A kind of preparation method of radioactivity iodine-125 and continuous circulation loop device
Technical field
The present invention relates to radioisotopic preparation field, and in particular to a kind of preparation method of radioactivity iodine-125 and
Continuous circulation loop device.
Background technology
Iodine-125 is a kind of radionuclide (59.4 days half-life period) more long of half-life period, is released energy by electron capture
It is the X-ray of 27.4KeV, is the gamma-rays of 35.5KeV with emitted energy.Because iodine-125 half-life period is more long, gamma-rays energy
Amount is low, without β radiation, the radiation injury produced to tissue is small, therefore iodine-125 is in biomedical, radio-immunity in-vitro diagnosis
It is widely applied with the aspect such as brachytherapy tumour.Especially in recent years, in radiation physics and radioecology
Flourish on the basis of, seeds implanted treatment system improve constantly with it is perfect, implanted treatment equipment is updated, and iodine-125 is near
Distance treatment achieves good result.Nineteen fifty-one, I.Bergstro reports raw under reactor Thermal Neutron Irradiation with natural xenon
The method for producing iodine-125.From this, constantly improved using the method for reactor large-scale production iodine-125.Its nuclear reaction is:
During reactor irradiation xenon -124, also in the presence of two secondary nuclear reactions, i.e.,:
This secondary nuclear reaction produces energy iodo- 126 impurity (about 13 days half-life period) higher, reduces the product of iodine-125
Volume, adverse effect is caused to iodine-125 product quality.In addition, the abundance of natural xenon -124 is only 0.095%, generally require to adopt
Short irradiation is carried out in reactor as target material with the xenon -124 of enrichment high, to increase the yield of iodine-125, is reduced
Iodo- 126 content.
At present, reactor irradiation production iodine-125 mainly has two methods of high pressure target cylinder method and intermittent cyclic loop method.
High pressure target cylinder irradiation method is will to be made target piece in the gas compression of xenon -124 to aluminum barrel, be put into the irradiation channel of reactor
Internal irradiation certain hour, then takes out target cylinder and places about one month, waits most of xenon -125 (half-life period about 17h) to decay into product
Thing iodine-125, while iodo- 126 impurity for making half-life period shorter decays to less than the 1% of iodine-125 content, then by Strong oxdiative
Sodium solution dissolving extraction obtains iodine-125 product.
Xenon -124 is persistently subject to neutron exposure in static target piece in the production method, and the iodine-125 of generation may proceed to absorb
Neutron constantly produces iodo- 126 impurity, and the thermal-neutron reaction section of iodine-125 is more much bigger than xenon -124, leads to after Long-Duration Exposure
Cross125I(n,γ)126I reactions will produce substantial amounts of iodo- 126 impurity,126I impurity is accounted for12510% or so of I is, it is necessary to pass through more long
The decay of time makes126I exists125Content in I products is down to and meets use requirement, therefore125The decay loss of I products is very big.
In order to overcome the drawbacks described above of high pressure target cylinder method, people devise intermittent cyclic loop method and carry out process modification.
2004, Miao of China Atomic Energy Science Research Institute increased magnitude and devises a set of intermittent cyclic loop for preparing125I, and apply
Patent, Application No. 200410037654.8, patent name is " radioactivity125The preparation method of I and intermittent cyclic loop fill
Put ".Intermittent cyclic loop method is a closed circuit system, an irradiation capsule is provided with reactor, using pipeline loop
Xenon -124 is injected into irradiation capsule, neutron irradiation 1 day or so, then by irradiated xenon -124 from out-pile storage tank with pump valve system
Gas be transferred to decay bottle in place 5-7 days, after xenon -125 fully decay generation iodine-125 after, will decay bottle in xenon -
124 gases are sent back in irradiation capsule and continue to irradiate.It is typically provided with 2-7 decay bottle so that have xenon -124 to be in all the time in irradiation capsule
Irradiation behaviour, makes full use of reactor.Decay bottle is sent to workshop, and the iodine-125 to adsorbing on inwall is extracted, and leads to
Diluted sodium hydroxide solution washing decay bottle is commonly incorporated into, iodine-125 is dissolved and is reclaimed.After gas decays 5 days in the bottle that decays,126I is miscellaneous
Matter is accounted for1250.05% or so of I.
Intermittent cyclic loop method major defect is that xenon -124 is still static irradiation in irradiation capsule, decay generation
Iodine-125 may proceed to activation iodo- 126 impurity of generation, although impurity content is less than high pressure target cylinder method, but in process not
Being optimal, iodo- 126 impurity can also further be greatly reduced.
