GB2607011A

GB2607011A - Method for pipe filling

Info

Publication number: GB2607011A
Application number: GB2107220.2A
Authority: GB
Inventors: Ditte Richard
Original assignee: Steve Vick Int Ltd
Current assignee: Steve Vick Int Ltd
Priority date: 2021-05-20
Filing date: 2021-05-20
Publication date: 2022-11-30
Anticipated expiration: 2041-05-20
Also published as: GB2607011B; GB202107220D0

Abstract

A method of filling a pipe 10 (e.g. a pipe contaminated by radioactive waste such as at a decommissioned nuclear facility) comprises inserting a first 1 and second 2 seals into the pipe, the second seal being axially spaced from the first. A first vent 4 is formed in the pipe proximal the first seal and an expandable material 20, e.g. polyurethane foam, is injected through a first port 6 in the pipe into the space between the seals. The expandable material expands to fill the space between the seals. The first port can be located proximal the second seal, and the expandable material can then be injected proximal the second seal. A third seal 3 can be inserted into the pipe, it being spaced from the second seal which is then in between the first and third seals. A second vent 5 can then be formed in the pipe and expandable material injected through a second port 7 proximal the second seal, into the space between the second and third seals. Waste material from the pipe can be collected into a first receptacle connected to the first vent and/or a second receptacle connected to the second vent.

Description

METHOD FOR PIPE FILLING

Field of the Disclosure

The present disclosure relates to a method for filling pipes. In particular, the present disclosure relates to a method for decommissioning contaminated pipes e.g. during decommissioning of nuclear facilities such as power plants.

Background

Decommissioning of nuclear facilities typically involves the sealing and optionally the removal of pipes that are contaminated with radioactive material. The presence of radioactive material presents significant health and environmental challenges necessitating costly and time-consuming processes.

Previous methods for sealing contaminated pipes at nuclear facilities include filling the pipes with concrete and then either simply leaving the pipes in situ or, preferentially, removing the pipes and transporting them to a designated nuclear waste storage facility. Transportation of nuclear waste is necessarily carried out in shielded containers having a standardised volume. This requires cutting of the decommissioned pipes into specific lengths to fit within the shielded containers.

Pipes filled with concrete are difficult to cut and heavy to manoeuvre and transport. This increases the costs and time of the decommissioning process.

In more recent years, chambers/voids at decommissioned nuclear facilities (e.g. glove boxes and drains) have been filled to a desired level with polyurethane foam using successive mix and pour steps in the open atmosphere. The entry and exit points of the chamber/voids are first sealed using fabric bags filled with polyurethane foam. These processes have not provided a method that allows filling and removal of a decommissioned contaminated pipe.

There is a need to provide an improved, safe and cost-effective system and method for decommissioning contaminated pipes.

Summary

In a first aspect, there is provided a method of filling a pipe by: inserting a first seal into the pipe; inserting a second seal into the pipe, the second seal being axially spaced from the first seal; forming a first vent in the pipe proximal the first seal; injecting an expandable material through a first port in the pipe into the space between the first and second seals; and allowing the expandable material to expand to fill the space between the first and second seals.

By providing two seals to create a closed section of pipe and then filling the space between the seals with expandable material, allowing venting of the pressure created through the first vent as the space is filled, the method provides an improved method of filling pipes at decommissioned nuclear facilities. The seals constrain the expanded material to allow pressurisation of the closed section of pipe and ensure that escape of contaminants from the ends of the pipes is avoided. Instead, the expanded material encapsulates any contaminants thus reducing health and environmental hazards and any non-encapsulated contaminants are channelled in a controlled manner from the first vent. Furthermore, post-filling, any cutting and removal of the pipes is facilitated as the expanded material has a density (created by the pressure within the closed section of pipe) that is high enough to maintain its integrity when cut but which is less dense (thus easier to cut) and less heavy (thus easier to manoeuvre and transport) than concrete.

Optional features will now be set out. These are applicable singly or in any combination with any aspect.

The expandable material may be an expandable foam e.g. an expandable polymeric foam such as an expandable polyurethane foam. The foam may be a closed-cell foam. The expandable material e.g. expandable foam may have an expansion ratio of between 2:1 and 19:1 e.g. between 3:1 and 12:1 such as around 10:1. In some embodiments, the expandable material may contain one or more additives. For example, for underwater applications where the pipes may be filled with water, the expandable material may further comprise a non-expansion polymeric material such as a non-expansion epoxy. A particularly preferred expandable material for underwater applications comprises an expandable foam having an expansion ratio of around 3:1 and a non-expansion epoxy.

