JPS6168327A - Recovering apparatus of gaseous uranium hexafluoride - Google Patents

Abstract

PURPOSE:To recover gaseous UF6, etc. with high efficiency using aq simplified apparatus by compressing gaseous UF6 then solidifying by cooling in a recovering vessel in a cooling tank, sucking the solidified product by controlling the pressure in the vessel and adsorbing gaseous UF6 and gaseous HF to each trap. CONSTITUTION:Gaseous UF6 discharged from a UF6 gas treating plant and compressed by a compressor 1 is introduced into an accumulator 20 having a closed cylindrical structure as recovering vessel provided in a cooling tank 5, and solidified by cooling. The pressure in the accumulator 20 is controlled through a pressure sensor 15, pressure controller 16, and a pressure control valve 18 so as not to liquefy accumulated gaseous HF, and gaseous HF accompanying a small amt. of UF6 is led to a UF6 adsorbing trap 11 packed with NaF pellets provided to a waste gas treating system 22 to adsorb UF6 sufficiently. The gaseous HF is then led to an HF adsorbing trap 12 packed with activated alumina pellets. where the gaseous HF is adsorbed and remaining air alone is sucked by a rotary pump 14 and discharged to the outside and treated as waste gas.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a 111 collection device for uranium hexafluoride gas in which the uranium hexafluoride gas is gastrically compressed by a compressor and directly recovered into a 1:11 container such as an accumulator. Regarding.

[Technical background of the invention]

Uranium hexafluoride gas (hereinafter referred to as UF6 gas) is handled at below atmospheric pressure.
As a device for recovering F6 gas, a system is adopted in which the compressed (JF6) is solidified and recovered by compressing it through a conbrerator (1) and solidifying and recovering the compressed (JF6) gas into a cooled LIFG cylinder. (This is based on the fact that when compressed UF6 gas is cooled, it undergoes a phase change from gas to solid.)

Figure 2 is a system diagram showing the four components of a conventional UF6 gas recovery device.

In this figure, reference numeral 1 indicates a compressor for compressing tJF6 gas, and the tJF6 gas compressed by this compressor 1 is sent from a discharge side pipe 2 to a UF6 cylinder 3 via a connecting pipe 4.

The UF6 cylinder 3 is housed in a cooling tank 5 and maintained at a predetermined temperature. Connection pipe 4 has pressure 516 and branch pipe 7
is connected to the branch pipe 7, and a valve 8 is interposed in the branch pipe 7.

The downstream side of the branch pipe 7 is a cold trap 9. Pressure regulating valve 10, (J"6 suction trap 11, hydrogen fluoride (HF)
) Adsorption 1 to lap 12, pressure regulating valve 13 and rotary pump 14 are connected in sequence. A pressure detector 15 and a pressure rJJ regulator 16 are installed between the cold 1-lap 9 and the pressure regulating valve 10;
A pressure detector 171I; and a pressure regulator 18 are provided between the two pressure regulating valves 13, and each F'force regulator 16.18 adjusts the valve opening degree of the pressure regulating valves 10 and 13. It's in control.

The UF6 cylinder 3 is cooled in the cooling tank 5, and the gas introduced into the UF6 cylinder 3 is cooled, solidified, and collected in the UF6 cylinder 3. tJF6 cylinder 3 is A
Cylinder type jJF specified by NS I regulations
It is a transport container, (j "6 shillings has one gas inlet; it is just an old spelling.

(Problems with the technology in the previous section) By the way, U6 gas contains l-IF gas as an impurity, and since the UF6 handling pro wrestling is operated at below atmospheric pressure, there is no gas in the IJF6 gas recovery system. Air that has leaked in also exists as an impurity. Therefore, when IJF6 gas is continued to be recovered using a conventional UF6 gas recovery device, 1-1F gas and air become UF6 gas.
6 cylinder 3 and UF6 cylinder 3
The recovered UF6fn within the cylinder also increases, and the volume of the gas phase within the UF6 cylinder decreases.

For this reason, a phenomenon occurred in which the recovery pressure gradually increased, resulting in a problem in which the recovery efficiency of the compressor decreased by 7%.

