Method for separating and enriching chlorine-37 isotope using laser photochemical reaction

Abstract

The present invention relates to a method for separating and enriching a chlorine-37 isotope using a laser photochemical reaction and, specifically, to a method for separating and enriching a high-purity chlorine-37 isotope, which is essential for a next-generation molten chloride fast reactor (MCFR) and the like, by selectively photolyzing specific isotopic molecules of iodine monochloride (ICl) using a high-power fiber laser or a solid-state Raman laser and reacting same with a radical scavenger to effectively terminate a chain reaction. Accordingly, by employing, as a light source, a single-frequency fiber laser or a solid-state Raman laser that has higher power efficiency and easier maintenance than conventional dye lasers and is capable of achieving high power of several kW or more through modular expansion, mass production on an industrial scale can be realized and the economic feasibility of the process can be significantly secured.

Description

Method for Separation and Concentration of Chlorine-37 Isotopes Using Laser Photochemical Reactions

[0001] The present invention relates to a method for separating and concentrating chlorine-37 isotopes using a laser, and more specifically, to a method for separating and concentrating high-purity chlorine-37 isotopes essential for next-generation molten salt reactors (MCFR), etc., by selectively photodecomposing specific isotope molecules of iodine monochloride (ICl) using a high-power fiber laser or a solid-state Raman laser and reacting them with a radical scavenger to effectively terminate a chain reaction.

[0002] Recently, in order to address climate change and achieve carbon neutrality, the development of Small Modular Reactors (SMRs) is accelerating worldwide, and among them, Molten Chloride Fast Reactors (MCFRs) are attracting attention as fourth-generation reactors equipped with high thermal efficiency and safety.

[0003] MCFR uses molten chloride salts, such as sodium chloride (NaCl), as both a coolant and a nuclear fuel solvent. However, chlorine-35, which accounts for about 76% of the chlorine existing in nature ( 35 Cl) has a very high thermal neutron absorption cross-section of approximately 44 barn, which severely impedes the neutron economy of the reactor. In addition, chlorine-35 ( 35 Chlorine-36, a long-lived radioisotope with a half-life of approximately 300,000 years when Cl absorbs a neutron ( 36 It is converted into Cl), causing radioactive waste disposal problems. On the other hand, Chlorine-37, which has a natural composition ratio of about 24%, ( 37 Cl) has a neutron absorption cross-section of only about 0.4 barn and a short half-life of its radioactive products, making it an essential material for use as a coolant in MCFRs.

[0004] Meanwhile, for the commercialization of MCFR, high-purity chlorine-37 of 90% or more, preferably 99% level (37 Technology capable of supplying Cl in ton units is required. However, conventional thermal diffusion and centrifugation methods lack economic feasibility due to low separation efficiency. Furthermore, past laser separation methods have not yet reached commercialization due to issues such as low light output, efficiency problems, and isotope scrambling.

[0005] (Reference 1) U.S. Patent No. 3,983,020

[0006] (Reference 2) Russian Registered Patent No. 2,530,062

[0007] The present invention progressively resolves the chemical and physical limitations of conventional iodine monochloride (ICl) photolysis-based isotope separation technology, thereby enabling industrial-scale high-purity chlorine-37 ( 37 We intend to provide a production process for Cl).

[0008] First, the invention aims to overcome the output limitations of conventional lasers used for photolysis. Although the continuous-wave (CW) dye lasers used in conventional technology are suitable for selective photolysis due to their narrow linewidth, their output is low (less than 1W), making it impossible to separate and produce a visible amount of isotopes. Accordingly, the present invention aims to enable industrial mass production through high output of tens of W or more by introducing a single-frequency fiber laser or fiber Raman laser that maintains a narrow linewidth to secure high isotope selectivity.

[0009] Second, this invention addresses the issues of radical propagation and isotope scrambling caused by radical scavengers. Hydrocarbon (CH₄)-based scavengers used in conventional technology had a limitation in that they could not prevent isotope scrambling, as organic radicals generated after reacting with chlorine radicals would trigger a chain reaction with the raw material, ICl. This invention aims to fundamentally eliminate the problem of reduced selectivity by introducing nitric oxide (NO) to induce 'radical reaction termination,' which effectively blocks the radical chain reaction.