In preferred embodiments, the first port is provided proximal the second seal so that the method comprises injecting the expandable material proximal the second seal. In this way, as the expandable material is injected through the first port, it is forced from proximal the second seal upstream towards the first seal/first vent so as to fill the entirety of the space between the seals.

In some embodiments, the first seal comprises an envelope e.g. a porous envelope such as a fabric envelope and the method comprises inserting the first seal envelope into the pipe. In such embodiments, the method further comprises filling the first seal envelope within the pipe with a material e.g. an expandable material such as an expandable foam into order to seal the pipe. Preferably, the expandable material/foam passes through the porous first seal envelope to adhere to the pipe. The first seal may comprise a FOAMBAGTm as provided by Steve Vick International Ltd. The expandable material used to fill the first seal envelope may be the same expandable material as that injected into the first port.

In some embodiments, the second seal comprises an envelope e.g. a porous envelope such as a fabric envelope and the method comprises inserting the second seal envelope into the pipe. In such embodiments, the method further comprises filling the second seal envelope within the pipe with a material e.g. an expandable material such as an expandable foam into order to seal the pipe. Preferably, the expandable material/foam passes through the porous second seal envelope to adhere to the pipe. The second seal may comprise a FOAMBAGTm as provided by Steve Vick International Ltd. The expandable material used to fill the second seal envelope may be the same expandable material as that injected into the first port (and/or that used to fill the first seal envelope).

The expandable material/foam in the first and second envelopes is preferably allowed to cure e.g. for at least 30 minutes prior to injection of the expandable material into the first port.

Each of the first and/or second seals (e.g. each of the first and/or second seal envelopes) may be inserted into the pipe through an airtight valve. Thus the method may comprise drilling a first hole in the pipe using an airtight hot tapping system (also known as an under pressure drilling system) and fitting a first airtight, operational under pressure tee (UPT) and valve in the first hole. The first seal e.g. the first seal envelope may then be inserted into the pipe through the first UPT/valve. The first seal envelope may be filled with the expandable material/foam through the first UPT/valve. The first UPT/valve may be formed of plastics material to reduce weight and allow incineration if required.

The method may further comprise drilling a second hole in the pipe using the airtight hot tapping system and fitting a second airtight, operational under pressure tee (U PT) and valve in the second hole. The second seal e.g. the second seal envelope may then be inserted into the pipe through the second UPT/valve. The second seal envelope may be filled with the expandable material/foam through the second UPT/valve. The second UPT/valve may be formed of plastics material.

The axial spacing between the first and second seals depends on the diameter of the pipe. For example, for a pipe having a diameter of around 2 inches/5 cm, the axial spacing may be up to 45m. For a pipe having a diameter of between around 3 inches/7.6 cm and around 4 inches/10 cm, the axial spacing may be up to 31m.

Accordingly, in some embodiments, the method comprises inserting the first and second seals with an axial spacing of up to 31m or 45m, e.g. between 5 and 31 or 45 m, such as between 10 and 31 or 45 m, for example between 15 or 20 and 31 or 45 m. It will thus be appreciated that this method can be used to fill pipes having a significant length.

The method may comprise drilling the first port in the pipe using the airtight hot tapping system and fitting a first port airtight, operational under pressure tee (U PT) and valve in the first port. The first port UPT/valve may be formed of plastics material.

The method may further comprise connecting an injection umbilical to the first port e.g. to the first port UPT/valve e.g. via a first port hose. The injection umbilical (which may be formed of nylon) may be up to 60m long and is connected to an injector e.g. a foam injector. Thus the method preferably comprises injecting the expandable material into the first port from an injector up to 60m away from the pipe, e.g. between 1 and 60m, such as between 5 and 60m or 10 and 60m. The length of the injection umbilical allows the user to remain a significant distance away from the contaminated pipe as the expandable material is injected into the space between the first and second seals.

In some embodiments, the method comprises determining the spacing between the first seal and second seal (and thus the volume of the closed pipe section between the first and second seals), calculating the amount of expandable material required to fill the determined space and injecting only the calculated amount of expandable material.

The method may comprise drilling the first vent in the pipe using the airtight hot tapping system and fitting a first vent under pressure tee (UPT) and valve (e.g. full bore valve) in the first vent. The first vent UPT/valve may be formed of plastics material. The method may further comprise fitting the first vent with a first vent hose e.g. using a connector such as clip. Ideally, the connector/clip is lightweight and easy to handle since the user fitting the clip will be wearing bulky PPE. A clip e.g. a jubilee clip which may be ratchet tightened e.g. torque ratchet tightened may be used.

