CN111584111B - Dissolver for spent fuel element and processing method of dissolving liquid - Google Patents
Dissolver for spent fuel element and processing method of dissolving liquid Download PDFInfo
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- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 claims description 45
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- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 8
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- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 3
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- WJWSFWHDKPKKES-UHFFFAOYSA-N plutonium uranium Chemical compound [U].[Pu] WJWSFWHDKPKKES-UHFFFAOYSA-N 0.000 description 1
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- 229910002027 silica gel Inorganic materials 0.000 description 1
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
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- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
- G21F9/00—Treating radioactively contaminated material; Decontamination arrangements therefor
- G21F9/04—Treating liquids
- G21F9/06—Processing
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- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
- G21F9/00—Treating radioactively contaminated material; Decontamination arrangements therefor
- G21F9/02—Treating gases
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
- G21F9/00—Treating radioactively contaminated material; Decontamination arrangements therefor
- G21F9/28—Treating solids
- G21F9/30—Processing
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Abstract
Description
技术领域technical field
本发明涉及乏燃料后处理技术领域,具体涉及一种用于乏燃料元件的溶解器及溶解液的处理方法。The invention relates to the technical field of post-processing of spent fuel, in particular to a dissolver used for spent fuel elements and a method for processing dissolved liquid.
背景技术Background technique
乏燃料溶解是乏燃料后处理的第一道化学处理工艺。具体地,将乏燃料元件经过一定破碎剪切后形成短段、颗粒、粉末等形态,通过溶解将这些形态的固体乏燃料元件转化为溶液形式,制备出合格的溶解液,为之后的化学分离过程制备出合格料液。合格料液包含有许多要求,如对铀、酸的浓度有严格的限制,对重要核素的价态要求,对溶液中微小固体的粒径以及量限制等。因此,溶解工艺是整个乏燃料化学处理过程的重要起点,为之后的化学分离过程的稳定运行奠定基础。Dissolution of spent fuel is the first chemical treatment process for spent fuel reprocessing. Specifically, the spent fuel elements are crushed and sheared to form short segments, particles, powders, etc., and the solid spent fuel elements in these forms are converted into solutions by dissolving to prepare a qualified solution for subsequent chemical separation. Process to prepare qualified feed liquid. Qualified feed liquid contains many requirements, such as strict restrictions on the concentration of uranium and acid, requirements on the valence state of important nuclides, and restrictions on the particle size and quantity of tiny solids in the solution. Therefore, the dissolution process is an important starting point for the entire spent fuel chemical treatment process, laying the foundation for the stable operation of the subsequent chemical separation process.
上述乏燃料溶解液对后续萃取流程的萃取效果以及工艺的稳定运行具有重要的作用,在给后续萃取流程供料之前乏燃料溶解液要经过精细的“调料”过程。上述“调料”过程一般包括调价和除碘。The above-mentioned spent fuel dissolving liquid plays an important role in the extraction effect of the subsequent extraction process and the stable operation of the process. Before feeding the subsequent extraction process, the spent fuel dissolving liquid must undergo a fine "seasoning" process. The above-mentioned "seasoning" process generally includes price adjustment and iodine removal.
具体地,调价是对钚、镎等价态的调节。以调节钚的价态为例,需要将溶解过程产生的Pu(VI)(六价钚)还原为Pu(IV)(四价钚),因为Pu(VI)与Pu(IV)在后续的萃取分离工艺的萃取行为具有一定差异,通过将钚还原可以提高钚的分配比,有利于提高钚的回收率,达到较好的提取效果。在现有技术中,后处理厂通常做法是在溶解器之后额外设置调料槽,通过在保温条件下加入NaNO2或者NO2(N2O4)等试剂来达到调节钚价态的目的。Specifically, the price adjustment is the adjustment of the equivalence states of plutonium and neptunium. Taking the adjustment of the valence state of plutonium as an example, it is necessary to reduce Pu(VI) (hexavalent plutonium) produced in the dissolution process to Pu(IV) (tetravalent plutonium), because Pu(VI) and Pu(IV) are in the subsequent extraction process. The extraction behavior of the separation process has certain differences. By reducing the plutonium, the distribution ratio of plutonium can be increased, which is beneficial to improve the recovery rate of plutonium and achieve better extraction effect. In the prior art, the common practice of post-processing plants is to additionally set up a seasoning tank after the dissolver, and to adjust the plutonium valence state by adding reagents such as NaNO 2 or NO 2 (N 2 O 4 ) under thermal insulation conditions.
此外,还需要采用一定的工艺将溶解液中的碘离子转化为易挥发的单质碘除去,避免碘进入后续流程引起溶剂劣化、有机碘形成以及铀钚产品中碘超标等问题。在现有技术中,后处理厂通常做法是在溶解器之后额外设置除碘的专用设备,当溶解液从溶解器出来后该专用设备中通过鼓入空气、鼓入NO2的方法或者加入非放射性的KIO3来降低放射性碘浓度,从而实现除碘。In addition, it is also necessary to adopt a certain process to convert the iodide ions in the dissolved solution into volatile elemental iodine to remove, so as to avoid problems such as solvent deterioration, organic iodine formation and excessive iodine in uranium-plutonium products caused by iodine entering the subsequent process. In the prior art, the common practice of post - processing plants is to additionally set up special equipment for removing iodine after the dissolver. Radioactive KIO 3 to reduce the concentration of radioactive iodine, thereby achieving iodine removal.
然而,上述现有技术中,无论是调价还是除碘都需要在溶解器外部额外设置专用设备来进行这些操作,整个系统的结构复杂,运行成本较高。However, in the above-mentioned prior art, both price adjustment and iodine removal require additional special equipment outside the dissolver to carry out these operations, the structure of the entire system is complex, and the operating cost is relatively high.
发明内容SUMMARY OF THE INVENTION
本发明的主要目的在于提供一种用于乏燃料元件的溶解器及溶解液的处理方法,以解决现有技术中对乏燃料溶解液料液调节需要在溶解器外部额外设置专用设备,结构复杂,运行成本较高的问题。The main purpose of the present invention is to provide a dissolver for spent fuel elements and a method for processing the dissolving liquid, so as to solve the problem that the adjustment of the dissolving liquid of spent fuel in the prior art requires additional special equipment outside the dissolver, and the structure is complex , the problem of higher operating costs.
