EP2997579A1

EP2997579A1 - Pressure-relief and activity-restraint system for a nuclear plant

Info

Publication number: EP2997579A1
Application number: EP14726552.4A
Authority: EP
Inventors: Robert Feuerbach; Axel Hill
Original assignee: Areva GmbH
Current assignee: Areva GmbH
Priority date: 2013-05-17
Filing date: 2014-05-15
Publication date: 2016-03-23
Also published as: DE102013209191A1; JP2016521843A; WO2014184296A1; CN105210153A

Abstract

The invention relates to a pressure-relief and activity-restraint system (2) for a nuclear plant (6), particularly a nuclear power plant, having a containment (4) enclosed by a containment shell (8), to which containment a pressure-relief line (10) for relieving pressure in the event of malfunctions or accidents is connected. The following components are connected in series in the pressure-relief line (10), as viewed in the flow direction of the pressure-relief flow: a catalytic recombiner (14) for reacting hydrogen contained in the pressure-relief flow with oxygen in order to produce water vapour; a wet scrubber (24), or alternatively a dry filter (100, for separating out aerosols from the pressure relief flow; and a line section having at least two parallel line portions, each comprising an adsorber column (44) for retaining noble gases contained in the pressure-relief flow. In addition, a flushing and feedback system (56) is connected to the adsorber columns (44), and at least one of the adsorber columns (44) can be decoupled from the pressure-relief flow by means of associated valves (46, 48, 84, 86) and shifted to a flushing operation mode, in which noble gases collected in said absorber column (44) are flushed back into the containment (4) with the assistance of a flushing agent. The flushing and feedback system (56) is designed as a passive system, which is driven by the heat of decay contained in the containment (4) or the pressure-relief flow.

Description

description

Pressure relief and activity retention system

for a nuclear facility

The invention relates to a pressure relief and activity restraint system for a nuclear installation, in particular for a nuclear power plant. It also relates to an associated operating method.

In a nuclear power plant, a potentially significant increase in pressure within the containment must be expected in the event of an accident or accident, depending on the particular incident and any countermeasures taken. In order to avoid possibly resulting structural impairments of the containment or of the containment per se or of system components arranged therein, nuclear power plants can be designed for venting the containment as required by venting the containment atmosphere (venting). For this purpose, a pressure relief line can be connected to the containment of a nuclear facility.

In the containment atmosphere, however, heavy accidents usually contain radioactive material, such as noble gases, iodine or aerosol, which could enter the vicinity of the nuclear power plant on venting.

Airborne activity levels (aerosols) within the containment can occur in particularly high concentrations, especially in the case of comparatively severe incidents with potentially occurring meltdown, so that in the presence of high leaks or in the formation of impermissible overpressure situations, significant quantities of such aerosols or quantities of activity are released into the environment of the nuclear facility could occur. Such airborne activities may be particularly due to the high half lives of possibly entrained components such as Iodine or cesium isotopes cause a relatively long-lasting land contamination.

In order to avoid this, the pressure relief systems provided for venting the containment atmosphere are usually provided with filter or retaining devices intended to prevent the release of airborne activity quantities entrained in the containment atmosphere to the environment. With modern venting and filtration systems for the vent flow, retention rates of 99.5% and more are actually achieved with respect to aerosols and iodine constituents, especially organoiodine.

Furthermore, the containment atmosphere, however, contains radioactive noble gases such as xenon and krypton, which are currently not sufficiently retained during pressure relief and, depending on weather conditions, in particular make the power plant site inaccessible to accident countermeasures.

Object of the present invention is therefore to remedy this situation and to provide a device and an associated method with which in a simple and cost-effective manner a reliable retention of noble gases in venting the containment of a nuclear installation can be realized, so that the otherwise expected negative Impact on the environment can be avoided.

With respect to the device, the object is achieved according to the invention by the features of claim 1.

It is therefore a pressure relief and activity restraint system for a nuclear facility provided with a containment enclosed by a containment to which a pressure relief line for pressure relief in case of accidents or accidents is connected, with the following components are connected in series in the pressure relief line in the flow direction of the pressure relief flow : A catalytic recombiner for (preferably flameless) conversion of hydrogen contained in the pressure relief stream with oxygen to water vapor,

A wet scrubber or alternatively a dry filter for aerosol separation from the pressure relief flow,

• A line section with at least two parallel sub-strands, each with an adsorber column for delay / retention of noble gases contained in the pressure relief flow.

