RU2723473C1 - Device for loading liquid nuclear fuel into nuclear homogeneous reactor - Google Patents

Abstract

FIELD: nuclear physics and equipment.SUBSTANCE: invention relates to additional equipment of nuclear homogeneous reactor of solution type, intended, for example, for production of medical isotopes. To achieve this technical result, liquid nuclear fuel loading device is proposed, which is a system of tanks and pipelines equipped with shutoff valves arranged on a single mobile frame. Structure of the device includes container-dispenser of not more than 3,000 cmwith level gauge on the weighing device (strain gauge) with an accuracy better than 1 %, air filter, volumetric vacuum meter and pipelines with shutoff valves for fuel drain into reactor housing and removal of gases into pumping and localization system of said gases. In lower part device has tray and supports, and along perimeter protective casing. All elements in contact with liquid fuel are made from 12H18N10T steel.EFFECT: technical result is possibility of dosed nuclear-safe, remote supply of liquid nuclear fuel into housing of core of homogeneous nuclear reactor of solution type.3 cl, 2 dwg

Description

Technical field

The invention relates to additional equipment for a nuclear homogeneous solution-type reactor intended, for example, for the production of medical isotopes.

State of the art

The equipment for a solution of a nuclear reactor for producing medical radioisotopes, RF patent 2624823, determines the feasibility of using a liquid nuclear fuel loading system (UTT), for which a peripheral device can be used.

A known complex of nuclear mortar reactors, patent for the invention of the Russian Federation 2630259, a distinctive feature of which is that the reactor contains a system for loading fresh fuel solution. However, the design of the fresh fuel solution loading system is not disclosed in detail.

The technical problem of accidents during the handling of liquid nuclear fuel and, to the solution of which the claimed invention is directed, is to increase nuclear safety when refueling a reactor with nuclear fuel both during the physical start-up of a homogeneous solution-type nuclear reactor and during scheduled maintenance work on it.

Disclosure of the invention

The technical result is the possibility of a dosed nuclear-safe, remote supply of liquid nuclear fuel to the core of a nuclear reactor of a homogeneous solution-type reactor.

To achieve this technical result, a device for loading liquid nuclear fuel (UZT) into a nuclear homogeneous reactor is proposed, including a system of tanks located on weighing devices, a filter, pipelines equipped with shutoff valves, placed on a single mobile frame with a tray and a casing.

The structure of the proposed device includes a frame attached to it: a dispensing tank with a volume of not more than 3000 cm ³ and a filling tank, mounted on weighing devices with an accuracy of at least 1%, an aerosol air filter, a pressure sensor and pipelines with shutoff valves.

Solenoid valves on the pipeline from the refueling tank and on the pipeline to the reactor vessel are electrically connected to the CPS of the nuclear reactor kit.

The frame at the bottom has a pallet and supports, and along the perimeter there is a protective casing, and all the elements in contact with liquid fuel and the casing are made of steel 12X18H10T.

Dosing tank with a volume of not more than 3000 cm ³ (the volume of tanks must meet the requirements of nuclear safety according to NP-009-17., I.e. the rate of introduction of positive reactivity is not more than 0.07 b _eff / s)

Brief Description of the Drawings

In FIG. 1 shows the elements of the technological scheme of a device for loading liquid (UZT) nuclear fuel into a nuclear homogeneous reactor, where:

VN1, VN4, VN5, VN7, VN9 - electromagnetic valve;

VN2, VNZ, VN6, VN8 - manual valve;

E1 - refueling capacity;

E2 - dispenser;

P - pressure sensor;

F - aerosol filter;

G1, G2 - strain gauge.

In FIG. 2 shows one of the possible structural solutions of the device for loading liquid nuclear fuel into a nuclear homogeneous reactor, where:

1 - dispenser E2;

2 - electromagnetic valve BH4;

3 - a partition;

4 - a casing;

5 - pallet;

6 - refueling capacity E1;

7 - technological box;

8 - support;

9, 11 - manual valve BH2, BH8;

10 - pressure sensor P;

12 - frame;

13 - highway fuel solution;

The implementation of the invention

A possible structural solution of the device for loading liquid nuclear fuel into a nuclear homogeneous reactor, shown in FIG. 2 is a frame 12 on which all the elements of the flow diagram of FIG. 1.

The dispenser E2 is connected to the valves BH6, BH2 and electrically operated valves BH7, BH1, BH4 and BH5 with welded pipe connections. The dispenser E2 itself is located and secured with screw connections on a G2 strain gauge. The metering tubes have bends to minimize the effect on the weight reading when measuring the dose of liquid fuel. The BH7 solenoid valve on the opposite side from the dispenser pipes E2 is connected by a welded pipe connection to the emergency manual valve BH8 and then to the threaded connection to the reactor refueling line. The BH5 electrically operated valve on the opposite side from the dispenser pipes E2 is welded to the pipe and then threadedly connected to the E1 refueling tank, which is delivered each time from the nuclear fuel storage room, clamped to UZT strain gauge scales G1 and connected to the UZT pipes. The BH4 solenoid valve is connected by a pipe and a welded joint to the BH9 solenoid valve and then to the aerosol filter for communication with the atmosphere. The BH1 solenoid valve is threadedly connected to a gas pumping system or ULG. In front of the valve from the dispenser side E2, a pressure sensor P is connected via a tee and valves BH2 and BH3.