为实现上述目的,根据本发明的一个方面,提供了一种用于乏燃料元件的溶解器,包括:外壳,内部具有空腔,空腔内设有相互连通的溶解区和溶解液缓冲区;工艺通料口,与溶解液缓冲区连通,通过工艺通料口向溶解液缓冲区内通入用于乏燃料溶解液调价和/或除碘的工艺原料;保温装置,用于使溶解液缓冲区的温度满足预设温度条件。In order to achieve the above object, according to one aspect of the present invention, a dissolver for spent fuel elements is provided, comprising: an outer shell with a cavity inside, and the cavity is provided with a dissolving zone and a dissolving liquid buffer zone that communicate with each other; The process feed port is connected to the dissolving liquid buffer, and the process raw materials for adjusting the price of spent fuel dissolving liquid and/or removing iodine are passed into the dissolving liquid buffer through the process feeding port; the heat preservation device is used for buffering the dissolving liquid The temperature of the zone meets the preset temperature conditions.
进一步地,还包括:尾气出口,与空腔连通;尾气净化系统,尾气净化系统的第一侧与尾气出口连通,尾气净化系统的第二侧与工艺通料口连通,由尾气出口排出的溶解尾气至少部分经过尾气净化系统净化得到氮氧化物气体,氮氧化物气体的至少部分作为工艺原料由工艺通料口通入溶解液缓冲区。Further, it also includes: a tail gas outlet, which is communicated with the cavity; a tail gas purification system, the first side of the tail gas purification system is communicated with the tail gas outlet, and the second side of the tail gas purification system is communicated with the process feed port, and the dissolved gas discharged from the tail gas outlet is dissolved. At least part of the tail gas is purified by the tail gas purification system to obtain nitrogen oxide gas, and at least part of the nitrogen oxide gas is passed into the solution buffer buffer through the process feed port as a process raw material.
进一步地,尾气净化系统包括碘吸附装置和/或气液分离装置。Further, the exhaust gas purification system includes an iodine adsorption device and/or a gas-liquid separation device.
进一步地,还包括后续尾气处理系统和气体分配装置,气体分配装置具有气体进口、第一气体出口以及第二气体出口,气体进口与尾气净化系统的第二侧连通,第一气体出口与工艺通料口连通,第二气体出口与后续尾气处理系统连通。Further, it also includes a subsequent tail gas treatment system and a gas distribution device, the gas distribution device has a gas inlet, a first gas outlet and a second gas outlet, the gas inlet communicates with the second side of the tail gas purification system, and the first gas outlet communicates with the process. The material port is communicated, and the second gas outlet is communicated with the subsequent tail gas treatment system.
进一步地,还包括鼓泡装置,工艺通料口与鼓泡装置连通,鼓泡装置至少部分位于溶解液缓冲区内。Further, a bubbling device is also included, the process feed opening is communicated with the bubbling device, and the bubbling device is at least partially located in the buffer zone of the solution.
进一步地,鼓泡装置包括鼓泡管和连接管,连接管连接在工艺通料口和鼓泡管之间,鼓泡管位于溶解液缓冲区内,鼓泡管上设有多个鼓泡孔,多个鼓泡孔沿鼓泡管的延伸方向间隔设置,各鼓泡孔的开孔方向朝向溶解液缓冲区的底壁。Further, the bubbling device includes a bubbling pipe and a connecting pipe, the connecting pipe is connected between the process material feed port and the bubbling pipe, the bubbling pipe is located in the buffer buffer of the solution, and the bubbling pipe is provided with a plurality of bubbling holes. , a plurality of bubbling holes are arranged at intervals along the extending direction of the bubbling tube, and the opening direction of each bubbling hole faces the bottom wall of the solution buffer zone.
进一步地,鼓泡管靠近溶解液缓冲区的底壁设置,鼓泡管的各个位置与溶解液缓冲区的底壁之间的距离均相等。Further, the bubbling tube is arranged close to the bottom wall of the lysate buffer zone, and the distances between each position of the bubbling tube and the bottom wall of the lysate buffer zone are equal.
进一步地,还包括:溶解液出口,与空腔的端部连通,溶解液缓冲区靠近溶解液出口设置;挡流件,位于溶解液缓冲区内并靠近溶解液出口。Further, it also includes: a dissolving liquid outlet communicated with the end of the cavity, and a dissolving liquid buffer zone is arranged near the dissolving liquid outlet; a flow blocking member is located in the dissolving liquid buffer zone and close to the dissolving liquid outlet.
根据本发明的另一个方面,提供了一种应用上述溶解器处理乏燃料溶解液的处理方法,包括以下步骤:步骤S10:将乏燃料元件和溶剂加入至溶解器内的溶解区进行溶解,溶解生成的乏燃料溶解液进入溶解液缓冲区;步骤S20:使溶解液缓冲区的温度满足预设温度条件;步骤S30:向溶解液缓冲区内通入用于乏燃料溶解液调价和/或除碘的工艺原料;步骤S40:得到合格的乏燃料溶解液;其中,步骤S20和步骤S30顺序并不固定。According to another aspect of the present invention, a method for treating spent fuel dissolving liquid by applying the dissolver is provided, comprising the following steps: Step S10: adding spent fuel elements and a solvent to a dissolving zone in the dissolver for dissolving, dissolving The generated spent fuel dissolving liquid enters the dissolving liquid buffer; Step S20: Make the temperature of the dissolving buffer meet the preset temperature condition; Step S30: Passing the dissolving liquid into the dissolving buffer for price adjustment and/or removal of spent fuel The process raw material of iodine; Step S40: obtaining a qualified spent fuel dissolving solution; wherein, the sequence of steps S20 and S30 is not fixed.
进一步地,溶解器还包括尾气净化系统,步骤S30还包括:乏燃料元件和溶剂溶解产生的溶解尾气至少部分经过尾气净化系统净化得到氮氧化物气体,氮氧化物气体的至少部分作为用于乏燃料溶解液调价和/或除碘的工艺原料通入溶解液缓冲区内。Further, the dissolver also includes a tail gas purification system, and step S30 further includes: at least part of the dissolved tail gas generated by dissolving the spent fuel element and the solvent is purified by the tail gas purification system to obtain nitrogen oxide gas, and at least part of the nitrogen oxide gas is used for spent fuel. The process raw materials for fuel dissolving liquid price adjustment and/or iodine removal are passed into the dissolving liquid buffer.