[0010] Third, the invention optimizes conflicting process variables. Increasing NO pressure to prevent isotope recombination improves scavenging efficiency, but trade-offs occur in which spectroscopic selectivity and yield actually decrease due to pressure linewidth expansion caused by intermolecular collisions and collisional quenching. The present invention aims to provide a high-efficiency separation process by identifying the correlations between these variables and deriving the optimal operating range.

[0011] The technical problems of the present invention are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art from the description below.

[0012] The present invention provides the following means to achieve the above-mentioned objectives.

[0013] One embodiment of the present invention includes the step of selectively photodecomposing specific isotope molecules of iodine monochloride using a fiber laser; and the step of capturing the generated chlorine radicals by reacting them with a radical scavenger. Here, the radical chain reaction is terminated by converting the chlorine radicals into nitrosyl chloride (NOCl) using nitric oxide (NO) as the radical scavenger. In addition, to optimize process conditions, the reaction temperature is maintained at 240 K to 270 K and the NO partial pressure is controlled at 50 Torr to 150 Torr, while the ICl partial pressure is maintained at 1 / 500 or less of the NO partial pressure, thereby maximizing scavenging efficiency while preventing pressure linewidth increase and quenching loss.

[0014] Furthermore, the present invention includes the following specific embodiments depending on the target isotope.

[0015] As one example, chlorine-37 ( 37 Cl) and chlorine-35( 35 A step of injecting iodine monochloride (ICl) containing the Cl isotope and nitric oxide (NO), a radical scavenger, into a reactor; and irradiating the reactor with a laser to [inject] the target isotope I in the ICl. 37 By selectively photodecomposing Cl 37 A step of generating Cl radicals; the generated 37 The product (NO) formed by the reaction of Cl radicals with the above nitric oxide (NO) 37 Cl) and residual ICl that has not been photodegraded (I 35 A step of separating Cl; and the separated product (NO₂ 37 Recovered and concentrated Cl) 37 It may include a step of obtaining Cl.

[0016] As one example, chlorine-37 ( 37 Cl) and chlorine-35( 35A step of injecting iodine monochloride (ICl) containing the Cl isotope and nitric oxide (NO), a radical scavenger, into a reactor; and irradiating the reactor with a laser to [inject] the target isotope I in the ICl. 35 By selectively photodecomposing Cl 35 A step of generating Cl radicals; the generated 35 The product (NO) formed by the reaction of Cl radicals with the above nitric oxide (NO) 35 Cl) and residual ICl that has not been photodegraded (I 37 A step of separating Cl); and the remaining ICl (I 37 Recovered and concentrated Cl) 37 It may include a step of obtaining Cl.

[0017] As one example, the raw material chlorine-37 ( 37 Cl) and chlorine-35( 35 Iodine monochloride (ICl) containing the Cl) isotope and nitric oxide (NO), a radical scavenger, are injected into a first reactor, and a laser is irradiated to target the isotope I 37 Primary concentrated product (NO) by selectively photodegrading Cl 37 A first step of obtaining Cl); the primary concentrated product (NO) obtained in the first step. 37 A step of reacting Cl) with iodine (I2) to chemically convert it into iodine monochloride (ICl); and injecting the chemically converted iodine monochloride (ICl) into a second reactor as a raw material and irradiating it with a laser to produce I 37 By selectively photodegrading Cl, compared to the primary concentrated product above 37 It may include a second step of obtaining a secondary concentrated product with a higher concentration of Cl.

[0018] As one example, the raw material chlorine-37 ( 37 Cl) and chlorine-35( 35Iodine monochloride (ICl) containing the Cl) isotope and nitric oxide (NO), a radical scavenger, are injected into a first reactor, and a laser is irradiated to target the isotope I 37 Primary concentrated product (NO) by selectively photodegrading Cl 37 A first step of obtaining Cl); the primary concentrated product (NO) obtained in the first step. 37 A step of reacting Cl) with iodine (I2) to chemically convert it into iodine monochloride (ICl); and injecting the chemically converted iodine monochloride (ICl) into a second reactor as a raw material and irradiating with a laser to remove the impurity isotope I 35 Selectively remove Cl by photodecomposition, and remove the remaining ICl (I₂) that is not photodecomposed. 37 Recovered Cl) and secondary concentrated 37 It may include a second step of obtaining Cl.

