177Lu irradiation production method based on pressurized water reactor

Abstract

The invention belongs to the technical field of isotope production, and particularly relates to a 177Lu irradiation production method based on a pressurized water reactor. Comprising the following steps: step 1, packaging Lu2O3 powder in a target box, performing sealing treatment, and storing the target box in a storage tank of a rabbit system outside a reactor core; 2, during the operation period of the pressurized water reactor, transporting the target piece box into the reactor core through a running rabbit system; 3, the target piece box receives neutron irradiation at the axial middle position of the central instrument pipe, and 176Lu reacts to generate 177Lu; 4, when the 177Lu generated by the irradiation of the 176Lu in the target box reaches the designed saturation specific activity, transporting the target box to a post-irradiation target storage tank outside the reactor core; and 5, during the operation period of the pressurized water reactor, repeating the steps 2-4 until the reactor is shut down. The method has the beneficial effects that the single irradiation time of the target boxes can be controlled through analysis, so that a plurality of target boxes can be irradiated in a single refueling period of the pressurized water reactor, and the yield of 177 Lu is greatly improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of isotope production, and specifically relates to a pressurized water reactor-based 177 Lu irradiation production method. Background Art

[0002] 177 Lu is an important medical isotope that mainly emits beta rays when it decays, with a half-life of 6.6443 days. It is used in targeted radiotherapy to treat diseases such as neuroendocrine tumors and prostate cancer. Medical grade 177 Lu kills cancer cells while leaving healthy cells unaffected.

[0003] The Bruce Nuclear Power Plant in Canada produces nuclear power indirectly through irradiation. 176 Yb production 177 Lu. Lu produced by the indirect production route must be separated from the irradiated Yb target. 177 The quality of Lu preparations depends largely on the separation method used. Since Yb ​​is present in large quantities (tens of milligrams) and Lu is present in the target material at only microgram levels, separation becomes very complicated. Summary of the invention

[0004] The purpose of the present invention is to provide a 177Lu irradiation production method based on a pressurized water reactor, which can place the irradiated target in the empty instrument tube remaining in the commercial pressurized water reactor, and produce the target by utilizing the neutron irradiation environment provided by the reactor during operation. 177 Lu.

[0005] The technical solution of the present invention is as follows: a pressurized water reactor based on 177 The Lu irradiation production method comprises the following steps:

[0006] Step 1: Encapsulate Lu2O3 powder in a target box, seal it, and store the target box in a storage tank of the Paotu system outside the core;

[0007] Step 2: During the operation of the pressurized water reactor, the target box is transported to the core through the running rabbit system;

[0008] Step 3: The target box is irradiated with neutrons in the middle of the central instrument tube. 176 Lu reaction generates 177 Lu;

[0009] Step 4: Target Box 176 Lu irradiation 177 When Lu reaches the designed saturated specific activity, the target box is transported to the irradiated target storage tank outside the core;

[0010] Step 5: During the operation of the pressurized water reactor, repeat steps 2 to 4 until the reactor is shut down.

[0011] In the step 1, Lu2O3 powder is packaged in a metal aluminum cylindrical target box with an outer diameter of 5 to 7 mm and a height of 10 to 30 mm.

[0012] The target box is filled with helium.

[0013] In step 2, compressed gas or mechanical means is used to transport the target box to the central instrument tube of the core fuel assembly through the target conduit connecting the outside and the inside of the core in the running rabbit system.

[0014] The target catheter has a length of 20 to 24 m, an outer diameter of 9 to 10 mm, and an inner diameter of 7 to 8 mm. The target catheter extends to the axial middle of the central instrument tube.

[0015] In step 4, compressed gas or mechanical means is used to transport the target box through the target guide tube to the irradiated target storage tank outside the core.

[0016] After the reactor is shut down in step 5, the target guide tube is taken out from the central instrument tube of the core fuel assembly.