Further is

• a rinsing and recirculation system connected to the adsorber columns,

• by means of associated (shut-off) valves, at least one of the adsorber columns can be decoupled from the pressure relief stream for the initiation of a rinsing operation in which noble gases accumulated in this adsorber column are rinsed back into the containment with the aid of a rinsing agent,

• the purge and recovery system is designed as a passive system that

is driven by the decay heat contained in the containment or in the pressure relief stream.

In summary, the inventive concept consists essentially of a filtered pressure relief of the containment for the separation of the aerosol-supported activities and a downstream passive process for inert gas delay with recirculation into the containment. In this case, two adsorber columns are preferably provided in twin configuration and with a switchover facility in order to enable backwashing of the columns during ongoing venting operation.

The advantages achieved thereby are, in particular, that in addition to the airborne activities of the aerosols and organoiodine, the noble gases are retained. The activity-containing noble gases are namely recirculated into the containment. In other words: An essential aspect is the pressure relief with simultaneous delay and the return of the noble gases in the containment, where they can safely submerge included. Even long-living noble gas isotopes such as krypton 85 can be separated from the vent flow with the process. The harmless gases like nitrogen, oxygen and steam, on the other hand, are discharged to the environment via a chimney after filtering and lead to pressure relief of the containment.

The procedural conditions in the adsorber columns required for the Edelgasabscheideprozess be passively generated, preferably with superheated steam through a jet pump and taking advantage of the Nachzerfallswärme the accumulated fission products in the wet scrubber. The Nachzerfallswärme is thus out of the preferably designed as Venturi scrubber wet scrubber and used to generate steam for the backwashing and vacuum generation in the adsorber columns. As a result, the water reservoir in the venturi container is cooled and thus remains available for longer without such a measure.

Further advantageous embodiments of the device as well as procedural aspects will become apparent from the dependent claims and from the detailed description of the figures.

Various embodiments of the invention are explained below with reference to drawings. In each case show in highly simplified and schematic representation:

FIG. FIG. 1 shows a nuclear installation with a containment shell and with a first variant of a pressure relief and activity retention system for the enclosure enclosed by the containment shell based on a wet wash of the pressure relief flow, FIG.

FIG. FIG. 2 shows a second variant of the pressure relief and activity retention system based on dry filtering of the pressure relief flow, and FIG

FIG. 3 is a modification of the concept of FIG. 2, which also applies to the variant according to FIG. 1 is applicable. Identical parts are provided with the same reference numerals in all figures.

The in FIG. 1 schematically illustrated pressure relief and activity restraint system 2 allows a filtered pressure relief (venting) referred to as containment 4 safety enclosure a nuclear facility 6, in particular a nuclear power plant in accident or accident situations with significant pressure build-up in the containment 4. In the present case, in addition to the rear - attitude of radioactive aerosols and iodine / iodine compounds a special emphasis of the interpretation laid on the retention of radioactive noble gases.

For this purpose, the pressure relief and activity restraint system 2 comprises a pressure relief line 10 led outwardly from the containment 8 through the containment 8 (also referred to as containment) and into the environment into which various devices for treatment and purification / filtration of the conduit pass flowing pressure relief flow are switched.

The portion of the pressure relief line 10 located within the containment 8 has downstream of the inlet port 12 for the gas and vapor mixture (vent gas) flowing from the containment 4 into the pressure relief line 10 in depressurization operation, a recombiner 14 of known design for flameless recombination of hydrogen entrained in the pressure relief stream with oxygen to water vapor. During the exothermic recombination reaction, the pressure relief stream, which as a rule already flows into the inlet orifice 12 at a relatively high temperature, is overheated considerably above saturated steam conditions.

A first cooling of the pressure relief flow to a manageable in the downstream cleaning and filtering devices temperature level is still within the containment 8 by a here only schematically indicated, downstream of the recombiner 14 arranged gas cooler 16, the example is recooled by natural draft (natural convection) within the containment 4. Alternatively or additionally, the gas cooler 16 can be recooled on the secondary side by a cooling liquid, which is preferably sucked passively by means of a jet pump or the like from a corresponding template within the containment (not shown here). In a further variant, the recooling can also take place partially or completely outside the containment 4.

