JP2007155355A - Nuclear power generation equipment - Google Patents

Abstract

An object of the present invention is to provide a nuclear power generation facility that reduces the concentration of tritium contained in hydrogen gas generated by radiolysis in a nuclear reactor to below an emission standard and recovers generally available hydrogen gas. is there.
A hydrogen tritium separation device for removing tritium by reducing the tritium concentration of hydrogen gas generated by radiolysis in a nuclear reactor is provided, and the hydrogen gas from which tritium has been removed by the hydrogen tritium separation device is provided. A hydrogen gas recovery device 35 for recovery is provided.
[Selection] Figure 1

Description

  The present invention relates to a nuclear power generation facility capable of effectively utilizing hydrogen generated in a nuclear reactor.

FIG. 7 shows a schematic diagram of the nuclear power generation facility. In FIG. 7, the nuclear reactor power vessel 30 is provided with the reactor pressure vessel 1. The main steam generated in the reactor pressure vessel 1 is guided to the turbine 2 through the main steam pipe 31. The main steam that has worked in the turbine 2 is condensed in the condenser 6 to become condensate, boosted by the condensate pump 7, heated by the feed water heater 8, and then boosted again by the feed water pump 9 to react with the reactor pressure. It is led into the container 1 as water supply.

Hydrogen gas and oxygen gas are generated from the feed water that has become the reactor water in the reactor pressure vessel 1 by radiolysis. These are sent to the turbine 2 through the main steam pipe 31 together with the main steam and discharged to the exhaust gas system 32. Thereafter, the hydrogen gas and oxygen gas generated by the radiolysis are superheated again by the preheater 4 through the steam air extractor 3 and recombined by the recombiner 5 using a catalytic reaction to become water vapor. It enters the water tank 33 and is condensed to become water. The uncondensed exhaust gas is discharged to the outside of the system, and the water condensed in the exhaust gas condenser 33 is returned to the condenser 6 to be fed back into the reactor pressure vessel 1 again.
JP 2005-83946 A

Considering the coming hydrogen society, if hydrogen gas produced as a by-product in the nuclear reactor can be recovered without returning it to water, energy can be used effectively.

The amount of hydrogen gas contained in the water vapor at the turbine outlet is, for example, 86 Nm3 / h for an 80 MeW-class boiling water reactor. This is an amount of 6.4 bottles per hour and 154 bottles a day when converted into a cylinder of 90 L and 150 atmospheres. If a hydrogen recovery system is put into practical use, hydrogen can be obtained without making a production facility. However, the generated hydrogen gas contains tritium, which is an isotope of hydrogen. Since tritium is a radioactive element, the emission standard outside the furnace is elemental tritium (tritium gas), air concentration limit: 90 Bq / cc ^{, and} tritiated water air concentration limit: 0.005 Bq / cc, water concentration limit: 60Bq / cc

In order to use it outside the plant, it is necessary to reduce the concentration until the standard is achieved.

An object of the present invention is to provide a nuclear power generation facility that reduces the concentration of tritium contained in hydrogen gas generated by radiolysis in a nuclear reactor to below an emission standard and recovers hydrogen gas that can be used generally.

In order to achieve the above object, the present invention includes a hydrogen tritium separation device that removes tritium by reducing the tritium concentration of hydrogen gas generated in a nuclear reactor, and the tritium is removed by this hydrogen tritium separation device. Provided is a nuclear power generation facility including a hydrogen gas recovery device for recovering hydrogen gas.

According to the nuclear power generation facility according to the present invention, there is provided a nuclear power generation facility for reducing the concentration of tritium contained in hydrogen gas generated by radiolysis in a nuclear reactor to below an emission standard and recovering generally available hydrogen gas. be able to.

Hereinafter, a nuclear power generation facility according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a schematic configuration diagram of the nuclear power generation facility of the present invention. In FIG. 1, the same parts as those in FIG.

In FIG. 1, water vapor containing hydrogen gas extracted from the turbine 2 passes through a vapor air extractor 3 and then passes through a palladium (Pd) separation membrane 10 to separate water vapor and oxygen gas. Water vapor and oxygen gas are separated, and the remaining hydrogen gas and tritium gas enter a hydrogen tritium separator (hereinafter referred to as a hydrogen / tritium separator) 11 for separating hydrogen and tritium, and reduce the tritium concentration of the hydrogen gas. After separating the tritium, hydrogen gas is obtained through a pressurizing device. The separated tritium is returned to the upstream side of the preheater 4 through the tritium return pipe 40.

Next, a schematic configuration of the hydrogen / tritium separation apparatus 11 will be described with reference to FIG. As this embodiment, a separation system in the case of using a hydrogen storage alloy 21 containing Pd is shown.

The hydrogen / tritium separation apparatus 11 holds at least two lines having the same configuration in which a hydrogen storage alloy is arranged as shown in FIG. In the present embodiment, for convenience of description of the lines, two lines of line a and line b are used. First, hydrogen gas containing tritium is introduced into the hydrogen / tritium separator 11 from the pipe 22. The introduced hydrogen gas containing tritium is introduced into the line a or the line b through the first electromagnetic valves 12 and 15.