In addition, 11F gas has the property of liquefying when the pressure exceeds a certain level71, so if the recovery operation is continued in a place with high pressure, I-IF gas will be liquefied as an impurity in the recovered U[6].
is mixed in. Further, when the recovered UF6 is Fuchizaki 1 uranium, it is determined that the temperature of the water M in the recovered UF6 is equal to or lower than a predetermined value. For this reason, in the conventional UF6 gas recovery system, the recovered gas pressure is monitored with a pressure gauge 6, and when the pressure in the UF6 gas recovery system exceeds a certain value, the valve 8 is closed and the gas in the recovery system is exhausted. It was necessary to perform an operation to lower the recovery pressure. However, there is a problem in that during the exhaust operation to listen to valve 8 and exhaust the gas, the recovered IJF6 gas is also evacuated at the same time. Cold 1 to Lap 9 for processing
, UF6 adsorption trap 11, HF adsorption 1 lap 12 and rotary pump 14, and the pressure fj of each adsorption trap.
An exhaust gas treatment system consisting of a J I2I+ device is required, and that's it [M4' of the exhaust gas treatment system? i has become complicated and expensive.

(Objective of the Invention) The present invention has been made by reconsidering the above-mentioned circumstances, and is capable of efficiently recovering jJF6 gas compressed by a compressor into a recovery container, and also to remove impurities such as HF gas (light gas) in the recovery container. gas components).

The purpose is to reduce the amount of tJF6 gas contained in the exhaust gas and to develop a uranium hexafluoride gas recovery device with a simplified configuration of the exhaust gas treatment system.

[Summary of the invention]

In order to achieve the above-mentioned object, the present invention has been developed to provide a cold f
A recovery container, which is housed in this cooling tank and is removably connected to the gas introduction pipe and the exhaust gas pipe, respectively, is connected to the exhaust gas pipe in sequence. i l-rap, hydrogen fluoride adsorption trap, and 00':pump, and the exhaust gas treatment system has a hexafluoride suction system, 'f trap, and upstream of the Q pressure pump. The pressure control valves provided on each side are arranged on the right side, and the pressure on the back side of the collection container is controlled by the pressure control valves.

In the present invention, the back pressure of the same container such as an accumulator is controlled by 1-roll 1.
It is possible to exhaust the exhaust gas, which is a gas component of the FF gas, and it is possible to reduce the amount of UF6 gas contained in the II+ gas and removed from the IJ1 gas.

[Embodiments of the invention]

An embodiment of the UF6 gas recovery apparatus according to the present invention will be described below with reference to FIG.

FIG. 1 shows a system diagram of the configuration of the UF6 gas recovery apparatus of the present invention. In FIG. 1, the same parts as in FIG. 2 are denoted by the same reference numerals, and the explanation of the overlapping parts will be omitted.

In Figure 1, reference numeral 1 indicates a compressor 1 which compresses the product ()F6 gas discharged from the gas Nt cascade, and the gas discharge part of this compressor 1f1 is connected to the gas 3r extending inside the cooling tank 5. It is connected to an accumulator 20, such as a collection container, via a human pipe 4. Aki”,
The mullet 20 is formed into a sealed cylindrical structure and is housed in the cooling tank 5 so as to be freely taken out. A1. Yumuleta 2
Connect the gas pipe 4 to the upper part of ~・ side of 0 () "6
Gas 3rI in 020
This can be done in Jl'M5 using flanges etc. in a way that can be easily viewed. The nt air gas pipe 21 connects to the cooling tank 5 and is ashes to the outside, and an exhaust gas treatment system 22 for treating exhaust gas such as HF gas is provided at the extension thereof.

The exhaust gas treatment system 22 adsorbs UF6 to the exhaust gas pipe 21.
- Constructed by sequentially connecting a wrap 11, an HF adsorption trap 12, and a rotary pump 14 as a negative pressure pump, and pressure regulating valves 10 and 13 are installed on the upstream side of the tJF6 adsorption 1-lap 11 and rotary pump 74, respectively. be done.

The pressure regulating valve 10.13 is operated and controlled by a pressure regulator 16.18, and the valve opening degree is adjusted. Pressure regulator 16.1
A detection signal from pressure detection Z15.17 is input to 8. , each pressure detector 15.17 has a pressure regulating valve 10.13.
installed on the upstream side of the

One pressure regulating valve 10 regulates the pressure on the side of the accumulator 20, and the pressure regulating valve 13 on the other hand controls the pressure of the adsorption traps 11 and 12. L installed to increase efficiency. The setting value (pressure) of the pressure regulating valve 13 for one shift is about half of the setting value (pressure) of one of the pressure regulating valves 10, and by controlling the operation of the pressure regulating valve 13 in this way, the pressure regulating valve 13 can be It becomes possible to use the critical line 1'1, and it is possible to prevent the influence of the pressure change 1 on the downstream side from reaching the upstream side.

Next, the action of the UF6 gas recovery unit 6 will be explained.

The vapor pressure curve for 11F is calculated by converting Pll' to 1-1F gas pressure (
81m1-1), and if t is 1-IF wetness (°C), then wa'' 10PIF = 8, 38036-1952, '55/
'(335.

52 + t).