进一步地,步骤S20还包括:使溶解液缓冲区的温度满足第一预设温度条件,其中,第一预设温度条件为温度大于等于60℃小于等于90℃;步骤S30还包括:向溶解液缓冲区内通入用于乏燃料溶解液调价的工艺原料。Further, step S20 further includes: making the temperature of the buffer buffer of the dissolving solution meet a first preset temperature condition, wherein the first preset temperature condition is that the temperature is greater than or equal to 60°C and less than or equal to 90°C; step S30 further includes: adding a temperature to the dissolving solution Process raw materials for adjusting the price of spent fuel solution are passed into the buffer zone.
进一步地,步骤S20还包括:使溶解液缓冲区的温度满足第二预设温度条件,其中,第二预设温度条件为温度大于等于50℃小于等于90℃;步骤S30还包括:向溶解液缓冲区内通入用于乏燃料溶解液除碘的工艺原料。Further, step S20 further includes: making the temperature of the buffer buffer of the dissolving solution meet a second preset temperature condition, wherein the second preset temperature condition is that the temperature is greater than or equal to 50°C and less than or equal to 90°C; step S30 further includes: adding a temperature to the dissolving solution Process raw materials for removing iodine from spent fuel dissolving liquid are passed into the buffer zone.
进一步地,步骤S20还包括:使溶解液缓冲区的温度满足第三预设温度条件,其中,第三预设温度条件为温度大于等于80℃小于等于90℃;步骤S30还包括:向溶解液缓冲区内通入用于乏燃料溶解液调价和除碘的工艺原料。Further, step S20 further includes: making the temperature of the buffer buffer of the dissolving solution meet a third preset temperature condition, wherein the third preset temperature condition is that the temperature is greater than or equal to 80°C and less than or equal to 90°C; step S30 further includes: adding a temperature to the dissolving solution Process raw materials for adjusting the price of spent fuel solution and removing iodine are passed into the buffer zone.
应用本发明的技术方案,在空腔内设置溶解区和溶解液缓冲区,乏燃料元件和溶剂在溶解区进行溶解,溶解生成的乏燃料溶解液进入溶解液缓冲区。将上述溶解液缓冲区作为调价和/或除碘工艺实施的场所,保温装置使溶解液缓冲区的温度满足预设温度条件,通过工艺通料口向溶解液缓冲区内通入工艺原料,从而实现在溶解液缓冲区进行乏燃料溶解液的调价和/或除碘。上述结构充分合理利用溶解器内部空间,无需增加额外的专用设备,只需再加入工艺原料即可在溶解器内乏燃料元件溶解的同时实现对乏燃料溶解液的进一步处理,也就是实现溶解、调价与除碘同步完成,从而简化乏燃料后处理首端工艺,简化结构设备,降低运行成本。此外,在溶解液缓冲区内还能够混匀液体,并且尽量使溶液中的固体残渣沉降,得到的溶解液质量更好。By applying the technical scheme of the present invention, a dissolving area and a dissolving liquid buffer area are arranged in the cavity, the spent fuel elements and the solvent are dissolved in the dissolving area, and the dissolving liquid generated by dissolving the spent fuel enters the dissolving liquid buffer area. The above-mentioned solubilizing solution buffer zone is used as a place where the price adjustment and/or iodine removal process is implemented, and the temperature of the solubilizing solution buffer zone meets the preset temperature condition by the thermal insulation device, and the process raw materials are introduced into the solubilizing solution buffer zone through the process feeding port, thereby Realize price adjustment and/or iodine removal of spent fuel lysate in the lysate buffer. The above structure makes full and reasonable use of the internal space of the dissolver, and does not need to add additional special equipment. It only needs to add process raw materials to realize the further processing of the spent fuel dissolved liquid while dissolving the spent fuel elements in the dissolver. The price adjustment and iodine removal are completed simultaneously, thereby simplifying the head-end process of spent fuel reprocessing, simplifying the structure and equipment, and reducing operating costs. In addition, the liquid can be mixed evenly in the buffer buffer of the solution, and the solid residue in the solution can be settled as much as possible, so that the quality of the obtained solution is better.
附图说明Description of drawings
通过下文中参照附图对本发明所作的描述,本发明的其它目的和优点将显而易见,并可帮助对本发明有全面的理解。Other objects and advantages of the present invention will be apparent from the following description of the present invention with reference to the accompanying drawings, and may assist in a comprehensive understanding of the present invention.
图1是根据本发明一个实施例的用于乏燃料元件的溶解器的主体部分剖视示意图;1 is a schematic cross-sectional view of a main body of a dissolver for spent fuel elements according to an embodiment of the present invention;
图2是图1的溶解器的盒体等下半部结构的剖视示意图;Fig. 2 is a schematic cross-sectional view of a lower half structure such as a box body of the dissolver of Fig. 1;
图3是图2的溶解器的盒体等下半部结构的俯视示意图;Fig. 3 is the top view schematic diagram of the lower half structure such as the box body of the dissolver of Fig. 2;
图4是图2的溶解器的盒体等下半部结构的侧视示意图;Fig. 4 is the side view schematic diagram of the lower half structure such as the box body of the dissolver of Fig. 2;
图5是图2的溶解器的A-A向剖视图;Fig. 5 is the A-A sectional view of the dissolver of Fig. 2;
图6是图4的溶解器的B-B向剖视图;Fig. 6 is the B-B sectional view of the dissolver of Fig. 4;
图7是图1的溶解器的盖体等上半部结构的剖视示意图;FIG. 7 is a schematic cross-sectional view of the upper half of the structure such as the cover of the dissolver of FIG. 1;
图8是图7的溶解器的盖体等上半部结构的俯视示意图;8 is a schematic plan view of an upper half structure such as a cover of the dissolver of FIG. 7;
图9是图1的溶解器的鼓泡装置的结构示意图;Fig. 9 is the structural representation of the bubbling device of the dissolver of Fig. 1;
图10是图9的鼓泡装置的侧视示意图;Figure 10 is a schematic side view of the bubbling device of Figure 9;
图11是图9的鼓泡装置的C-C向剖视图;Fig. 11 is the C-C sectional view of the bubbling device of Fig. 9;
图12是图1的溶解器的整体(主体部分、气体分配装置以及尾气净化系统)结构示意图;以及FIG. 12 is a schematic diagram of the structure of the dissolver of FIG. 1 as a whole (the main body, the gas distribution device, and the exhaust gas purification system); and
图13是根据本发明一个实施例的溶解液的处理方法的工艺流程示意图。FIG. 13 is a schematic process flow diagram of a method for treating a dissolving solution according to an embodiment of the present invention.
需要说明的是,附图并不一定按比例来绘制,而是仅以不影响读者理解的示意性方式示出。It should be noted that the accompanying drawings are not necessarily drawn to scale, but are only shown in a schematic manner that does not affect the reader's understanding.
