RU2413020C1 - Procedure and device for production of molybdenum-99 - Google Patents

Abstract

FIELD: metallurgy. ^ SUBSTANCE: production of Mo-99 consists in filling solution reactor with fuel solution of uranyl-sulphate, in starting reactor up to specified power, in forming Mo-99 in fuel solution, in reactor shut-down, in conditioning fuel solution for decay of short-lived radionuclide and in sorption of Mo-99 from solution. Also, after reactor shut-down fuel solution is poured out of the reactor into at least one nuclear-safe reservoir; fuel solution is conditioned in this nuclear-safe reservoir. An empty reactor is repeatedly filled with fuel solution, is started up to specified power and Mo-99 is repeatedly generated in fuel solution. For the period of Mo-99 generation in the fuel reactor poured fuel solution in the nuclear-safe reservoir is conditioned. Mo-99 is sorbed from conditioned fuel solution by pumping it through at least one sorption column wherefrom Mo-99 is sorbed into at least one nuclear-safe reservoir for fuel solution conditioning. Fuel solution is conditioned, if necessary. Repeatedly emptied reactor is filled with fuel solution from the nuclear-safe reservoir for fuel solution conditioning. ^ EFFECT: raised efficiency of solution reactor producing Mo-99 under discrete mode due to reduced idle time. ^ 9 cl, 1 dwg, 1 ex

Description

The invention relates to the production of radionuclides and can be used for the production of Mo-99.

A known method of production of Mo-99 (RF Patent for the invention No. 2296712, 05.24.2005. Method of production of Mo-99 and a device for its implementation, Ermolov N.A., Zrodnikov A.V., Nerozin N.A., Smetanin E. I., Khamyanov S.V.).

The method consists in the fact that a fuel solution is pumped through the active zone of a working solution reactor with a gaseous medium filled with a compensation chamber and a sorption column, after which Mo-99 is desorbed from the sorption column and it is cleaned of radionuclide and chemical impurities. During pumping, the fuel solution is kept in the fuel solution holding apparatus, which consists of two vessels communicating at the bottom, equipped with compensation chambers located above the overflow port of the first communicating vessel, connected to each other and with the compensation chamber of the solution reactor, and pumped through the heat exchanger to cool to the optimum sorption temperatures.

The method is based on the continuous operating mode of Mo-99, which provides for the continuous selection of the fuel solution from the active zone of the working reactor, pumping the selected fuel solution through the sorption column and returning to the active zone of the fuel solution purified by sorption of Mo-99.

The disadvantage of this method is the additional complexity in ensuring the nuclear safety of a working solution reactor, associated with the need to continuously select a fuel solution from a working reactor, separate Mo-99 by sorption from the selected fuel solution, losing some of the fuel, and return the fuel solution purified from Mo-99 into a working reactor.

Closest to the technical nature of the claimed method is a method for the production and isolation of Mo-99 [US Patent No. 5910971, 07/08/99. Method and equipment for the production and separation of Mo-99. Ponomarev-Stepnoy N.N., Pavshuk V.A., Bebikh G.F., Khvostionov V.E., Trukhlyaev P.S., Shvetsov I.K.].

The method includes:

- conclusion of the reactor to a power of 20-100 kW and the operating time of fission products in the fuel solution, including Mo-99;

- decommissioning the reactor and keeping it inoperative for the decay of short-lived radionuclides accumulated in the fuel solution during reactor operation;

- pumping out the fuel solution from the reactor, transferring the pumped out fuel solution to a column containing a sorbent for sorption of Mo-99 and returning the fuel solution purified from Mo-99 to the reactor. The process continues until a substantial part of the fuel solution is passed through the sorbent.

The method is based on a discrete operating time of the Mo-99.

The reactor can operate from several hours to a week. During this time, fission products, including Mo-99, accumulate in a fuel solution in a certain amount.

After a period of operation, the reactor is stopped and kept in a subcritical state to reduce the overall activity of fission products in the fuel solution and cool the reactor. The exposure time can vary from 15 minutes to several days.

Typically, the reactor is started for five days, allowed to cool for one day, and Mo-99 is isolated on the seventh day.