In some embodiments, the method comprises collecting waste material (e.g. contaminated water) from the pipe (i.e. from the first vent) into a first receptable e.g. drum connected to the first vent. The first receptable may be connected to the first vent by the first vent hose. The first receptable/drum may be fitted with an outlet valve having an air filter (e.g. a P3 filter) for filtering airborne contaminants.

The first vent hose may be transparent. This allows identification of expandable material and or waste material before it enters the first receptable.

In some embodiments, the method further comprises: inserting a third seal into the pipe, the third seal being axially spaced from the second seal with the second seal interposed between the first and third seals; forming a second vent in the pipe proximal the third seal; injecting an expandable material through a second port in the pipe into the space between the first and second seals; and allowing the expandable material to expand to fill the space between the second and third seals.

In preferred embodiments, the second port is provided proximal the second seal so that the method comprises injecting the expandable material proximal the second seal. In this way, as the expandable material is injected through the second port, it is forced from proximal the second seal downstream towards the third seal/second vent so as to fill the entirety of the space between the seals.

The second seal may be equally spaced from the first and third seals i.e. the second seal may divide the axial space between the first and third seals equally.

In some embodiments, the third seal comprises an envelope e.g. a porous envelope such as a fabric envelope and the method comprises inserting the third seal envelope into the pipe. In such embodiments, the method further comprises filling the third seal envelope within the pipe with a material e.g. an expandable material such as an expandable foam into order to seal the pipe. Preferably, the expandable material/foam passes through the porous third seal envelope to adhere to the pipe. The third seal may comprise a FOAM BAGTM as provided by Steve Vick International Ltd. The expandable material used to fill the third seal envelope may be the same expandable material as that injected into the second port (and/or as that used to fill the first and/or second seal envelopes).

The expandable material/foam in the third envelope is preferably allowed to cure e.g. for at least 30 minutes prior to injection of the expandable material into the second port.

The third seal (e.g. the third seal envelope) may be inserted into the pipe through an airtight valve. Thus the method may comprise drilling a third hole in the pipe using the airtight hot tapping system and fitting a third airtight, operational under pressure tee (UPT) and third valve in the third hole. The third UPT/valve may be formed of plastics material. The third seal e.g. the third seal envelope may then be inserted into the pipe through the third UPT/valve. The third seal envelope may be filled with the expandable material/foam through the third U PT/valve.

The axial spacing between the second and third seals depends on the diameter of the pipe. For example, for a pipe having a diameter of around 2 inches/5 cm, the axial spacing may be up to 45m. For a pipe having a diameter of between around 3 inches/7.6 cm and around 4 inches/10 cm, the axial spacing may be up to 31m.

Accordingly, in some embodiments, the method comprises inserting the second and third seals with an axial spacing of up to 31m or 45m, e.g. between 5 and 31 or 45 m, such as between 10 and 31 or 45 m, for example between 15 or 20 and 31 or 45 m.

The method may comprise drilling the second port in the pipe using the airtight hot tapping system and fitting a second port airtight, operational under pressure tee (UPT) and valve in the second port. The second port UPT/valve may be formed of plastics material.

The method may further comprise connecting an injection umbilical to the second port e.g. to the second port UPT/valve e.g. via a second port hose. The method preferably comprises injecting the expandable material into the second port from the injector up to 60m away from the pipe.

The injection into the first and second ports may be simultaneous e.g. using two foam injectors or sequential e.g. using a single foam injector (connected sequentially to the first and second ports).

In some embodiments, the method comprises determining the spacing between the second seal and third seal (and thus the volume of the closed pipe section between the second and third seals), calculating the amount of expandable material required to fill the determined space and injecting only the calculated amount of expandable material.

The method may comprise drilling the second vent in the pipe using the airtight hot tapping system and fitting a second vent under pressure tee (UPT) and valve (e.g. full bore valve) in the second vent The second vent UPT/valve may be formed of plastics material. The method may further comprise fitting the second vent with a second vent hose e.g. using a connector such as clip e.g. a jubilee clip which may be ratchet tightened. The second vent hose may be transparent.

In some embodiments, the method comprises collecting waste material (e.g. contaminated water) from the pipe (i.e. from the second vent) into a second receptable (e.g. drum) connected to the second vent. The second receptable may be connected to the second vent by the second vent hose. The second receptable/drum may be fitted with an outlet valve having an air filter for filtering airborne contaminants.