[0017] The beneficial effects of the present invention are as follows: the present invention can realize the production of short-lived radioactive isotopes by utilizing neutrons in the reactor while improving the utilization rate of the instrument tube; the transmission of the irradiated target without stopping the reactor can be realized by the running rabbit device, and the irradiation time of the irradiated target can be controlled more flexibly during the operation of the reactor, which is particularly suitable for 177 The production of short-lived radioactive isotopes such as Lu; the single irradiation time of the target box can be controlled by analysis, so that multiple target boxes can be irradiated in a single refueling cycle of the pressurized water reactor, which greatly improves 177 Road output. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of loading the target box in the core;

[0019] Figure 2 This is a schematic diagram of the target box after the fuel assembly is loaded;

[0020] Figure 3 Schematic diagram of the target box in the instrument tube.

[0021] In the figure: 1 old assembly, 2 new assembly, 3 new assembly loaded into the irradiation target box, 4 fuel rod, 5 guide tube, 6 instrument tube loaded into the target box, 7 instrument tube, 8 pressure boundary of the rabbit running device in the instrument tube, 9 target box cladding, 10 target material. DETAILED DESCRIPTION

[0022] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] The invention proposes a 177Lu irradiation production method based on a pressurized water reactor, which uses a direct production method. In the direct production method, the main component of the product is Lu, and separation is relatively simple. 176 The thermal neutron cross section of Yb is only 2.4 bar, while 176 The thermal neutron cross section of Lu can reach 2000 bar, and the direct production method has a higher thermal neutron utilization rate.

[0024] When a commercial pressurized water reactor is operating at its designed power, neutrons are continuously generated and disappear in the reactor, which will maintain a relatively stable neutron field environment. The specific neutron flux density varies to a certain extent at different positions in the fuel assembly, but the basic order of magnitude is the same. The stable and effective neutron irradiation environment provided by the reactor during operation can be used to irradiate targets.

[0025] A pressurized water reactor 177 Lu irradiation production method, the target box is transported between the inside and outside of the pile by a rabbit running device, the rabbit running device is connected to the central instrument tube of the fuel assembly in the reactor inside the pile, and is connected to the target box collection device outside the pile. The target box is transported to the central instrument tube of the fuel assembly in the reactor by the rabbit running device for irradiation, and the target material in the target box is transported to the outside of the reactor by the rabbit running device after reaching the target activity; the irradiation position of the target box is preferably the position of the instrument tube of the fuel assembly with a relatively high power level in the pile; there are positioning pins in the instrument tube, which can fix the target box in the middle position of the active section of the fuel rod assembly with a higher neutron flux in the axial direction of the instrument tube, and the pressure boundary of the rabbit running device in the pile is located in the instrument tube; the target box is cylindrical, and consists of a target box cladding and a target material encapsulated inside. The target box cladding material is aluminum, the target material is Lu2O3 powder, and the target box is filled with helium. The outer diameter of the target box is smaller than the inner diameter of the pressure boundary of the rabbit device in the instrument tube, so that it can be transported through the rabbit device. Only one target box is placed in a single instrument tube at a time. After the target box reaches the target activity after being irradiated for a suitable time in the instrument tube, it is transported to the reactor, and a new target box is transported to the reactor for irradiation. The irradiation time of a single target box is much shorter than a single refueling cycle of a pressurized water reactor, so multiple target boxes can be irradiated in a single refueling cycle of a pressurized water reactor.

[0026] A pressurized water reactor 177 The Lu irradiation production method comprises the following steps:

[0027] Step 1: Lu2O3 powder is packaged in a metal aluminum cylindrical target box with an outer diameter of 5-7 mm and a height of 10-30 mm, sealed, and filled with helium inside the target box, and the target box is stored in a storage tank of the Paotu system outside the core;

[0028] Step 2: During the operation of a commercial pressurized water reactor, the target box is transported to the core through the Rabbit system. Specifically, compressed gas or mechanical means are used to transport the target box to the central instrument tube of the core fuel assembly through the target tube connecting the outside and inside of the core in the Rabbit system, wherein the target tube is 20 to 24 meters long, with an outer diameter of 9 to 10 mm, an inner diameter of 7 to 8 mm, and a smooth inner wall. The target tube extends to the axial middle of the central instrument tube. The portion of the target tube in the central instrument tube is the pressure boundary. The length of the portion of the target tube in the central instrument tube is about 2 meters. The inner diameter of the central instrument tube of the CF3 fuel assembly is 11.45 mm.