附图标记说明:Description of reference numbers:
11、盒体;12、盖体;20、溶解区;30、溶解液缓冲区;40、工艺通料口;50、尾气出口;61、碘吸附装置;62、气液分离装置;70、气体分配装置;71、气体进口;72、第一气体出口;73、第二气体出口;80、鼓泡装置;81、鼓泡管;811、鼓泡孔;82、连接管;90、溶解液出口;100、挡流件;110、物料进口;120、溶剂进口;130、废包壳出口;140、排渣口;150、送料结构。11. Box body; 12. Cover body; 20. Dissolution zone; 30. Dissolution buffer zone; 40. Process feed port; 50. Exhaust gas outlet; 61. Iodine adsorption device; 62. Gas-liquid separation device; 70. Gas Distribution device; 71, gas inlet; 72, first gas outlet; 73, second gas outlet; 80, bubbling device; 81, bubbling tube; 811, bubbling hole; 82, connecting pipe; 90, solution outlet ; 100, baffle; 110, material inlet; 120, solvent inlet; 130, waste cladding outlet; 140, slag outlet; 150, feeding structure.
具体实施方式Detailed ways
为使本发明的目的、技术方案和优点更加清楚,下面将结合本发明实施例的附图,对本发明的技术方案进行清楚、完整地描述。显然,所描述的实施例是本发明的一个实施例,而不是全部的实施例。基于所描述的本发明的实施例,本领域普通技术人员在无需创造性劳动的前提下所获得的所有其他实施例,都属于本发明保护的范围。In order to make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiment is one, but not all, of the embodiments of the present invention. Based on the described embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.
除非另外定义,本发明使用的技术术语或者科学术语应当为本发明所属领域内具有一般技能的人士所理解的通常意义。Unless otherwise defined, technical or scientific terms used in the present invention should have the ordinary meaning as understood by one of ordinary skill in the art to which the present invention belongs.
如图1至图8所示,本实施例的用于乏燃料元件的溶解器包括外壳、物料进口110、溶剂进口120、废包壳出口130、排渣口140、送料结构150、溶解液出口90、工艺通料口40以及保温装置。其中,外壳包括盒体11和盖设在盒体11上的盖体12,外壳内部具有空腔,送料结构150设置在空腔内,物料进口110与送料结构150的第一端连通,溶剂进口120、废包壳出口130均与送料结构150的第二端连通,溶解液出口90、排渣口140均与空腔靠近送料结构150的第一端的端部连通。空腔内设有相互连通的溶解区20和溶解液缓冲区30。工艺通料口40与溶解液缓冲区30连通。通过工艺通料口40向溶解液缓冲区30内通入用于乏燃料溶解液调价和除碘的工艺原料。保温装置用于使溶解液缓冲区30的温度满足预设温度条件,该预设温度条件为对乏燃料溶解液调价和除碘时所需的温度范围。保温装置为设置在壳体底部外围的保温夹套,采用水浴(蒸汽)或者电加热的方式可以实现对溶解液缓冲区30的温度控制。As shown in FIGS. 1 to 8 , the dissolver for spent fuel elements in this embodiment includes a casing, a
如图1、图2、图5以及图12所示,本实施例的溶解器还包括挡流件100。空腔对应送料结构150的区域形成溶解区20,送料结构150的端面与溶解液出口90之间形成溶解液缓冲区30。挡流件100位于溶解液缓冲区30内并靠近溶解液出口90。挡流件100可以加强液体从送料结构150流出到从溶解液出口90流出过程的折流,从而进一步增强缓冲效果。并且尽量使溶液中的固体残渣沉降,得到的溶解液质量更好As shown in FIG. 1 , FIG. 2 , FIG. 5 and FIG. 12 , the dissolver of this embodiment further includes a
在本实施例中,挡流件100为挡流板,该挡流板的两个侧边与空腔的两个侧壁紧密连接,该挡流板的底边与空腔的底壁之间具有一定缝隙,这样可以保证料液调节后的溶解液能够最终从溶解液出口90流出。上述通过挡流件100隔出溶解液缓冲区30的方式结构更加简单,并且易于加工和安装。当然,溶解液缓冲区30形成的方式不限于此,在图中未示出的其他实施方式中,溶解液缓冲区可以由其他结构形成,只要保证溶解液缓冲区能够与溶解区连通、并且溶解液缓冲区内的溶解液能够取出即可。例如,溶解液缓冲区可以由多个围板围成,至少一个围板上具有过流孔。此外,挡流件100也不限于挡流板,在其他实施方式中,也可以为其他形式的挡流件,例如隔网等。In this embodiment, the
当溶解器开始工作时,乏燃料元件从物料进口110进入到送料结构150的第一端,并在送料结构150的转动下逐渐移动至送料结构150的第二端。在此过程中,从溶剂进口120进入的溶剂(硝酸)在送料结构150中(溶解区20)与乏燃料元件逆流接触。乏燃料元件中可溶的芯块或粉末被溶解进入硝酸溶液中形成溶解液,该溶解液流入空腔并进入溶解液缓冲区30。乏燃料元件中不溶的包壳移动送料结构150的第二端并从废包壳出口130排出。When the dissolver starts to work, the spent fuel elements enter the first end of the
应用本实施例的溶解器,在空腔内设置溶解区20和溶解液缓冲区30,乏燃料元件和溶剂在溶解区20进行溶解,溶解生成的乏燃料溶解液进入溶解液缓冲区30。将上述溶解液缓冲区30作为调价和除碘工艺实施的场所,保温装置使溶解液缓冲区30的温度满足预设温度条件,通过工艺通料口40向溶解液缓冲区30内通入工艺原料,从而实现在溶解液缓冲区30进行乏燃料溶解液的调价和除碘。合格的乏燃料溶解液最终从溶解液出口90流出。上述结构充分合理利用溶解器内部空间,无需增加额外的专用设备,只需再加入工艺原料即可在溶解器内乏燃料元件溶解的同时实现对乏燃料溶解液的进一步处理,也就是实现溶解、调价与除碘同步完成,从而简化乏燃料后处理首端工艺,简化结构设备,降低运行成本。Using the dissolver of this embodiment, a dissolving