For example, hydrogen gas containing tritium introduced into the line a enters the hydrogen storage device 34 having the pressure gauge 18 and the heater 19 disposed in the area A, so that the hydrogen storage alloy accommodated in the hydrogen storage device 34 is obtained. 21 is absorbed.

FIG. 3 shows the relationship between temperature and pressure during absorption and release of hydrogen and tritium when Pd is used as the hydrogen storage alloy. 3A shows an example of hydrogen, and FIG. 3B shows an example of tritium.

According to FIG. 3, Pd starts releasing hydrogen at a temperature of 140 ° C when the temperature rises, ends most of the emission at 180 ° C, starts absorbing at 160 ° C when the temperature drops, and almost stops absorbing at 120 ° C. To do. On the other hand, when the temperature rises, tritium starts to be released at about 90 ° C and ends at 125 ° C. When the temperature falls, absorption starts at 95 ° C and ends at 60 ° C. Therefore, hydrogen is absorbed, but tritium is released. If kept at a set temperature and pressure, for example, 120 ° C. and pressure 1100 mbar (0.11 MPa), hydrogen is absorbed, but tritium is released. And tritium can be separated.

The tritium gas that has passed through the hydrogen storage alloy 21 accommodated in the hydrogen storage device 34 by controlling the temperature and pressure in this way passes through the second electromagnetic valve 14 (second electromagnetic valve 17 in the case of line b). And flows upstream of the recombination line of the offgas system, that is, the preheater 4.

After flowing hydrogen gas containing tritium up to the hydrogen storage limit in the separation area A, the first electromagnetic valve 12 is closed, the first electromagnetic valve 15 is opened, and the hydrogen gas containing tritium flows only in the line b. To do.

On the other hand, in area A, hydrogen gas is released from the hydrogen storage alloy 21 at a temperature 185 ° C. and a pressure of 0.19 MPa, which are the condition temperature and pressure at which the hydrogen storage alloy 21 releases hydrogen.

The second electromagnetic valve 14 (second electromagnetic valve 17 in the case of line b) is closed, and the third electromagnetic valve 13 (third electromagnetic valve 16 in the case of line b) is opened to store the released hydrogen gas. The temperature and pressure at which the alloy 36 absorbs hydrogen is introduced into the hydrogen recovery device 35 in the separation area B controlled at a temperature of 120 ° C. and a pressure of 0.11 MPa, for example, and absorbed by the hydrogen storage alloy 36 accommodated in the hydrogen recovery device 35. .

Thereafter, the temperature and pressure at which the hydrogen storage alloy 36 releases hydrogen in the separation area B are controlled to, for example, a temperature of 185 ° C. and a pressure of 0.19 MPa, hydrogen gas is released from the hydrogen storage alloy 21, and the hydrogen gas is recovered in the hydrogen gas cylinder 20. To do.

At this time, the tritium contained in the hydrogen gas is made to be below the atmospheric release standard. For example, assuming that the tritium concentration generated in a boiling water reactor is about 300 (Bq / cc), the tritium concentration limit in the air is 60 (Bq / cc), so the generated tritium concentration is 20% or less. Need to be reduced to

Similar recovery is performed in line b. During operation, continuous recovery can be performed by alternately using line a and line b.

Depending on the type of the hydrogen storage alloy, the temperature and pressure conditions of the separation area A to the separation area D described above differ, and it is necessary to operate the hydrogen / tritium separation device 11 under conditions optimal for absorption and release of hydrogen and tritium for separation. There is.

Next, a second embodiment of the present invention will be described with reference to FIG. 4, the same parts as those in FIG. 2 are denoted by the same reference numerals, and the description of the configuration of those parts is omitted.

In FIG. 4, an adsorbent 23, a catalyst, and a metal film are installed in the separation area A and the separation area C constituting the hydrogen / tritium separation device 37, and tritium is adhered and reduced. The reduced gas flows to area B or area D and is recovered using the hydrogen storage alloy 36. Even if there is no area including the hydrogen storage alloy 36, it is possible to recover the hydrogen gas as it is. Also in this embodiment, as described above, hydrogen is continuously recovered by operating line a and line b alternately.

As the adsorbent, silica gel, metallic palladium, a granular sieve, a graphite intercalation compound, and activated alumina are used. As the catalyst, a hydrophilic catalyst using platinum-supported alumina or PTFE and divinylbenzene crosslinked polystyrene are used. A hydrophobic catalyst is used as a carrier. The metal film may be a palladium alloy film.

Next, a third embodiment of the present invention will be described with reference to FIG. 5, the same parts as those in FIG. 2 are denoted by the same reference numerals, and the description of the configuration of those parts is omitted.

In FIG. 5, a heat diffuser 25 having a heater 24 is installed in the separation area A and the separation area C that constitute the hydrogen / tritium separation device 38.

This thermal diffuser 25 separates hydrogen and tritium by utilizing the temperature gradient and the weight difference between hydrogen and tritium. By generating a temperature gradient by the heater 24, heavy tritium is added to the heat diffuser 25. The tritium moved to the lower part and recovered to the lower part by opening the second electromagnetic valves 14 and 17.