[0019] Accordingly, the present invention can achieve the following effects.

[0020] First, by adopting a single-frequency fiber laser or solid-state Raman laser as a light source, which has higher power efficiency and is easier to maintain compared to conventional dye lasers, and can achieve high output of several kW or more through module expansion, it is possible to realize industrial-scale mass production and significantly secure the economic efficiency of the process.

[0021] Second, by introducing nitric oxide (NO) as a radical scavenger, high isotope selectivity can be stably secured by blocking the chain reaction and isotope mixing phenomena caused by radicals generated during the photodecomposition process.

[0022] Third, by precisely controlling the pressure and temperature inside the reactor to optimize conflicting process variables, spectroscopic losses resulting from pressure linewidth expansion and quenching caused by intermolecular collisions are minimized. This maximizes the high-power characteristics of the fiber laser, enabling commercial-grade mass production on an annual ton scale.

[0023] Figure 1 is a flowchart of a method for concentrating chlorine-37 by a photochemical reaction of iodine monochloride (ICl).

[0024] FIG. 2 is a configuration diagram of a photochemical reaction apparatus according to one embodiment of the present invention,

[0025] FIG. 3 is a process diagram for the production of highly concentrated chlorine-37 according to one embodiment of the present invention,

[0026] FIG. 4 is a hybrid process diagram for the production of co-enriched chlorine-37 according to one embodiment of the present invention,

[0027] Figure 5 is I 37 Cl or I 35 This is the ICl absorption spectrum usable for Cl photolysis.

[0028] [Explanation of the symbol]

[0029] 100, 200, 302, 402, 405 : Photochemical reactor

[0030] 101, 201, 301, 401: Ingredients 102, 202: Radical scavenger (NO)

[0031] 103, 203: Fiber laser 104, 208, 307, 407: Product

[0032] 105, 207, 303, 306, 403, 406 : Residue

[0033] 204: 1st Cold Trap 205: 2nd Cold Trap

[0034] 206: Scroll pump 304, 404: Chemical conversion

[0035] The present invention will be described in detail below.

[0036] Unless otherwise defined in this specification, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this application.

[0037] In describing the components of the embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc., may be used. These terms are intended only to distinguish the components from other components, and the essence, order, or sequence of the components is not limited by the terms. The singular form used in this specification may be intended to include the plural form unless specifically indicated otherwise in the context.

[0038] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, each embodiment is merely illustrative and is not limited to the specific embodiments disclosed.

[0039] The present invention provides a method for separating and concentrating chlorine-37 isotopes using a laser photochemical reaction, which can separate and concentrate chlorine isotopes using a laser.

[0040] (1) Laser

[0041] In various embodiments of the present invention, a laser used as a light source may be a single frequency with a fundamental wavelength in the range of 1080 to 1140 nm and a linewidth of 50 MHz or less. These wavelength and linewidth characteristics can be efficiently achieved through fiber lasers, fiber Raman lasers, solid-state Raman lasers, or diamond Raman lasers, and the narrow linewidth contributes to increasing the selective photodecomposition efficiency for specific isotopes.

[0042] For example, a single-mode fiber laser with a narrow linewidth can provide output power in the range of tens of watts in the 540–570 nm range, which is the optical absorption wavelength band of iodine monochloride (ICl), through Second Harmonic Generation (SHG). In this case, the optical absorption cross-section of iodine monochloride (ICl) in the corresponding wavelength band is 3–4 × 10⁻⁶. -20 cm 2 It is at the molecule level.

[0043] The fiber laser (103) applied in the present invention has the advantages of high energy efficiency, being compact relative to output, and simple maintenance, as well as being able to easily expand output to several to tens of kW through modularization. Here, the fiber laser can be provided with specifications in which the pulse width is several to tens of ns and the pulse repetition rate is several hundred kHz.