此外,设计溶解液缓冲区30的主要目的有:In addition, the main purposes of designing the
首先,作为溶解液的缓冲空间可以消除由送料结构150流出的溶解液的浓度波动,使流出的溶解液保持一个平稳的数值。送料结构150流出的溶解液受固体物料投料影响,固体物料中的粉末溶解比较快,每次固体物料落入送料结构150会伴随一个短暂的送料结构150出液浓度升高。通过设置溶解液缓冲区30可以消除这种波动。First, as the buffer space for the dissolving liquid, the concentration fluctuation of the dissolving liquid flowing out from the feeding
其次,刚加入的固体物料芯块中的细小粉末会部分穿过送料结构150的包裹壳上的出液部,利用溶解液缓冲区30可以将这一部分未完全溶解的粉末进行溶解。Secondly, the fine powder in the newly added solid material pellets will partially pass through the liquid outlet on the envelope shell of the
需要说明的是,乏燃料溶解液的处理过程是一个复杂精细的过程,合格的乏燃料溶解液对铀浓度和酸度也有一定的要求,而铀浓度和酸度的调节实际上是溶解工艺控制的问题。在本实施例中,由于溶解液缓冲区30为溶解液提供了一个缓冲场所,液体混合更加均匀,这对于得到的稳定的铀、酸浓度的溶解液是十分有利的,有可能省去铀、酸的调节工序。It should be noted that the treatment process of spent fuel dissolving liquid is a complex and delicate process. Qualified spent fuel dissolving liquid also has certain requirements for uranium concentration and acidity, and the adjustment of uranium concentration and acidity is actually a problem of dissolution process control. . In the present embodiment, since the lysing
在本实施例中,通过工艺通料口40向溶解液缓冲区30内通入工艺原料,用以对乏燃料溶解液同时进行调价和除碘,具体是将溶解过程产生的Pu(VI)(六价钚)还原为Pu(IV)(四价钚),并同时将溶解液中I-、IO3 -离子转化为I2将其除去。当然,在其他实施方式中,调价还可以对其他离子进行调价,例如镎,即将Np(VI)(六价镎)还原为Np(V)(五价镎);也可以仅对乏燃料溶解液进行调价,或者仅对乏燃料溶解液进行除碘。In the present embodiment, process raw materials are introduced into the dissolving
此外,需要说明的是,本实施例的溶解器为连续溶解器,反燃料元件的溶解、调价和除碘、溶解液出液、反燃料元件进料、添加溶剂等这些操作可以同时进行。当然,在图中未示出的其他实施方式中,溶解器也可以为批式溶解器,在批式溶解器的溶解液缓冲区中也可以加入工艺原料进行料液调节操作。In addition, it should be noted that the dissolver in this embodiment is a continuous dissolver, and operations such as dissolving, adjusting and removing iodine of the anti-fuel element, discharging the solution, feeding the anti-fuel element, and adding solvent can be performed simultaneously. Of course, in other embodiments not shown in the figures, the dissolver can also be a batch dissolver, and process raw materials can also be added to the dissolving buffer of the batch dissolver to perform the feed liquid adjustment operation.
如图3、图4、图6至图8以及图12所示,在本实施例的溶解器中,溶解器还包括尾气出口50和尾气净化系统。尾气出口50与空腔连通,乏燃料元件溶解过程中产生的尾气从尾气出口50排出。尾气净化系统的第一侧与尾气出口50连通,尾气净化系统的第二侧与工艺通料口40连通。由尾气出口50排出的溶解尾气经过尾气净化系统净化得到氮氧化物气体,该氮氧化物气体主要成分为NO和NO2气体。上述氮氧化物气体的一部分作为工艺原料(工艺气体)由工艺通料口40通入溶解液缓冲区30。利用溶解尾气作为工艺气体,即溶解尾气经过尾气净化系统净化处理后部分返回溶解器,作为料液调节的气体来源,进行溶解液的调价与除碘处理,这样不仅节省试剂,还简化了试剂的储存与输送的整套设施,其优点具体如下:1)、极大地简化了相关试剂的供料设备;2)、消除了使用NaNO2调价带来的盐分增加,高放废液增加的问题;3)、消除了N2O4供料、储存带来的设备腐蚀问题;4)、气体返回有利于降低溶解酸耗,节约溶剂。As shown in FIG. 3 , FIG. 4 , FIG. 6 to FIG. 8 and FIG. 12 , in the dissolver of this embodiment, the dissolver further includes a
需要说明的是,调价和除碘的工艺原料不限于乏燃料元件溶解过程中产生的尾气,在其他实施方式中,也可以直接额外添加调价和除碘的试剂到溶解液缓冲区进行溶解液处理,此时添加的试剂与现有的处理方法中的试剂相同,在此不再赘述。It should be noted that the process raw materials for price adjustment and iodine removal are not limited to the tail gas generated during the dissolving process of spent fuel elements. In other embodiments, additional reagents for price adjustment and iodine removal can also be directly added to the solution buffer for solution treatment. , the reagents added at this time are the same as those in the existing treatment methods, and are not repeated here.