The hydrogen gas moved to the upper part is moved to the area B or the area D by opening the third electromagnetic valves 13 and 16, and recovered using the hydrogen storage alloy 36. Even if there is no area including the hydrogen storage alloy 36, it is possible to recover the hydrogen gas as it is. This is also continuously collected by operating line a and line b alternately.

Next, a fourth embodiment of the present invention will be described with reference to FIG. In FIG. 6, the same parts as those in FIG. 2 are denoted by the same reference numerals, and description of the structure of those parts is omitted.

In FIG. 6, a laser, for example, a carbon dioxide laser 26 is installed in the separation area A and the separation area C constituting the hydrogen / tritium separation device 39 to strongly absorb the abdominal compound containing the isotope to be separated in the laser oscillation region. Separate by excitation. The separated gas is moved to area B or D and recovered using a hydrogen storage alloy. Even if there is no area including the hydrogen storage alloy 36, it is possible to recover the hydrogen gas as it is. This is also continuously collected by operating line a and line b alternately.

The schematic block diagram of the nuclear power generation equipment which concerns on this invention. The schematic block diagram of the hydrogen / tritium separation apparatus shown in FIG. (A) And (b) is a characteristic view which shows the relationship between the temperature and pressure at the time of absorption and release of hydrogen and tritium when Pd is used as a hydrogen storage alloy. The schematic block diagram which shows 2nd Embodiment of the hydrogen / tritium separation apparatus shown in FIG. The schematic block diagram which shows 3rd Embodiment of the hydrogen / tritium separation apparatus shown in FIG. The schematic block diagram which shows 4th Embodiment of the hydrogen / tritium separation apparatus shown in FIG. The schematic block diagram which shows the prior art example of a nuclear power generation equipment.

Explanation of symbols

1 Reactor pressure vessel
2 Turbine
3 Steam type air extractor
4 Preheater
5 Recombiner
6 Condenser
7 Condensate pump
8 Water heater
9 Water supply pump
10 Panadium separator
11 Hydrogen / tritium separator
12,15 1st solenoid valve
13,16 3rd solenoid valve
14,17 2nd solenoid valve
18 Pressure gauge
19 Heater
20 Hydrogen gas cylinder
21,36 Hydrogen storage alloy
22 Piping
23 Adsorbent
24 heater
25 Heat spreader
26 Laser
27 Lens
28 windows
29 Separation container
30 Nuclear power generation facilities
31 Main steam piping
32 Exhaust gas system
33 Exhaust gas condensate
34 Hydrogen storage container
35 Hydrogen recovery container
37,38,39 Hydrogen / tritium separator
40 Tritium return piping

Claims (12)

A hydrogen tritium separation device that removes tritium by reducing the concentration of tritium contained in hydrogen gas generated in a nuclear reactor, and a hydrogen gas recovery device that recovers hydrogen gas from which tritium has been removed by the hydrogen tritium separation device. A nuclear power generation facility characterized by comprising. The nuclear power generation facility according to claim 1, wherein the hydrogen tritium separation device and the hydrogen gas recovery device are installed in an exhaust gas system disposed in a turbine constituting the nuclear power generation facility. The nuclear power generation facility according to claim 1 or 2, wherein the hydrogen tritium separation device or the hydrogen gas recovery device contains a hydrogen storage alloy as means for reducing the tritium concentration. The nuclear power generation facility according to claim 1 or 2, wherein the hydrogen tritium separator uses an adsorbent that selectively attaches tritium as means for reducing the tritium concentration. The nuclear power generation facility according to claim 4, wherein the adsorbent comprises at least one member selected from silica gel, metallic palladium, molecular sieve, graphite intercalation compound, and activated alumina. 3. The nuclear power generation facility according to claim 1, wherein the hydrogen tritium separation device uses a metal film for selectively attaching tritium as means for reducing the tritium concentration. The nuclear power generation facility according to claim 1 or 2, wherein a catalyst for selectively attaching tritium is used in the hydrogen tritium separation device as means for reducing the tritium concentration. 8. The catalyst according to claim 7, wherein the catalyst is at least one member selected from a hydrophilic catalyst using alumina as a carrier or a hydrophobic catalyst using PTFE and divinylbenzene-crosslinked polystyrene as a carrier, each of which contains platinum. Nuclear power generation equipment. 3. The hydrogen tritium separator uses a thermal diffuser that separates tritium by utilizing a weight difference between hydrogen and tritium and a temperature gradient as means for reducing the tritium concentration. The nuclear power plant described. 3. The nuclear power generation facility according to claim 1, wherein a laser for exciting tritium or hydrogen is used as the means for reducing the tritium concentration in the hydrogen tritium separation device. The hydrogen tritium separation device uses any two or more of a hydrogen storage alloy, an adsorbent, a metal film, a catalyst, a heat diffuser, and a laser as means for reducing the tritium concentration. Item 3. A nuclear power generation facility according to item 1 or 2. 3. The nuclear power generation facility according to claim 1, wherein the hydrogen gas recovery device holds the tritium concentration in the recovered hydrogen gas so as to reduce it to an atmospheric release standard or less.

Images