Downstream of the passage 18 through the containment shell 8, two check valves 20 are connected in series in the pressure relief line 10, which are closed during normal operation of the nuclear facility 6 and to initiate the pressure relief operation in accidents or incidents with significant pressure increase within the containment enclosed by the containment 4 4th be opened.

Downstream of the two shut-off valves 20, a recuperative heat exchanger 22 is connected in the pressure relief line 10, also referred to as venting line, in which the vent gas is further cooled. The re-cooling of the heat exchanger 22 is preferably carried out by the pressure relief flow at a lower temperature level in a further downstream section of the pressure relief line 10 (see below).

Subsequent to the heat exchanger 22, the still under high pressure vent gas enters a designed as Venturi scrubber wet scrubber 24 a. The wet scrubber 24 comprises a washing container 26 surrounded on all sides by a surrounding wall with cleaning or washing liquid 28 held therein up to a maximum level, namely essentially water. The vent gas flowing into the wash tank 26 via the pressure relief line 10 enters the washing liquid 28 via a number of parallel-connected venturi nozzles 30.

The venturi nozzles 30 are arranged below the liquid level 32. When the Venturi nozzles 30 flow through, the Ventgas tears over an example se configured as a ring slot feed intake in the constriction (throat) of the respective nozzle tube, the surrounding washing liquid 28 from the washing tank 26 with. This results in an intimate interaction of the vent gas laden with suspended particles (aerosol particles) with the entrained and fragmented liquid droplets of the washing liquid 28, as a result of which the suspended particles are stored in the washing liquid.

For a possible concrete realization of the Venturi scrubber reference is made to EP 0285845 A1 or to EP 1658621 B1.

The mixture of vent gas and washing liquid 28 ejected from the outlet openings of the venturi 30 subsequently separates again into its constituents as a result of gravity, the aerosol particles separated off from the vent gas remaining largely enclosed in the washing liquid 28. The aerosol particle purified vent gas accumulates in a plenum 34 above the liquid level 32, passes through a liquid separator 36 and then exits the wash tank 26 by entering the next portion of the pressure relief line 10 which is connected to the top of the wash tank 26 is.

Further downstream, a throttle valve 38 is connected in the pressure relief line 10, which causes a relaxation and, consequently, a drying of the vent gas (expansion drying).

Subsequently, as shown in FIG. 1, the pressure relief line 10 to form a heat exchanger surface (cooling coil 40) again be guided into the washing tank 26, so that a heat transfer from the washing liquid 28 takes place on the now slightly cooled Ventgasstrom.

Thereafter, the vent gas flows through a molecular sieve 42 in the overheated state, in which condensation of the constituent vapor components is reliably prevented. The molecular sieve 42 is primarily for the retention of iodine and iodine-containing compounds, in particular organic compounds with lower Chain length (organoiodine), designed and realized for this purpose, for example, as a zeolite-based sorption filter. Deviating from the graphic representation, the molecular sieve 42 can be structurally integrated into the wet scrubber 26 and directly thermally coupled. The molecular sieve 42 provided for the purpose of iodine retention can as a rule not be regenerated, in contrast to the activated carbon which is used for inert gas retention (see below). It is therefore preferably designed in terms of capacity for the complete pressure relief process, from the beginning to the end. However, it may be a division of the retention capacity provided on several paralall connected molecular sieves.

Downstream of the molecular sieve 42, in the recuperative heat exchanger 22, the vent gas discharged from the aerosol filtration in the wet scrubber 24 receives a portion of the heat content from the vent gas entering the wet scrubber 24. As a result of this further overheating of the vent gas, the vapor components in the downstream noble gas adsorber columns (see below) are reliably prevented from condensing.