如图12所示,在本实施例的溶解器中,尾气净化系统包括碘吸附装置61和气液分离装置62。溶解尾气从尾气出口50排出,排出的尾气首先经过气液分离装置62除去气体中的大部分水蒸气;之后气体进入碘吸附装置61,碘吸附装置61为碘吸附柱,碘吸附柱内填充附银硅胶,在100至150℃(优选为120℃左右)的高温条件下能够将气体中的碘吸附,吸附容量大,选择性好。经过以上处理的气体主要成分为比较纯净的NO和NO2气体。在本实施例中,气液分离装置62处于碘吸附装置61的上游,这样净化效果更好。当然,在图中未示出的其他实施方式中,在保证溶解尾气处理后能够应用于调价和除碘的前提下,尾气净化系统中气液分离装置和碘吸附装置的位置调换,或者仅包括碘吸附装置或气液分离装置,或者包括其他能够进行尾气处理的装置。此外,碘吸附装置61的具体类型也不限于此,在其他实施方式中,碘吸附装置可以为其他以银离子为活性物质的吸附剂,如附银沸石等;或者,也可以为其他吸附碘的分子筛、浓硝酸等。气液分离装置62可以采用冷凝或者离心分离,这是比较成熟的工艺,此处不再赘述。As shown in FIG. 12 , in the dissolver of this embodiment, the exhaust gas purification system includes an
如图12所示,在本实施例的溶解器中,溶解器还包括后续尾气处理系统(图中未示出)和气体分配装置70。气体分配装置70具有气体进口71、第一气体出口72以及第二气体出口73。气体进口71与尾气净化系统的第二侧连通,第一气体出口72与工艺通料口40连通,第二气体出口73与后续尾气处理系统连通。为了保证气体流动需要在气路中设有真空泵等动力装置为气体循环提供动力。一般情况下,溶解尾气的量相比于料液调节所需的量较多,上述气体分配装置70用于将净化后的气体分流,一部分作为工艺气体由工艺通料口40通入溶解液缓冲区30内,一部分通向后续尾气处理系统作后续处理。将溶解尾气先通过尾气净化系统净化后再分流,也可看作是对流向后续尾气处理系统的尾气进行预处理,这样有利于提高该部分尾气的后续处理效果。后续尾气处理系统可以包括硝酸再生、水洗、碱洗、高效过滤器、气体加热、AgX沸石、过滤器等,其中,硝酸再生、水洗、碱洗是除气体中的NO和NO2,气体加热和AgX沸石处理是吸附气体中的碘,过滤器和高效过滤器是为了过滤气溶胶。上述后续尾气处理系统中应用的结构和工艺均为现有存在的,在此不再赘述。As shown in FIG. 12 , in the dissolver of this embodiment, the dissolver further includes a subsequent tail gas treatment system (not shown in the figure) and a
需要说明的是,如果在某些情况下溶解尾气的量相比于料液调节所需的量相差不是很大,或者在壳体上另外设置流向后续尾气处理系统的出口,尾气出口中排出的溶解尾气经过净化后可以全部返回溶解液缓冲区,不需要对溶解尾气进行分流,也就不用设置气体分配装置;或者,将气体分配装置设置在尾气净化系统的上游,溶解尾气先经过气体分配装置分流,一部分溶解尾气进入尾气净化系统进行净化,净化后返回溶解器,另一部分溶解尾气直接进入后续尾气处理系统进行后续处理。It should be noted that, in some cases, if the amount of dissolved exhaust gas is not much different from the amount required for material liquid adjustment, or an outlet for the subsequent exhaust gas treatment system is additionally provided on the shell, the exhaust gas discharged from the exhaust gas outlet The dissolved exhaust gas can be completely returned to the solution buffer after being purified, and there is no need to split the dissolved exhaust gas, so there is no need to set up a gas distribution device; alternatively, the gas distribution device is set upstream of the exhaust gas purification system, and the dissolved exhaust gas passes through the gas distribution device first. Diversion, a part of the dissolved exhaust gas enters the exhaust gas purification system for purification, and returns to the dissolver after purification, and the other part of the dissolved exhaust gas directly enters the subsequent exhaust gas treatment system for subsequent treatment.
如图1至图6、图9至图11所示,在本实施例的溶解器中,溶解器还包括鼓泡装置80,工艺通料口40与鼓泡装置80连通,鼓泡装置80包括鼓泡管81和连接管82,连接管82连接在工艺通料口40和鼓泡管81之间,鼓泡管81位于溶解液缓冲区30内。通过上述鼓泡装置80在溶解液缓冲区30内鼓泡,可以增加搅拌,促进溶解液缓冲区30内固体粉末的溶解,也有利于混匀溶液,得到连续的出料浓度稳定的溶解液。在本实施例中,鼓泡管81上设有多个鼓泡孔811,多个鼓泡孔811沿鼓泡管81的延伸方向间隔且均匀设置并形成一排,各鼓泡孔811的开孔方向朝向溶解液缓冲区30的底壁,各鼓泡孔811同时向下出气,这样可以保证气体在溶解液中的充分分散,提高工艺气体的利用率,同时,对溶解液缓冲区30内的溶解液的搅拌效果更好,并且结构更加易于加工。当然,鼓泡孔811的设置形式不限于此,在图中未示出的其他实施方式中,鼓泡孔也可以设置多排,或者各个鼓泡孔的开孔方向也可以不相同或部分相同。As shown in FIGS. 1 to 6 and 9 to 11 , in the dissolver of the present embodiment, the dissolver further includes a bubbling
如图3至图6以及图9至图11所示,在本实施例的溶解器中,鼓泡管81靠近溶解液缓冲区30的底壁设置,连接管82的第一端从壳体的端壁穿出,连接管82的第一端与工艺通料口40连通,连接管82弯折向下,连接管82的第二端与鼓泡管81连通。溶解液缓冲区30的底壁的横截面呈弧形,鼓泡管81设置为弯管,其形状也为弧度相同的弧形,这样可以使鼓泡管81的各个位置与溶解液缓冲区30的底壁之间的距离均相等,从而使鼓泡管81可以更好地贴近于溶解液缓冲区30的底壁,达到从溶解液底部鼓泡的目的,进而促进溶解液缓冲区30底部的固体粉末的溶解,混匀溶液效果较好。当然,鼓泡管81的形状不限于此,在图中未示出的其他实施方式中,鼓泡管也可以为其他形状,例如鼓泡管为直杆状,或者为两根直杆呈一定角度连接在一起形成的V形。此外,连接管82的形状和与连接管82的连接位置不限于此,可以根据具体布置环境进行设计。As shown in FIGS. 3 to 6 and 9 to 11 , in the dissolver of the present embodiment, the bubbling
需要说明的是,鼓泡装置80的具体结构不限于此,在图中未示出的其他实施方式中,鼓泡装置可以为其他现有的鼓泡装置,鼓泡装置至少部分位于溶解液缓冲区内,在此不再赘述。甚至于,在一些实施方式中也可以不设置鼓泡装置,将净化后的气体通过管线直接通入溶解液缓冲区。It should be noted that the specific structure of the bubbling
如图1至图4所示,在本实施例的溶解器中,溶解器的排渣口140连接在外壳的侧壁上并通过弯管连通至溶解液缓冲区30的底部,该排渣口140是用来抽出溶解液中极细小固体颗粒(不溶残渣)的,这种细小颗粒不会随包壳从废包壳出口130排出,会随溶解液流走。间隔一段时间后利用排渣口140将积累的固体颗粒排出。溶解过程中产生微小的不溶颗粒(不溶残渣)是乏燃料溶解的固有普遍现象,因此溶解器的设计必须考虑不溶残渣的排出问题。在本实施例中,排渣口140从外壳的侧壁引入,而不是从外壳的底壁打孔焊接,其目的是减少连续溶解器底面的焊缝,降低腐蚀泄漏风险。As shown in FIG. 1 to FIG. 4 , in the dissolver of the present embodiment, the
在本实施例中,乏燃料元件的UO2芯块溶解的溶解尾气作为乏燃料溶解液调料所用的工艺气体,调价与除碘工艺相近,工艺气体的产生与利用过程涉及的化学反应如下:In this embodiment, the dissolved tail gas dissolved by the UO 2 pellets of the spent fuel element is used as the process gas used for the seasoning of the spent fuel solution.