The UTF frame 12 of FIG. 2 with the equipment placed, it is closed by a casing 4 having doors on two opposite sides in the figures not shown. The front door of FIG. 2 not shown serves to access the installation site of the refueling tank E1 pos. 6 and the process box 7, the rear door of FIG. 2 not shown - for access to other units, incl. to manual valves. The partition 3 separates the workplace of the personnel installing and removing the refueling tank E1 pos. 6, from the rest of the UZT units. Pallet 5 provides for the localization of a possible drip leak from the lines of the fuel solution 13. Hoses and electric cables of the external connection in FIG. 2, not shown, rolled into coils, fixed inside the casing 4. During operation, electrical cables are connected through the terminal box to the CPS of a homogeneous reactor. The main structural material of the equipment in contact with the fuel and the casing 4 is steel 12X18H10T. The material of the frame 12 and supports 8 is carbon steel coated with paint resistant to decontamination solutions.

According to the flow chart of FIG. 1 vacuum in the dispenser E2 pos. 1 is provided by a gas localization device (ULG), which is part of the reactor complex or by a vacuum system, when the valve BH1 is opened and is controlled by a pressure sensor P pos. 10. The amount of solution in the refueling tank E1 pos. 6 and in dispenser E2 pos. 1 at the first stage of the cycle is controlled respectively by two strain gauge sensors G1 and G2 (not shown in FIG. 2). Valve BH4 pos. 2 serves to evacuate the dispenser E2 pos. 1 with the aim of stopping the flow of a solution into it when recruiting the required amount. Valve BH7 serves to dispense the solution from the dispenser E2 pos. 1 to the reactor, valve BH6 - to return from the dispenser E2 pos. 1 into the refueling tank E1 pos. 6 excess solution. Valves VN2 and VNZ are used to cut off the sensor P from the UZT lines when replacing the sensor, repairing it, or metrological calibration.

The operation of UZT is as follows. The UZT fittings are brought to the initial position - the valves ВН2 and ВН8 are open, the rest of the valves and valves are closed. Refueling capacity pos. 6 E1 with the prepared portion of the fuel solution is installed on the strain gauge G1 and is connected to the UTT pipelines. In this case, the gas cavity of the refueling tank pos. 6 E1 is connected to the atmosphere through the filter F. All subsequent operations are carried out remotely by commands from the central control panel of the CPS. Also, from the CPS remote control, the size of each portion is set in accordance with the established algorithm, but not more than 3 liters in one portion.

When the BH1 valve is opened, the vacuum from the ULG is transferred to the dispenser E2 pos. 1. When opening the valve BH5 solution from the refueling tank E1 pos. 6 under the action of rarefaction begins to flow into the dispenser E2 pos. 1. The readings of the strain gauge G2 increase, the readings G1 decrease. Upon reaching the dispenser E2 pos. 1 of the required amount of solution, the BH4 valve opens, connecting the dispenser cavity with the atmosphere. Filling the dispenser E2 pos. 1 stops, the remainder of the solution from the supply pipe is discharged into the filling tank E1 pos. 6. The BH5 valve closes, the BH7 valve opens, a portion of the solution from dispenser E2 pos. 1 is discharged into a reactor (not shown in FIGS. 1 and 2). The UZT fittings are brought to the initial position, the empty refueling tank E1 pos. 6 changes to the fuel filled from the storage room, and the cycle repeats.

Given the possibility of servicing several reactors with one UST, it can be performed mobile and autonomous. The presence of four supports, pos. 8, and a rigid pallet (not shown in Fig. 2) in the UZT design in the lower part of the frame, pos. 12 allows the possibility of its movement from the storage room to the place of work and back with the help of a hydraulic trolley.

UZT and loading containers with fuel solution are delivered from storage to the place of work. Docking of the hydraulic line of the UZT with the loading branch pipe of the reactor and the pneumatic line of the UZT with the branch pipe ULG, which ensures the evacuation of the E2 dispenser pos. 1. On UZT manual valves are opened - feeding the solution into the reactor and connecting to the pressure sensor P pos. 10. After that, all loading operations are performed according to control signals from the reactor protection control system (CPS).

In accordance with the requirements of NP-09-17, liquid nuclear fuel is pumped from refueling tanks to the reactor vessel to ensure safety requirements in metered portions from 100 to 2000 cm ³ with an accuracy of no worse than 1% or no more than ± 20 cm ³ . Dosing is provided by two weight measuring devices. In order to ensure nuclear safety, each loading cycle of one portion of liquid nuclear fuel is carried out in two stages:

- pumping a portion of the fuel solution from the refueling tank E1 to the dispenser E2 under the influence of the vacuum created in the dispenser by the ULG system;

- draining fuel by gravity from the dispenser into the reactor vessel through a high-speed valve with an electric actuator BH7.

In this case, the electromagnetic valves that block the flow of the solution into the reactor vessel and into the dispenser E2 pos. 1, prevent uncontrolled ingress of fuel into the reactor, as The electric control circuit for these valves, located in the control and safety system, is equipped with a mutual interlock, which excludes the possibility of their simultaneous opening. In addition, an emergency shut-off valve with an electromechanical actuator VN7 is installed in the line connecting the UZT to the reactor. At the end of loading, all valves are closed, the lines are undocked, and if necessary, washed with water. UZT moves to storage.

Claims (3)

1. A device for loading liquid nuclear fuel into a nuclear homogeneous reactor, characterized by an autonomous design consisting of a frame with a fixed thereto: a dispensing tank with a volume of not more than 3000 cm ³ and a refueling tank installed on weighing devices with an accuracy of at least 1%, aerosol air filter, pressure sensor and piping with valves. 2. The device according to claim 1, characterized in that the electromagnetic valves on the pipeline from the refueling tank and on the pipeline into the reactor vessel are electrically connected to the CPS of the nuclear reactor kit. 3. The device according to p. 1 and 2, characterized in that the frame in the lower part has a pallet and supports, and along the perimeter a protective casing, and all elements in contact with liquid fuel and the casing are made of steel 12X18H10T.

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