一定速度通过核燃料棒传送孔道4，热中子诱发核燃料中²³⁵U发生裂变反应，产生高激发态的裂变产物，高激发态的裂变产物通过β^-衰变的方式退激发，释放出大量γ射线(裂变退激γ射线)；在中子源强度、辐照时间和冷却时间一定的条件下，裂变退激γ射线强度与²³⁵U富集度成正相关；通过核燃料棒传送孔道4末端设置的γ探测器系统5测量裂变退激γ射线强度，实现对核燃料棒²³⁵U富集度的测量及均匀性的检测；整体外围采用γ屏蔽体包裹，屏蔽体外表面30cm处的环境辐射剂量当量率小于2.5μSv/h的国家安全标准。本装置具备检测出²³⁵U富集度±1％异常芯块的能力，且检测置信度大于98％。Neutron moderator² moderates^2.45MeV DD fast neutrons into thermal neutrons or epithermal neutrons. Neutron-epithermal neutrons account for more than 85%; a thermal neutron field is formed in the nuclear fuelrod transmission channel 4 set in theneutron moderator 2; the fuel rod passes through the nuclear fuelrod transmission channel 4 at a certain speed, and thermal neutrons induce The²³⁵ U in the nuclear fuel undergoes a fission reaction, producing highly excited fission products, which are de-excited by β^- decay, releasing a large amount of gamma rays (fission de-excited gamma rays); Under certain conditions of irradiation time and cooling time, the intensity of fission de-excited γ-rays is positively correlated with the enrichment degree of²³⁵ U; the γ-ray intensity of fission de-excited γ-rays is measured by the γ-detector system 5 set at the end of the nuclear fuelrod transmission channel 4 to realize the detection of fission de-excited γ-rays. Measurement of²³⁵ U enrichment in nuclear fuel rods and detection of uniformity; the entire periphery is wrapped with a gamma shield, and the environmental radiation dose equivalent rate at 30cm on the outer surface of the shield is less than 2.5μSv/h National safety standard. The device has the ability to detect abnormal pellets with²³⁵ U enrichment ±1%, and the detection confidence is greater than 98%.

为了提高裂变退激γ射线在线测量计数，本发明提出了贯穿式、二单元、高探测效率BGO闪烁体γ探测器系统，参照图2，γ探测器系统5包括BGO晶体501、光电倍增管502、钨材料503和铅屏蔽层504，BGO晶体对燃料棒所张立体角接近4π，单位时间内释放的γ光子几乎全部进入到BGO晶体。核燃料棒传送孔道4穿过BGO晶体501，同时，为了降低γ射线在两个探测器中的串扰问题，沿核燃料棒传送孔道4的长度方向在BGO晶体501的前后两侧设置钨材料503做γ准直器，BGO晶体501上方为光电倍增管502，BGO晶体501、光电倍增管502和钨材料503置于铅屏蔽层504中。γ探测器固有探测效率大于90％(200keV-2MeV)。In order to improve the online measurement and counting of fission de-excited γ-rays, the present invention proposes a through-type, two-unit, high detection efficiency BGO scintillator γ detector system. Referring to FIG. 2 , theγ detector system 5 includes a BGO crystal 501 and aphotomultiplier tube 502 ,tungsten material 503 andlead shielding layer 504, the solid angle of the BGO crystal to the fuel rod is close to 4π, and almost all the γ photons released per unit time enter the BGO crystal. The nuclear fuelrod transmission channel 4 passes through the BGO crystal 501. At the same time, in order to reduce the crosstalk problem of gamma rays in the two detectors,tungsten materials 503 are arranged on the front and rear sides of theBGO crystal 501 along the length direction of the nuclear fuelrod transmission channel 4 to make gamma rays. The collimator, above theBGO crystal 501 is aphotomultiplier tube 502 , theBGO crystal 501 , thephotomultiplier tube 502 and thetungsten material 503 are placed in thelead shielding layer 504 . The intrinsic detection efficiency of the gamma detector is greater than 90% (200keV-2MeV).

以上所述仅为本发明的较佳实施例而已，并不用以限制本发明，凡在本发明的精神和原则之内所作的任何修改、等同替换和改进等，均应包含在本发明的保护范围之内。The above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included in the protection of the present invention. within the range.

Claims (7)

1. Nuclear fuel rod based on D-D neutron source²³⁵The device for detecting the U enrichment and the uniformity is characterized by comprising a compact D-D neutron source, a neutron moderating body, a gamma shield, a nuclear fuel rod conveying pore channel and a gamma detector system, wherein the compact D-D neutron source is externally wrapped with a hydrogen-containing neutron moderating body with a certain thickness, the gamma shield is wrapped at the periphery of the neutron moderating body,and a nuclear fuel rod conveying pore channel is arranged in the neutron moderating body at a certain distance above the compact D-D neutron source and used for conveying nuclear fuel rods on line, and a gamma detector system is arranged at the tail end of the nuclear fuel rod conveying pore channel.

2. The nuclear fuel rod based on a D-D neutron source of claim 1²³⁵The device for detecting the U enrichment degree and the uniformity is characterized in that a two-unit BGO scintillator gamma detector system is adopted by the gamma detector system.

3. The nuclear fuel rod based on a D-D neutron source of claim 1²³⁵The device for detecting the U enrichment and the uniformity is characterized in that the gamma detector system comprises a BGO crystal, a photomultiplier, a tungsten material and a lead shielding layer, a nuclear fuel rod conveying pore passage penetrates through the BGO crystal, the tungsten material serving as gamma collimators are arranged on the front side and the rear side of the BGO crystal along the length direction of the nuclear fuel rod conveying pore passage, the photomultiplier is arranged above the BGO crystal, and the BGO crystal, the photomultiplier and the tungsten material are arranged in the lead shielding layer.

4. The nuclear fuel rod based on a D-D neutron source of claim 1²³⁵The device for detecting the U enrichment degree and the uniformity is characterized in that the thickness of the neutron moderating body is 15 cm.

5. The nuclear fuel rod based on a D-D neutron source of claim 1²³⁵The device for detecting the U enrichment degree and the uniformity is characterized in that the nuclear fuel rod conveying pore channel is arranged above the compact D-D neutron source and is 15-18cm away from the compact D-D neutron source.

6. Nuclear fuel rod based on a D-D neutron source as claimed in any one of claims 1 to 5²³⁵The detection method of the device for detecting the U enrichment and the uniformity is characterized in that a compact D-D neutron source is adopted to provide exogenous neutrons, a hydrogen-containing neutron moderator is wrapped outside the compact D-D neutron source, a gamma shield is wrapped on the periphery of the neutron moderator, and 2.4 is wrapped by the neutron moderatorSlowing D-D fast neutrons of 5MeV into thermal neutrons or epithermal neutrons, forming a thermal neutron field in a nuclear fuel rod conveying channel arranged in a neutron slowing body above a compact D-D neutron source, and inducing the nuclear fuel by using the thermal neutrons²³⁵U is subjected to fission reaction, the generated high-excited-state fission product is inactivated in a beta-decay mode, a large amount of gamma rays are released, the intensity of the fission inactivated gamma rays is measured through a gamma detector system arranged at the tail end of a nuclear fuel rod conveying pore channel, and the nuclear fuel rod is subjected to fission reaction²³⁵Measuring U enrichment degree and detecting uniformity.

7. Nuclear fuel rod based on a D-D neutron source as claimed in any one of claims 1 to 5²³⁵Nuclear fuel rod with U enrichment and uniformity detection device²³⁵And (3) application in the aspects of U enrichment degree and uniformity detection.

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