In some embodiments, the method comprises monitoring the filling of the axial space(s) between the first and second seals and/or between the second and third seals. For example, where an expandable foam is used and the expansion reaction is exothermic, a thermal imaging camera can be used to monitor the filling of the axial space(s). This ensures that sufficient expandable material is injected into the first and/or second port(s) to enable complete filling of the axial space(s). It also provides an indication of when the expandable material will reach the first/second vent(s).

Any one or more (e.g. all) of the first UPT/valve, second UPT/valve, third UPT/valve, first port UPT/valve and second porUUPT valve may be fitted to the pipe using a connector e.g. a clip such as a jubilee clip. This helps to minimise contaminated waste (which is costly to dispose of) created during the decommissioning process as such clips are smaller and lightweight that traditional UPT connectors.

Summary of the Figures

Embodiments and experiments illustrating the principles of the invention will now be discussed with reference to the accompanying figures in which: Figure 1 shows a pipe fitted with seals prior to injection of expandable material; Figure 2 shows the pipe during injection of expandable material; and Figure 3 shows the pipe after injection of expandable material.

Detailed Description

Aspects and embodiments will now be discussed with reference to the accompanying figures. Further aspects and embodiments will be apparent to those skilled in the art.

The method disclosed herein relates to the filling a pipe 10 which may be a pipe at a decommissioned nuclear facility. Such a pipe will be contaminated by radioactive waste. In this embodiment, the pipe has an internal diameter of 2 inches/5cm.

In a first step shown in Figure 1, a first seal 1, second seal 2 and a third seal 3 are inserted into the pipe 10.

In order to insert the first seal 1, a first hole is drilled into the pipe using an airtight hot tapping system (also known as an under pressure drilling system) and a first airtight, operational under pressure tee (U PT) and valve are inserted into the first hole.

This is repeated for the second and third seals i.e. the drilling system is used to provide second and third holes into which second and third UPT/valves are inserted respectively.

The first/second/third UPTs/valves are formed of plastic material and are affixed to the pipe 10 using respective jubilee clips secured using torque ratchet tightening (which can easily be carried out by a user wearing bulky PPE). Using plastic UPTs/valves and jubilee clips helps facilitate contaminated waste disposal after removal of the pipe. The UPTs/valves can be incinerated and the jubilee clips are lighter weight and smaller than conventional clips thus reducing the mass/volume of contaminated waste.

The first seal 1 comprises a porous fabric envelope such as a fabric envelope which is inserted into the pipe 10 through the first UPT/valve. Similarly, the second seal 2 and third seal 3 also each comprise a respective porous fabric envelope each of which is inserted into the pipe 10 through the respective second/third UPT/valve.

Next, each of the first seal envelope, second seal envelope and third seal envelope within the pipe 10 are filled with an expandable polyurethane foam into order to form the first, second and third seals 1, 2, 3 to seal the pipe 10. The expandable foam passes through the pores in the first, second and third seal envelopes to adhere to the pipe 1.

The second seal 2 is interposed and equally spaced between the first seal 1 and third seal 3. The axial spacing x between each of the first and second seals 1, 2 and the second and third seals 2, 3 is around 45m. Thus the seals 1,2, 3 divide the pipe 10 into two equal, closed pipe sections 10a, 10b.

The polyurethane foam in the first, second and third seal envelopes is allowed to harden for around 30 minutes.

Next, a first vent 4 is formed in the pipe proximal the first seal 1 and a second vent 5 is formed in the pipe proximal the third seal 3. The first and second vents 4, 5 are formed in the pipe using the airtight hot tapping system and each vent is fitted with a respective UPT and full-bore valve. Each of the vents is fitted with a respective transparent vent hose secured using a torque ratchet tightened jubilee clip, each vent hose extending to a respective waste drum fitted with a P3 air filter.

A first port 6 is provided proximal the second seal 2 on an upstream side and a second port 7 is provided proximal the second seal 2 on a downstream side i.e. the second seal 2 is interposed between the first and second port 6, 7.

The first and second ports 6, 7 port are formed in the pipe 10 using the airtight hot tapping system and each is fitted with a respective plastic airtight, operational under pressure tee (U PT) and valve (secured using jubilee clips).

A 60m long nylon injection umbilical is connected to each of the first port 6 and second port 7 via a respective port hose. The injection umbilicals are each connected to a respective foam injector. The length of the injection umbilicals allows the injectors to be located a significant distance away from the contaminated pipe 1.

An expandable, closed cell polyurethane foam 20 with an expansion ration of 10:1 is injected through the ports 6, 7 proximal the second seal 2, and is forced under the pressure created by its expansion and by the injector away from the second seal 2 upstream towards the first seal 1 and downstream towards the third seal 3 as shown in Figure 2.