Further downstream, the pressure relief line 10 in the 3-way valve 46 (more precisely, a 3/2-way valve with three ports and two switch positions) branches into two parallel sub-strands, in each of which a noble gas adsorber, short adsorber 44, is switched. Downstream of the two adsorber columns 44, the two sub-strands in the analogous to the 3-way valve 46 constructed 3-way valve 48 are brought together again (twin arrangement). The two 3-way valves 46, 48 are preferably coupled to each other mechanically or by an associated control electronics, so that in the pressure relief operation, depending on the valve position either one or the other of the two adsorber columns 44 is flowed through by the Ventgas. Thus, in each case only one of the two adsorber columns 44 is active with respect to the vent gas cleaning, ie in the adsorption mode. The in each case decoupled from the pressure relief line 10, inactive adsorbent column 44 can be rinsed in this state and thus prepared for the next phase of activity (see below). Instead of the two 3-way valves 46, 48 and other valve combinations can be used with appropriate effect.

In each active moderately active adsorber 44 contained in the vent gas noble gases, in particular xenon and krypton, retained by dynamic adsorption to an adsorbent. To achieve a high inert gas retention rate for various noble gases, several adsorbents may be present and possibly combined with one another. The adsorbent / adsorbents can be constructed, for example, from a plurality of layers and / or from a plurality of successive zones of activated carbon and / or zeolite and / or molecular sieves in the flow direction. For additional deposition of radioactive methyl iodide by isotope exchange or salt formation, preference is furthermore given to using impregnated activated carbon (for example with potassium iodide impregnation).

The throttle valve 38 arranged in the middle line section of the pressure relief line 10 between the wet scrubber 26 and the adsorber columns 44 is set such that a pressure reduction of the vent gas takes place with respect to the first line section, in which the pressure essentially corresponds to the containment pressure, but that there is still an excess pressure Relation to the atmospheric pressure is present. The adsorber columns 44 are thus operated in overpressure in order to reduce the gas volume flowing through them. After the adsorber columns 44, another throttle valve 50 is disposed in the pressure relief line 10 to effect pressure equalization to the surrounding atmosphere.

The pressure relief line thus has a high-pressure section upstream of the throttle valve 38, a middle-pressure section between the two throttle valves 38 and 50 and a low-pressure section downstream of the throttle valve 50.

Downstream of the throttle valve 50, a filter 52 for retaining adsorbent particles, which possibly dissolve in the adsorber columns 44 from the adsorbents, into the last line section of the pressure relief line 10th connected. Finally, the cleaned and filtered vent stream is blown into the environment via a chimney 54.

Before the discharge operation is initiated, both adsorber columns 44 have their maximum uptake and retention capacity. With the beginning of the pressure relief by opening the two shut-off valves 20, for example by firstly controlling the three-way valves 46, 48, the first one shown in FIG. 1 left adsorber 44 is actively switched, while the right adsorber 44 is decoupled from the pressure relief flow and thus, as it were kept in a standby state. In the left Adsorberkolonne 44 is now a selective separation of the noble gases from the carrier gas stream. The column is loaded. Shortly before reaching the capacity limit ("breakthrough") of the left adsorber 44 is then switched to the right adsorber 44.

The noble gases previously adsorbed in the left adsorber column 44 are fed back into the containment 4 during the adsorption operation of the right adsorber column 44 (and vice versa after the next switching operation). The adsorber column 44 located in the backwashing operation is thereby regenerated. For this purpose, a rinsing and recirculation system 56 for the adsorber columns 44 is provided, which will be described in more detail below.

The purge and recovery system 56 preferably operates passively and is powered by the (post) decay heat of the decay products and activity carriers contained in the containment atmosphere and / or in the pressure relief stream.

In the in FIG. 1 variant is shown using the heat of decomposition of the accumulated in the wet scrubber 24 cleavage products a water supply evaporated. The water vapor generated in this way serves as a flushing medium for the adsorber columns 44 and at the same time as a driving medium for a jet pump 58 for transport / promotion of the flushing medium.

Specifically, there is a steam boiler 62 filled at least partially with water 60, which is thermally attached to the wash tank 26 of the wet scrubber 24 in such a way. is coupled, that a heat transfer from the enriched in the course of the pressure relief operation with fission products washing liquid 28 takes place on the water feed in the steam boiler 62. For this purpose, the steam boiler as shown in FIG. 1 structurally integrated into the wet scrubber 24 or arranged immediately adjacent. However, the washing liquid 28 and the water 60 in the steam boiler are preferably separated from one another by partitions. As an alternative to water 66, another vaporizable liquid which fulfills the requirements placed on it as a flushing medium and / or as a propellant (see below) could also be provided.