The disadvantage of this method is that

- the fuel solution purified from Mo-99 upon returning to the nuclear reactor is partially mixed in it with the crude fuel solution. Therefore, not the entire fuel solution that was in the reactor immediately after shutting down the reactor was passed through the sorption column, but its substantial part;

- in the discrete operating mode of Mo-99 according to the known method, the reactor after its operation for any time (from several hours to a week) actually stands idle from one to two days. During this time, the reactor is kept to reduce the overall activity of the fuel solution and Mo-99 is isolated from it.

The technical result related to the method consists in increasing the productivity of a solution reactor producing Mo-99 in discrete mode by reducing its downtime.

A device for the production of Mo-99 is known (RF Patent for the invention No. 2296712, 05.24.2005. Method for the production of molybdenum-99 and a device for its implementation. Ermolov N.A., Zrodnikov A.V., Nerozin N.A., Smetanin E. . I., Khamyanov S.V.). The composition of the known device includes a nuclear solution reactor containing a compensation chamber above the active zone, connected in series with a sorption column in the circuit of the fuel solution, located above the solution reactor and sorption column, an apparatus for holding the fuel solution, consisting of two communicating vessels equipped with compensation cameras, the first communicating vessel is also equipped with pressure and overflow nozzles, to which pressure and overflow are connected respectively pipelines connecting the apparatus for holding the fuel solution with a nuclear solution reactor, the second communicating vessel is equipped with a drain pipe located below the overflow pipe of the first communicating vessel, to which a drain pipe connecting the apparatus for holding the fuel solution with the sorption column is connected, while the compensation chambers of the first and second communicating vessels, located above the overflow pipe of the first communicating vessel, are interconnected and with the compensation chamber nuclear a solution reactor.

The device is designed for the production and separation of Mo-99 in the mode of its continuous operation, which provides for the continuous selection of the fuel solution from the active zone of the working reactor, pumping the selected fuel solution through the sorption column and returning to the active zone the fuel solution purified by sorption from Mo-99.

A disadvantage of the known device is the complexity of the hydraulic circuit, which provides continuous selection of the fuel solution from the working solution reactor, while isolating Mo-99 from the selected fuel solution and returning it to the working solution reactor. The complexity of the hydraulic circuit of the known device makes it difficult to ensure nuclear safety of a working solution reactor. The fuel content in the fuel solution will decrease over time due to burnout. Technological losses of fuel and water during the release of Mo-99 are also possible. Therefore, sometimes it will be necessary to stop the reactor and adjust the fuel solution for acidity and the content of water and fuel in it.

The closest in technical essence to the claimed device is a device for the production and separation of Mo-99 [US Patent No. 5910971, 07/08/1999, Method and equipment for the production and separation of Mo-99. Ponomarev-Stepnoy N.N., Pavshuk V.A., Bebikh G.F., Khvostionov V.E., Trukhlyaev P.S., Shvetsov I.K.].

The composition of the known device includes a nuclear solution reactor and a sorption column. The known device is intended for the production and separation of Mo-99 in the mode of its discrete operating hours, which involves filling the reactor with a fuel solution, bringing the reactor to power, accumulating Mo-99 in the fuel solution of the working reactor, shutting down the reactor, holding and cooling the fuel solution in it, pumping the fuel solution through a sorption column with the return of the fuel solution to the reactor, the output of the reactor to power and the second run of the Mo-99.

A disadvantage of the known device is that it does not exclude significant downtime of the solution reactor and thereby does not provide a possible higher productivity of the Mo-99 in the mode of its discrete operating hours.

The technical result related to the device consists in increasing its productivity by reducing the downtime of the reactor.

To achieve a technical result in the production method of Mo-99, which includes filling the solution reactor with a uranyl sulfate fuel solution, bringing the reactor to power, operating time in the Mo-99 fuel solution, shutting down the reactor, holding the fuel solution for the decay of short-lived radionuclides and sorption of Mo-99 from the solution, offered

- after stopping the reactor, pour the fuel solution from it into at least one nuclear-safe tank and keep the fuel solution in the nuclear-safe tank, at the same time fill the empty reactor with the fuel solution again, bring it to power and turn it back into the fuel solution М- 99;

- during the operating time of Mo-99 in the fuel solution, extract the drained fuel solution, sorb Mo-99 from the aged fuel solution by pumping it through at least one sorption column sorbing Mo-99 into at least one nuclear-safe tank for conditioning the fuel solution; if necessary, conditioning the fuel solution entering the conditioning tank;

- empty the reactor once again filled from a nuclear-safe tank for conditioning the fuel solution.