[0044] Meanwhile, a diamond Raman laser, which can be used as another embodiment, may be somewhat more complex to maintain compared to a fiber laser, but it has the advantage of enabling high output and relatively stable operation.

[0045] (2) Radical remover (NO)

[0046] The radical scavenger (102, 202, 302, 310) according to an embodiment of the present invention plays a role in rapidly reacting with chlorine (Cl) radicals generated by photodecomposition to form a relatively stable compound. By suppressing the chain propagation and recombination of radicals through this, the isotope selectivity defined by the following equation (1) ( Prevents ) from decreasing.

[0047] Equation (1)

[0048] (Here, X f and X p ε₀ is the ratio of target isotope components in the feed and product, respectively.

[0049] In various embodiments of the present invention, nitric oxide (NO) is introduced as the radical scavenger. NO combines with photodecomposed chlorine radicals (Cl·) to form chemically stable nitrosyl chloride (NOCl), and the reaction equation is as follows.

[0050] Cl · + NO + M → NOCl + M Equation (2)

[0051] (Here, M refers to a third body or collision medium that absorbs collision energy.)

[0052] The reaction rate constant of the above equation (2) is k0 = 1.8 × 10 -32 × (T / 300) -1.8 [cm 6 molecule -2 s -1 ] As such, the capture reaction using NO is very fast and corresponds to a termination step that does not generate additional active radicals. Therefore, the phenomenon of isotope scrambling, in which the generated chlorine radicals react with the raw material ICl and mix again, can be effectively blocked, and as a result, high isotope selectivity (e.g., 30 or higher) can be secured.

[0053] (3) Optimization of Trade-offs

[0054] When introducing NO as a radical scavenger, it is essential to establish a balance that considers the trade-off between securing scavenging efficiency and preventing physical losses.

[0055] a. Low-temperature reaction control

[0056] The scavenging reaction (Cl + NO → NOCl) exhibits a negative temperature dependence, meaning the reaction rate increases as the temperature decreases. On the other hand, the product loss reaction (Cl + NOCl → NO + Cl2) and the isotope mixing reaction ( 37 Cl + I 35 Cl → 35 Cl + I 37 Cl) has the characteristic that the reaction rate slows down as the temperature decreases. Accordingly, the present invention controls the scavenging reaction to gain a rate advantage over competing reactions by maintaining the internal temperature of the reactor at a low temperature of 240 K to 270 K (preferably 250 K).

[0057] B. Pressure Control

[0058] If the partial pressure of NO exceeds 200 Torr, pressure broadening due to intermolecular collisions reaches several GHz, reducing the selectivity for photoresolution of the target isotope and decreasing the yield due to collisional quenching. On the other hand, if the partial pressure of NO is less than 50 Torr, the isotope mixing reaction with the feedstock ICl (rate constant k = 1.0 × 10⁻⁶ -11 [cm 3 molecule -1 s -1 It cannot effectively suppress ].

[0059] Accordingly, the present invention sets an optimal operating range that can maximize scavenging efficiency by limiting the NO pressure to a range of 50 Torr to 200 Torr and maintaining the ICl pressure relatively low at 0.4 Torr or less (a ratio of 1 / 500 or less relative to the NO partial pressure).

[0060] The present invention will be described in detail below for each embodiment.

[0061] First embodiment

[0062] Referring to FIG. 2, the first embodiment of the present invention is a process of selectively photodecomposing a target isotope using iodine monochloride (ICl) as a raw material and recovering it by reacting it with a radical scavenger (NO).

[0063] A. Photodecomposition product recovery method

[0064] First, the target isotope 37 Product (NO) generated by the selective photodecomposition of Cl 37 By recovering Cl) 37 Cl can be concentrated.

[0065] Specifically, iodine monochloride (ICl, 201), which is a raw material, and nitric oxide (NO, 202), which is a radical scavenger, are injected into a photochemical reactor (200) in which the internal temperature is maintained at a low temperature of 240 K to 270 K (preferably 250 K). Here, I 37 A laser (203) tuned to the absorption wavelength band of Cl, 540 to 570 nm (see FIG. 5), is irradiated to I 37 Selectively photodecomposes Cl.