Furthermore, there is preferably a natural circulation loop 64 projecting on the one hand into the washing liquid 28 of the wet scrubber 24 and on the other hand into the water reservoir of the steam boiler 62, in which a suitable transfer medium (heat transfer medium, eg a refrigerant or thermal oils) by natural convection in the manner of a thermosyphon or a heat pipe (heat pipe) circulates with or without phase change and thereby causes the desired heat transfer. The washing liquid 28 in the wet scrubber 24 is thereby cooled, ie evaporates more slowly without this measure and is available without refilling longer.

In particular, for the initial phase of the pressure relief operation (start-up operation), the steam boiler 62 may be equipped with an auxiliary heater 66 which alternatively operates, preferably also passively, by means of a flow medium heated by the decay heat of the nuclear reactor or for example by means of electrical energy stored in electrical accumulators becomes.

Replenishment of spent water in the boiler 62 as well as in the wash tank 26 is possible via corresponding external connections.

The pressurized steam 67 produced in this manner forms above the water level 68 a steam cushion 70 in the steam boiler 62 (steam storage). A removal of the steam takes place with the shut-off Valve 72 via the steam extraction line 74. A first partial flow of the steam flow is used to drive a jet pump 58 (English Steam Injector). For this purpose, a branch line 76 is led from the steam extraction line 74 to the propellant connection 77 of the motive nozzle of the jet pump 58 (of course, instead of a branch line, a direct connection to the steam boiler 62 could also be provided, see also the variant according to FIG.

A second partial flow of the steam 67 with a lower mass flow in relation to the first partial flow is conducted via the branch line 80 provided with a throttle valve 78 as the flushing medium to the adsorber column 44, which is currently not active and is decoupled from the pressure relief flow. The branch line 80 can therefore also be referred to as a flushing agent supply line. Via a branching 82 and downstream shut-off valves 84, alternatively a 3-way valve at the branch 82, the supply of the flushing medium to the currently in flushing adsorber 44 occurs. The flushing takes place here expediently contrary to the present in the adsorption flow. In other words, in each of the two adsorber columns 44, the inlet side for the pressure relief flow forms the outlet side for the detergent flow and vice versa.

As seen in the flow direction of the flushing medium, lines which are provided with shut-off valves 86 at the output side are connected to the two adsorber columns 44, which lines are combined in a union 88 to form a single flushing agent discharge line 90. Alternatively, here again a 3-way valve on the union 88 is possible. By a suitable coupling and / or control of the valves 46, 48, 84, 86 it is ensured that the switching of the pressure relief flow from one to the other adsorber 44 is accompanied by a correspondingly opposite switching of the detergent flow.

When flowing through with flushing medium, the noble gases previously adsorbed (adsorbed) in the respective adsorber column 44 are released again (desorbed) and carried away with the flushing agent stream. The adsorber column 44 is thereby refreshed again for the next adsorption cycle. According to the embodiment in FIG. 1, the noble gases dissolved in the rinsing process from the respective adsorber column 44 are conveyed back into the containment 4. For this purpose, the flushing agent discharge line 90 leading away from the adsorber columns 44 is connected to the suction connection 92 of the jet pump 58 and continues on the outlet side in the return line 94, which is guided through the containment 8 into the containment 4. In accordance with the usual operating principle of the jet pump 58, the rinsing agent loaded with inert gases (water vapor under relatively low pressure) is sucked in by the propellant (water vapor under relatively high pressure and high flow velocity), mixed with it under momentum transfer and compressed and via the return line 94 into the Containment 4 transported back. The flushing agent discharge line 90 and the return line 94 together can also be referred to as the recirculation line.

In the section of the return line 94 lying outside the containment shell 8, two check valves 96 are connected in series in the immediate vicinity of the containment shell 8 so as to be able to close the return line 94 securely in the event of a line break or a leak. As a result, leakage of the containment atmosphere via this line into the environment is prevented in such cases.

The connecting line 98 between the washing tank 26 and the return line 94 is used to empty the wet scrubber 24 after completion of the containment pressure relief (venting).