The content of the invention
It is an object of the invention to provide new method prepared by a kind of radioactivity iodine-125, the method is in intermittent cyclic loop
Further improvement is made that on the basis of method, the endless form of xenon in iodine-125 loop is changed to from intermittent cycle continuously to follow
Ring, iodo- 126 impurity content can reduce by 2 orders of magnitude, reach 2/1000000ths of iodine-125 or so (~0.0002%), solution
Current production iodine-125 of having determined yields poorly, the technical barrier that iodine 126- impurity contents are high.And by method of the present invention correspondence
Device can also quantitative collection iodine-125.
The present invention is achieved through the following technical solutions:A kind of preparation method of radioactivity iodine-125, including xenon is in reaction
Irradiation in heap, circulate, the technique such as gaseous iodine absorption, iodine desorption, iodine absorb;It is placed on the irradiation bottle of core section
Closed system is constituted by major loop pipeline, continuous one-way circulation flows in return by driven by mechanical pump xenon,
The gas of xenon -124 absorbs neutron and is converted into xenon -125 when flowing through irradiation bottle, xenon -125 gradually decays and produces iodine-125, iodine-125 warp
Cross when major loop pipeline is recycled to out-pile iodine adsorber and be captured, xenon will not be adsorbed by iodine adsorber, and xenon passes through major loop
Pipeline flows back to in-pile irradiation bottle, and neutron is absorbed again, then flow to out-pile, again passes by iodine adsorber, and so on constantly
Circulation.
The rate of circulating flow of xenon is 1mL/min-20L/min in loop;Loop gas temperature is 20 DEG C -100 DEG C.
Thermal neutron fluence rate is not less than 1.0 × 10 during irradiation11n·cm2·s-1, thermal neutron is E<The neutron of 0.625eV.
Air pressure in continuous circulation production process can be malleation or negative pressure, wherein, the gas in loop is natural xenon
Gas, the enrichment gas of xenon -124 or the gas containing xenon -124 diluted with inert gas
For the absorption of gaseous state iodine-125 sorbing material is for the one kind in metal platinum, copper-based platinum or contains arbitrary proportion
State the mixture of material.
Iodine-125 desorption method is sodium hydroxide solution drip washing in iodine adsorber, and NaOH is dense in sodium hydrate aqueous solution
It is 0.001mol/L-10mol/L to spend.
Continuous circulation loop device, including xenon bottle, irradiation bottle, wherein irradiation bottle is arranged on core section, also wrap
Include heat-exchange device outside core section, gaseous iodine adsorbent equipment, gas circulator, xenon bottle, the xenon bottle,
Irradiation bottle, heat-exchange device, gaseous iodine adsorbent equipment, gas circulator are sequentially connected into a circulation loop, xenon bottle it is defeated
Go out end to be connected with the main gas circuit of circulation loop, gaseous iodine adsorbent equipment is mounted with one kind or weight of sorbing material platinum, copper-based platinum
Than two kinds of mixtures for any ratio.
Also include vavuum pump, efficiently remove iodine filter, the vavuum pump is connected with the main gas circuit of circulation loop, efficiently removes iodine mistake
Filter is connected with vavuum pump.
Irradiation bottle be stainless steel or aluminum alloy material, return be stainless steel, aluminium alloy, corundum, zirconium, zircaloy,
One kind in teflon.
The present invention is different from prior art, has the following advantages and advantages:
1st, circulation absorption method of the invention is excellent is:The present invention solves people all the time and urgently wants that what is solved asks
Topic, the radioactivity iodine-125 in the xenon of loop is just no longer participate in circuit cycle once trapping, will not further generate iodo- 126 miscellaneous
Matter, iodo- 126 impurity content is reduced to extremely low degree (iodo- 126 impurity content is about the 0.0002% of iodine-125), realizes
The notable volume increase of iodine-125 and124The direct recycling of Xe gases, improves125The quality and production efficiency of I.
2nd, continuous circulation loop method of the invention need not set 2-7 decay bottle, irradiation bottle need to be only retained on major loop, is returned
Road pipeline, circulating pump and iodine adsorber can meet most basic service requirement, and can realize complete Absorption quantity.
Brief description of the drawings
Accompanying drawing described herein is used for providing further understanding the embodiment of the present invention, constitutes of the application
Point, do not constitute the restriction to the embodiment of the present invention.In the accompanying drawings:
Fig. 1 is schematic structural view of the invention.