[0066] Referring to Fig. 5, when the partial pressure of NO is 200 Torr, the isotopic selectivity at a wavelength of 562 nm is confirmed to be greater than 30. Produced by photolysis 37 The Cl radical rapidly reacts with coexisting NO to form chemically stable nitrosyl chloride (NOCl), and the reaction equation is as shown in equation (3) below.

[0067] I 37 Cl + I 35 Cl + 2NO + hv → I 35 Cl + NO 37 Cl + I Equation (3)

[0068] The gas mixture passing through the reactor passes through a multi-stage cold trap and is separated. In the first cold trap (204), which is maintained at a temperature of 180 K to 220 K (preferably 200 K), the residual I that has not been photodegraded 35 Cl (207) is condensed and captured, and then in a second cold trap (205) maintained at a temperature of 100 K to 140 K (preferably 120 K), NO, a photodecomposition product, is captured. 37 Cl (208) is selectively captured. Unreacted radical scavenger NO (202) that is not captured is recovered and recirculated by a scroll pump (206), etc. I captured in the first cold trap (204) 35 Cl (207) is reused or discarded, and NO captured in the second cold trap (205) 37 Concentrated by finally recovering Cl 37 You can obtain Cl.

[0069] B. Method for removing photodegradation products

[0070] Meanwhile, unnecessary I 35 Cl is removed by photolysis, and concentrated from the remaining unreacted ICl 37 A removal method that acquires Cl is also possible. In this case, I within the 540 to 570 nm wavelength range. 35 By irradiating a laser (203) tuned to the absorption wavelength of Cl, I 35 Selectively photodecomposes Cl. Photodecomposed 35 Cl radicals react with NO to form NO 35 Cl is formed and removed. Afterwards, unreacted I captured in the first cold trap (204) 37 Cl(207) was recovered and highly concentrated 37Cl can be obtained. At this time, the byproduct NO captured in the second cold trap (205) 35 Cl is discarded.

[0071] Recovered I 37 Cl is reacted with sodium hydroxide (NaOH), etc., as shown in the following formula (4) to produce stable sodium chloride (Na₂O₃). 37 It can be extracted in the form of Cl).

[0072] I 37 Cl + 2NaOH → Na 37 Cl + NaIO + H2O Equation (4)

[0073] 2nd embodiment

[0074] Referring to FIG. 3, a second embodiment of the present invention continuously performs primary concentration and secondary concentration to obtain high purity 37 It is a two-step process for obtaining Cl.

[0075] Stage 1 (Primary Concentration and Chemical Transformation)

[0076] first, 37 Cl (approx. 24%) and 35 The entire iodine monochloride (ICl, 301) gas, in which Cl (approx. 76%) is mixed in its natural abundance, is injected into the first reactor as a raw material. Subsequently, a fiber laser is irradiated onto the mixed gas coexisting within the first reactor to target the target isotope I. 37 Selectively photodecompose only Cl (302).

[0077] At this time, the residue (303) remaining that did not participate in the photodecomposition reaction, i.e., I, in which the target isotope has been impoverished 35The gas, which is mainly composed of Cl, is discharged outside the first reactor and disposed of, or, if necessary, can be recycled as a raw material (301) of the first stage for process efficiency. Meanwhile, nitrosyl chloride (NOCl), which is a primary concentrated product generated through the photodecomposition reaction, is recovered separately. The recovered NOCl is converted into the form of ICl through a chemical conversion process (304), such as reacting with iodine (I2), so that it can be used as a raw material for the photodecomposition reaction in the next stage.

[0078] Stage 2 (Secondary Concentration)

[0079] Primary concentrated ICl obtained through the above chemical conversion (304) 37 A state in which the Cl ratio has increased to approximately 80%) is used as a raw material for the second stage and introduced into the second reactor. In the second stage, the primary concentrated ICl mixture is subjected to I again 37 Cl is selectively photodecomposed (305) to maximize concentration. The final product (307) that has undergone this second stage process is 37 The product becomes a highly concentrated product with a purity of 99%.