UO2芯块溶解产生NO与NO2气体:UO 2 pellets dissolve to produce NO and NO 2 gas:
UO2+4HNO3→UO2(NO3)2+2NO2+2H2O (1)UO 2 +4HNO 3 →UO 2 (NO 3 ) 2 +2NO 2 +2H 2 O (1)
UO2+2.7HNO3→UO2(NO3)2+0.7NO+1.3H2O (2)UO 2 +2.7HNO 3 →UO 2 (NO 3 ) 2 +0.7NO+1.3H 2 O (2)
产生的NO与NO2气体可以作为调价、除碘的工艺气体;The generated NO and NO 2 gas can be used as process gas for price adjustment and iodine removal;
在温度满足第一预设温度条件(即温度大于等于60℃小于等于90℃)时,NO2气体可以将钚价态调节Pu(VI)还原为Pu(IV):When the temperature meets the first preset temperature condition (that is, the temperature is greater than or equal to 60°C and less than or equal to 90°C), NO 2 gas can reduce the plutonium valence state-adjusted Pu(VI) to Pu(IV):
PuO2 2++NO2 -+2H+→Pu4++H2O+NO3 - (3)PuO 2 2+ +NO 2 - +2H + →Pu 4+ +H 2 O+NO 3 - (3)
在温度满足第二预设温度条件(即温度大于等于50℃小于等于90℃)时,NO2可以将IO3 -还原为单质碘,从而实现碘的驱除:When the temperature meets the second preset temperature condition (that is, the temperature is greater than or equal to 50°C and less than or equal to 90°C), NO 2 can reduce IO 3 - to elemental iodine, thereby realizing the removal of iodine:
2IO3 -+10NO2+4H2O→I2+8H++10NO3 - (4)2IO 3 - +10NO 2 +4H 2 O→I 2 +8H + +10NO 3 - (4)
IO3 -+I-+6H+→I2+3H2O (5)IO 3 - +I - +6H + →I 2 +3H 2 O (5)
在硝酸中通入NO与NO2,气体与HNO3发生复杂的反应,最终存在着多种反应产物的平衡,主要的反应如下:When NO and NO 2 are introduced into nitric acid, the gas reacts with HNO 3 in a complex manner, and finally there is a balance of various reaction products. The main reactions are as follows:
2NO2+H2O→HNO3+HNO2 (6)2NO 2 +H 2 O→HNO 3 +HNO 2 (6)
3HNO2→HNO3+2NO+H2O (7)3HNO 2 →HNO 3 +2NO+H 2 O (7)
2NO+O2→2NO2 (8)2NO+O 2 →2NO 2 (8)
所以在氮氧化物气体通入硝酸中时,体系中NO、NO2、NO2 -和NO3 -是同时共存的。Therefore, when nitrogen oxide gas is passed into nitric acid, NO, NO 2 , NO 2 - and NO 3 - coexist at the same time in the system.
如图13所示,本申请还提供了一种应用上述溶解器处理乏燃料溶解液的处理方法,根据本申请的实施例包括以下步骤:As shown in FIG. 13 , the present application also provides a method for treating spent fuel dissolving liquid by applying the above dissolver. According to an embodiment of the present application, the following steps are included:
步骤S10:将乏燃料元件和溶剂加入至溶解器内的溶解区20进行溶解,溶解生成的乏燃料溶解液进入溶解液缓冲区30;Step S10 : adding the spent fuel elements and solvent to the
步骤S20:使溶解液缓冲区30的温度满足第三预设温度条件,其中,第三预设温度条件为温度大于等于80℃小于等于90℃;Step S20: making the temperature of the
步骤S30:乏燃料元件和溶剂溶解产生的溶解尾气经过尾气净化系统净化得到氮氧化物气体,部分氮氧化物气体作为用于乏燃料溶解液调价和除碘的工艺原料通入溶解液缓冲区30内;Step S30 : the dissolved exhaust gas generated by the dissolving of the spent fuel element and the solvent is purified by the exhaust gas purification system to obtain nitrogen oxide gas, and part of the nitrogen oxide gas is passed into the dissolved
步骤S40:得到合格的乏燃料溶解液;Step S40: obtaining a qualified spent fuel dissolving solution;
其中,氮氧化物气体主要为NO和NO2气体,步骤S20和步骤S30顺序并不固定。The nitrogen oxide gas is mainly NO and NO 2 gas, and the sequence of step S20 and step S30 is not fixed.
需要说明的是,本实施例的处理方法中同时对乏燃料溶解液进行调价和除碘操作,因此,溶解液缓冲区30的温度需要满足第三预设温度条件。当然,在其他实施方式中,如果只对乏燃料溶解液进行调价操作,溶解液缓冲区30的温度需要满足第一预设温度条件,第一预设温度条件为温度大于等于60℃小于等于90℃;如果只对乏燃料溶解液进行除碘操作,溶解液缓冲区30的温度需要满足第二预设温度条件,第二预设温度条件为温度大于等于50℃小于等于90℃。It should be noted that, in the processing method of this embodiment, the dissolving liquid of spent fuel is simultaneously adjusted for price and iodine removal. Therefore, the temperature of the dissolving
此外,乏燃料元件和溶剂溶解产生的溶解尾气一般只通入至溶解液缓冲区30内,才能较好地实现对溶解液的料液调节。具体理由说明如下:In addition, the dissolving exhaust gas generated by the dissolving of spent fuel elements and the solvent is generally only passed into the dissolving
溶解液中的碘是伴随溶解过程从固体芯块中溶解到溶解液中的,而溶解过程中本身会产生NO2。在溶解过程中大部分的碘已经进入溶解尾气了,也就是说在有NO2气体的溶解条件下,有少部分碘保留在了溶液中,此时再通入NO2气体的效果不是很明显。等待溶解液流出溶解区20后(即进入溶解液缓冲区30)通入NO2气体,将少部分残留的碘进行除去,同时,通过溶解液缓冲区30加长溶解液与NO2气体的反应时间来达到对碘的较高比例除去。The iodine in the dissolving solution is dissolved from the solid pellets into the dissolving solution along with the dissolving process, and NO 2 is generated in the dissolving process itself. During the dissolution process, most of the iodine has entered the dissolved exhaust gas, that is to say, under the dissolving conditions of NO 2 gas, a small amount of iodine remains in the solution. At this time, the effect of introducing NO 2 gas is not very obvious. . After waiting for the dissolving solution to flow out of the dissolving zone 20 (that is, entering into the dissolving
钚价态的调节是将PuO2 2+调节为Pu4+。PuO2 2+是在高温溶解过程产生的,比例一般较小。在高温、高酸条件下有利于PuO2 2+的形成和稳定。HNO2可以将PuO2 2+还原为Pu4+,高温条件下反应进行速度较快。在溶解液缓冲区30调价的理由是因为,溶解液缓冲区30是高温高酸区域,加入NO2气体,既可以抑制新的PuO2 2+生成,也可以将溶解过程形成的PuO2 2+调节为Pu4 +。The adjustment of the plutonium valence state is to adjust PuO 2 2+ to Pu 4+ . PuO 2 2+ is produced in the high temperature dissolution process, and the proportion is generally small. The formation and stability of PuO 2 2+ are favorable under high temperature and high acid conditions. HNO 2 can reduce PuO 2 2+ to Pu 4+ , and the reaction proceeds faster under high temperature conditions. The reason for the price adjustment in the
在本实施例中,以处理能力为1kg/h的实验规模连续溶解器为例,其尾气的产生与返回利用过程如下:In this embodiment, taking the experimental-scale continuous dissolver with a processing capacity of 1kg/h as an example, the generation and recycling process of its tail gas is as follows:
按照初始235U富集度为3.7%,燃耗为37000MWd/tU,冷却时间8年的条件下,1kg的乏燃料芯块中与本工艺相关的主要元素组成列于表1。According to the condition that the initial 235 U enrichment is 3.7%, the burnup is 37000MWd/tU, and the cooling time is 8 years, the main element compositions related to this process in 1kg spent fuel pellets are listed in Table 1.