Fig. 2, Fig. 3 are the schematic diagram of embodiment 7.
Mark and corresponding parts title in accompanying drawing:
1- irradiation bottle, 2- heat-exchange devices, 3- iodine adsorbers, 4- gas circulators, 5- xenons bottle, 6- vavuum pumps, 7- are high
Effect removes iodine filter, 8- thermometers, 9- pressure gauges, 10- flowmeters, 11- valves, 12- irradiation bottles, 13- xenons bottle, 14- gases
Circulating pump, 15- iodine adsorbers, 16- vavuum pumps, 17- efficiently removes iodine filter, 18- heat exchangers, 19- iodine adsorbers, 20- iodine
Absorber, 21,22,23,24- valves.
Specific embodiment
To make the object, technical solutions and advantages of the present invention become more apparent, with reference to embodiment and accompanying drawing, to this
Invention is described in further detail, and exemplary embodiment of the invention and its explanation are only used for explaining the present invention, do not make
It is limitation of the invention.
The method for preparing radioactivity iodine-125:By the reacted heap active region irradiation of xenon recycle stream, flow through reactor activity
Absorption is re-circulated into the continuous circulation production process of core section irradiation outside area, the adsorbed product warp that adsorption process is obtained
It is desorbed to obtain radioactivity iodine-125.
Embodiment 1
As shown in figure 1, a kind of continuous circulation loop system for preparing radioactivity iodine-125, including xenon bottle, irradiation devices,
Wherein irradiation devices are arranged on core section, and xenon bottle is arranged on outside core section, also including being lived in reactor
Property area outside heat-exchange device, iodine adsorber, gas circulator, the xenon bottle, irradiation devices, heat-exchange device, iodine absorption
Device, gas circulator are sequentially connected into a circulation loop, and the output end of xenon bottle is connected with main circulation loop.
Iodine adsorber, can be for 1,2 or multiple, wherein, with parallel connection between the gaseous state iodine adsorber of 2 or more
Mode is connected, and can at any time take or change one of iodine adsorber, without the gas circulation in stop loop, reach it is online and
Quantity-produced purpose.Gaseous state iodine adsorber working region is provided with shielding work box, facilitates replacing and transfer of iodine adsorber etc.
Operation, security of system is high.
Also include vavuum pump and environmental monitoring system, vavuum pump is connected with the output end of irradiation devices, and vavuum pump is also connected with
Have efficiently except iodine filter;Environmental monitoring system includes thermometer, pressure gauge, flowmeter, the input of heat sink, output end
Thermometer, pressure gauge are provided with the output end of iodine adsorber, the output end of heat sink is provided with flowmeter.
Embodiment 2
Fig. 2, Fig. 3 are to prepare radioactivity125A kind of implementation method of the continuous circulation loop system of I.Including irradiation bottle 12,
Heat exchanger 18, iodine adsorber 15 and gas circulator 14 etc..
1st, reactor irradiation
Before reactor operation, whole circuit system is vacuumized with vavuum pump 16, it is ensured that system air-tightness is conformed to
After asking, vavuum pump 16 and branch road valve are closed, open valve 11, in making loop in xenon bottle 13 in the gas infusion circuit of xenon -124
Air pressure reaches 100KPa, is then shut off valve 11.
Gas circulator 14 is opened, xenon is continuously circulated in closed loop, start reactor, to core section
Irradiation bottle 12 carries out neutron irradiation, and the gas of xenon -124 for flowing through irradiation bottle 12 is produced xenon -125 by Thermal Neutron Irradiation, and xenon -125 is not
Disconnected decay is iodine-125, after the xenon containing iodine-125 flows through the heat exchanger 18 of out-pile by circulation loop, about 50 DEG C of temperature,
Into after the iodine adsorber 15 equipped with copper-based alloy platinum material125I is adsorbed, and the gas of xenon -124 continues cycling through inflow irradiation bottle 12 and enters
Row irradiation.Iodine adsorber system is two iodine adsorbers of parallel connection (Fig. 3), when the iodine-125 in iodine adsorber 19 reach it is a certain amount of
When, valve 21,22 is closed, bypass valve 23,24 is opened, iodine adsorber 20 in parallel is started working.Meanwhile, by iodine adsorber 19
The desorption that iodine-125 is carried out between being transferred to chemical treatment is extracted, and obtains iodine-125 product, so completes the circulation life of irradiation-absorption
Product process.