In particular cases, the application of the method is proposed

- for sorption of Mo-99, use at least one sorption column from at least one set of parallel-mounted sorption columns sorbing Mo-99, and after the column has developed its technical resource, use a new sorption column from the set, after all columns from the set have developed them technical resource for the sorption of Mo-99 use a sorption column from another set of parallel installed sorption columns;

- filter the fuel solution drained from the reactor;

- cool the fuel solution discharged into a nuclear-safe tank for holding the fuel solution.

To achieve a technical result in a device for the production of Mo-99, including a nuclear solution reactor connected by pipelines and at least one sorption column adsorbing Mo-99, it is proposed to provide the device with at least one nuclear-safe fuel solution holding tank connected by pipelines to the outlet pipe of the mortar reactor and the inlet pipe of at least one sorption column adsorbing Mo-99, and at least one nuclear-safe tank for air conditioning of fuel solution, connected by pipelines to the outlet pipe of at least one sorption column sorbing Mo-99, and the inlet pipe of the solution reactor.

In special cases, the performance of the device is proposed

- the device is equipped with at least one sorption column from at least one set of parallel mounted sorption columns sorbing Mo-99, equipped with remotely controlled detachable connections at the input and output of the fuel solution;

- equip the nuclear-safe tank for holding the fuel solution with a cooling system;

- install a filter for cleaning the fuel solution between the mortar reactor and the nuclear-safe tank for holding the fuel solution;

- the device is equipped with a pump for pumping the fuel solution through at least one sorption column.

The invention is illustrated in the drawing, one of the possible technological schemes of the device for the production of Mo-99.

The following notation is used in the drawing and in the text:

1 - inlet pipe of the solution reactor; 2 (1) -2 (6) - inlet nozzles of sorption columns; 3 - outlet pipe of the mortar reactor; 4 (1) -4 (6) - output nozzles of sorption columns; 5 (1) -5 (4) - remotely controlled plug-in connections; 6 (1) -6 (20) - shut-off valves; 7 - protective box; 8 (1) -8 (2) - sets of sorption columns; 9 - pump; 10 - mortar reactor; 11 - cooling system of a nuclear-safe tank for holding a fuel solution; 12 (1) -12 (6) - sorption columns; 13 - filter; 14 - a nuclear-safe tank for holding fuel solution; 15 - nuclear-safe tank for conditioning the fuel solution.

The drawing shows a process diagram of a device for the production of Mo-99, including a nuclear solution reactor 10 connected by pipelines and at least one sorption column 12 (1) -12 (6), sorbing Mo-99. The device is equipped with at least one nuclear-safe tank 14 for holding the fuel solution, connected by pipelines to the outlet pipe 3 of the solution reactor 10 and the inlet pipe 2 (1) -2 (6) of at least one sorption column 12 (1) -12 ( 6), sorbing Mo-99, and at least one nuclear-safe tank 15 for conditioning the fuel solution, connected by pipelines to the outlet pipe 4 (1) -4 (6) of at least one sorption column 12 (1) -12 ( 6), sorbing Mo-99, and the inlet pipe 1 of the solution reactor 10.

Mortar reactor 10 is designed to produce Mo-99 in a fuel solution.

At least one sorption column 12 (1) -12 (6) is intended for the sorption of Mo-99 from the fuel solution.

Nuclear-safe tank 14 is designed to hold the fuel solution discharged from the solution reactor 10 during the decay time of short-lived radionuclides contained in the drained fuel solution.

The nuclear-safe tank 15 is designed for conditioning, if necessary, a fuel solution purified from Mo-99, according to acidity, the content of fuel and water in it, and filling the solution reactor 10 with fuel solution.

In special cases, the execution of the device for the production of Mo-99:

1) the device is equipped with at least one sorption column from at least one set of 8 (1) -8 (2) parallel mounted sorption columns 12 (1) -12 (6), sorbing Mo-99, equipped with remotely controlled detachable connections 5 (1) -5 (4) at the inlet and outlet of the fuel solution;

2) the nuclear-safe tank 14 for holding the fuel solution is equipped with a cooling system 11;

3) between the mortar reactor 10 and the nuclear-safe tank 14 for holding the fuel solution, a filter 13 is installed for cleaning the fuel solution;

4) the device is equipped with a pump 9 for pumping the fuel solution through at least one sorption column 12 (1) -12 (6).