[0029] Step 3: The target box is irradiated with neutrons in the middle of the central instrument tube. 176 Lu reaction generates 177 Lu;

[0030] Step 4: Target Box 176 Lu irradiation 177 When Lu reaches the designed saturated specific activity, about 40 to 50 days later, compressed gas or mechanical means are used again to transport the target box through the target guide tube to the irradiated target storage tank outside the core;

[0031] Step 5: During the operation of the commercial pressurized water reactor, repeat steps 2 to 4 until the reactor is shut down. After the reactor is shut down, the target guide tube is removed from the central instrument tube of the core fuel assembly to avoid affecting the fuel assembly loading and unloading operation after the reactor is shut down.

[0032] Example:

[0033] The following is an example of a Hualong model in operation, in which the Hualong model reactor is composed of 177 CF3 fuel assemblies, and the reactor refueling cycle is 18 months. The method of the present invention comprises the following steps:

[0034] Four new assemblies near the core center area were selected for production 177 Lu, the target box is loaded and removed by the running rabbit system during the operation of the reactor. The target box is loaded in the core as follows Figure 1 As shown, the target box is loaded into the fuel assembly as shown in Figure 2 As shown;

[0035] When the target box is transported to the instrument tube by the running rabbit system, it is arranged in the axial middle area of ​​the instrument tube by the positioning pin, such as Figure 3 As shown;

[0036] The target box is a straight cylinder with an outer diameter of 6mm, a side wall thickness of 1mm, a thickness of 2mm at both ends, and a height of 20mm. The target box shell material is aluminum. A single target box is filled with 1.9g of chemical purity of 99.99%. 176Lu2O3 powder with Lu enrichment of 68.90%;

[0037] After the target box is irradiated in the reactor for 42 equivalent full-power days, it is transported out of the core through the running rabbit device, and a new target box is transported into the reactor for irradiation at the same time;

[0038] The reactor balance cycle length is 502 equivalent full-power days. If the loading, irradiation and removal time of a single target box is conservatively assumed to be 45 equivalent full-power days, a single instrument tube can be finally extracted during a single cycle. 177 The number of Lu target boxes is about 11, and the cumulative amount of target particles that can be generated by a single instrument tube during a single cycle is 177 The Lu activity is about 3.3×10 3 Ci.

Claims

1. A pressurized water reactor 177 Lu irradiation production method, characterized in that, The following steps are involved: Step 1: Encapsulate Lu2O3 powder in a target box, seal it, and store the target box in a storage tank of the Paotu system outside the core; Step 2: During the operation of the pressurized water reactor, the target box is transported to the core through the running rabbit system; Step 3: The target box is irradiated with neutrons in the middle of the central instrument tube. 176 Lu reaction generates 177 Lu; Step 4: Target Box 176 Lu irradiation 177 When Lu reaches the designed saturated specific activity, the target box is transported to the irradiated target storage tank outside the core; Step 5: During the operation of the pressurized water reactor, repeat steps 2 to 4 until the reactor is shut down.

2. A pressurized water reactor as claimed in claim 1 177 Lu irradiation production method, characterized in that: In the step 1, Lu2O3 powder is packaged in a metal aluminum cylindrical target box with an outer diameter of 5 to 7 mm and a height of 10 to 30 mm.

3. A pressurized water reactor based on claim 1 or 2 177 Lu irradiation production method, characterized in that: The target box is filled with helium.

4. A pressurized water reactor based on claim 1 177 Lu irradiation production method, characterized in that: In step 2, compressed gas or mechanical means is used to transport the target box to the central instrument tube of the core fuel assembly through the target conduit connecting the outside and the inside of the core in the running rabbit system.

5. A pressurized water reactor based on claim 4 177 Lu irradiation production method, characterized in that: The target catheter has a length of 20 to 24 m, an outer diameter of 9 to 10 mm, and an inner diameter of 7 to 8 mm. The target catheter extends to the axial middle of the central instrument tube.

6. A pressurized water reactor based on claim 1 177 Lu irradiation production method, characterized in that: In step 4, compressed gas or mechanical means is used to transport the target box through the target guide tube to the irradiated target storage tank outside the core.

7. A pressurized water reactor based on claim 1 177 Lu irradiation production method, characterized in that: After the reactor is shut down in step 5, the target guide tube is taken out from the central instrument tube of the core fuel assembly.

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