2nd, the desorption of iodine-125
It is and de- after the shielding work box that iodine adsorber 19 containing a certain amount of iodine-125 product is transferred between chemical treatment
Adsorption device is connected, and drip washing is carried out to iodine adsorber with 0.1mol/LNaOH solution, obtains the inorganic salt solution containing iodine-125.
Assuming that core section thermal neutron fluence rate is 5E+13ncm-2s-1, irradiation bottle product 2.4L, loop gas
It is 10% gas of xenon -124 (enrichment 99%) and 90% helium, gas flow rate 200mL/min, continuous circulation is irradiated 9 days,
Iodine-125 product about 100Ci can be produced, wherein iodo- 126 impurity content is about the 0.0002% of iodine-125.
Embodiment 3
Assuming that core section thermal neutron fluence rate is 5E+13ncm-2s-1, irradiation bottle product 2.4L, loop gas
It is 20% gas of xenon -124 (enrichment 99%) and 80% helium, gas flow rate 300mL/min, the reacted heap of recycle stream is lived
Property area irradiation, flow through outside core section, gas is continued cycling through in the loop after through iodine adsorber, iodine-125 is trapped, operation
After 9 days, iodine-125 product about 200Ci can be produced, wherein iodo- 126 impurity content is about the 0.0002% of iodine-125.
Embodiment 4
Assuming that core section thermal neutron fluence rate is 5E+13ncm-2s-1, irradiation bottle product 2.4L, loop gas
It is 30% gas of xenon -124 (enrichment 99%) and 70% helium, gas flow rate 400mL/min, the reacted heap of recycle stream is lived
Property area irradiation, flow through outside core section, gas is continued cycling through in the loop after through iodine adsorber, iodine-125 is trapped, operation
After 9 days, iodine-125 product about 300Ci can be produced, wherein iodo- 126 impurity content is about the 0.0002% of iodine-125.
Embodiment 5
Assuming that core section thermal neutron fluence rate is 5E+13ncm-2s-1, irradiation bottle product 2.4L, loop gas
It is 50% gas of xenon -124 (enrichment 99%) and 50% helium, gas flow rate 500mL/min, the reacted heap of recycle stream is lived
Property area irradiation, flow through outside core section, gas is continued cycling through in the loop after through iodine adsorber, iodine-125 is trapped, operation
After 9 days, iodine-125 product about 500Ci can be produced, wherein iodo- 126 impurity content is about the 0.0002% of iodine-125.
Embodiment 6
Assuming that core section thermal neutron fluence rate is 5E+13ncm-2s-1, irradiation bottle product 2.4L, loop gas
It is the gas of xenon -124 (enrichment 99%), gas flow rate 1000mL/min that the reacted heap active region of recycle stream irradiates, flows through reaction
Outside heap active region, gas is continued cycling through in the loop after through iodine adsorber, iodine-125 is trapped, and after running 9 days, can be produced iodo-
125 products about 1000Ci, wherein iodo- 126 impurity content is about the 0.0002% of iodine-125.
Embodiment 7
Assuming that core section thermal neutron fluence rate is 5E+13ncm-2s-1, irradiation bottle product 2.4L, loop gas
It is 10% gas of xenon -124 (enrichment 99%) and 90% helium, gas flow rate 1000mL/min, the reacted heap of recycle stream
Active region is irradiated, flows through outside core section, and gas is continued cycling through in the loop after through iodine adsorber, iodine-125 is trapped, fortune
After row 18 days, iodine-125 product about 200Ci can be produced, wherein iodo- 126 impurity content is about the 0.0002% of iodine-125.
To further illustrate remarkable result of the invention, three kinds of iodine-125 preparation methods are compared:It is basic in parameter
In the case of identical, three kinds of method iodine-125 yields are close in principle, and difference is mainly reflected on iodo- 126 impurity content.Under
Table can be seen that, it can be seen that, the present invention solves the urgent issue to be resolved of people all the time, realizes production efficiency and carries
The limitation of 126 impurity high and iodo-.
Sequence number |
Method |
Iodo- 126 impurity content in iodine-125 |
1 |
Continuous circulation loop method (present invention) |
0.0002% |
2 |
Intermittent cyclic loop method |
0.05% |
3 |
High pressure target cylinder method |
10% |
Above-described specific embodiment, has been carried out further to the purpose of the present invention, technical scheme and beneficial effect
Describe in detail, should be understood that and the foregoing is only specific embodiment of the invention, be not intended to limit the present invention
Protection domain, all any modification, equivalent substitution and improvements within the spirit and principles in the present invention, done etc. all should include
Within protection scope of the present invention.