At least one set of 8 (1) -8 (2) parallel mounted sorption columns 12 (1) -12 (6), sorbing Mo-99, equipped with remotely controlled plug-in connections 5 (1) -5 (4) at the input and the output of the fuel solution is intended to replace the sorption columns with sets.

The cooling system 11 of the nuclear-safe tank 14 is designed to remove heat generated in the fuel solution during the decay of short-lived radionuclides.

The filter 13 is designed to clean the fuel solution from corrosion products.

The pump 9 is designed to pump the fuel solution through at least one sorption column 12 (1) -12 (6).

Shut-off valves 6 (1) -6 (8) and remotely controlled detachable connections are designed for switching sets of sorption columns and replacing sorption columns with sets. Shut-off valves 6 (9) -6 (20) are intended for switching sorption columns. The protective box 7 serves to accommodate sorption columns and other equipment not shown in the drawing for the isolation and purification of Mo-99.

The safety of the nuclear solution reactor 10 is ensured by regular reactivity controls. The safety of nuclear-safe tanks 14 and 15 can be achieved by their nuclear-safe design.

This device is used to implement the production method of Mo-99, including filling the solution reactor 10 with a uranyl sulfate fuel solution, outputting the reactor 10 to a power of 50-100 kW, operating hours in the Mo-99 fuel solution, shutting down the reactor 10, holding the fuel solution for decay of short-lived radionuclides and Mo-99 sorption from solution. After stopping the reactor 10, the fuel solution from it is poured into at least one nuclear-safe tank 14 and the fuel solution is aged in the nuclear-safe tank 14, while the emptied reactor 10 is again filled with fuel solution, it is brought to a power of 50-100 kW and again produced in the fuel solution Mo-99. During the operating time of Mo-99 in the fuel solution, the drained fuel solution is aged, Mo-99 is sorbed from the aged fuel solution by pumping it through at least one sorption column 12 (1) -12 (6), which adsorbs Mo-99 into at least one nuclear-safe tank 15 for conditioning the fuel solution; if necessary, conditioning the fuel solution received in the conditioning tank. Once again empty, the reactor 10 is filled from the nuclear-safe tank 15 for conditioning the fuel solution.

In particular cases of applying the production method of Mo-99:

1) for sorption of Mo-99 use at least one sorption column from at least one set of 8 (1) -8 (2) parallel mounted sorption columns 12 (1) -12 (6), sorbing Mo-99. After the column has developed its technical resource, a new sorption column from the set is used, after all the columns from the set of their technical resource have developed for the Mo-99 sorption, a sorption column is used from another set of parallel installed sorption columns;

2) the fuel solution discharged from the reactor 10 is filtered;

3) cool the fuel solution, drained into a nuclear-safe tank 14 for holding the fuel solution.

An example of a specific implementation of the device for the production of Mo-99.

1. The power of the nuclear solution reactor 10 is 50 kW.

2. Fuel solution - an aqueous solution of uranyl sulfate.

3. Enrichment of fuel with uranium-235 - 20%.

4. The volume of fuel solution in the core of a nuclear reactor is 20 liters.

5. The volume of the nuclear-safe tank 14 for aging fuel solution of 20 liters.

6. The volume of a nuclear-safe tank for conditioning a fuel solution of 20 liters.

7. The temperature of the fuel solution is 80 ° C.

8. The performance of the device according to Mo-99 is approximately 100 Ci / day.

The parameters of the sorption column, the capacity of the circulation pump, the capacity of the cooling system of a nuclear-safe tank for holding the fuel solution, the diameters of the pipelines and other characteristics of the device are determined by calculation and experimentally.

An example of a specific application of the production method of Mo-99.

The nuclear solution reactor 10 is filled with an aqueous solution of uranyl sulfate. The reactor is brought to a power of 50 kW. They accumulate Mo-99 in the fuel solution for five days and shut down the reactor 10. The fuel solution from the stopped reactor 10 is poured into a nuclear-safe tank 14 for holding the fuel solution during the decay of short-lived radionuclides. The empty reactor 10 is again filled with a fuel solution, it is brought to a power of 50 kW, and it is again produced in a Mo-99 fuel solution. During the re-production of Mo-99 in the fuel solution of the working reactor 10, the fuel solution is poured into a nuclear-safe tank 14, during the decay time of short-lived radionuclides, the heat generated in this case is removed by the cooling system 11, and Mo-99 is sorbed from the aged fuel solution by pumping it through a pump 9 through at least one sorption column 12 (1) -12 (6) into a nuclear-safe tank 15 for conditioning the fuel solution, if necessary, condition the fuel solution, p stumbled into the tank 15 for conditioning.