[0080] Process conditions and efficiency

[0081] When the process conditions are controlled in the first step above to maintain the partial pressures of the ICl mixed gas and the radical scavenger (NO) at 0.2 Torr and 200 Torr, respectively, and the gas flow velocity at approximately 2 m / s, the gas concentrated to approximately 80% 37 The Cl product can be obtained with a fractionation rate (Cut, θ) of about 8% (or 10% or less).

[0082] Subsequently, in the second step using ICl concentrated to approximately 80% as a raw material, the process is performed under conditions of a cut rate (θ) of approximately 40% (or 30% or more), thereby producing a highly concentrated ICl of approximately 99% or more 37 Cl products can be finally obtained (see Table 1 below).

[0083] 2-Step Chlorine-37 Concentration Process Example Classification Step 1 (1st Concentration) Step 2 (2nd Concentration) Raw Material (Feed) ICl (Natural Abundance approx. 24%) 1st Concentration (~80%) Target Isotope I 37 ClI 37 Cl Splitting Rate (Cut, θ) 8% 40% Product Concentration ~ 80% 99% Residue Waste Reintroduced as Stage 1 Raw Material

[0084] Third embodiment

[0085] Referring to FIG. 4, the third embodiment of the present invention performs a hybrid process in which the target is directly recovered in the first step and impurities are removed in the second step to achieve high concentration.

[0086] Step 1 (Direct Concentration)

[0087] The first step of the process of this embodiment is performed in the same way as the first step of the second embodiment (Fig. 3). That is, from the ICl raw material (401) of natural component ratio, I 37 Cl is selectively photodecomposed (402) to obtain a primary concentrated product (NOCl), which is then chemically converted and supplied as a raw material for the second stage (404). At this time, the residue (403) can be recycled as in the second embodiment.

[0088] Step 2 (Removal Method)

[0089] Unlike the first step, the second step process of this embodiment is an impurity I 35 A method for selectively photodecomposing Cl (405) is adopted. ICl, which is the raw material for the second stage supplied through the first stage, is I 35 Cl is about 20%, and the target is I 37 It contains about 80% Cl.

[0090] At this time, I, which accounts for a large amount 37 Instead of recovering Cl (80%) by photolysis, I, an impurity that accounts for a small amount, is recovered. 35Cl (20%) is selectively photodecomposed (405) to remove it in the form of a reaction product (406), and from the highly concentrated ICl (406) which is the unreacted remaining residue (tail). 37 Acquiring Cl is advantageous in terms of Photon Utility Factor.

[0091] As described in each of the aforementioned embodiments, the present invention 37 The 'direct concentration method' for directly recovering Cl, and I 35 It is configured in various ways, including a 'removal method' that recovers residues by removing Cl, and a 'hybrid method' that combines these to achieve high concentration efficiency. This process design enables the efficient use of laser energy, allowing for expansion to commercial facilities operating on an annual ton scale.

[0092] As described above, the present invention has been explained by limited embodiments, but this is provided only to aid in a more comprehensive understanding of the invention, and the invention is not limited to the above embodiments, and various modifications and variations are possible from this description by those skilled in the art.

[0093] Accordingly, the scope of the present invention is not limited to the described embodiments, and all things equivalent to or having equivalent variations to the claims set forth below, as well as the claims set forth below, shall be considered to fall within the scope of the concept of the present invention.

[0094] Accordingly, the present invention adopts a single-frequency fiber laser or a solid-state Raman laser as a light source, which has higher power efficiency and is easier to maintain compared to conventional dye lasers, and is capable of high output of several kW or more through module expansion, thereby enabling mass production on an industrial scale and significantly securing the economic efficiency of the process.

[0095] In addition, by introducing nitric oxide (NO) as a radical scavenger, high isotope selectivity can be stably secured by blocking the chain reaction and isotope mixing phenomena caused by radicals generated during the photodecomposition process.

[0096] Furthermore, by precisely controlling the pressure and temperature inside the reactor to optimize conflicting process variables, spectroscopic losses resulting from pressure linewidth expansion and quenching caused by intermolecular collisions are minimized. This maximizes the high-power characteristics of the fiber laser, enabling commercial-grade mass production on an annual ton scale.