表1Table 1
假设UO2按照式(1)和式(2)在硝酸中溶解,依据1kg/h的处理量计算得到溶解过程中产生的NO与NO2尾气速率分别为33L/h与94L/h。Assuming that UO 2 is dissolved in nitric acid according to formula (1) and formula (2), the exhaust gas rates of NO and NO 2 generated during the dissolution process are calculated to be 33L/h and 94L/h, respectively, based on the treatment capacity of 1kg/h.
在溶解过程中产生的高价态镎、钚的比例分别为40%和5%,即在溶解液300g/L铀浓度时,需要调价的镎、钚浓度分别为0.14g/L和0.19g/L。假设碘全部以IO3 -的形式存在,同样溶解液中碘浓度为0.13g/L。以调节钚的价态和除碘为例,按照式(3)和式(4)计算,调节钚与除碘需要的理论NO2流量为0.34L/h。从尾气产生量与调价除碘理论消耗量比较,溶解尾气是数百倍过量,但是实际过程中NO2的利用率极低,利用效率与气体的分散程度、反应时间、液体停留时间等多个因素确定,因此实际的气体加入倍数往往需要经实验验证确定。The proportions of high-valence neptunium and plutonium produced in the dissolution process are 40% and 5%, respectively, that is, when the concentration of uranium in the dissolution solution is 300g/L, the neptunium and plutonium concentrations that need to be adjusted are 0.14g/L and 0.19g/L, respectively. . Assuming that all iodine exists in the form of IO 3 - , the concentration of iodine in the same solution is 0.13 g/L. Taking adjusting the valence state of plutonium and removing iodine as an example, according to formula (3) and formula (4), the theoretical NO 2 flow required for adjusting plutonium and removing iodine is 0.34L/h. Comparing the amount of tail gas produced with the theoretical consumption of iodine removal through price adjustment, the dissolved tail gas is hundreds of times excessive, but the utilization rate of NO 2 is extremely low in the actual process. Therefore, the actual gas addition multiple often needs to be determined by experimental verification.
假设溶解液缓冲区30的体积约为5L,溶解液的出料速度为3.2L/h。计算溶解液在溶解液缓冲区30的平均停留时间为1.56h。设计缓冲区的温度为80至90℃,设置返回气体的比例使20L/h的溶解尾气返回缓冲区。It is assumed that the volume of the
在以上工艺条件下,即温度优选为80℃,停留时间为1.56h,NO2鼓泡速率为20L/h的条件下,调价后NpO2 +比例提高至85%,Pu4+比例提高至99%以上。溶解液中IO3 -的浓度由10-4M至10-5M降低至10-7M。完全满足后续处理流程对料液的调价与除碘的要求。Under the above process conditions, that is, the temperature is preferably 80°C, the residence time is 1.56h, and the NO 2 bubbling rate is 20L/h, the NpO 2 + ratio is increased to 85% and the Pu 4+ ratio is increased to 99% after the price adjustment. %above. The concentration of IO 3 - in the solution decreased from 10 -4 M to 10 -5 M to 10 -7 M. It fully meets the requirements of the subsequent treatment process for the price adjustment and iodine removal of the feed liquid.
本实施例为一种利用溶解尾气返回与连续溶解同步进行料液调节的一体化溶解工艺,属于乏燃料后处理-首端处理技术领域,应用于乏燃料元件溶解后料液的进一步制备过程。其提供了一个非常适合的溶解液调料的环境,连续溶解同时实现料液调节。针对溶解液调价、除碘工艺条件相近的特点,并利用连续溶解器的独特结构,在连续稳定溶解的同时,实现对价态的调节以及溶解液中碘驱除的效果,并简化尾气处理工艺。This embodiment is an integrated dissolving process that utilizes dissolving tail gas return and continuous dissolving to synchronously adjust feed and liquid, belonging to the technical field of spent fuel post-processing-head-end treatment, and is applied to the further preparation process of spent fuel element dissolving feed liquid. It provides a very suitable environment for dissolving liquid seasoning, and realizes continuous dissolving and liquid adjustment at the same time. Aiming at the similar characteristics of dissolving solution valence adjustment and iodine removal process conditions, and using the unique structure of the continuous dissolver, while continuously and stably dissolving, the adjustment of the valence state and the effect of iodine removal in the dissolving solution are realized, and the tail gas treatment process is simplified.
对于本发明的实施例,还需要说明的是,在不冲突的情况下,本发明的实施例及实施例中的特征可以相互组合以得到新的实施例。For the embodiments of the present invention, it should also be noted that, in the case of no conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other to obtain new embodiments.
以上,仅为本发明的具体实施方式,但本发明的保护范围并不局限于此,本发明的保护范围应以权利要求的保护范围为准。The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto, and the protection scope of the present invention should be subject to the protection scope of the claims.
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