The injection may be simultaneous using two foam injectors (as shown in Figure 3) or sequential using a single foam injector (connected sequentially to the first and second ports).

Prior to injection, the volumes of the closed pipe sections 10a, 10b between the first seal 1 and second seal 2 and between the second seal 2 and third seal 3 are calculated and this is used to calculate the amount of expandable polyurethane foam 20 required to fill the closed pipe sections 10a, 10b.

The calculated amount of polyurethane foam 20 is injected so as completely fill the pipe 10 between the seals 1, 2, 3 as shown in Figure 3.

As the pipe 10 is filled, pressure and any waste material within the pipe (between the seals 1, 2, 3) is forced out of the first and second vents 4, 5. Waste material is collected in the waste drums (each fitted with a P3 air filter which traps air-borne particulates) . A thermal imaging camera is used to monitor the filling of the closed pipe sections. This provides an indication of when the expandable material will reach the first and second vents 4, 5 and also provides assurance that the closed pipe sections 10a, 10b are completely filled.

The expanded polyurethane foam 20 encapsulates any contaminants contained within the closed pipe sections 10a, 10b thus reducing health and environmental hazards and any non-encapsulated contaminants are channelled in a controlled manner from the first and second vent 4, 5 into waste drums that can be disposed of appropriately. After complete curing of the polyurethane foam 20, the pipe 10 can be cut into appropriately sized portions for removal. The curing of the polyurethane foam 20 under pressure within the closed pipe sections 10a, 10b results in a robust foam that remains intact when cut but which is lightweight to facilitate subsequent removal of the pipe 10.

The features disclosed in the foregoing description, or in the following claims, or in the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for obtaining the disclosed results, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

While the disclosure includes the exemplary embodiments described above, many equivalent modifications and variations will be apparent to those skilled in the art when given this disclosure. Accordingly, the exemplary embodiments set forth above are considered to be illustrative and not limiting. Various changes to the described embodiments may be made without departing from the scope of the claims.

Throughout this specification, including the claims which follow, unless the context requires otherwise, the word "comprise" and "include", and variations such as "comprises", "comprising", and "including" will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

It must be noted that, as used in the specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from "about' one particular value, and/or to "about" another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by the use of the antecedent "about," it will be understood that the particular value forms another embodiment. The term "about" in relation to a numerical value is optional and means for example +/-10%.

Claims

Claims: 1. A method of filling a pipe by: inserting a first seal into the pipe; inserting a second seal into the pipe, the second seal being axially spaced from the first seal; forming a first vent in the pipe proximal the first seal; injecting an expandable material through a first port in the pipe into the space between the first and second seals; and allowing the expandable material to expand to fill the space between the first and second seals.
2. A method according to claim 1 wherein the first port is provided proximal the second seal and the method comprises injecting the expandable material proximal the second seal.
3. A the method according to claim 1 or 2 further comprising: inserting a third seal into the pipe, the third seal being axially spaced from the second seal with the second seal interposed between the first and third seals; forming a vent in the pipe proximal the third seal; injecting an expandable material through a second port in the pipe into the space between the first and second seals; and allowing the expandable material to expand to fill the space between the second and third seals.
4. A method according to claim 3 wherein the second seal is equally spaced from the first and third seals.
5. A method according to claim 3 or 4 wherein the second port is provided proximal the second seal and the method comprises injecting the expandable material proximal the second seal.
6. A method according to any one of the preceding claims wherein the expandable material is an expandable polyurethane foam.
7. A method according to any one of the preceding claims wherein any one or more of the first seal and/or second seal and/or third seal comprises a respective envelope and the method comprises inserting a first seal envelope and/or a second seal envelope and/or third seal envelope into the pipe, the method further comprising filling the first seal envelope and/or second seal envelope and/or third seal envelope within the pipe with an expandable material.
8. A method according to any one of the preceding claims comprising inserting the first and second seals with an axial spacing of up to 45m and/or inserting the second and third seals with an axial spacing of up to 45m.
9. A method according to any one of the preceding claims comprising injecting the expandable material into the first port and/or second port from an injector up to 60m away from the pipe.
10. A method according to any of the preceding claims comprising determining the spacing between the first seal and second seal and/or between the second and third seal, calculating the amount of expandable material required to fill the determined space and injecting only the calculated amount of expandable material.
11. A method according to any one of the preceding claims further comprising collecting waste material from the pipe into a first receptable connected to the first vent and/or into a second receptable connected to the second vent.
12. A method according to any one of the preceding claims comprising monitoring the filling of the axial space(s) between the first and second seals and/or between the second and third seals using a thermal imaging camera.