The design of the relevant system components of the rinsing and recirculation system 56 on the one hand such that the delivery pressure of the jet pump 58 is sufficient on the pressure side to promote the mixed with the blowing agent, activity-loaded rinse against the prevailing system pressure in the containment 4 back , On the other hand, the resulting increase in pressure in the containment 4 is small compared to the pressure relief via the pressure relief line 10, so that in fact there is a significant net pressure relief of the containment 4. Alternatively, the jet pump 58 can be operated with a separate propellant gas, in particular nitrogen, which is kept under pressure in a corresponding storage container.

Instead of a jet pump 58, other pump types can be used to recover the loaded with inert gases flushing medium in the containment 4. Preferably, such pumps are passively driven by the decay heat contained in the containment 4.

In the in FIG. 2 illustrated variant of the pressure relief and activity restraint system 2 is in contrast to the in FIG. 1 variant shown instead of a wet scrubber 26, a dry filter 100, z. As a sand bed filter, connected in the pressure relief line 10.

This eliminates the from FIG. 1 known possibility, the steam boiler 62 for the effective as blowing and flushing water vapor 67 thermally coupled to the washing liquid container 26.

Instead, an alternative heating of the steam boiler 62 may be provided by the decay heat present in the containment 4, as indicated schematically by the double arrow 102. For this purpose, for example, operated in natural circulation with or without phase transition convection cycles can be led out of the containment 4 through the containment 8. With relatively small temperature differences between the heat source and the heat sink, heat pump circuits may also be used, the feed pump of which is preferably driven passively by the available heat sources in the containment 4, possibly also via the detour of other forms of energy (eg compressed air, electricity). The heat source used in this context is, in particular, the catalytic recombiner 14 within the containment 4 and / or the gas cooler 16 downstream of it. Instead of steam, for example, nitrogen (or another purge gas) can be used for the backwashing of the adsorber 44, which is taken from a nitrogen pressure vessel.

In order to ensure adequate operating temperatures, a separate heating of the adsorber columns 44 can be provided beyond the inherent heating through the vent gas conducted through to the noble gas adsorption.

An advantageous in this context recuperative heating variant, which with the in FIG. 1 and FIG. 2 illustrated embodiments can be combined, is shown in FIG. 3 shown. In this case, the hot vent gas is first passed to the adsorber 44 after passing through the security envelope 8 and brought into thermal contact with them for the purpose of heat transfer, before then in the manner described above, a dry filter 100 (alternatively a wet scrubber 24 as in 1) and finally enters the adsorber columns 44 and interacts there with the adsorbents.

For this purpose, the respective adsorber column 44 may, for example, have a double jacket, wherein the good heat-conducting inner jacket encloses the flow channel containing the adsorbents for the medium-pressure relief stream pre-cleaned in the dry filter 100 (alternatively in the wet scrubber 24). In the intermediate space between the inner shell and the outer jacket of the coming directly from the containment 4 high-pressure relief flow, preferably in countercurrent to the medium-pressure relief flow, and there is a part of its heat content to the inside for heating the adsorber.

Furthermore, a passive heat storage may be integrated into the adsorber columns 44, such as a heat storage plate or the like.

The various in connection with FIG. 2 and FIG. 3 described modifications of the basic concept are taken alone or together in the system of FIG. 1 applicable. Instead of two adsorber columns 44 connected in parallel, three or more adsorber columns 44 can also be present, of which expediently at least one is always in adsorption mode during the pressure relief, while the remaining columns can be in flushing mode or in stand-by mode , The wiring and the valve assembly must be adjusted accordingly in this case.

Although the depressurization and activity retention system according to the invention is preferably used in a nuclear power plant with a nuclear reactor enclosed by a containment shell, other applications are also possible, for example in a research reactor or in a plant for processing nuclear fuel. In addition, an application in non-nuclear industrial plants is conceivable in which hazardous substances are processed within a hermetically sealed containment envelope, and in which accident situations over-design overpressure conditions can occur.