Claims

1. Chlorine-37( 37 Cl) and chlorine-35( 35 A step of injecting iodine monochloride (ICl) containing the Cl isotope and nitric oxide (NO), a radical scavenger, into a reactor; A laser is irradiated onto the above reactor to target I₂, which is the target isotope among the ICl. 37 By selectively photodecomposing Cl 37 Step of generating Cl radicals; The above generated 37 The product (NO) formed by the reaction of Cl radicals with the above nitric oxide (NO) 37 Cl) and residual ICl that has not been photodegraded (I 35 Step of separating Cl); and The above separated product (NO 37 Recovered and concentrated Cl) 37 A method for separating and concentrating a chlorine-37 isotope using a laser photochemical reaction, comprising the step of obtaining Cl. 2.Chlorine-37( 37 Cl) and chlorine-35( 35 A step of injecting iodine monochloride (ICl) containing the Cl isotope and nitric oxide (NO), a radical scavenger, into a reactor; A laser is irradiated onto the above reactor to target I₂, which is the target isotope among the ICl. 35 By selectively photodecomposing Cl 35 Step of generating Cl radicals; The above generated 35 The product (NO) formed by the reaction of Cl radicals with the above nitric oxide (NO) 35 Cl) and residual ICl that has not been photodegraded (I 37 Step of separating Cl); and The above residual ICl (I 37 Recovered and concentrated Cl) 37 A method for separating and concentrating a chlorine-37 isotope using a laser photochemical reaction, comprising the step of obtaining Cl.

3. In Paragraph 1 or 2, A method for separating and concentrating chlorine-37 isotopes using a laser photochemical reaction, characterized in that the laser is selected from the group consisting of a fiber laser, a fiber Raman laser, a solid-state Raman laser, and a diamond Raman laser, and the wavelength of the laser is in the range of 540 nm to 570 nm.

4. In Paragraph 1 or 2, A method for separating and concentrating a chlorine-37 isotope using a laser photochemical reaction, characterized in that the partial pressure of the nitric oxide (NO) is 50 to 200 Torr.

5. The raw material, Chlorine-37 ( 37 Cl) and chlorine-35( 35 Iodine monochloride (ICl) containing the Cl) isotope and nitric oxide (NO), a radical scavenger, are injected into a first reactor, and a laser is irradiated to target the isotope I 37 Primary concentrated product (NO) by selectively photodegrading Cl 37 Step 1 of obtaining Cl; The primary concentrated product (NO) obtained in the first step above 37 A step of reacting Cl) with iodine (I2) to chemically convert it into iodine monochloride (ICl); and The chemically converted iodine monochloride (ICl) is used as a raw material and injected into a second reactor, and a laser is irradiated to produce I 37 By selectively photodegrading Cl, compared to the primary concentrated product above 37 A method for separating and concentrating a chlorine-37 isotope using a laser photochemical reaction, comprising: a second step of obtaining a secondary concentrated product with a high concentration of Cl.

6. The raw material, Chlorine-37 ( 37 Cl) and chlorine-35( 35 Iodine monochloride (ICl) containing the Cl) isotope and nitric oxide (NO), a radical scavenger, are injected into a first reactor, and a laser is irradiated to target the isotope I 37 Primary concentrated product (NO) by selectively photodegrading Cl 37 Step 1 of obtaining Cl; The primary concentrated product (NO) obtained in the first step above 37 A step of reacting Cl) with iodine (I2) to chemically convert it into iodine monochloride (ICl); and The chemically converted iodine monochloride (ICl) is injected into a second reactor as a raw material, and a laser is irradiated to remove the impurity isotope I 35 Selectively remove Cl by photodecomposition, and remove the remaining ICl (I₂) that is not photodecomposed. 37 Recovered Cl) and secondary concentrated 37 A method for separating and concentrating a chlorine-37 isotope using a laser photochemical reaction, comprising a second step of obtaining Cl.

7. In Paragraph 6, The ICl supplied as a raw material for the above second stage is 37 Cl content 35 It is in a state higher than the content of Cl, and the second step above is I, an impurity present in a small amount. 35 A method for separating and concentrating chlorine-37 isotopes using a laser photochemical reaction, characterized by setting Cl as a photodecomposition target to increase photon efficiency.

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