The UF6 gas discharged from the process of the UF6 gas processing plant is compressed by the compressor 1, and the compressed U6 gas is guided to the accumulator 20 in the cold mulch tank 5 to solidify the cold I, RL, In this case, when the amount of UF6 recovered into the accumulator 20 is small, the partial pressure of the impurity UF6 gas is sufficiently low, and the recovery pressure in the UF6 accumulator 20 is also low, so the pressure is low. The control valve 10 is open.As the recovery operation continues, I-IF gas, etc. gradually accumulates in the UF6 gas recovery system, and the pressure in the recovery system decreases, causing the accumulator 2
There is a possibility that the HF gas introduced into the reactor will liquefy.

However, in this case, the cooling (cooling temperature of 15
Applying it to the steam curve equation of
J: The internal pressure of the accumulator 20 (71 side pressure) is controlled by the pressure control valve 1o. Can defend against 1 hit.

In addition, the inside of the accumulator 20 is filled with gas and a small amount of H.
When F gas passes through, Lj r2. Since most of the gas t, L II is solidified, the ()6 partial pressure in the exhaust) This is about 1/10 of the vapor pressure of 1-IF when compared with cooling temperature of 10℃ to 20''C, and the cold trap function is Therefore, the U exhausted from the UF6 gas recovery section
IT6 gas is rarely entrained in HF gas, and only UF6 gas is exhausted.

Therefore, in the equipment that processes the gas exhausted from this tJF6 gas recovery section, I feel that it is unnecessary to use one plate of the -]-rud trap shade. Gas treatment can be sufficiently carried out using a UF6 suction trap 11 in which a packed tower is filled with helium (NaF) pellets. ) Carry out 1-1F suction ?'11-wrap 12 filled with pellets17.

Therefore, from the rotary pump 14, only the static electricity that has flowed into the 11-gas processing system 22 can be sucked and exhausted to the outside.

〔Effect of the invention〕

As described above, the U6 gas recovery device according to the present invention is housed in a cold 1.L tank and connects the exhaust gas piping to the recovery container. Connect the uranium fluoride adsorption 1-lap, fluoride water poison absorption 61-lap and negative pressure pump in sequence to the exhaust gas system, and install the uranium hexafluoride adsorption trap (υ
A pressure control valve is provided on the upstream side of the J and negative pressure pumps, and the pressure on the back side of the recovery container is adjusted by the pressure control valve, thereby ensuring the liquefaction of the l-IF gas within the recovery container. 1-1 is removed from the city and exhausted from the collection container.
[UF6 gas emitted along with impurities in the gas tank n
In addition, since the recovery container has a cold wrap function, it is not necessary to use a cold trap in the exhaust gas treatment system. can be simplified and constructed at low cost. Even without installing a wrap around the exhaust gas treatment system, it is possible to efficiently recover tJF60,000 gas and HF gas.

[Brief explanation of drawings]

FIG. 1 is a system diagram schematically showing an embodiment of a uranium hexafluoride gas recovery device according to the present invention, and FIG. 2 is a system diagram schematically showing a conventional uranium hexafluoride gas recovery device. . . 1... Combrera 1, 3... UF6 cylinder, 5
...cold 7J] tank, 9...]-rudo (-wrap, 10
．． 13...Pressure nof control valve, 11...tJF6@arrival 1
~Wrap, 12...;-1 "Adsorption trap, 14...
・Rotary pump, 20...Akicomulator, 22・
...11 ki gas cry science system.

Claims (1)

[Scope of Claims] 1. A cooling tank through which a uranium hexafluoride gas introduction pipe and an exhaust gas pipe pass, and a cooling tank in which the gas introduction pipe and the exhaust gas pipe are detachably connected to each other by being housed in the cooling tank. a recovery container, an exhaust gas treatment system consisting of a uranium hexafluoride adsorption trap, a hydrogen fluoride adsorption trap, and a negative pressure pump connected in sequence to the exhaust gas piping; a uranium hexafluoride adsorption trap of the exhaust gas treatment system; 1. A recovery device for uranium hexafluoride gas, comprising a pressure control valve provided upstream of a negative pressure pump, and wherein the pressure control valve adjusts and controls the pressure on the back side of a recovery container. 2. The recovery container is a cylindrical sealed container such as an accumulator, and the recovery container has a gas inlet for connecting a gas introduction pipe on one side and a gas outlet for connecting an exhaust gas pipe on the other side. A recovery device for uranium hexafluoride gas according to claim 1. 3. The six-foot valve according to claim 1, wherein the pressure regulating valve is operated and controlled by a pressure regulator that inputs a detection signal from a pressure detector provided in the exhaust gas piping upstream of the pressure regulating valve. Uranium oxide gas recovery equipment.