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17

LIST OF REFERENCE NUMBERS

2 pressure relief and 62 steam boilers

Activity retention system 64 Natural circulation loop

4 Containment 66 additional heating

6 nuclear installation 67 water vapor

8 Safety cover 68 Water level

10 Pressure relief line 70 Steam pad

12 inlet port 72 shut-off valve

14 recombiner 74 steam extraction line

16 gas cooler 76 branch line

18 Execution 77 Propellant connection

20 shut-off valve 78 throttle valve

22 heat exchanger 80 branch line

24 wet scrubber (detergent supply line)

26 wash tank 82 branch

28 Washing fluid 84 Shut-off valve

30 Venturi nozzle 86 Shut-off valve

32 liquid level 88 union

34 collecting space 90 detergent discharge line

36 liquid separator 92 suction connection

38 throttle valve 94 return line

40 cooling coil 96 stop valve

42 molecular sieve 98 connecting line

44 adsorber column 100 dry filter

46 3-way valve 102 Double arrow

48 3-way valve

50 throttle valve

52 filters

54 fireplace

56 rinsing and recovery system

58 jet pump

60 water

Claims

claims

1 . Pressure relief and activity retention system (2) for a nuclear installation (6), in particular a nuclear power plant, with a containment (4) enclosed by a containment (8) to which a pressure relief line (10) is connected for pressure relief in case of accident or accident; wherein in the pressure relief line (10) seen in the flow direction of the pressure relief flow, the following components are connected in series:

A catalytic recombiner (14) for reacting hydrogen contained in the pressure relief stream with oxygen to form water vapor,

A wet scrubber (24) or alternatively a dry filter (100) for aerosol removal from the pressure relief flow,

A line section having at least two parallel sub-strands, each having an adsorber column (44) for the retention of noble gases contained in the pressure relief flow,

furthermore

A purge and recycle system (56) is connected to the adsorber columns (44),

• by means of associated valves (46, 48, 84, 86), at least one of the adsorber columns (44) can be decoupled from the pressure relief stream and put into a purge mode, in which noble gases accumulated in this adsorber column (44) are introduced into the containment (4) with the aid of a rinsing agent. to be backwashed,

and wherein the purge and recycle system (56) is configured as a passive system driven by the post-decay heat contained in the containment (4) or in the pressure relief stream.

A pressure relief and activity restraint system (2) according to claim 1, wherein there is provided as a rinse water vapor (67) produced by evaporation of water (60) in a steam boiler (62), and wherein the steam boiler (62) is heated to a heat source in the containment (4) and / or in the pressure relief line (10) is thermally coupled.

3. pressure relief and activity restraint system (2) according to claim 2, wherein a in the pressure relief line (10) connected wet scrubber (24) for Ae rosolabscheidung serves as a heat source for heating the steam boiler (62).

4. pressure relief and activity restraint system (2) according to claim 3, wherein a natural rolling loop (64) for heat transport from the wet scrubber (24) protrudes into the boiler (62).

5. pressure relief and activity retention system (2) according to claim 3 or 4, wherein the wet scrubber (24) is designed as Venturi scrubber.

6. pressure relief and activity retention system (2) according to any one of claims 3 to 5, wherein between the wet scrubber (24) and the Adsorberkolonnen (44) a molecular sieve (42) for the separation of iodine in the pressure relief line (10) is connected.

7. pressure relief and activity retention system (2) according to one of claims 3 to 6, wherein between the wet scrubber (24) and the adsorber columns (44), a throttle valve (38) in the pressure relief line (10) is connected.

8. pressure relief and activity retention system (2) according to claim 7, wherein seen in the direction of the pressure relief flow after the adsorber columns (44), a throttle valve (50) in the pressure relief line (10) is connected.

9. pressure relief and activity restraint system (2) according to any one of claims 2 to 8, wherein one with steam (67) from the steam boiler (62) driven jet pump (58) for the return transport of effective as a rinse water vapor (67) in the containment (4) is present.

10. pressure relief and activity retention system (2) according to any one of claims 2 to 9, wherein an upstream of the adsorber columns (44) lying portion of the pressure relief line (10) past the adsorber columns (44) and is thermally coupled to the preheating.

1 1. Nuclear power plant with a nuclear reactor enclosed by a containment (8) and with a pressure relief and activity retention system (2) according to one of claims 1 to 10.

12. A method of operating a nuclear power plant with a pressure relief and activity restraint system (2) according to one of claims 1 to 10, wherein by means of the contained in the containment (4) or in the pressure relief stream Nachzerfallswärme water is evaporated, and wherein the water vapor (67 ) is used as a rinsing agent for backwashing the noble gases collected in the adsorber columns (44) into the containment (4).

13. The method of claim 12, wherein the water vapor (67) is also used as a propellant for a rinse-promoting jet pump (58).