The shutdown of the reactor, draining of the fuel solution from it, filling the reactor with a new solution and bringing it to a power of 50 kW can be performed in up to 8 hours. The exposure of the drained fuel solution may take from 2 to 24 hours. Sorption of Mo-99 from the aged solution can be performed in about 8 hours. The conditioning of the fuel solution by acidity, the content of water and fuel in it can also be carried out in about 8 hours. Almost three days before the next shutdown of the reactor in the nuclear-safe tank 15 is a fuel solution prepared for the next filling of the reactor. A simple reactor 10, operating Mo-99 in discrete mode, is from four to eight hours.

The technical result of the invention is obtained, the productivity of a solution reactor producing Mo-99 in discrete mode is increased, due to the reduction of its downtime.

List of items

No. of poses Name one Mortar reactor inlet 2 (1) ÷ 2 (6) Sorption column inlets 3 Mortar Reactor Outlet 4 (1) ÷ 4 (6) Outlets for sorption columns 5 (1) ÷ 5 (4) Remotely controlled plug-in connections 6 (1) ÷ 6 (20) Stop valves 7 Protective box 8 (1) ÷ 8 (2) Sorption column sets 9 Pump 10 Solution reactor eleven Cooling System for a Nuclear-Safe Tank for Holding Fuel Solution 12 (1) ÷ 12 (6) Sorption columns 13 Filter fourteen Nuclear-safe fuel solution holding tank fifteen Nuclear-safe fuel conditioning tank

Claims (9)

1. The method of production of Mo-99, including filling the mortar reactor with a uranyl sulfate fuel solution, bringing the reactor to power, operating time in the Mo-99 fuel solution, shutting down the reactor, holding the fuel solution to decompose short-lived radionuclides and sorbing Mo-99 from the solution, characterized in that after the reactor is stopped, the fuel solution is poured from it into at least one nuclear-safe tank and the fuel solution is kept in the nuclear-safe tank, while the emptied reactor is again filled then solution, bring it to power and turn it on again in the Mo-99 fuel solution, during the operation of the Mo-99 in the fuel reactor, the drained fuel solution is held in a nuclear-safe tank, Mo-99 is sorbed from the aged fuel solution by pumping it through at least one sorption column sorbing Mo-99, at least one nuclear-safe tank for conditioning the fuel solution, if necessary, condition the fuel solution, emptied once again Torr fill the fuel solution from the tank safe nuclear fuel conditioning solution. 2. The method according to claim 1, characterized in that at least one sorption column from at least one set of parallel installed sorption columns sorbing Mo-99 is used for Mo-99 sorption, and after the column has developed its technical resource, a new sorption column is used a column from the set, after all the columns from the set of their technical resource have developed for sorption, the Mo-99 sorption column is used from another set of parallel installed sorption columns. 3. The method according to claim 1, characterized in that the fuel solution discharged from the reactor is filtered. 4. The method according to claim 1, characterized in that the fuel solution, drained into a nuclear-safe tank for holding the fuel solution, is cooled. 5. Device for the production of Mo-99, comprising a nuclear solution reactor connected by pipelines and at least one sorption column adsorbing Mo-99, characterized in that it is equipped with at least one nuclear-safe fuel solution holding tank, connected by pipelines to the outlet pipe of the mortar reactor and the inlet of at least one sorption column adsorbing Mo-99, and at least one nuclear-safe tank for conditioning the fuel solution, nym pipes with an outlet of at least one adsorption column, absorbing Mo-99, and the inlet of the reactor mortar. 6. The device according to claim 5, characterized in that it is equipped with at least one sorption column from at least one set of parallel-mounted sorption columns sorbing Mo-99, equipped with remotely controlled detachable connections at the input and output of the fuel solution. 7. The device according to claim 5, characterized in that the nuclear-safe tank for holding the fuel solution is equipped with a cooling system. 8. The device according to claim 5, characterized in that a filter for cleaning the fuel solution is installed between the mortar reactor and the nuclear-safe tank for holding the fuel solution. 9. The device according to claim 5, characterized in that it is equipped with a pump for pumping the fuel solution through at least one sorption column.

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